Introduction

Apiaceae (syn. Umbelliferae) is one of the largest families of Plant Kingdom: it comprises 434 genera and 3780 species. Most of these species are aromatic plants with hollow stems, and several representatives are used as vegetables or condiments (Stevens 2001). The genus Prangos Lindley (syn. Cryptodiscus Fischer & C. A. Meyer, Koelzella Hiroe; Neocryptodiscus Hedge & Lamond), distributed from Portugal to Tibet, consists of 45 species (Stevens 2001). The centre of the diversity of Prangos genus is the Irano-Turanian region. The main anatomical and morphological features characteristic to Apiaceae species, can also be discovered in Prangos species with some specific morphological changes regarding fruits, endosperms and mesocarp. According to phylogeny studies, Prangos is a monophyletic taxon closely related to Bilacunaria and Cachrys (Lyskov et al. 2017) genera. Species of Prangos genus have been used in the traditional medicine of the Mediterranean region and the Middle East.

Prangos species possess a great importance as spices and medicinal plants in Asia, especially in Iran, Turkey, and Iraq. The above-ground part, the roots and the essential oil of different species have been applied internally and externally as well. The most popular indications of the plants are the alleviation of different gastrointestinal symptoms, but various other uses have also been reported. In the recent years, the number of papers reporting experimental data on the biological effects of Prangos species have been increased. However, there is no systematic review available that summarizes the current knowledge on these species.

Coumarin derivatives, particularly furocoumarins have been isolated and identified as the predominant secondary metabolites of several Prangos species. Considering the fact that furocoumarins may possess phototoxic and carcinogenic effects (Melough et al. 2018), the assessment of qualitative and quantitative data on the furocoumarin content of these plants is of primary importance. Furthermore, the summary of phytochemical components of the genus may be useful to understand better the described bioactivities and also to provide new directions for further research.

Our aim was to review scientific data on traditional use, bioactivity, and phytochemical profile of the Prangos genus, by searching for the keyword “Prangos” (from 1974 to 2019) on PubMed, and Web of Science databases (last search: 01. 11. 2019).

Traditional use of Prangos species

The ethnomedicinal applications of the Prangos genus are shown in Table S1. In Turkey, Prangos plants are used as carminative, tonic, and anthelmintic agents, in the treatment of external bleeding, gastric or digestive disorders, wounds, scars, and leuckoplakia. Moreover, Prangos species are also used as stimulants, aphrodisiacs and natural fertilizers (Oke Altuntas et al. 2016; Ozek et al. 2018). Some species of this genus are consumed as spices or food additives as well.

Due to its aphrodisiac, coagulant, carminative and tonic effects, different Prangos species are part of the traditional medicine (Razavi et al. 2010c; Abolghasemi and Piryaei 2012). The most commonly used species of this genus are P. ferulacea and P. pabularia. The leaves of these plants are traditionally used as laxative, antihypertensive, and carminative agents and are also recommended for the treatment of digestive disorders (Dokovic et al. 2004; Sagun et al. 2006; Kazerooni et al. 2006; Durmaz et al. 2006; Özek et al. 2007; Ahmed et al. 2011a; Razavi 2012b; Farooq et al. 2014a; Shokoohinia et al. 2014; Namjoyan et al. 2015; Seidi Damyeh et al. 2016; Tabanca et al. 2016; Gheisari et al. 2016; Yousefi et al. 2017; Delnavazi et al. 2017; Kiliç et al. 2017; Ozek et al. 2018; Sadeghi and Bazdar 2018; Abbas-Mohammadi et al. 2018; Numonov et al. 2018). In Western North Iran, the essential oil from roots of P. ferulacea has been traditionally used for wound healing (Yousefi et al. 2017).

The fresh fruits and roots of P. pabularia are also consumed in Tajikistan (local name: Yugan) for its putative effects in the treatment of vitiligo, and because these are considered to have tonic effects (Numonov et al. 2018). In India, only P. pabularia (local names: Komal, Kurangas) is native. The roots and fruits of this species are used as laxative, liver tonic, diuretic, carminative, and stimulant. Infusion from the roots is used in the treatment of flatulence, indigestion and improving of menstrual cycle in women (Farooq et al. 2014b). In Turkish folk medicine, the roots of P. pabularia, and P. meliocarpoides are eaten with honey as aphrodisiac (Ozek et al. 2018).

In Kurdish traditional medicine (eastern part of Iraq), the aerial part of P. haussknechtii is used for its carminative, diuretic, and sedative effects (Dissanayake et al. 2017).

Besides their medicinal use, Prangos species are extensively used as food additives, spices and flavouring agents (Table S1). P. ferulacea is used in Iran (Iranian name: Djashir) as yogurt flavouring, and animal fodder (Damyeh et al. 2016; Abbas-Mohammadi et al. 2018, Shokoohinia et al. 2014), whereas in Turkey (local names: Casir, Caksir) it is used as food ingredient, e.g. in Van herby cheese, aroma and flavour component (Sagun et al. 2006; Ozek et al. 2018) and as stimulant tea (Kiliç et al. 2017). The young stems and shoots of P. platychlaena Boiss. (local names: Cagsir, Caksir, Kirkor, and Korkor) are eaten freshly and used as pickle in Eastern Turkey, while it is consumed after baking in the central part of the country. Furthermore, the roots of the plant are often powdered and mixed with honey to consume as aphrodisiac (Ozek et al. 2018; Tabanca et al. 2018).

Pharmacological and biological activities

Bioactivity of extracts, essential oils, and isolated secondary metabolites of Prangos species have been investigated by several research groups. The most extensively studied effect of Prangos species have been experimented in vitro. Among them antioxidant activity is the major bioactivity evaluation. The only in vivo study is evaluation of abortifacient effect of the P. ferulacea leaves extracts. Antimicrobial (antibacterial, antifungal, and antiviral), anti-cancer (cytotoxic and antiproliferative), anti-inflammatory, anti-diabetic, neuroprotective and other pharmacological activities of Prangos species have also been assessed. Allelopathic effects including phytotoxic, insecticidal and repellent activities of EOs of Prangos species have also been reported. In the majority of the experiments, aerial parts were used, usually as methanolic or hydroethanolic extracts. The pharmacological studies that had been performed on Prangos spp. are listed in Table S2.

Antioxidant activities

Free radicals are generally synthesized as by-products in all living organisms and can result in oxidative damage to biological molecules like DNA, fatty acids, and amino acids. Free radicals and oxidative stress are proved to play an essential role in the development of certain chronic diseases (Sarma et al. 2010), hence plants possessing remarkable antioxidant activity may play role in health protection.

