Chem. Biodiversity 2016, 13, 483 – 503 483 REVIEW Advances in Chemistry and Bioactivity of the Genus Chisocheton BLUME by Jamil A. Shilpia)b), Sanjib Sahab), Soon-Lim Chongc), Lutfun Nahard), Satyajit D. Sarkerd), and Khalijah Awang*a)c) a ) Centre for Natural Products and Drug Discovery, University of Malaya, Kuala Lumpur 50603, Malaysia (phone: +60379674064; fax: +60379674193; e-mail: khalijah@um.edu.my) b ) Pharmacy Discipline, Life Science School, Khulna University, Khulna 9208, Bangladesh c ) Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia d ) Medicinal Chemistry and Natural Products Research Group, School of Pharmacy and Biomolecular Sciences, Faculty of Science, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK Chisocheton is one of the genera of the family Meliaceae and consists of ca. 53 species; the distribution of most of those are confined to the Indo-Malay region. Species of broader geographic distribution have undergone extensive phytochemical investigations. Previous phytochemical investigations of this genus resulted in the isolation of mainly limonoids, apotirucallane, tirucallane, and dammarane triterpenes. Reported bioactivities of the isolated compounds include cytotoxic, anti-inflammatory, antifungal, antimalarial, antimycobacterial, antifeedant, and lipid droplet inhibitory activities. Aside from chemistry and biological activities, this review also deals briefly with botany, distribution, and uses of various species of this genus. Keywords: Chisocheton, Limonoids, Apotirucallane triterpenes, Tirucallane triterpenes, Dammarane triterpenes. Content 1. Introduction 2. The Genus Chisocheton BLUME 2.1. Morphology 2.2. Species of this Genus 2.3. Distribution 2.4. Uses 3. Chemistry 3.1. Limonoids 3.2. Apotirucallane Triterpenes 3.3. Tirucallane and Dammarane Triterpenes 3.4. Other Classes of Compounds 4. Biological Activities 4.1. Cytotoxic Activity 4.2. Anti-Inflammatory Activity 4.3. Antiobesity Activity 4.4. Antimalarial Activity 4.5. Antimycobacterial Activity 4.6. Antifungal Activity 4.7. Antifeedant Activity 5. Conclusions regions of Asia, mostly in Malesia (Malaysia and Indonesia) extending toward Solomon Islands, the Vanuatu (former New Hebrides), and Australia (Queensland) [1][2]. Meliaceous plants of the genus Aglaia, Aphanamixis, Dysoxylum, Trichilia, and in particular, Chisocheton have been the focus of natural product scientists for bioactivity screening and phytochemical studies for novel structures as well as for bioactive compounds [3 – 10]. Azadirachta indica, one of the most well-known plants of Meliaceae, was investigated in 1940, with the identification of azadirachtin in 1968, while the first report of compounds from the genus Chisocheton appeared only in 1978 [11][12]. Isolation of 1,2-dihydro-6a-(acetyloxy)azadirone (44) from Chisocheton paniculatus fruits as antifungal agent was the first report of bioactive compound from this genus [13]. Most of the pharmacological and phytochemical studies on this genus have been reported over the past 8 years. This review aims to present the plants of the genus Chisocheton along with their distribution, uses, chemical constituents, and bioactivity. 2. The Genus Chisocheton BLUME 1. Introduction 2.1. Morphology The genus Chisocheton BLUME belongs to the family Meliaceae and consists of ca. 53 species. The plants of this genus are distributed in tropical and subtropical The plants are exclusively trees. Leaves are alternate, pinnate, and leaflets opposite to subopposite. Inflorescences are axillary thyrses or spikes containing 4 – 6 flowers DOI: 10.1002/cbdv.201400373 © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich 484 Chem. Biodiversity 2016, 13, 483 – 503 articulated with 4 – 6 distinct petals. Staminal tube is slightly shorter than petals having cylindrical shape, sometimes contracted or extended at the mouth and anthers usually locellate, disc obscured and inserted within the tube, alternating with the tube lobes. Ovary 2 – 8, locular with one ovule in each locule and thick trichomes covers the outside of the ovary. Fruits are capsule, surface leathery, containing 2 – 8 locules with irregular valves [2][14]. Although the seeds of the Meliaceae plants are diverse in construction, plants of the Chisocheton are unique with their orthotropous seeds. Size of the seeds may vary from as small as arillate seeds (Chisocheton sapindinus) (3 cm long) to large orange segment-shaped sarcotestal seeds (Chisocheton medusae) (5 cm long) [15]. Plants of this genus can be easily distinguished from other genera of Meliaceae as the species of this genus have leaves terminating in a bud (pseudogemmula) and the bud continues to produce such leaflets until much of the life of the leaf [2][16 – 18]. species while C. tomentosus is categorized as least concerned species [22][23]. 2.3. Distribution The distribution of the plants of this genus extends from eastern India to southern China, throughout the islands of South China Sea, i.e., Philippines, Brunei, Malaysia, and Indonesia, and can be found in the northern part of Australia and Vanuatu. The plants of this genus are quite common in low-lying rain forests of Indonesia, Malaysia, and New Guinea. They rarely grow in highlands except Chisocheton ceramicus, Chisocheton pentandrus, and C. cumingianus ssp. kinabaluensis, which can be found in the upper hills of Mount Kinabalu in Borneo [15]. Chisocheton ruber is the only species having a preferable habitat in Sarawak limestones while C. anabilis grows in freshwater peat swamp forests. Out of 53 species, 48 grow in Malesia with five species being endemic, three grow in continental Asia, and only one in Vanuatu (Table 1) [17][19]. 2.2. Species of this Genus The genus search in the ‘International Plant Name Index’ (www.ipni.org/) resulted in 155 entries although, according to ‘The Plant List’ website (www.theplantlist.org/), 53 names are accepted. According to the Bulletin of British Museum Natural History (Botany), published in 1979, this genus consisted of 51 species [15]. Due to its exclusive distribution, discovery of these plants were brought through botanical expeditions in the Indo–Malay region. The first plant to be identified is Chisocheton tomentosus in Penang in 1802 by Christopher Smith. Report of other species continued with the identification of more than a half of all plants before 1900. Periodic identification of plants from this genus continued throughout the 20th century along with the discovery of Chisocheton rex in 1970 from Vanuatu by Timothy Whitmore, a Cambridge botanist [15]. The latest additions to the list were Chisocheton maxilla-pisticis and Chisocheton velutinus in 2003 [19]. A species that has been the subject of many phytochemical studies is C. paniculatus HIERN. The name first appeared in Hooker’s Flora of British India [20] and the plant was later described as a synonym of Chisocheton cumingianus ssp. balansae which is one of the three recognized subspecies of C. cumingianus. [17]. A report of limonoids from C. paniculatus was followed by a correction in the name as C. cumingianus ssp. balansae [1][21]. Chisocheton siamensis is another synonym of C. cumingianus ssp. balansae and its occurrence is restricted to the Asiatic mainland [14]. For some of the species, many synonyms can be found, which probably evolved due to the naming of the same plant by different authors or due to the existence of subspecies. According to the IUCN Red List of threatened species, Chisocheton pauciflorus, Chisocheton perakensis, and Chisocheton stellatus have been classified as vulnerable www.cb.wiley.com 2.4. Uses Plants from this genus are used in traditional medicine for the treatment of several ailments including stomach complaints, kidney complaints, backache, fever, rheumatism, and malaria [29][30]. Due to the limited distribution of the plants of this genus, traditional uses are also confined to ethnobotanical practices of selective regions. The small- to medium-sized trees of this genus are of little importance for commercial purpose or in timber industry [15]. In the Indo–Malay region, the wood is used for construction purposes, but may not be sought for in particular [17]. Various uses of the plant species of this genus are listed in Table 2. 