Many plant products (EOs, different extracts and pure constituents) obtained from different parts of Prangos species have been evaluated for their free radical scavenging activity, and several of these natural products possessed noteworthy antioxidant potential. Antioxidant tests, including ABTS, CUPRAC, DPPH, FRAP, LPO, ORAC and TBA assays were carried out in vitro. Of the tested samples, the methanolic extracts of P. ferulacea demonstrated high antioxidant activity in various assays; and among the isolated compounds, the coumarin scopoletin (9) obtained from P. uloptera exhibited the most significant activity (Razavi et al. 2008b).

Crude extracts and essential oils

In a study, various extracts of Prangos species have been subjected to antioxidant activity assays. Aqueous extracts of P. denticulata leaf (IC50: 0.048 mg/mL) and P. heyniae fruit (IC50: 0.119 mg/mL) showed the highest antioxidant activities using the DPPH test compared to α-tocopherol (IC50: 0.011 mg/mL), BHA (IC50: 0.003 mg/mL), and BHT (IC50: 0.023 mg/mL) as controls. In metal chelating assay the aqueous leaf extract of P. denticulata (0.94 mg/mL) and methanol root extract of P. heyniae (0.74 mg/mL) were the most potent extracts. Aqueous extracts from leaves and fruits of P. denticulata were the strongest antioxidant agents with inhibition values of 69.93% and 68.98%, respectively, by using plasma lipid peroxidation method (Oke-Altuntas et al. 2015). In a comparative study, the hot water extract of P. denticulata leaf exerted the highest ability in scavenging free radicals (IC50: 0.048 mg/mL), compared to various extracts of the species and the aqueous extract of P. platychloena was equally active (IC50: 0.048 mg/mL) (Oke Altuntas et al. 2011).

The antioxidant activities of the EO and the hydroalcoholic extracts (particularly methanolic) of P. ferulacea have been extensively studied. The hydroalcoholic extract obtained from P. ferulacea flowers possesses the highest antioxidant capacity with IC50 = 8.01 μL/mL in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The other samples derived from this species were less active: hydroalcoholic extract of flowers (IC50: 8.01 ± 0.60 μL/mL) > hydroalcoholic extract of leaves (IC50: 10.99 μL/mL) > aqueous extract of flowers (IC50: 14.59 μL/mL) > aqueous extract of leaves (18.61 μL/mL) > EO of leaves (22.99 μL/mL) > EO of flowers (23.90 μL/mL) (Bazdar et al. 2018). Evaluation of free radical scavenging activity of hydroalcoholic extracts obtained from ten Iranian P. ferulacea samples revealed moderate activities with EC50 values of the most potent samples of 0.013 mg/mL and 10.55 mmol Trolox equivalent (TE)/g in the DPPH and oxygen radical absorbance capacity (ORAC) assays, respectively (Bagherifar et al. 2019). In a similar study, antioxidant activities of methanolic and aqueous extracts obtained from the roots, herbs, and flowers of four Prangos species (P. ferulacea, P. uechtritzii, P. heyniae, P. meliocarpoides var. meliocarpoides) collected in Turkey were measured by the thiobarbituric acid assay (TBA). Among the tested extracts, the methanolic extract of P. ferulacea and P. uechtritzii fruits had the highest antioxidant activities with IC50 values of 0.047 mg/mL and 0.049 mg/mL, respectively (Ahmed et al. 2011b). In a comparative study, radical scavenging and lipid peroxidation inhibitory activities of P. ferulacea were compared to other Apiaceae species including Chaerophyllum macropodum Boiss. and Heracleum persicum Desf. The methanolic extract of aerial parts of P. ferulacea with IC50 = 0.242 and 0.152 mg/mL for DPPH radical scavenging and lipid peroxidation inhibition (LPO), respectively, showed better antioxidant activities in comparison with the two other investigated plants (Çoruh et al. 2007). From P. ferulacea samples, the ethyl acetate extract of the plant had the highest antioxidant activity among the different extracts using the DPPH and the ABTS assays, showing IC50 values of 1.4 mg/g and 5.4 mg/g, respectively (Dagdelen et al. 2014). MeOH extract of P. ferulacea fruit exerted a good potency in scavenging of free radicals in the DPPH assay, with 6.4% of inhibition compared with ascorbic acid (4.0%) as the positive control at a concentration of 0.01 mg/mL (Cesur et al. 2017). A methanolic extract of P. ferulacea (IC50: 0.228 mg/mL) exhibited moderate antioxidant activity, evaluated by the DPPH method (Mavi et al. 2004).

The antioxidant activity of EO, n-hexane, dichloromethane, and methanolic extracts obtained from aerial parts of P. gaubae were evaluated in the DPPH, cupric ion reducing activity (CUPRAC) and ferric reducing antioxidant power (FRAP) assays. The methanolic extract was the most active extract using the DPPH (0.47 mmol TEs/g), CUPRAC (0.89 mmol TEs/g), and FRAP (0.52 mmol TEs/g) assays, whereas the EO had the highest capacity in scavenging of free radicals using the ABTS method (2.02 mmol TEs/g) (Bahadori et al. 2017a).

Yazici et al. (2013) reported that the methanolic extracts of P. hulusii aerial parts had stronger antioxidant activity compared to its roots analysed by different assays (Yazici et al. 2013).

The fruits of P. meliocarpoides were extracted with various solvents, and among the extracts the methanolic extract showed the highest DPPH radical scavenging effect (IC50: 0.088 mg/mL), followed by the aqueous, acetone and ethyl acetate extracts (Oke Altuntas et al. 2016).

The dichloromethane extract of P. pabularia roots (collected from Iran) displayed the highest antioxidant activity using the DPPH assay with an RC50 (concentration of the test material that reduces 50% of the free radical concentration) value of 0.08 mg/mL followed by the methanolic and n-hexane extracts with RC50s of 0.17 and 1.38 mg/mL, respectively (Salehi et al. 2016).

Pure compounds

8-Geranyloxy psoralen (32), a furocoumarin isolated from the roots and fruits of P. uloptera exerted weak antioxidant effect with RC50 of 0.262 mg/mL in the DPPH assay (Razavi et al. 2009a). Scopoletin (9) was the most active antioxidant compound from the five extracted coumarins (xanthotoxin (36), prangenin (73), scopoletin (9), deltoin (79) and prangolarin (syn. oxypeucedanin) (48)) from the aerial parts of P. uloptera, with an RC50 value of 0.0243 mg/mL (Razavi et al. 2008b). The free radical scavenging activity of oxypeucedanin (48), isolated from leaves of P. uloptera was evaluated by the DPPH assay (RC50 value of 51.25 mg/mL) (Razavi et al. 2010b). Aviprin (89), isolated from P. uloptera with RC50 of 0.54 mg/mL was more effective than aviprin-3″-O-d-glucopyranoside (90) (RC50: 5 mg/mL) in the DPPH assay (Zahri et al. 2012). Among the isolated phytochemicals from aerial parts of P. haussknechtii, hydroxy osthol-epoxide (4) was the most potent antioxidant compound with IC50s of 0.048 and 0.043 mM measured by MTT and LPO, respectively (Dissanayake et al. 2017).