3. Chemistry The first report of secondary metabolites from this genus appeared in 1978 when Saikia et al. [11] published the isolation of limonoids from the fruits of C. paniculatus followed by another article by Connolly et al. [35]. Only a few articles could be found in the following three decades until 2007, when a constant rise in articles on compounds including bioactive ones from this genus has been noticed. All secondary metabolites obtained from this genus are from 11 plants, C. ceramicus, C. paniculatus, C. erythrocarpus, C. polyandrus, C. cumingianus ssp. balansae, C. tomentosus, C. siamensis, C. penduliflorus, Chisocheton weinlandii, Chisocheton microcarpus, and C. macrophyllus. A total of 130 compounds, recorded in this review, have been isolated from this genus to date. Interestingly, more than half of all reported compounds from this genus are from the three subspecies of C. cumingianus. The broader distribution of aforementioned plants in various countries including India, China, Indonesia, and Malaysia might have facilitated their investigation by researchers of different countries. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 Table 1. Distribution of different species of the genus Chisocheton 485 Table 1. (cont.) Plant name Distribution Plant name Distribution C. aenigmaticus MABB. Indonesia, Sumatra, New Guinea [17] Borneo, Sumatra, Peninsular Malaysia [15] Philippines (Samar, Mindanao) [15] Borneo (Buitenzorg), Indonesia [15] Vietnam, Thailand, Brunei, Philippines, Papua New Guinea, and Malesia; in Borneo it can be found in Sarawak, Brunei, Sabah, South and East Kalimantan [15][17] Indonesia, Malaysia [17] Thailand, India (Assam), Bangladesh (Sylhet), China, Myanmar, Vietnam and Laos [24], Philippines [25] Indonesia, Malaysia, Philippines [17] Indonesia (Sumatra) [15] Thailand, Myanmar, India [20][24][26] Coastal regions of Peninsular Malaysia and northern Borneo, Indonesia (Kalimantan, Sebatik Island) [15] Papua New Guinea [2] Borneo (Kutai) [15] Thailand, Myanmar, India [20][24] Borneo (Buitenzorg) [15] Borneo (Kutai) [15] Indonesia, Malaysia [17] Papua New Guinea, Indonesia [2][27] Indonesia, Malaysia [17] Papua New Guinea, Solomon Islands, Nicobar Islands in the Indian Ocean, Australia (Queensland) Malaysia (northern Borneo), southern Philippines [17] Malesia (Malay Peninsula, Great Nicobar, Sumatra, Anambas Islands, Borneo, Java) [17] Malaysia (Borneo: Sabah, Palawan, Kalimantan), Southwest Philippines [19] Malesia (northern Borneo, Sarawak, Sabah, East Kalimantan) [17] Malesia, Philippines (Samar) [15][17] C. polyandrus MERR. Malesia (Borneo: northern Sarawak, Sabah, South Kalimantan), Brunei [17] Vanuatu [17] Malesia (Borneo, Sarawak, 1st Division) [17] Papua New Guinea [2] Malesia (Northeast Borneo, Sulawesi) [15] Malesia (Malay Peninsula, Bangka, Borneo) [17] Papua New Guinea [2] Papua New Guinea [2] Malesia (Borneo: Sarawak, Sabah, Central Kalimantan), Brunei [17] Papua New Guinea [2] Papua New Guinea [2] Thailand, Peninsular Malaysia and Sumatra [22] Malesia (Borneo: Kalimantan, Sarawak), Brunei [19] Indonesia (northern Sumatra: Indonesia, Sumatra, Aceh, Alaslanden) [15][17] Malesia (Central and North Celebes) [17] C. amabilis (MIQ.) C. DC. C. cauliflorus MERR. C. celebicus KOORD. C. ceramicus (MIQ.) C. DC. C. crustularii MABB. C. cumingianus (C. DC. ) HARMS C. curranii MERR. C. diversifolius MIQ. C.dysoxylifolius (KURZ) KURZ C. erythrocarpus HIERN C. C. C. C. C. C. C. gliroides P.F.STEVENS granatum MABB. grandiflorus (KURZ) HIERN koordersii MABB. lansiifolius MABB. laosensis PELLEGR. lasiocarpus (MIQ.) VALETON C. lasiogynus BOERL. & KOORD. C. longistipitatus (F.M.BAILEY) L.S.SM. C. macranthus (MERR.) AIRY SHAW C. macrophyllus KING C. maxilla-pisticis MABB. C. medusae AIRY SHAW C. mendozai F.H.HILDEBR. ex STEENIS C. montanus P.F.STEVENS C. novobritannicus P.F.STEVENS C. patens BLUME C. pauciflorus King C. pellegrinianus MABB. C. penduliflorus PLANCH. ex HIERN C. pentandrus (BLANCO) MERR. C. perakensis (HEMSL.) MABB. C. pilosus C. DC. C. pohlianus HARMS Malesia, Papua New Guinea [2] Papua New Guinea (Bismarck Archipelago) [2] Thailand, Myanmar, Malaysia, Singapore, Brunei, Indonesia, Philippines [17] Peninsular Malaysia [17][22] Vietnam [15] Southern Thailand, Peninsular Malaysia, India [20] Thailand, Peninsular Malaysia, Borneo, Philippines, Sulawesi, Moluccas, Java, Lesser Sunda Islands; in forests at low elevations [17][28] Peninsular Malaysia [22] Malesia, West New Guinea [17] Malesia, Papua New Guinea [2][17] © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich C. rex MABB. C. ruber RIDL. C. sapindinus P.F.STEVENS C. sarasinorum HARMS C. sarawakanus (C. DC.) HARMS C. sayeri (C. DC.) P.F.STEVENS C. schoddei P.F.STEVENS C. setosus RIDL. C. stellatus P.F.STEVENS C. tenuis P.F.STEVENS C. tomentosus (ROXB.) MABB. C. velutinus MABB. C. vindictae MABB. C. warburgii HARMS Majority of the isolated compounds are either limonoids or protolimonoids. The rest of the compounds are triterpenes (tirucallane, dammarane, lupane, and oleanane types), steroids, sesquiterpenes, anthraquinones, spermidine alkaloids, coumarins, and simple phenolics. Plant parts investigated for phytochemical constituents include leaves, twigs, bark, wood, root wood, seeds, and fruits. Only two limonoids were isolated from the leaves, while most of the limonoids were isolated from the bark. It is not clear whether the phytochemical investigations were targeted to isolate limonoids or these plants are highly rich in limonoids. 3.1. Limonoids The family Meliaceae is rich in limonoids, also known as tetranortriterpenoids due to their formation from protolimonoids by losing four C-atoms on the side chain. Majority of the compounds isolated from this genus are also limonoids. Investigation of six plants, namely C. siamensis, C. cumingianus ssp. balansae, C. paniculatus, C. microcarpus, C. ceramicus, and C. erythrocarpus resulted in the isolation of a total of 55 limonoids (1 – 55; Table 3, Figs. 1 – 5). Almost one-third of the limonoids belong to the azadirone class, while the rest are mainly vilasinin, phragmalin, mexicanolide, and nimbolinin type limonoids [36]. Recently reported limonoids, namely, chisomicine A (53), malayanine A (54), and malayanine B (55), possess novel AB-ring arrangements considerably www.cb.wiley.com 486 Chem. Biodiversity 2016, 13, 483 – 503 Table 2. Various uses of Chisocheton species Plant name Various uses C. cumingianus As fish poison in New Guinea [17]. Anti-plant pathogen and antimalarial, used externally to treat rheumatism and inflammation caused by edema, internally for gastric pain and cholera, oil used for bowel movement. The oil is used as purgative in Philippines [15] Fruits are poisonous and inedible [31] Leaflets are used for wrapping sago and other food in cooking [17] The seed oil is used for illumination. Because the leaves contain triterpenoids which show antiviral activities, they might have some medicinal importance. The wood is of little use as timber because it is not durable and it splits easily [28][31][32] The fruits are edible and have medicinal value [31][33] Seed oil is used as hair oil [15] In the treatment of diabetes, malaria, liver disease, and cancer [34] C. erythrocarpus C. lasiocarpus C. macrophyllus C. penduliflorus C. pentandrus C. tomentosus different than those of the phragmalins or mexicanolides. Possibly, these compounds derive from phragmalin class limonoids. However, the absence of phragmalins in C. erythrocarpus or in Trichilia connaroides, which produces trichiliton A, a limonoid similar to that of chisomicine A (53) suggests that mexicanolides act as the precursor toward the formation of aforementioned molecules [37][38]. Based on the previously proposed biosynthetic pathways, mexicanolides undergo a photoinitiated Norrish II reaction for the production of phragmalins and related limonoids [36][39][40]. Therefore, in this review, these three compounds were placed under the category named ‘mexicanolide-derived A,B-seco limonoids’. Three mexicanolide-type limonoids, namely erythrocarpines A – C (30 – 32, resp.) along with two phragmalin-type limonoids, erythrocarpines D and E (28 and 29, resp.) were isolated from C. erythrocarpus bark collected from Hutan Simpan Terenas of Kedah, a northern state of Peninsular Malaysia [50]. However, when the same plant part was collected from Johor, the most southern state of Malaysia, two new limonoids, malayanine A (54) and malayanine B (55), were isolated [38]. Erythrocarpines were also present in the extract; thus, a biogenetic pathway from erythrocarpine A (30) to malayanine A (54) and malayanine B (55) was proposed, where it was suggested that erythrocarpine A (30) might give rise to malayanine A (54) through C(29)–C(1) bridge formation and C(1)–C(2) bond cleavage, whereas a C (29)–C(1) bridge formation and C(10)–C(1) bond cleavage by oxygen radical-mediated coupling leads to malayanine B (55). www.cb.wiley.com Phytochemical investigation of C. ceramicus bark afforded various classes of limonoids including highly modified structures of phragmalins and mexicanolides. Based on the published biogenetic pathways toward the formation of various limonoids, a plausible biogenetic pathway (Scheme 1) is proposed in this review toward the formation of mexicanolides and phragmalins of C. ceramicus from ring D-seco-limonoid gedunin (51) [37][38][54]. The phragmalin class limonoids reported by Najmuldeen et al. [49][55] have a b-orientation for the 19-methyl which might have arisen from the configurational ambiguity at C(10) [37]. An a-orientation has been adopted for 19-methyl in this review to comply with the conventional way. The absolute configuration of ceramicine B (17), a vilasinin-type limonoid isolated from C. ceramicus was confirmed through CD spectrum and X-ray crystallographic analysis [46]. Ceramicine B (17) has been found to be potent in several bioassays showing, e.g., cytotoxic, antiobesity, and antiplasmodial activities. In another study, the absolute configuration of chisomicine A (53), a unique limonoid from C. ceramicus having bicyclo[5.2.1] dec-3-en-8-one ring system, an isochromenone, and a b-furyl ring at C(17) was established by Najmuldeen et al. [48] from CD spectral analysis which indicated it as a (3R,4R,5S,9S,10R,13R,17R) isomer while for chisomicine B (24), crystal structure was reported. Trichiliton A, a limonoid from the leaves of T. connaroides (Meliaceae) is the only other natural product reported so far with the same structural feature and differs from chisomicine A (53) by the presence of an O-acetyl group at C(3) instead of an O-2-methylbut-2-enoyl moiety [37]. In a previous report, a CD spectrum was used by Bordoloi et al. [13] to establish the absolute configuration of dysobinin (1) and 1,2-dihydro-6a-(acetyloxy)azadirone (44). Absolute configuration of another limonoid, 14-deoxyxyloccensin K (34), belonging to mexicanolide class, was established by Xray crystallography. It is the deoxygenated product of xyloccensin K, which was first isolated from Xylocarpus granatum and later from several other Meliaceous plants [12][51]. In a previous review on limonoids by Tan and Luo [12], the structure of chisocheton compounds E and F (15 and 16, resp.) were wrongly drawn and no names were provided. In this review, the names have been cited as described by Gunning et al. [42]. The structures and names of the above compounds were cross checked with a recent version of Dictionary of Natural Products [56]. Phytochemical investigation of CHCl3-soluble fraction of 95% EtOH extract of the twigs of C. cumingianus ssp. balansae led to the isolation of seven nimbolinin-type limonoids (35 – 41) and is the only source of such type of limonoids so far from this genus. Moreover, these compounds were the first C-seco limonoids having C(12)–C (15) ether linkage instead of a C(12)–C(15) hemiacetal or lactone ring. The structures and relative configuration were confirmed on the basis of 1D- and 2D-NMR data, while © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 487 Table 3. Limonoids from the genus Chisocheton No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 Name Azadirone class limonoids Dysobinin Azadiradione Mahonin (6a-(acetyloxy)-16-oxoazadirone) Chisocheton compound G 6a,7a-Dihydroxymeliaca-1,14-diene-3,16-dione Azadirone Paniculatin (6a-(acetyloxy)azadirone) 6a-(Acetyloxy)-17b-hydroxyazadiradione 14b,15b-Epoxyazadiradione 6a-(Acetyloxy)nimbinin (6a-(acetyloxy)-14b,15b-epoxyazadiradione) 6a-(Acetyloxy)-14b,15b-epoxyazadirone Chisosiamensin 6-De(acetyloxy)-23-oxochisocheton F 6-De(acetyloxy)-23-oxo-7-O-deacetylchisocheton F Chisocheton compound E Chisocheton compound F Vilasinin class limonoids Ceramicine B Ceramicine C Ceramicine H Ceramicine I Ceramicine D Ceramicine J Vilasinin 1,3-diacetate Phragmalin class limonoids Chisomicine B Chisomicine D Chisomicine E Chisomicine C Erythrocarpine D Erythrocarpine E Mexicanolide class limonoids Erythrocarpine A Erythrocarpine B Erythrocarpine C 6-Deoxyswietenolide (proceranolide) 14-Deoxyxyloccensin K Nimbolinin class limonoids Chisonimbolinin A Chisonimbolinin B Chisonimbolinin C Chisonimbolinin D Chisonimbolinin E Chisonimbolinin F Chisonimbolinin G Other classes of limonoids Havanensin class limonoids Chisopanin L 14,15-Deepoxyhavanensin 3a,7a-diacetate Ring-intact azadirone class limonoid 1,2-Dihydro-6a-(acetyloxy)azadirone Hexanortriterpenoids Ceramicine A Ceramicine F Ceramicine G Ceramicine K Ceramicine L Ceramicine E Mexicanolide-derived A,B-seco-limonoids Gedunin 6a-(Acetyloxy)gedunin © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Source plant(s) Plant part Reference C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. siamensis siamensis siamensis paniculatus paniculatus microcarpus paniculatus paniculatus siamensis siamensis paniculatus siamensis microcarpus microcarpus paniculatus paniculatus Seeds Seeds Seeds Seeds Fruits Leaves Root wood Seeds Seeds Seeds Seeds Seeds Leaves Leaves Seeds Seeds [13][41] [41] [13][41] [35] [11][13] [42] [11][13][43][44] [43] [41] [35][41][43] [43] [41] [42] [42] [42] [35] C. C. C. C. C. C. C. ceramicus ceramicus ceramicus ceramicus ceramicus ceramicus paniculatus Bark Bark Bark Bark Bark Bark Wood [45] [45] [46] [46] [45] [47] [35] C. C. C. C. C. C. ceramicus ceramicus ceramicus ceramicus erythrocarpus erythrocarpus Bark Bark Bark Bark Bark Bark [48] [49] [49] [48] [50] [50] C. C. C. C. C. erythrocarpus erythrocarpus erythrocarpus ceramicus ceramicus Bark Bark Bark Bark Bark [50] [50] [50] [51] [48] C. C. C. C. C. C. C. cumingianus cumingianus cumingianus cumingianus cumingianus cumingianus cumingianus Twigs Twigs Twigs Twigs Twigs Twigs Twigs [1][21] [1][21] [1][21] [1][21] [1][21] [1][21] [1][21] C. paniculatus C. paniculatus Twigs Seeds [52] [35] C. paniculatus Fruits [13] C. C. C. C. C. C. Bark Bark Bark Bark Bark Bark [53] [46] [46] [47] [47] [46] Seeds Seeds [35] [43] ceramicus ceramicus ceramicus ceramicus ceramicus ceramicus C. paniculatus C. paniculatus ssp. ssp. ssp. ssp. ssp. ssp. ssp. balansae balansae balansae balansae balansae balansae balansae www.cb.wiley.com 488 Chem. Biodiversity 2016, 13, 483 – 503 Table 3. (cont.) No. Name Source plant(s) Plant part Reference 53 54 55 Ring ABD-seco-limonoids Chisomicine A Malayanine A Malayanine B C. ceramicus C. erythrocarpus C. erythrocarpus Bark Bark Bark [48] [38] [38] the absolute configuration of chisonimbolinin A (35) was determined through X-ray crystallographic data [1][21]. 3.2. Apotirucallane Triterpenes Apotirucallanes or protolimonoids are produced during the intermediate steps of limonoid production from euphanes or tirucallanes [57]. Thus, they are formed through the methyl shift and oxidation in the side chain of euphanes or tirucallanes. Further removal of four carbons from the side chain and lactone ring formation gives rise to limonoids [58]. As a result, plants that produce limonoids are often rich in apotirucallanes [59]. A total of 43 apotirucallanes (56 – 98) were isolated from this genus, which is the second largest class of compounds from this genus (Table 4, Figs. 6 – 7). All of these apotirucallanes were isolated from C. paniculatus or its subspecies, C. cumingianus ssp. balansae. Most of the apotirucallanes were isolated from the twigs, and the rest from wood or root wood. Two apotirucallanes, paniculatins G and H reported from C. paniculatus were claimed as the configurational isomers of paniculatins B and D (89 and 92, resp.), respectively, but the structures were not reported since the authors failed to determine the absolute configuration of the isomers [44]. A plausible biogenetic pathway has been given in Scheme 2 toward the formation of various protolimonoids through the side-chain modification. Inspired by the recent reports on potent anti-inflammatory activity of apotirucallanes, Yang et al. [60] studied the CHCl3-soluble fraction of the twigs of C. paniculatus which led to the isolation of 11 new (62 – 65, 68 – 74) and 13 known (77, 78, 80, 82 – 88, 90, 91, 93) apotirucallanes. The structures of the new compounds were established by HR-ESI-MS and NMR data and the absolute configuration of chisopanin A (62) was confirmed by single-crystal X-ray diffraction. Further phytochemical study on one of the subfraction from the CHCl3-soluble fraction further yielded two more apotirucallanes (75, 76) [52]. dammarane triterpenes (99 – 110) were isolated from five species with five of these triterpenes having cytotoxic activity (Table 5, Fig. 8). Most of these isolated triterpenes were dammarane triterpenes. The structures of the isolated dammarane triterpenes vary widely being as simple as dammara-20,24-dien-3-one (99) or complex as eichlerialactone (104) with opening of the ring A and furanolactone formation in the side chain. 