Antimicrobial activities

Extracts, essential oils and pure compounds of Prangos species showed noteworthy antibacterial, antifungal, and antiviral effects. The antibacterial activities of the plant materials have been evaluated mostly by disc diffusion and microtiter broth dilution assays. Remarkably high activities were observed in case of the EO of the leaves of P. ferulacea against Pseudomonas aeruginosa, Staphylococcus epidermidis, S. aureus, and Bacillus cereus strains. Mainly the Gram-positive bacteria (particularly S. aureus and B. cereus) were inhibited by various Prangos species, especially by EOs and methanolic extracts of P. ferulacea. P. ferulacea, P. pabularia and P. platychlaena which were active against C. albicans.

Antibacterial activities

Crude extracts and essential oils

The EO of the fruit of P. asperula was evaluated for its antibacterial activity and showed a moderate effect against S. aureus with a minimum inhibitory concentration (MIC) of 0.128 mg/mL (Khoury et al. 2018). S. aureus was the most susceptible strain against the EO obtained from the aerial parts of P. asperula (growth inhibition zone (IZ): 15.0 mm), the EO was less active on Escherichia coli (IZ: 11.8 mm) and Salmonella enterica (IZ: 3.8 mm). The results of the MbD assay reassured these observations (Mneimne et al. 2016).

The acetone extract of the fruit of P. denticulata collected from Turkey was characterized with an IZ of 11.9 mm against Bacillus cereus RSKK 863 (Oke-Altuntas et al. 2012).

Among EOs obtained from various organs of P. ferulacea, the EO obtained from the leaves was the most active one with the following MIC values: Pseudomonas aeruginosa (0.0000625 mg/mL), S. epidermidis (0.00025 mg/mL), and S. aureus (0.0005 mg/mL), while the EO obtained from the flowers were most active EO against B. cereus (0.0005 mg/mL). The EO obtained from the stem part was less active (Akbari et al. 2010). Razavi et al. (2010a) reported that B. cereus (IZ of 15 mm) was the most susceptible strain to the EOs of P. ferulacea fruits and umbels (Razavi et al. 2010a). EO of P. ferulacea root showed high inhibitory activity against S. paratyphi and E. coli with MIC values of 0.01 and 0.005 mg/mL, respectively (Yousefi et al. 2017).

The antimicrobial activities of some medicinal plants used in traditional Turkish cheeses were analysed in an experiment. The methanolic extract of P. ferulacea was active against Enterococcus faecalis with a MIC value of 250 mg/mL (Dagdelen et al. 2014), on other microbes the activity was even less pronounced. The methanol extract of P. ferulacea showed moderate antibacterial activity against B. cereus, B. subtilis, Micrococcus luteus, and S. aureus with IZs of 12–18 mm (Durmaz et al. 2006). Gheisari et al. (2016) investigated the antibacterial activities of the methanolic extracts from the aerial parts of P. ferulacea by two methods. Using the disc diffusion method, C. freundii was the most susceptible strain with an IZ value of 12.76 mm. Furthermore, these results were supported by the microtiter broth dilution method, where the extract exerted 99% inhibition on the growth after 24 h (Gheisari et al. 2016). Methanolic and ethanolic extracts of P. ferulacea showed more significant activity against Listeria monocytogenes serotype 4ab with IZs of 13 and 11 mm, respectively, compared to its aqueous and n-hexane extracts having no activity (Sagun et al. 2006).

The antibacterial activities of roots, flowers, leaves, stems, and seeds of P. ferulacea and P. uloptera were analysed using disc diffusion assay. The methanolic extracts of the roots of both species possessed high activity with MIC values of ≤ 0.25–1 mg/mL against the tested strains including S. aureus, S. pyogenes, B. subtilis, E. coli, S. enterica, and Serratia marcescens (Nosrati and Behbahani 2016). EO of P. ferulacea indicated a significant activity against E. faecalis (IZ: 23 mm) compared to gentamicin (IZ: 8 mm) as positive control (Nazemisalman et al. 2018).

In a study carried out with different extracts of P. hulusii roots collected in Turkey, the most potent antibacterial activity was attributed to the dichloromethane extract of the plant on E. coli with a MIC value of 0.156 mg/mL (Tan et al. 2017). Yazici et al. (2013) reported that P. hulusii possessed no activity against S. aureus, E. coli, Klebsiella pneumoniae, B. cereus, and Proteus vulgaris (Yazici et al. 2013).

The hydro-distilled EO of P. pabularia fruits demonstrated antibacterial activity against two Gram-positive [S. epidermidis and methicillin-resistant S. aureus (MRSA)], and four Gram-negative bacteria (E. coli, P. aeruginosa, P. vulgaris, and Salmonella typhimurium), and antifungal activity against C. albicans; while among the studied microorganisms the most susceptible was the MRSA (clinical isolate, MIC: 0.00125 mg/mL) (Özek et al. 2007).

In another study, the EO of P. peucedanifolia leaves was active against S. mutans, S. pyogenes, and S. aureus with MIC values less than 1.9 mg/mL, whereas the EO of the fruits was less active (Brusotti et al. 2013).

The evaluation of the antibacterial properties of EOs of fruits of P. platychlaena and P. uechtritzii revealed high activities against E. coli (MIC: 9 mg/mL) and B. subtilis (MIC: 36 mg/mL), respectively (Uzel et al. 2006).

Among different extracts (n-hexane, methanol, and dichloromethane) obtained from P. uloptera roots, the dichloromethane fraction demonstrated the most pronounced antibacterial effect against S. aureus analysed by the disc diffusion method (IZ: 15.8 mm); whereas no activity was observed against E. coli. Microbroth dilution assay reassured these results, where the highest and lowest activity was observed on S. aureus and E. coli, respectively (Razavi et al. 2010c).

Pure compounds

Oxypeucedanin (48) and imperatorin (44) isolated from the chloroform extract of P. platychlaena showed slight activity against E. coli (MIC of 0.048 mg/mL) (Ulubelen et al. 1995), whereas oxypeucedanin (48) was not active against the plant pathogen bacteria Xanthomonas compestris and Erwinia cartovorum (Razavi et al. 2010b).

Compounds isolated from P. uloptera were subjected to antimicrobial screening, and 8–geranyloxy psoralen (32) was found to be effective against S. epidermidis with a MIC value of 100 mg/mL (Razavi et al. 2009a). In another study, isoarnottinin 4′-glucoside (28) isolated from P. uloptera possessed high antibacterial activity (particularly against E. carotovora with a MIC value of 0.1 mg/mL) (Razavi et al. 2011b).

From ten isolated prenylated coumarins of P. hulusii, the new coumarin 4′–senecioiloxyosthol (20), showed the highest activity against a series of bacteria and was especially active against B. subtilis (MIC of 0.005 mg/mL) (Tan et al. 2017).