3.4. Other Classes of Compounds Aside from the tirucallane triterpenes, only two other triterpenes, namely moronic acid (111) and betulonic acid (112) were isolated from this genus. Among the six sesquiterpenes from this genus, two compounds from C. cumingianus ssp. balansae belong to the eudesmene type, while the rest are of the aromadendrane type and are from C. cumingianus ssp. balansae and C. penduliflorus. Phytochemical investigation of the aqueous EtOH extract of C. penduliflorus leaves and wood revealed allo-aromadendrane-10b,14-diol (121) to be the major compound (yield ~ 0.08%) of the extract [65]. The only alkaloids reported from this genus are two spermidine alkaloids, namely chisitines 1 and 2 (128 and 129, resp.) from C. weinlandii [27]. Although more than 50 putrescine alkaloids were reported so far from the family Meliaceae, none of these were obtained from Chisocheton species [66]. Miscellaneous compounds (111 – 130) isolated from various Chisocheton species are presented in Table 6 and Fig. 9. 4. Biological Activities A good number of compounds with important biological activities have been reported from the genus Chisocheton. The bioactivities of the extracts are listed in Table 7 while those of limonoids or of other classes of compounds are given in Tables 8 and 9, respectively. 3.3. Tirucallane and Dammarane Triterpenes 4.1. Cytotoxic Activity Unlike many other meliaceous plants, species from the genus Chisocheton also accumulate some nondegradated tirucallane and dammarane triterpenes [59]. Dammaranetype triterpenes are of great interest because they often show biological activities including anti-inflammatory, immunosuppressive, antitubercular, and in particular, cytotoxic activities [62][63]. A total of 12 tirucallane and An acetone/hexane extract of the seeds of C. siamensis, exhibited cytotoxic activity against KB (oral human epidermal carcinoma), NCI-H187 (human, small cell lung cancer), and MCF7 (human breast adenocarcinoma) cell lines with IC50 values of 5.43, 2.78, and 5.33 lg/ml, respectively [69]. Four limonoids, namely, dysobinin (1), azadiradione (2), mahonin (3), and epoxyazadiradione www.cb.wiley.com © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 489 Scheme 1. Plausible biogenetic pathway for the formation of mexicanolide, phragmalin, and mexicanolide-derived A,B-seco limonoids in Chisocheton [37][38][54]. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich www.cb.wiley.com 490 Chem. Biodiversity 2016, 13, 483 – 503 Fig. 1. Azadirone class limonoids 1 – 16 from Chisocheton. (9), isolated from this extract, showed cytotoxic activities against all the tested cancer cell lines. Ellipticine and doxorubicin were used as the positive controls in this study. Dysobinin (1) was the most potent cytotoxic compound with IC50 values of 3.38, 6.41, and 4.35 lM, against NCIH187, KB, and MCF7 cell lines, respectively. Mahonin (3) was inactive against KB cell line, while 6a-(acetyloxy)14b,15b-epoxyazadiradione (10) was inactive against all the cell lines tested [69]. A limonoid, ceramicine A (45), isolated from the CHCl3-soluble fraction of the EtOH extract of C. ceramicus bark exhibited cytotoxic activity with an IC50 value of 34.07 lM against P388 murine leukemia cells [53]. In a further study, ceramicines B – D (17, 18, and 21, resp.) isolated during the above phytochemical works exhibited weak cytotoxic activities against P388 cells with IC50 values of 36.74, 11.17, and 63.64 lM, respectively [45]. Five limonoids, ceramicines E – I (50, 46, 47, 19, and 20, resp.) www.cb.wiley.com isolated from the MeOH extract of the bark of C. ceramicus, were tested for cell growth inhibitory activities on a range of cell lines, namely, HL-60, A549, MCF7, and HCT116, but only ceramicines G and I (47 and 20, resp.) showed moderate activities and others did not show any noticeable inhibition (IC50 > 50 lM). Ceramicine G (47) displayed inhibitory activities with IC50 values of 26.1, 27.3, and 41.4 lM against HL-60, MCF7, and A549 cell lines, respectively, whereas ceramicine I (20) showed IC50 values of 42.2 and 44.0 lM against HL-60 and MCF7 cell lines, respectively. Cisplatin was used as positive control in this assay (IC50 0.87, 16.0, 27.7, and 27.8 lM for HL-60, HCT116, MCF7, and A549 cell lines, resp.) [46]. Ceramicines J – L (22, 48, 49, resp.), isolated from the hexanesoluble fraction of the MeOH extract of C. ceramicus bark, exhibited dose dependent but weak cytotoxic activities against HL-60 cell line in 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl-2H-tetrazolium bromide (MTT) assay with © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 491 Fig. 2. Vilasinin class limonoids 17 – 23 from Chisocheton. Fig. 3. Phragmalin class limonoids 24 – 29 from Chisocheton 36, 33, and 25% inhibition at 50 lM, respectively, while cisplatin was used as positive control (IC50 0.87 lM) [47]. Erythrocarpines A – E (30 – 32, 28, and 29, resp.), a series of five limonoids isolated from the bark of C. erythrocarpus, showed cytotoxic activities against P-388 murine leukemia cells with IC50 values of 3.50, 10.17, 16.06, 16.28, and 25.31 lM, respectively. Mitomycin C, used as positive control in this assay exhibited an IC50 value of 0.45 lM [50]. The cytotoxic activity of erythrocarpine E (29) was further investigated against a wide range of human cancer cell lines, in which, it displayed cytotoxic activities against human oral squamous carcinoma cells (HSC-4, HSC-2), human cervical carcinoma cells (Ca Ski), human hepatocyte carcinoma cells (HepG2), and human breast adenocarcinoma cells (MCF-7) with IC50 values of 4.0, 7.0, 8.5, 6.0, and 14.0 lM, respectively [73]. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich The cell viability was obtained from the MTT assay after 24 h of exposure, and normal human bronchial epithelial cells were used as normal cell control. Further investigations, including the annexin V-fluorescein isothiocyanate (FITC), poly-ADP ribose polymerase (PARP) cleavage, and DNA fragmentation assays demonstrated that erythrocarpine E (29) could induce apoptosis-mediated cell death in HSC-4 cells. DNA laddering (approximately at 200 bp intervals) caused by endonuclease action between nucleosomes was observed in erythrocarpine E-treated cells. The association of caspase-3 with erythrocarpine Einduced apoptosis was proved through the identification of PARP, a marker protein for the initiation of apoptosis. Western blotting analysis revealed an increase in proapoptotic protein p53 and a decrease in antiapoptotic protein Bcl-2 in erythrocarpine E (29)-treated HCS-4 cells. Based on these results, it was concluded that the activation of p53 by the limonoid under investigation activates caspase-9 and caspase-3 through Bcl-2 and Bax pathway and the cell dies by apoptosis [73]. A series of seven limonoids of the nimbolinin class, chisonimbolinins A – G (35 – 41, resp.), isolated from twigs of C. cumingianus ssp. balansae, were tested for cytotoxic activities against human cervical cancer (HeLa) and human hepatoma cancer (SMMC-7721) cell lines in the MTT assay. Chisonimbolinins C and D (37 and 38, resp.) showed moderate cytotoxic activities against the HeLa cell line with IC50 values of 13.0 and 32.0 lM, respectively, while chisonimbolinins B – D (36 – 38, resp.) showed weak activities against SMMC-7721 cell line with IC50 values ranging from 50 to 65 lM [1][21]. Four dammarane triterpenoids, cabraleadiol (103), eichlerialactone (104), cabraleahydroxylactone (105), and cabralealactone (106), isolated from the wood and leaves of C. penduliflorus, showed weak cytotoxic activities against breast cancer (BC) cell line with IC50 values of 38.01, 29.07, 43.27, and 40.82 lM, respectively, while ellipticine was the positive control with an IC50 value of 1.42 lM. In addition, only cabralealactone (106) was moderately cytotoxic against small-cell lung cancer (NCIH187) cell line, with an IC50 value of 18.36 lM [65]. The MeOH extract of C. macrophyllus leaves showed significant inhibitory effects on Epstein–Barr viral antigen www.cb.wiley.com 492 Chem. Biodiversity 2016, 13, 483 – 503 Fig. 4. Mexicanolide class limonoids 30 – 34 from Chisocheton. (EBV-EA) activation caused by the strong tumor promoter compound 12-O-tetradecanoylphorbol-13-acetate (TPA), and the inhibitory effect was assayed by the viability of Raji cells. Further, a C(24) epimeric mixture of 24hydroxydammara-20,25-dien-3-one (100), and two known triterpenes, moronic acid (111) and betulonic acid (112) were isolated from the MeOH extract and showed inhibitory effects on EBV-EA production. Moronic acid (111) showed most strong inhibition at the ratios of 500 and 100 M triterpenoid/1 M TPA without affecting much of the viability of Raji cells. Betulonic acid (112) was promising as moronic acid (111) as EBV-EA inhibitor, while the C (24) epimeric mixture of 24-hydroxydammara-20,25-dien3-one (100) exhibited no remarkable activity. Moronic acid (111) and betulonic acid (112) were more potent inhibitors than oleanoic acid and betulinic acid [64]. A rare natural phytosterol oxide, 7a-hydroxy-b-sitosterol (116), isolated from the bark of C. tomentosus was tested for cytotoxic activities against different human tumor cell lines, namely, human breast adenocarcinoma (MCF-7), human hepatocyte carcinoma (HepG2), human oral squamous cell carcinoma (HSC-4), and human cervical carcinoma (Ca Ski). The compound was cytotoxic against MCF-7, HSC-4, and HepG2 cell lines with IC50 values of 16, 19.5, and 25.0 lM, respectively. The compound showed the least effect on human mammary epithelial cell (HMEC) with a cell viability level more than 80%. The mechanism involved in the observed cytotoxic activity was further investigated on MCF-7 cell line. An increase in proapoptotic Bax protein level and decrease in antiapoptotic Bcl-2, initiator procaspase-9, and executioner www.cb.wiley.com procaspase-3 protein levels indicated cytochrome cmediated apoptosis via the mitochondrial pathway [34]. 4.2. Anti-Inflammatory Activity The EtOH extract and its CHCl3-soluble fraction of the twigs of C. paniculatus significantly inhibited carrageenaninduced mice paw edema. The CHCl3-soluble fraction inhibited paw edema by 21.9 and 25.3% at the doses of 100 and 200 mg/kg, respectively. Several protolimonoids, chisopanins A – K (62 – 65 and 68 – 74, resp.), chisiamols B – E (87, 88, 77, and 78, resp.), 3-O-acetyl-21-O-methyltoosendanpentol (80), 21a-O-methylmelianodiol (82), and (23R,24R)-3-a-(acetyloxy)-21,24-epoxyapotirucall-14-ene-7a, 23,25-triol (90) isolated from the CHCl3-soluble fraction, showed inhibitory activities on inflammation factor-release (NO and TNF-a) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells in vitro. Chisopanins A and B (62 and 66, resp.) with an uncommon hemiketal tetrahydropyran ring at C(17), were most potent inhibitors with IC50 values of 5.4 and 7.9 lM for NO production, and 26.9 and 30.7 lM for TNF-a production, respectively, while dexamethasone (IC50 0.86 lM) and genistein (IC50 19.1 lM) were the positive controls for inhibiting NO and TNF-a production, respectively. In addition, chisopanins E – G (68 – 70, resp.) and I (72), and chisiamols C – E (88, 77, and 78, resp.) exhibited potent inhibition of NO production with the IC50 value < 10 lM. Chisopanins D and H (65 and 71, resp.) did not show inhibition of either NO or TNF-a production even at the highest concentration tested (50 and 100 lg/ml, resp.) [60]. Chisopanins L – O (42, 102, 75, and 76, resp.), isolated from the © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 493 Fig. 5. Nimbolinin class limonoids 35 – 41 and other classes of limonoids, 42 – 55, from Chisocheton. twigs of C. paniculatus, were also tested for NO or TNF-a inhibitory activities in RAW 264.7 cells. Chisopanins L, N, and O (42, 75, and 76, resp.) exhibited moderate inhibition with IC50 values of 6.6, 4.9, and 4.4 lM except chisopanin M (102; IC50 > 50), while dexamethasone was the positive control (IC50 0.86 lM) [52]. In a screening study for lipoxygenase (LOX) inhibitory activities of some Malaysian plants, the bark of C. polyandrus was found to be one of the most active plant extracts showing strong (71 – 100%) inhibitory activity. In the study, the flowers of C. macranthus, the bark of C. pentandrus, and the leaves of C. polyandrus exhibited moderate activities (41 – 70% inhibition), while the leaves of C. macranthus showed weak (21 – 40% inhi- © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich bition) activity [71]. Further, the CH2Cl2 extract of C. polyandrus leaves was studied to isolate LOX and cyclooxygenase (COX) inhibitory compounds thorough bioactivity-guided fractionation. Two dammarane triterpenoids, dammara-20,24-dien-3-one (99) and 24-hydroxydammara-20,25-dien-3-one (100), were isolated and identified as bioactive components by the soybean LOX assay. Both compounds were tested for human 5-LOX, 15LOX, COX-2, and ovine COX-1 inhibitory activity at the concentration of 100 lg/ml. Dammara-20,24-dien-3-one (99) showed IC50 values of 24.27, 31.91, and 3.17 lM for 5LOX, COX-1, and COX-2 inhibition, respectively, while 24-hydroxydammara-20,25-dien-3-one (100) displayed comparatively insignificant activity. However, both com- www.cb.wiley.com 494 Chem. Biodiversity 2016, 13, 483 – 503 Fig. 6. Apotirucallane triterpenes 56 – 91 from Chisocheton. pounds failed to inhibit 15-LOX. As positive controls, phenidone for soybean LOX (IC50 1.44 lM), zileuton for human 5-LOX (IC50 1.15 lM), nordihydroguaiaretic acid www.cb.wiley.com for human 15-LOX (IC50 9.63 lM), and indomethacin for ovine COX-1 and human COX-2 (IC50 4.90 and 8.90 lM, resp.) were used in this assay [30]. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 495 Fig. 7. Apotirucallane triterpenes 92 – 98 from Chisocheton. Fig. 8. Tirucallane and dammarane triterpenes 99 – 110 from Chisocheton. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich www.cb.wiley.com 496 Chem. Biodiversity 2016, 13, 483 – 503 Fig. 9. Miscellaneous compounds, 111 – 130, from Chisocheton. A limonoid, chisomicine A (53), isolated from the bark of C. ceramicus inhibited NO production in J774.1 cells stimulated by LPS in a dose-dependent manner (IC50 20.2 lM), while L-NMMA was used as positive control (IC50 13.8 lg/ml). In addition, chisomicine A (53) showed little effect on cell viability in the MTT assay [48]. 