Osthol (3), isolated from P. pabularia exerted a remarkable effect against MRSA and P. aeruginosa (MIC values of 0.031 mg/mL) compared to the other tested compounds (Tada et al. 2002).

Antifungal activities

Some natural products can permanently damage fungal cell membrane by increasing permeability and fluidity. The subsequent degradation of lipids, proteins and nucleic acids along with the coagulation of the cellular components results in the breakdown and death of fungal cells (Yoon et al. 2000). Several studies demonstrated that Prangos species possess antifungal activity against Gram-positive and Gram-negative fungi.

Crude extracts and essential oils

The EO of P. asperula fruits showed remarkable antifungal activity against Trichophyton rubrum and Trichophyton tonsurans with MICs of 0.064 mg/mL in both strains (Khoury et al. 2018). The EO obtained from the aerial parts of P. asperula inhibited the growth of Trichophyton mentagrophytes, Aspergillus fumigatus, and C. albicans, with IZ values of 7.3 mm, 9.1 mm, and 1.9 mm, respectively (Mneimne et al. 2016).

Yousefi et al. (2017) reported that the EO of the roots of P. ferulacea had inhibitory activity on C. albicans (MIC: 0.005 mg/mL) (Yousefi et al. 2017). The methanolic extract of this species did not inhibit growth of C. albicans (Dagdelen et al. 2014). The EO of P. ferulacea obtained at flowering stage significantly inhibited the growth of Sclerotinia sclerotiorum mycelia at doses exceeding 0.01 mg/mL; the inhibition was approximately 55% at 1.5 mg/mL concentration (Razavi 2012a). The EO obtained from fruits and umbels of P. ferulacea demonstrated an activity with 9–12 mm of inhibition against C. kefyr (Razavi et al. 2010a). By applying microbroth dilution method, the hydroalcoholic extract of P. ferulacea showed a weak effect (MIC: > 1000 mg/mL) against C. albicans (Dagdelen et al. 2014).

When assessing antifungal activity of EO of P. pabularia fruits, significant activity was observed against C. albicans (MIC: 0.0025 mg/mL) (Özek et al. 2007).

Brusotti et al. (2013) reported that the EO of P. peucedanifolia flowers has remarkable antifungal activity against Trichophyton rubrum with a MIC value of 2.4 mg/mL comparable to that of ampicillin (MIC: 0.5 mg/mL) (Brusotti et al. 2013).

The EOs yielded from fruits of P. platychlaena and P. uechtritzii had marginal activities against C. albicans, C. krusei, and C. tropicalis with MIC values exceeding 72 mg/mL (Uzel et al. 2006). The decoction (drug-extract ratio 1:2 w/v) of P. uechtritzii showed potent inhibitory activity at concentration of 80% on the growth of Alternaria alternata, Aspergillus parasiticus, and Penicillium digitatum with 57, 29, and 71% inhibition, respectively; however, no inhibitory activity was found against Aspergillus niger (Ozcan 1999).

Furthermore, the EO of the fruit of P. platychlaena had no antifungal activities against three Colletotrichum species. Nona-(2S)-3,5-diyn-2-yl acetate (134) from the EO and its semisynthetic derivative (2S)-3,5-nonadiyn-2-ol were also inactive against the above-mentioned fungi (Tabanca et al. 2018).

Pure compounds

A good antifungal effect (MIC > 0.4 mg/mL) of isoarnottinin 4′-glucoside (28) was revealed against S. sclerotiorum and C. kefyer (Razavi et al. 2011b).

In the study of Ulubelen et al. (1995) both oxypeucedanin (48) and imperatorin (44), isolated from P. platychlaena, showed strong antifungal activities against C. albicans with MICs of 0.054 mg/mL (Ulubelen et al. 1995).

8-Geranyloxy psoralen (32) isolated from P. uloptera has been reported to possess very weak activity against C. kruzei and C. kefyr, with MIC values of 300 and 100 mg/mL, respectively (Razavi et al. 2009a).

Quercetin-3-O-glucoside (98) isolated from P. ferulacea had no activity against C. kefyr (Razavi et al. 2009c). Oxypeucedanin (48) isolated form leaf extract of P. uloptera was found to be inactive against S. sclerotorium (Razavi et al. 2010b).

Antiviral activities

Crude extract

Antiviral activities of the ethanolic extracts of P. asperula leaf and seed samples were assessed against herpes simplex virus type 1 (HSV-1) and a moderate potency was demonstrated (IC50: 0.66 mg/mL) compared to acyclovir (IC50: 0.00377 mM) (Saab et al. 2012).

Pure compounds

From a series of coumarins isolated from P. tschimganica, psoralen (31) was identified as the most effective compound. It inhibited the replication of human immunodeficiency virus type 1 (HIV-1) (IIIB Strain) in H9 lymphocytes (EC50: 0.0001 mg/mL) and inhibited the growth of uninfected H9 cells (IC50: 0.0191 mg/mL) with IC50 and EC50 values comparable to those of the active control azidothymidine (EC50: < 0.001 mg/mL; IC50: 500 mg/mL) (Shikishima et al. 2001a).

Anti-herpes virus effects of the coumarins isolated from P. ferulacea were analysed on a confluent monolayer of Vero cells (an African green monkey kidney cell line) infected with 25 PFU (plaque-forming units) of HSV-1. None of the analysed coumarins possessed anti-HSV activity at non-toxic concentrations on Vero cells (Shokoohinia et al. 2014).

Phytotoxic activity

Phytotoxicity is the ability of plant to inhibit of plant growth, delay of seed germination or prevention of the other adverse effects caused by phytotoxins (Blok et al. 2019). The extracts, EOs, and isolated phytochemicals from three Prangos species including P. ferulacea, P. pabularia, and P. uloptera have been previously subjected to possess possible phytotoxicity by analysis of their potency in prohibition of growth of lettuce and Trifolium resupinatum.

Among aqueous and hydro-alcoholic extracts obtained from different plant parts (leaf, flower and shoot) of P. ferulacea, the hydro-alcoholic extract of the flowers showed phytotoxic effect by increasing the proline content and decreasing seedling growth and seed germination of Trifolium resupinatum (Bazdar and Sadeghi 2018; Sadeghi and Bazdar 2018). The EO of P. ferulacea obtained during the flowering period inhibited lettuce seed germination with an inhibition value of 97.0% (Razavi 2012a).

The EO extracted from P. pabularia showed strong phytotoxic effect with IC50 values of 0.14, 0.11 and 0.12 mg/mL for inhibition of the growth of the shoot, seed germination, and root of lettuce, respectively (Razavi 2012b).