4.3. Antiobesity Activity Lipid droplets accumulation (LDA) inhibitors are potential candidates for antiobesity drugs. In search for antiobesity drugs, ceramicines, a series of limonoids, isolated from the bark of C. ceramicus, were investigated for their anti-LDA activity. The anti-LDA activity was determined based on the amount of LDA after an incubation period of 6 days with the mixture of 1-methyl-3(2-methylpropyl)xanthine, dexamethasone, and insulin, and results were expressed as IC50 values. Nile red lipid droplets fluorescent staining method with slight modification was utilized to assess the quantity of LDA. The MeOH extract of C. ceramicus bark exhibited a dosedependent inhibition of LDA from the concentration www.cb.wiley.com 6.25 lg/ml in mouse preadipocyte cell (MC3T3-G2/ PA6). Through the activity-guided separation, the hexane-soluble fraction was identified as the most potent anti-LDA, and ceramicine B (17) was isolated from that fraction as a promising LDA inhibitor with the IC50 value of 1.8 lM [68]. Further, the structure–activity relationships (SAR) of ceramicines A – L (45, 17, 18, 21, 50, 46, 47, 19, 20, 22, 48, and 49, resp.) and nine derivatives of ceramicine B (17), as anti-LDA was studied. Ceramicine B (17) was used as template for SAR study because of its high anti-LDA activity. Based on SAR study, the furan moiety at C(17) plays an important role in the anti-LDA activity while the C=O group at C(1) and the C=C bond between C(14) and C(15) is important for the observed activity of the ceramicines. This report was followed by further studies on ceramicine B (17) to identify the underlying mechanism of its antidroplet action through a series of bioassays [72]. The RT-PCR results showed that in the presence of ceramicine B (17), adipocyte-specific genes, including glucose transporter type 4 (GLUT4), lipoprotein lipase (LPL), and 11b-hydroxysteroid dehydrogenase (HSD11b1) expressions were downregulated. A mixture © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 497 Table 4. Apotirucallane triterpenes from the genus Chisocheton No. Name Source plant(s) Plant part Reference 56 57 Chisiamol A (23R,24R)-3a-(Acetyloxy)-21,24-epoxyapotirucall14-ene-7a,23,25-triol (chisocheton B) Chisiamol H Sapelin B Odoratone Grandifoliolenone Chisopanin A Chisopanin B Chisopanin C Chisopanin D Chisiamol G (21R)-3a-(Acetyloxy)-21,23-epoxyapotirucall14-ene-7a,21,24,25-tetrol Chisopanin E Chisopanin F Chisopanin G Chisopanin H Chisopanin I Chisopanin J Chisopanin K Chisopanin N Chisopanin O Chisiamol D Chisiamol E Agladupol A 3-O-Acetyl-21-O-methyltoosendanpentol 21-O-Methyltoosendanpentol 21a-O-Methylmelianodiol 21-O-Methylmelianodiol Melianodiol 21a,25-Di-O-methylmelianodiol (13a,14b,21R,23S,24R)-21,23-Epoxy-24-hydroxy-21methoxylanosta-7,25-dien-3-one Chisiamol B Chisiamol C Paniculatin B (23R,24R)-3a-(Acetyloxy)-21,24-epoxyapotirucall14-ene-7a,23,25-triol Paniculatin C Paniculatin D Bourjotinoline A Arunachalin Chisocheton compound A (cneorin NP35) Chisocheton compound C Chisocheton compound D Melianone (24,25-epoxyflindissone, cneorin NP37) C. paniculatus C. paniculatus Twigs Wood [29] [35] C. C. C. C. C. C. C. C. C. C. paniculatus paniculatus cumingianus ssp. balansae cumingianus ssp. balansae paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs, wood [29] [29] [61] [61] [60] [60] [60] [60] [29] [29] C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus cumingianus ssp. balansae paniculatus cumingianus ssp. balansae paniculatus paniculatus paniculatus paniculatus paniculatus Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs Twigs [60] [60] [60] [60] [60] [60] [60] [52] [52] [60] [60] [1][21] [60] [1][21] [60] [60] [60] [60] [60] C. C. C. C. paniculatus paniculatus paniculatus paniculatus Twigs Twigs Root wood Twigs [60] [60] [44] [60] C. C. C. C. C. C. C. C. paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus paniculatus Twigs, root wood Root wood Twigs Root wood Wood Wood Wood Root wood [1][21][60] [44] [60] [44] [35] [35] [35] [44] 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 of 1-methyl-3-(2-methylpropyl)xanthine, dexamethasone, and insulin (MDI inducer) was used to induce adipocyte differentiation. Ceramicine B (17) also inhibited adipogenesis master regulating gene (PPARc and C/ EBPa) expressions, while MDI inducer upregulated the expressions. Besides, ceramicine B (17) also increased the level of the unphosphorylated Forkhead box O1 (Foxo1) protein in MDI-induced cells. The unphosphorylated Foxo1 suppresses PPARc mRNA transcription, © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich which in turn prevents adipocyte differentiation resulting in anti-LDA activity. 4.4. Antimalarial Activity An acetone/hexane 1:1 extract of the seeds of C. siamensis, showed antimalarial activity against the parasite P. falciparum with an IC50 value of 0.784 lg/ml. Five limonoids, dysobinin (1), azadiradione (2), mahonin (3), www.cb.wiley.com 498 Chem. Biodiversity 2016, 13, 483 – 503 Scheme 2. Plausible side-chain modification toward the formation of apotirucallanes in Chisocheton. epoxyazadiradione (9), and 6a-acetoxyepoxyazadiradione (10), isolated from the crude extract, showed antimalarial activities with IC50 values of 4.16, 6.46, 5.75, 6.82, and 12.04 lM, respectively, while dihydroartemisinine (IC50 0.0044 lM) was the positive control. IC50 Value was the concentration that caused 50% reduction in parasite growth, quantified by the microculture radioisotope technique [69]. www.cb.wiley.com Ceramicines A – D (45, 17, 18, and 21, resp.), four limonoids isolated from the bark of C. ceramicus, exhibited antiplasmodial activity against P. falciparum 3D7 in in vitro assessment. Ceramicine B (17) showed most potent activity with an IC50 value of 0.56 lM, whereas ceramicines A, C, and D (45, 18, and 21, resp.) exhibited IC50 values of 100.45, 4.83, and 5.07 lM, respectively. Chloroquine, used as positive control, © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 499 Table 5. Tirucallane and dammarane triterpenoids from the genus Chisocheton No. Name Source plant(s) Plant part Reference 99 100 Dammara-20,24-dien-3-one 24-Hydroxydammara-20,25-dien-3-one (isolated as C(24) epimeric mixture) Chisiamol F Chisopanin M Cabraleadiol Eichlerialactone Cabraleahydroxylactone Cabralealactone Hollongdione Phellochin Piscidinol A Hispidol A C. polyandrus C. polyandrus Leaves Leaves [30] [64] Twigs Twigs Wood, leaves Wood Wood Wood Leaves Twigs Twigs Twigs [61] [52] [65] [65] [65] [65] [65] [1][21] [1][21] [1][21] 101 102 103 104 105 106 107 108 109 110 C. C. C. C. C. C. C. C. C. C. cumingianus ssp. paniculatus penduliflorus penduliflorus penduliflorus penduliflorus penduliflorus cumingianus ssp. cumingianus ssp. cumingianus ssp. balansae balansae balansae balansae Table 6. Other classes of compounds isolated from the genus Chisocheton No. 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 Name Oleanane triterpene Moronic acid Lupane triterpene Betulonic acid Steroids Stigmasta-4,6-dien-3-one Stigmasterol b-Sitosterol 7a-Hydroxy-b-sitosterol Sesquiterpenes 1b,6a-Dihydroxyeudesm-4(14)-ene 1b,8a-Dihydroxyeudesm-4(14)-ene Alismoxide allo-Aromadendrane-10a,14-diol allo-Aromadendrane-10b,14-diol allo-Aromadendrane-10b,13,14-triol Anthraquinones Chrysophanol Emodin Emodin monomethyl ether Coumarins Scopoletin Scoparone Spermidine alkaloids Chisitine 1 Chisitine 2 Simple phenolic compound Vanillic acid Source plant(s) Plant part Reference C. macrophyllus Leaves [64] C. macrophyllus Leaves [64] C. C. C. C. C. tomentosus tomentosus paniculatus tomentosus tomentosus Bark Bark Heartwood Bark Bark [55] [55] [13] [55] [67] C. C. C. C. C. C. cumingianus ssp. balansae cumingianus ssp. balansae cumingianus ssp. balansae penduliflorus penduliflorus penduliflorus Twigs Twigs Twigs Wood Wood Wood [61] [61] [61] [65] [65] [65] C. cumingianus ssp. balansae C. cumingianus ssp. balansae Twigs Twigs Twigs [61] [61] [61] C. penduliflorus C. penduliflorus Wood Wood [65] [65] C. weinlandii C. weinlandii Leaves Leaves [27] [27] C. penduliflorus Wood [65] exhibited antiplasmodial activity with an IC50 value of 0.019 lM [45]. 4.5. Antimycobacterial Activity An acetone/hexane extract of the seeds of C. siamensis, showed inhibitory activity against M. tuberculosis in the microplate alamar blue assay (MABA) with a MIC value © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich of 100 lg/ml. A limonoid, azadiradione (2), isolated from the seed extract, showed inhibitory activity with a MIC value of 13.88 lM, while rifampicin, kanamycin, and isoniazid were the positive controls (MIC 0.023, 2.58, and 0.38 lM, resp.) [69]. Three aromadendrane sesquiterpenoids, allo-aromadendrane-10a,14-diol (120), allo-aromadendrane10b,14-diol (121), and allo-aromadendrane-10b,13,14-triol www.cb.wiley.com 500 Chem. Biodiversity 2016, 13, 483 – 503 Table 7. Biological activities of Chisocheton species Plant name Reported biological activity C. ceramicus Cytotoxic (P388 cell line) and lipid droplet inhibitory activities [68] Antimalarial (Plasmodium falciparum), antimycobacterial (Mycobacterium tuberculosis), and cytotoxic activities (NCI-H187, KB, and MCF-7 cell lines) [69] Anti-inflammatory activity [60] Anticholinergic activity [70] Anticholinergic [71] and anti-inflammatory activities [70] Inhibition of Epstein–Barr viral antigen promoted tumor [64] Cytotoxic (NCI-H187 cell line) and antimycobacterial activities (M. tuberculosis) [65] Anticholinergic [71] and anti-inflammatory activities [70] Anticholinergic [71] and anti-inflammatory activities [70] C. siamensis C. paniculatus C. erythrocarpus C. macranthus C. macrophyllus C. penduliflorus C. pentandrus C. polyandrus (103), eichlerialactone (104), cabraleahydroxylactone (105), and cabralealactone (106), isolated from the wood and leaves of the same plant also showed antimycobacterial activities with MIC values of 108.60, 58.14, 120.19, and 120.77 lM, respectively. Isoniazid (MIC 0.36 lM) and kanamycin sulfate (MIC 4.29 lM) were used as positive controls in the assay [65]. 4.6. Antifungal Activity Four limonoids, namely dysobinin (1), mahonin (3), 6a,7a-dihydroxymeliaca-1,14-diene-3,16-dione (5), paniculatin (7), and 1,2-dihydro-6a-(acetyloxy)azadirone (44), isolated from the petrol ether extract of C. paniculatus fruits showed inhibition against the plant pathogenic fungi Dreschleva oryzae (rice), Curvularia verruciformis (lemon grass), and Alternaria solani (tomato) [13]. However, no methodology for the bioassay or the extent of activity (MIC or zone of inhibition) was provided in the report. 4.7. Antifeedant Activity (122), isolated from the wood extract of C. penduliflorus exhibited antimycobacterial activities against M. tuberculosis with MIC values of 419.83, 209.92, and 16.70 lM, respectively. Four dammarane triterpenoids, cabraleadiol So far, no antifeedant compound has been isolated from this genus through bioassay-guided investigation. However, in one study, of the 11 extracts of six Chisocheton species, seven showed strong inhibition of cutworms, Table 8. Bioactive limonoids from the genus Chisocheton No. Name Reported biological activity 1 2 3 7 9 10 17 18 20 21 22 28 29 30 31 32 36 37 38 42 44 45 46 47 48 49 50 53 Dysobinin Azadiradione Mahonin Paniculatin (6a-(acetyloxy)azadirone) 14b,15b-Epoxyazadiradione 6a-(Acetyloxy)-14b,15b-epoxyazadiradione Ceramicine B Ceramicine C Ceramicine I Ceramicine D Ceramicine J Erythrocarpine D Erythrocarpine E Erythrocarpine A Erythrocarpine B Erythrocarpine C Chisonimbolinin B Chisonimbolinin C Chisonimbolinin D Chisopanin L 1,2-Dihydro-6a-(acetyloxy)azadirone Ceramicine A Ceramicine F Ceramicine G Ceramicine K Ceramicine L Ceramicine E Chisomicine A Cytotoxic and antiplasmodial activities [69] Cytotoxic, antiplasmodial, and antimycobacterial activities [69] Cytotoxic and antiplasmodial activities [69] Antifungal activity [13] Cytotoxic and antiplasmodial activities [69] Antiplasmodial activity [69] Cytotoxic [45][72], antiplasmodial [45], and antiobesity activities [72] Cytotoxic, antiplasmodial [45], and antiobesity activities [68] Cytotoxic and antiobesity activities [68] Antiplasmodial activity [45] Cytotoxic activity [47] Cytotoxic activity [50] Cytotoxic activity [50] Cytotoxic activity [50] Cytotoxic activity [50] Cytotoxic activity [50] Cytotoxic activity [1][21] Cytotoxic activity [1][21] Cytotoxic activity [1][21] Anti-inflammatory activity [52] Antifungal activity [13] Cytotoxic [53], antiplasmodial [45], and antiobesity activities [68] Antiobesity activity [68] Cytotoxic and antiobesity activities [68] Cytotoxic activity [68] Cytotoxic activity [68] Antiobesity activity [68] Anti-inflammatory activity [48] www.cb.wiley.com © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 501 Table 9. Bioactive apotirucallane, tirucallane, and dammarane triterpenes, and miscellaneous compounds from the genus Chisocheton No. 62 63 64 68 69 70 72 73 74 75 76 77 78 80 82 87 88 99 100 103 104 105 106 111 112 116 120 121 122 Name Reported biological activity Apotirucallanes Chisopanin A Chisopanin B Chisopanin C Chisopanin E Chisopanin F Chisopanin G Chisopanin I Chisopanin J Chisopanin K Chisopanin N Chisopanin O Chisiamol D Chisiamol E 3-O-Acetyl-21-O-methyltoosendanpentol 21a-O-Methylmelianodiol Chisiamol B Chisiamol C Other triterpenes Dammara-20,24-dien-3-one 24-Hydroxydammara-20,25-dien-3-one Cabraleadiol Eichlerialactone Cabraleahydroxylactone Cabralealactone Moronic acid Betulonic acid Steroid 7a-Hydroxy-b-sitosterol Sesquiterpenes allo-Aromadendrane-10a,14-diol allo-Aromadendrane-10b,14-diol allo-Aromadendrane-10b,13,14-triol Peridroma saucia [42]. Active plants include leaves of C. amboinensis, leaves and twigs of C. divergens var. robustus, C. lasiocarpus, C. macrophyllus, C. microcarpus, and C. weinlandii. The insect larvae under investigation were treated with diets containing 0.2% extract (w/w) and the weights of the larvae were recorded on the 7th and 10th day, and expressed as percent of control. The leaves of C. divergens var. robustus and C. microcarpus were the most active and killed the larvae. Bioassaydirected phytochemical investigation of the MeOH extract of C. microcarpus revealed that the CH2Cl2-soluble fraction retained the activity. Phytochemical investigation of the active fraction resulted in the isolation of two limonoids, 6-de(acetyloxy)-23-oxochisocheton F (13) and 6-de(acetyloxy)-23-oxo-7-O-deacetylchisocheton F (14). However, when tested, none of these compounds were active against the cutworms. Thus, although the derivatives of chisocheton compound F (16) were not active as antifeedant compound, chisocheton compound F (16) itself is antifeedant, which was isolated from the EtOH extract of the twigs of Carapa guianensis and showed antifeedant activity against Pieris brassicae. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory Anti-inflammatory activity activity activity activity activity activity activity activity activity activity activity activity activity activity activity activity activity [60] [60] [60] [60] [60] [60] [60] [60] [60] [52] [52] [60] [60] [60] [60] [60] [60] Anti-inflammatory activity [30] Cytotoxic activity [64] Cytotoxic and antimycobacterial Cytotoxic and antimycobacterial Cytotoxic and antimycobacterial Cytotoxic and antimycobacterial Cytotoxic activity [64] Cytotoxic activity [64] activities activities activities activities [65] [65] [65] [65] Cytotoxic activity [34] Antimycobacterial activity [65] Antimycobacterial activity [65] Antimycobacterial activity [65] Odoratone (60), a constituent of C. cumingianus ssp. balansae, was also isolated from C. guianensis in the above-mentioned study and was found to be active against Pieris brassicae [74]. Antifeedant activities of plants from Chisocheton against tobacco cutworm (Spodoptera litura) and the variegated cutworm, Peridroma saucia, were reported by Isman et al. [75] and the observed activity was attributed toward the limonoid content of these plants. 5. Conclusions The genus Chisocheton has been a good source of many bioactive molecules having cytotoxic, anti-inflammatory, antiobesity, antimycobacterial, and antiplasmodial activity. The genus is chemically rich in different types of natural products especially limonoids, apotirucallane, tirucallane, and dammarane triterpenes. This genus is abundant in limonoids possessing diverse structural features, in particular, modifications in rings A, B, and C. Some rare alkaloids of spermidine type have also been isolated. Investigation on C. erythrocarpus proved that variation in the habitat can bring www.cb.wiley.com 502 Chem. Biodiversity 2016, 13, 483 – 503 a change in the secondary metabolite content in plants of this genus. Thus, attempts may be made to increase the stress in plants of this genus by changing their habitat to trigger production of unusual types of secondary metabolites. Moreover, the remaining 84% uninvestigated plants of this genus can be brought into consideration for biological screening and bioassay-directed phytochemical investigation with a view to isolate bioactive novel structures that can be used as drug or drug lead. J. A. S. is a Postdoctoral Fellow at the Centre for Natural Products and Drug Discovery, University of Malaya. This work is supported by the grant from University of Malaya (UM-C/625/1/HIR/MOHE/SC/37). [25] [26] [27] [28] [29] [30] [31] REFERENCES [1] M.-H. Yang, J.-S. Wang, J.-G. Luo, X.-B. Wang, L.-Y. Kong, J. Nat. Prod. 2009, 72, 2014. [2] P. F. Stevens, Contr. Herb. Austral. 1975, 1975, 1. [3] H. Zhang, Z.-J. Song, W.-Q. Chen, X.-Z. Wu, H.-H. Xu, Biochem. Syst. Ecol. 2012, 41, 35. [4] G.-W. Wang, H.-Z. Jin, W.-D. Zhang, Phytochem. Rev. 2013, 12, 915. [5] F. Wang, Y. Guan, Fitoterapia 2012, 83, 13. [6] N. Malafronte, R. Sanogo, A. Vassallo, N. De Tommasi, G. Bifulco, F. Dal Piaz, Phytochemistry 2013, 96, 437. [7] K. Mohamad, T. Sevenet, V. Dumontet, M. Pa€ıs, M. Van Tri, H. Hadi, K. Awang, M.