The dichloromethane extract of P. uloptera exhibited higher stunting effect compared to the n-hexane, and methanolic fractions against root growth, seed germination, and shoot elongation of lettuce (Lactuca sativa L. CV. Varamin), with IC50s of 1.85, 2.00, and 2.08 mg/mL, respectively (Razavi et al. 2010c). Oxypeucedanin (48), isolated from P. uloptera exhibited phytotoxic effect by inhibiting the growth of lettuce shoots with an IC50 value of 0.21 mg/mL (Razavi et al. 2010b). Isoarnottinin 4′-glucoside (28) possessed considerable phytotoxic activity against root elongation of lettuce; whereas the length of the root was decreased from 38.72 to 5.84 mm at concentrations 0 to 1 mg/mL of isoarnottinin 4′-glucoside (28), respectively (Razavi et al. 2011b).

Insecticidal and repellent activity

In general, the insecticidal and repellent activities of EOs extracted from P. ferulacea, P. heyniae, and P. platychlaena have been evaluated. They showed a moderate activity comparing to the applied controls.

The EO of P. ferulacea was active against the egg stage of Trichogramma embryophagum with an LC50 value of 0.0021 mL/L (Sumer Ercan et al. 2013).

P. heyniae EO obtained from four different regions of Turkey possessed moderate larvicidal activity at 0.03125 and 0.062 mg/mL against Aedes aegypti compared to permethrin (0.000025 mg/mL) as positive control (Ozek et al. 2018).

The EO gained from P. platychlaena collected in Eastern part of Turkey showed repellent activity against female A. aegypti L. mosquito with a minimum effective dosage (MED) value of 0.156 mg/cm2 (Tabanca et al. 2018).

Suberosin (6), a coumarin from P. pabularia demonstrated moderate mosquito repellent effect compared to N,N-diethyl-3-methylbenzamide (DEET) as the positive control. This compound also showed a remarkable larvicidal activity with an LC50 value of 0.008 mg/mL at 24-h post treatment (Tabanca et al. 2016).

Cytotoxic and antiproliferative activities

The secondary metabolites isolated form plants have been demonstrated promising approach to discover potential drugs to be considered as a complementation of chemotherapeutics treatment (Newman and Cragg 2012). Nowadays, some of the phytochemicals are known for their strong potency as anti-tumour agents. The plants in the genus of Prangos have been subjected to evaluate their effects on various cancer cell lines possessing cytotoxicity and antiproliferation activities.

Crude extracts and essential oil

The ethanolic extract of aerial parts of P. asperula were investigated for cytotoxic effects on Vero cell line (ATCC: CCL 81) using the MTT assay, and it showed moderated activity with TC50 values higher than 1 mg/mL (Saab et al. 2012). The antiproliferative activity of the EO obtained from the leaves of P. asperula was investigated by the sulphorhodamine B assay, and an IC50 of 0.139 mg/mL was observed against renal cell adenocarcinoma (Loizzo et al. 2008b).

Rostami et al. (2012) studied the in vitro antiproliferative activity of aqueous extracts of P. platychloena by the Trypan Blue exclusion test. The extract was active at concentration of 1 mg/mL with maximum inhibitions 72% and 59% in colorectal cancer cell line (CCL-221) and colon cancer cell line (Caco-2), respectively (Rostami et al. 2012).

The dichloromethane extract of P. uloptera roots reduced the viability of HeLa cells after 24 h with an IC50 0.10 mg/mL; 100% cytotoxicity was recorded at concentrations exceeding 1 mg/mL (Razavi et al. 2010c).

Remarkable cytotoxic activity was reported for the dichloromethane extract of P. pabularia on HeLa cell line (IC50: 0.52 mg/mL at 24 h) in the MTT assay (Salehi et al. 2016).

Yazici et al. (2013) investigated the cytotoxic activity of various extracts of P. hulusii obtained from aerial parts and roots using the MTT and lactate dehydrogenase (LDH) assays. In the MTT assay, the extracts had no effects at the tested concentrations; however, petroleum ether extracts demonstrated low activity in the LDH assay on the rat kidney epithelial cell line (Yazici et al. 2013).

Using the MTT assay, the extracts of P. meliocarpoides were not toxic to baby hamster kidney fibroblast cell line (BHK 21) in concentrations of 0.01–0.1 mg/mL (Altuntas et al. 2011).

Pure compounds

Compounds isolated from P. ferulacea were tested on human ovarian carcinoma cell line (A2780S) using the MTT assay, and osthol (3) had an IC50 value of (0.38 mM, viability of 9.41%), while isoimperatorin (45) was less active (IC50: 1.1 mM) (Shokoohinia et al. 2014). From the EO of the root part of P. ferulacea 3,5-nonadiyne (133) was isolated, and this compound exhibited no activity against Thymic T lymphocytes rat cell line (Dokovic et al. 2004). The isolated quercetin 3-O-glucoside (98) from P. ferulacea showed no activity against McCoy cell line evaluated by MTT assay (Razavi et al. 2009c).

In a further experiment, osthol (3) was found to be the most active compound against lung (NCI-H322 and A549), melanoma (A375), prostate (PC-3), colon (HCT-116), and epidermoid carcinoma (A431) cell lines compared to other compounds from P. pabularia. Osthol (3) had IC50 values of 0.0145, 0.0032, and 0.0302 mM, for lung (A549), epidermoid carcinoma (A431), and colon (HCT-116) cell lines, respectively (Farooq et al. 2014a). Farooq et al. (2018) measured the cytotoxicity of the semi-synthesized analogues of osthol (3) using the MTT method. Among all the tested compounds, N-(2-methylpropyl)-3-{4 methoxy-3-(3-methylbut-2-enyl)-2-(prop-2-en-1-oxy)phenyl} prop-2-en-1-amide exhibited the best results against leukaemia cell line (THP1) with an IC50 of 0.005 mM (Farooq et al. 2018). Numonov et al. (2018) reported that the coumarin yuganin A (22), isolated for the first time from P. pabularia improved the proliferation of B16 melanoma cells; while the cell viability was 127.90% at concentration of 0.05 mM and the intracellular melanin content was significantly increased (Numonov et al. 2018).

In a study carried out by Razavi et al. (2009a), 8-geranyloxy psoralen (32) isolated from P. uloptera showed a good potency in reducing the viability of HeLa and Mc-Coy cell lines with IC50 values of 0.792 and 0.835 mM, respectively, determined by the MTT assay, and IC50 of 1.26 mM for Mc-Coy cell line evaluated by Tripan blue assay (Razavi et al. 2009b). Oxypeucedanin (48) and isoarnottinin 4′-glucoside (28) isolated from P. uloptera exhibited strong to moderate cytotoxic effects against HeLa cells with IC50 values of 0.314 mg/mL and 0.84 mg/mL, respectively (Razavi et al. 2010b, 2011b).

An MTT assay revealed that aviprin (89) inhibited HeLa and prostate cancer (LNCaP) cells with IC50 values of 0.265 and 0.411 mg/mL, respectively; whilst aviprin-3′’-O-d-glucopyranoside (90) showed mild effects on the above-mentioned cell lines, with IC50 values of 0.335 and 6.632 mg/mL, respectively (Zahri et al. 2012).

Anti-inflammatory effect

Inflammation is defined as the body response to defend against allergens and/or injury of the tissues, while they can cause various disorders (e.g. allergies, cardiovascular dysfunctions, metabolic syndrome, cancer, and autoimmune diseases) (Ghasemian et al. 2016). In order to decrease the adverse effects of the available anti-inflammatory drugs, the natural drugs can be promoted to replace. The plants are rich sources of natural products, considering they have been used in traditional medicine as natural anti-inflammatory agents. Among the Prangos species, the extracts of P. platychloena and isolated coumarins from P. haussknechtii have been assessed for their anti-inflammatory effects.

Aqueous extract of P. platychloena decreased the secretion of interleukin 8 (IL-8) in colorectal cancer cell line (CCL-221) from 519.07 to 28.3 pg/mL, while the methanolic extract reduced its secretion to 92.73 pg/mL; and the secretion of interleukin 6 (IL-6) was decreased from 63 to 1 and 4 pg/mL using the aqueous and methanolic extract, respectively (Rostami et al. 2012).

Coumarins isolated from P. haussknechtii inhibited cyclooxygenase enzymes (COX-1 and COX-2) with IC50 values ranging from 0.0368 to 0.0564 mM comparable to NSAIDs including aspirin (IC50 of 0.6 mM for COX-1), naproxen (IC50 of 0.0522 mM for COX-1, and -2), and ibuprofen (IC50 of 0.0728 mM for COX-1) (Dissanayake et al. 2017).

Anti-hypertensive effect

The angiotensin converting enzyme (ACE) inhibitory activity of different P. asperula extracts was tested in vitro, and only the n-hexane fraction was found to be active with an IC50 of 0.150 mg/mL (Loizzo et al. 2008a). The hydroalcoholic extract of P. ferulacea exhibited a weak inhibition of ACE with IC50 value of 4.057 mg/mL (Namjoyan et al. 2015).

Antidiabetic effects

The methanolic extract of P. asperula had no effects on α-amylase and α-glucosidase enzymes (Loizzo et al. 2008a). In the same assay, the EO of P. gaubae possessed the higher inhibitory activity against α-amylase (1.35 mmol acarbose equivalent (AE)/g oil), and α-glucosidase (38.84 mmol AEs/g oil) in comparison with its dichloromethane, methanol, and n-hexane extracts (Bahadori et al. 2017b).

Neuroprotective effect

The EO and dichloromethane extract of P. gaubae possessed the highest neuroprotective effects when compared to n-hexane, and methanolic soluble-extracts against acetylcholinesterase (AChE) and butyryl-cholinesterase (BChE) enzymes with inhibition values of 2.97 and 3.51 mg galanthamine equivalent (GE)/g, respectively (Bahadori et al. 2017a). In a similar work, various extracts of P. ferulacea were tested and the n-hexane fraction had the highest AChE inhibitory activity (75.6% at IC50: 0.05 mg/mL). The furocoumarin heraclenin (60) isolated from the above-mentioned n-hexane fraction showed the highest activity among the studied compounds with an IC50 value of 0.0568 mg/mL (Abbas-Mohammadi et al. 2018).

Abortifacient effect

In an in vivo study, the hydroalcoholic and aqueous extracts of P. ferulacea leaves were administered orally to 60 pregnant rats at different doses (25, 50, 100, 300, 500, and 1000 mg/g per day). No significant effect on abortion frequency was detected; however, the abortion rate was slightly and dose-independently increased by taking the hydroalcoholic extract (Kazerooni and Mousavizadeh 2005; Kazerooni et al. 2006).

Miscellaneous bioactivities

The EO of P. gaubae inhibited lipase enzyme activity [1.59 mmol orlistat equivalent (OE)/g] which might indicate an anti-obesity effect. The n-hexane extract of P. gaubae was more active than the dichloromethane and methanolic extracts against tyrosinase enzyme activity [36.33 mg kojic acid equivalent (KAE)/g], therefore, it seems to be worth for further testing as a natural skin-care agent (Bahadori et al. 2017a).

Regarding the glutathione-S-transferase (GST) activity, the methanolic extract obtained from the aerial parts of P. ferulacea was the most effective inhibitor from the studied plants (Chaerophyllum macropodum Boiss. and Heracleum persicum Desf.) with an IC50 value of 0.079 mg/mL (Çoruh et al. 2007).

Several compounds, including coumarins and γ-pyrone derivatives isolated from P. pabularia inhibited the release of cytokines interleukin (IL-2, IL-4, and IL-1β) and tumour necrosis factor (TNF-α) which indicates potential anti-inflammatory effects (Tada et al. 2002).

3,5-Nonadiyne (133) isolated from the EO of the root part of P. ferulacea exhibited a concentration-dependent inhibition on endogenous nitric oxide release on rat peritoneal macrophages with an IC50 of 0.0067 mM (Dokovic et al. 2004).

Phytochemistry

Phytochemicals are produced in higher plants as secondary metabolites, considering their crucial roles in plants (e.g. defending against herbivores, preserving under stress conditions, attracting of pollinators, etc.), their bioactivities for human are also considerable. In order to discover the potent natural drugs, isolation and identification of phytoconstituents are vital.

16 species of the Prangos genus have been studied for their secondary metabolites. Various coumarin derivatives have been isolated and identified as the major secondary metabolites of this genus. Overall, 30 simple coumarins (1–30), 66 linear and angular furocoumarins (31–96), six flavonoids (97–102), 16 terpenoids (103–118), seven γ-pyrones (119–125), three phytosterols (129–131), and eight other compounds (126, 127, 128, 132–136) have been isolated from different products of the Prangos genus. Totally 131 non-volatile natural products have been reported. These secondary metabolites along with the applied plant parts and plant products are listed in Table S3 and their chemical structures are shown in Fig. 1.

Fig. 1
figure 1figure 1figure 1figure 1

Chemical structures of the compounds of Prangos spp.

Full size image

Coumarins

Coumarins have been isolated from hundreds of plants species distributed in more than 40 different families with diversity of 1300 types. Families with occurrence numbers of > 100 are identified as Apiaceae (Umbelliferae), Rutaceae, Asteraceae (Compositae), Fabaceae (Leguminosae), Oleaceae, Moraceae, and Thymelaeaceae, respectively (Ribeiro and Kaplan 2002). Apiaceae is the major and most diverse source of coumarins, containing five major types of coumarin derivatives including simple coumarins, linear and angular furocoumarins, linear and angular pyranocoumarins (Ribeiro and Kaplan 2002; Kontogiorgis and Hadjipavlou-Litina 2003). So far, from the Prangos genus simple coumarins, linear and angular, glycosylated, and condensed furocoumarins, along with linear dihydro-furocoumarin derivatives have been identified.