-T. Martin, Phytochemistry 1999, 51, 1031. [8] V. Parcha, M. Gahlot, J. Kaur, Y. Tomar, J. Nat. Remedies 2004, 4, 1. [9] L. Pan, U. M. Acu~ na, J. Li, N. Jena, T. N. Ninh, C. M. Pannell, H. Chai, J. R. Fuchs, E. J. Carcache De Blanco, D. D. Soejarto, A. D. Kinghorn, J. Nat. Prod. 2013, 76, 394. [10] K. Awang, X.-M. Loong, K. H. Leong, U. Supratman, M. Litaudon, M. R. Mukhtar, K. Mohamad, Fitoterapia 2012, 83, 1391. [11] B. Saikia, J. C. S. Kataky, R. K. Marthur, J. N. Baruah, Indian J. Chem. Sect. B: Org. Chem. Incl. Med. Chem. 1978, 16, 1042. [12] Q.-G. Tan, X.-D. Luo, Chem. Rev. (Washington, DC, U.S.) 2011, 111, 7437. [13] M. Bordoloi, B. Saikia, R. K. Mathur, B. N. Goswami, Phytochemistry 1993, 34, 583. [14] ‘Meliaceae’ in ‘Flora of China’, Eds. Z. Y. Wu, P. H. Raven, D. Y. Hong, Science Press, Beijing and Missouri Botanical Garden Press, St. Louis, 2008, Vol. 11, p. 119. [15] D. Mabberley, Bull. Brit. Mus. (Nat. Hist.) Bot. 1979, 6, 1 – 386. [16] L. L. Forman, Kew. Bull. 1966, 20, 309. [17] D. J. Mabberley, C. M. Pannell, A. Sing, ‘Flora Malesiana: Series I. Spermatophyta’, Rijksherbariuni/Hortus Botanicus, Leiden University, The Netherlands, 1995, Vol. 12, Part 1. [18] J. B. Fisher, Bot. J. Linn. Soc. 2002, 139, 207. [19] D. J. Mabberley, Gard. Bull. Singapore 2003, 55, 189. [20] J. Hooker, ‘The Flora of British India’, L. Reeve & Co., London, 1872, Vol. 1, p. 740. [21] M.-H. Yang, J.-S. Wang, J.-G. Luo, X.-B. Wang, L.-Y. Kong, J. Nat. Prod. 2012, 75, 308. [22] L. S. L. Chua, 1998, ‘Chisocheton pauciflorus, The IUCN Red List of Threatened Species’, Version 2014.2, www.iucnredlist.org, downloaded on 22 September 2014. [23] P. J. Eddowes, 1998, ‘Chisocheton stellatus, The IUCN Red List of Threatened Species’, Version 2014.2, www.iucnredlist.org, downloaded on 22 September 2014. [24] J. S. Gamble, ‘A Manual of Indian Timbers: An Account of the Structure, Growth, Distribution, and Qualities of Indian www.cb.wiley.com [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] Woods’, Office of the Superintendent of Government Printing, Calcutta, 1881. E. D. Merrill, ‘A Dictionary of the Plant Names of the Philippine Islands’, Bureau of Public Printing, Manila, 1903. T. H. Wongprasert, C. Phengklai, T. Boonthavikoon, Thai Forest Bull. (Bot.) 2011, 39, 210. M. Tzouros, L. Bigler, S. Bienz, M. Hesse, A. Inada, H. Murata, Y. Inatomi, T. Nakanishi, D. Darnaedi, Helv. Chim. Acta 2004, 87, 1411. ‘Timber Trees: Lesser-Known Timbers’, Eds. M. S. M. Sosef, L. T. Hong, S. Prawirohatmodjo, Backhuys Publishers, Leiden, The Netherlands, 1998. F. Zhang, X.-F. He, W.-B. Wu, W.-S. Chen, J.-M. Yue, Nat. Prod. Bioprospect. 2012, 2, 235. K. Y. Chan, K. Mohamad, A. J. A. Ooi, Z. Imiyabir, L. Y. Chung, Fitoterapia 2012, 83, 961. I. H. Burkhill, ‘A Dictionary of the Economic Products of the Malay Peninsula’, Crown Agents for the Colonies, London, 1935, Vol. 1. ‘Plant Resources of South-East Asia No. 14: Vegetable Oils and Fats’, Eds. H. A. M. van der Vossen, B. E. Umali, Backhuys Publishers, Leiden, The Netherlands, 2001. C. Wiart, ‘Medicinal Plants of Asia and the Pacific’, CRC Press, Boca Raton, FL, 2006. M. Tasyriq, I. A. Najmuldeen, L. L. A In, K. Mohamad, K. Awang, N. Hasima, Evid.-Based Complem. Altern. Med. 2012, 2012, 765316. J. D. Connolly, C. Labbe, D. S. Rycroft, D. A. H. Taylor, J. Chem. Soc. Perkin Trans. 1 1979, 2959. X. Fang, Y. T. Di, X. J. Hao, Curr. Org. Chem. 2011, 15, 1363. X. Fang, Y. Di, Z. Geng, C. Tan, J. Guo, J. Ning, X. Hao, Eur. J. Org. Chem. 2010, 1381. S.-L. Chong, K. Awang, M. T. Martin, M. R. Mokhtar, G. Chan, M. Litaudon, F. Gueritte, K. Mohamad, Tetrahedron Lett. 2012, 53, 5355. Q. Zhang, Y.-T. Di, H.-P. He, X. Fang, D.-L. Chen, X.-H. Yan, F. Zhu, T.-Q. Yang, L.-L. Liu, X.-J. Hao, J. Nat. Prod. 2011, 74, 152. D. A. H. Taylor, Phytochemistry 1983, 22, 1297. S. Laphookhieo, W. Maneerat, S. Koysomboon, R. Kiattansakul, K. Chantrapromma, J. K. Syers, Can. J. Chem. 2008, 86, 205. P. J. Gunning, L. B. Jeffs, M. B. Isman, G. H. N. Towers, Phytochemistry 1994, 36, 1245. A. Chatterjee, L. Nayak, B. Das, A. Patra, K. P. Dhara, K. Mukherjee, J. Banerji, J. N. Shoolery, Indian J. Chem. Sect. B: Org. Chem. Incl. Med. Chem. 1989, 28, 231. R. D. Yadav, J. C. S. Kataky, R. K. Mathur, Indian J. Chem. Sect. B: Org. Chem. Incl. Med. Chem. 1999, 38, 243. K. Mohamad, Y. Hirasawa, M. Litaudon, K. Awang, A. H. A. Hadi, K. Takeya, W. Ekasari, A. Widyawaruyanti, N. C. Zaini, H. Morita, Bioorg. Med. Chem. 2009, 17, 727. C. P. Wong, M. Shimada, Y. Nagakura, A. E. Nugroho, Y. Hirasawa, T. Kaneda, K. Awang, A. H. A. Hadi, K. Mohamad, M. Shiro, H. Morita, Chem. Pharm. Bull. 2011, 59, 407. C. P. Wong, M. Shimada, A. E. Nugroho, Y. Hirasawa, T. Kaneda, A. H. A. Hadi, S. Osamu, H. Morita, J. Nat. Med. 2012, 66, 566. I. A. Najmuldeen, A. H. A. Hadi, K. Awang, K. Mohamad, K. A. Ketuly, M. R. Mukhtar, S.-L. Chong, G. Chan, M. A. Nafiah, N. S. Weng, O. Shirota, T. Hosoya, A. E. Nugroho, H. Morita, J. Nat. Prod. 2011, 74, 1313. I. A. Najmuldeen, A. H. A. Hadi, K. Mohamad, K. Awang, K. A. Ketuly, M. R. Mukhtar, H. Taha, N. Nordin, M. Litaudon, F. Gueritte, A. E. Nugroho, H. Morita, Heterocycles 2012, 84, 1265. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich Chem. Biodiversity 2016, 13, 483 – 503 [50] K. Awang, C. S. Lim, K. Mohamad, H. Morita, Y. Hirasawa, K. Takeya, O. Thoison, A. H. A. Hadi, Bioorg. Med. Chem. 2007, 15, 5997. [51] I. A. Najmuldeen, A. H. A. Hadi, K. Awang, K. Mohamad, S. W. Ng, Acta Crystallogr. Sect. E: Struct. Rep. Online 2010, 66, o1927. [52] M.-H. Yang, J.-S. Wang, J.-G. Luo, X.-B. Wang, L.-Y. Kong, Can. J. Chem. 2012, 90, 199. [53] K. Mohamad, Y. Hirasawa, C. S. Lim, K. Awang, A. H. A. Hadi, K. Takeya, H. Morita, Tetrahedron Lett. 2008, 49, 4276. [54] D. A. Mulholland, B. Parel, P. H. Coombes, Curr. Org. Chem. 2000, 4, 1011. [55] I. A. Najmuldeen, A. H. A. Hadi, K. Mohamad, Malaysian J. Sci. 2011, 30, 144. [56] ‘Dictionary of Natural Products’, Ed. J. Buckingham, Chapman and Hall/CRC, 2012. [57] D. E. Champagne, O. Koul, M. B. Isman, G. G. E. Scudder, G. H. N. Towers, Phytochemistry 1992, 31, 377. [58] Y. S. Sang, C. Y. Zhou, A. J. Lu, X. J. Yin, Z. D. Min, R. X. Tan, J. Nat. Prod. 2009, 72, 917. [59] R. Huang, L. J. Harrison, K.-Y. Sim, Tetrahedron Lett. 1999, 40, 1607. [60] R. D. Yadav, J. C. S. Kataky, R. K. Mathur, Indian J. Chem. Sect. B: Org. Chem. Incl. Med. Chem. 1999, 38, 1359. [61] M.-H. Yang, J.-S. Wang, L.-Y. Kong, Chin. J. New Drugs 2012, 21, 555. [62] V. Torpocco, H. Chavez, A. Estevez-Braun, A. G. Ravelo, Chem. Pharm. Bull. 2007, 55, 812. [63] A. Ikram, M. A. Versiani, S. Shamshad, S. K. Ahmed, S. T. Ali, S. Faizi, Rec. Nat. Prod. 2013, 7, 302. [64] A. Inada, M. Somekawa, H. Murata, T. Nakanishi, H. Tokuda, H. Nishino, A. Iwashima, D. Darnaedi, J. Murata, Chem. Pharm. Bull. 1993, 41, 617. © 2016 Verlag Helvetica Chimica Acta AG, Z€ urich 503 [65] J. Phongmaykin, T. Kumamoto, T. Ishikawa, R. Suttisri, E. Saifah, Arch. Pharmacal Res. 2008, 31, 21. [66] S. Bienz, R. Detterbeck, C. Ensch, A. Guggisberg, U. H€ausermann, C. Meisterhans, B. Wendt, C. Werner, M. Hesse, in ‘The Alkaloids: Chemistry and Biology’, Ed. G. A. Cordell, Academic Press, San Diego, CA, 2002, Vol. 58, p. 83. [67] I. A. Najmuldeen, A. H. A. Hadi, K. Awang, K. Mohamad, S. W. Ng, Acta Crystallogr. Sect. E: Struct. Rep. Online 2008, 64, o2163. [68] C. P. Wong, J. Deguchi, A. E. Nugroho, T. Kaneda, A. H. A. Hadi, H. Morita, Bioorg. Med. Chem. Lett. 2013, 23, 1786. [69] W. Maneerat, S. Laphookhieo, S. Koysomboon, K. Chantrapromma, Phytomedicine 2008, 15, 1130. [70] L. Y. Chung, K. F. Yap, M. R. Mustafa, S. H. Goh, Z. Imiyabir, Pharm. Biol. 2005, 43, 672. [71] L. Y. Chung, W. K. Soo, K. Y. Chan, M. R. Mustafa, S. H. Goh, Z. Imiyabir, Pharm. Biol. 2009, 47, 1142. [72] C. P. Wong, T. Kaneda, A. H. A. Hadi, H. Morita, J. Nat. Med. 2014, 68, 22. [73] N. H. Nagoor, N. S. J. Muttiah, C. S. Lim, L. L. A. In, K. Mohammad, K. Awang, PLoS One 2011, 6, e23661. [74] S. H. Qi, D. G. Wu, Y. B. Ma, X. D. Luo, Acta Bot. Sin. 2003, 45, 1129. [75] M. B. Isman, P. J. Gunning, K. M. Spollen, in ‘Phytochemicals for Pest Control’, Eds. P. A. Hedin, R. M. Hollingworth, E. P. Masler, J. Miyamoto, D. G. Thompson, American Chemical Society, Washington, DC, 1997. Received October 8, 2014 Accepted February 4, 2016 www.cb.wiley.com