Simple coumarins

Farooq et al. (2014a) isolated the simple coumarins umbelliferon (1), 6-hydroxycoumarin (2), osthol (3), and meranzin (11) from P. pabularia (Farooq et al. 2014a). Suberosin (6) (Tabanca et al. 2016), ulopterol (8), auraptenol (10), paniculal (14), tamarin (25) (Tada et al. 2002), and a new coumarin yuganin A (22) (Numonov et al. 2018) were also isolated and identified from this species.

A new coumarin 4′-senecioiloxyosthol (20), along with hydroxyl-osthol-epoxide (4), murraol (15), and macrocarpin (22) were isolated from P. hulusii roots (Tan et al. 2017).

From P. tschimganica, osthenol (5), demethyl-7 suberosin (7), scopoletin (9), isomeranzin (13), peucedanol (18), yuehgesin-B (19), and a new coumarin glycoside tschimganic ester A (30) have been isolated (Shikishima et al. 2001b).

Two novel prenylated coumarins 2-oxo-2H-1-benzopyran-8-yl-2-methyl-2-buten-1-yl ester (23) and butanoic acid, 3-methyl,(2E)-4-(7-methoxy-2-oxo-2H-1-benzopyran-8-yl)-2-methyl-2-buten-1-yl ester (24) were also isolated from aerial portions of P. haussknechtii (Dissanayake et al. 2017).

In a study performed by Abyshev (1974), ferudenol (16), ferudiol (17), and prangone (26) were isolated from the root part of P. ferulacea (Abyshev 1974).

A new coumarin glycoside 6-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-prenyletin (27), and two known coumarin glycosides [tortuoside (27), and isoarnottinin 4′-glucoside (28)] were obtained from the methanolic extract of P. uloptera roots (Razavi et al. 2008a, 2011b).

Linear furocoumarins

Psoralen (31) was isolated and identified from various extracts of P. lipskyi (Danchul et al. 1975a), P. acaulis (Kuznetsova et al. 1979), P. quasiperforata (Danchul et al. 1975b), P. tschimganica (Shikishima et al. 2001b), P. ferulacea (Shokoohinia et al. 2014), and P. hulusii (Tan et al. 2017). A psoralen derivative called 8-geranyloxy psoralen (32) was also isolated from n-hexane extract of the root part of P. uloptera (Razavi et al. 2009a).

In a study carried out by Shikishima et al. (2001a), the n-butanol extract from the aerial parts of P. tschimganica was fractionated to yield saxalin (33), (±)-8-(3-chloro-2-hydroxyl-3-methylbutoxy)-psoralen (syn. isosaxalin) (34), xanthotoxin (36), xanthotoxol (37), bergapten (38), isogosferol (42), imperatorin (44), isoimperatorin (45), oxypeucedanin hydrate (52), heraclenol (61), tert-O-methyl heraclenol (62), pabulenol (74), and pabularinone (80) (Shikishima et al. 2001b).

Different parts including aerial parts and roots of P. ferulacea have been studied for their phytochemical contents. From various extracts (chloroform, methanolic, acetone) 8-[2-(3-methylbutyroxy)-3-hydroxyl-3-methylbutoxylpsoralen (35), gosferol (41), oxypeucedanin (48), oxypeucedanin methanolate (59), heraclenin (60), isopimpinellin (68), phellopterin (72), pranferol (77), feruliden (86), and [3-hydroxy-2-methyl-4-(7-oxofuro[3,2 g]chromen-9-yl) oxybutan-2-yl] (Z)-2-methylbut-2-enoate (92) were isolated (Kuznetsova et al. 1966; Abyshev 1974; Shokoohinia et al. 2014; Gholivand et al. 2015; Abbas-Mohammadi et al. 2018).

Ulubelen et al. (1995) isolated bergaptol (39), n-butyl bergaptol (40), 8-acetyloxypeucedanin (49), and prangenin (73) from chloroform extract of P. platychlaena (Ulubelen et al. 1995).

Furthermore, various researchers have been investigated the secondary metabolite profile of P. pabularia. The linear furocoumarins allo-imperatorin methyl ether (46), oxypeucedanin hydrate 2′-O-monoacetate (53), oxypeucedanin hydrate monoacetate (55), heraclenol 3′-methyl ester (66), 8-((3,3-dimethyloxiran-2-yl) methyl)-7-methoxy-2H-chromen-2-one (syn. merangin) (75), and 4-((2-hydroxy-3-methylbut-3-en-1-yl) oxy)-7H-furo[3,2-g] chromen-7-one (76) were isolated from the plant (Koul et al. 1979; Tada et al. 2002; Farooq et al. 2014a).

Peucedanin (47) and isooxypeucedanin (50) were isolated and identified from P. biebersteinii, whereas aviprin (89) from P. uloptera (Abyshev and Brodskii 1974; Geidarov and Serkerov 2016; Heydarov and Serkerov 2017).

Linear dihydro-furocoumarins

From the methanolic extract of P. ferulacea roots, a new natural product, lindiol (43) have been isolated (Abyshev 1974). Sprengelianin (67) was isolated as a dihydro-furocoumarin derivative from n-hexane extract of aerial parts of P. ferulacea (Abbas-Mohammadi et al. 2018). Furthermore, marmesine (69) and its dehydrated glycosylated form marmesinine (70) were found in several Prangos species: P. ferulacea (Abbas-Mohammadi et al. 2018), P. latiloba (Serkerov et al. 1976), P. quasiperforata (Danchul et al. 1975a), P. tschimganica (Shikishima et al. 2001b), P. lipskyi (Danchul et al. 1975a) and P. biebersteinii (Geidarov and Serkerov 2016).

Prandiol (71) was isolated for the first time from methanolic extract of the roots of P. biebersteinii (Abyshev and Brodskii 1974). Diverse separation techniques were utilized to isolate pranchimgin (78) and deltoin (79) from different Prangos species as dihydro-furocoumarin compounds (Danchul et al. 1975a; Serkerov et al. 1976; Kuznetsova et al. 1979; Eshbakova et al. 2006; Razavi et al. 2008b).

Glycosylated furocoumarins

Several glycosylated furocoumarins were detected in three Prangos species. From P. pabularia, oxypeucedanin hydrate 3′-O-β-d-glucopyranoside (54), oxypeucedanin hydrate 3′-O-β-d-glucopyranoside (56), heraclenol 3′-O-β-d-glucopyranoside (63), 3″-O-(β-d-glucopyranosyl)-heraclenol (65), aviprin-3′’-O-d-glucopyranoside (90), and (-)9-[3-(β-d-glucopyranosyloxy)-2 hydroxy-3-methyl butoxy]-7H furo [3,2-g] [1]benzopyran-7-one (syn. komaline 2′-β-d-glucopyranoside) (91) were isolated (Koul et al. 1979; Tada et al. 2002; Farooq et al. 2014a; Numonov et al. 2018).

Two new compounds 3″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-oxypeucedanin hydrate (57) and 2″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-oxypeucedanin hydrate (58), along with 3″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-heraclenol (64) and aviprin-3′’-O-d-glucopyranoside (90) were isolated as glycosylated linear furocoumarins from the methanolic extract of P. uloptera roots (Razavi et al. 2008a; Zahri et al. 2012).

Shikishima et al. (2001a) isolated two new glycosylated furocoumarins, tschimganic ester B (87) and tschimganic ester C (88) from methanolic extract of P. tschimganica aerial parts (Shikishima et al. 2001b).

Angular furocoumarins

From the n-hexane extract of P. ferulacea, oroselol (93) was obtained (Abbas-Mohammadi et al. 2018). Majurin (94) was isolated from the n-hexane extract of P. pabularia stems (Tada et al. 2002). Columbianetin (95) and columbianetin-O-β-d-glucopyranoside (96) were isolated and identified from P. tschimganica (Shikishima et al. 2001b).

Condensed furocoumarin derivatives

The new furocoumarin derivatives pabularin A (81), pabularin B (82), and pabularin C (83) were obtained from the EtOAc extract of P. pabularia stems. A known compound rivurobirin E (84) was also isolated from the same plant extract (Tada et al. 2002). Rivulobirin A (85) was isolated from n-hexane extract of P. ferulacea (Abbas-Mohammadi et al. 2018).

Flavonoids

Two flavonoid aglycones: quercetin (97) and isorhamnetin (100) were isolated from P. ferulacea. Their glycosydes, quercetin-3-O-glucoside (98), and isorhamnetin-3-O-β-d-glucopyranoside (101), along with querciturone (99) were obtained from P. ferulacea (Razavi et al. 2009c; Mouri et al. 2014; Delnavazi et al. 2017; Abbas-Mohammadi et al. 2018). Rutin (102) was also reported as one of the components of P. denticulata and P. heyniae (Oke-Altuntas et al. 2015).

Terpenoids

From the methanolic extract of the aerial parts of P. tschimganica, two new monoterpenes, tschimganical A (103) and 1,1,5-trimethyl-2-hydroxymethyl-(2,5)-cyclohexadien-(4)-one (106), two known monoterpenes 1,1,5-trimethyl-2-formyl-4-methoxyl-(2,5)-cyclohexadiene (118) and 1,1,5-trimethyl-2-formyl-6-methoxyl-(2,4)-cyclohexadiene (119), along with five new monoterpene glycosides including 2,3,4-trimethylbenzylalcohol-O-β-d-glucopyranoside (106), 1,1,5-trimethyl-2-hydroxymethyl-(2,5)-cyclohexadien-(4)-one-O-β-d-glucopyranoside (105), 1,1,5-trimethyl-2-hydroxymethyl-5-cyclohexadien-(4)-one-7-O-β-d-glucopyranoside (107), vervenone-8-O-β-d-glucopyranoside (108), and vervenone-5-O-β-d-glucopyranoside (109) were isolated (Shikishima et al. 2001a). In this study, the presence of further terpenoids, namely spathulenol (110), globulol (111), 1β,6α-dihydroxyeudesm-4(15)-ene (syn. voleneol) (113), and (-)-caryophyllene-β-oxide (114) was detected (Shikishima et al. 2001a).

From the EO of P. heyniae a new eudesmane type sesquiterpene, 3,7(11)-eudesmadien-2-one (110) was isolated (Ozek et al. 2018).

The diterpenoid kauranol (115) was obtained and identified from P. pabularia (Tada et al. 2002).

A new terpenoid (118) was also isolated from P. haussknechtii aerial parts by using diverse range of chromatographic techniques (Dissanayake et al. 2017).

γ-Pyrones

From P. tschimganica the γ-pyrone aglycone maltol (119), and five glycosides including maltol-β-d-glucopyranoside (120), 3-hydroxyl-2-methyl-4-H-pyran-4-one-3-O-(6)-β-d-glucopyranoside (122), 3-hydroxyl-2-methyl-4-H-pyran-4-one-3-O-(6-O-cis-feruloyl)-β-d-glucopyranoside (123), 3-hydroxyl-2-methyl-4-H-pyran-4-one-3-O-(6-O-cis-isovaleryl)-β-d-glucopyranoside (124), and 3-hydroxyl-2-methyl-4-H-pyran-4-one-3-O-(6-O-cis-caffeoyl)-β-d-glucopyranoside (125) were isolated and identified (Shikishima et al. 2001a).

A new γ-pyrone derivative, maltol-(6-O-acetyl)-β-d-glucopyranoside (121) was also isolated for the first time from EtOAc extract of P. pabularia stem (Tada et al. 2002).

Other compounds

Beside the above-listed main constituents of the Prangos genus, a carotenoid named loliolide (126) from P. pabularia, caffeic acid glucosyl ester (127) from P. ferulacea, and chlorogenic acid (128) from P. denticulata and P. heyniae were reported (Tada et al. 2002; Oke-Altuntas et al. 2015; Delnavazi et al. 2017). The ubiquitous phytosterols stigmasterol (129) and β-sitosterol (130) were identified from P. hulusii roots, and β-sitosterol-β-d-glucopyranoside (131) from P. pabularia stems (Tada et al. 2002; Tan et al. 2017). Three polyacetylene compounds were also identified from the genus, namely: 1-O-isopropyl-β-d-glucopyranoside (132) from P. pabularia, 3,5-nonadiyne (133) from P. ferulacea, and nona-(2S)-3,5-diyn-2-yl acetate (134) from P. platychlaena (Tada et al. 2002; Dokovic et al. 2004; Tabanca et al. 2018).

2-(4-Hydroxyphenyl) ethyl triacontanoate (135) was also isolated from n-hexane extract of aerial parts of P. ferulacea (Abbas-Mohammadi et al. 2018). An amino acid derivative (136) was isolated from the methanolic extract obtained from the aerial parts of P. haussknechtii (Dissanayake et al. 2017).

Essential oils

Various parts of Prangos genus including fruits, seeds, and flowers at different growth stages were subjected to analyse the compositions of their EOs (Table S4). The roots of P. denticulata and immature seeds of P. ferulacea at flowering stage possessed the highest EO contents with 3.2% (v/w) and 3.0% (w/w), respectively (Kilic et al. 2010; Bagherifar et al. 2019). The chemical structures of the main EO components are given in Fig. 2. As demonstrated in Table S4, monoterpene hydrocarbons were the major EO constituents. Among them, α-pinene (137), β-pinene (138), γ-terpinene (139), β-phellandrene (140), and p-cymene (141) were characterized as the main terpenoids.

Fig. 2
figure 2

Major essential oil constituents of Prangos spp.

Full size image

Although monoterpenes were the most abundant volatile constituents, sesquiterpene hydrocarbons were further detected as significant fragrance components of the Prangos genus. In this terpenoid class, the genus was rich in germacrene D (155), γ-cadinene (156), β-elemene (157), and β-bisabolene (158) (Fig. 2).

Conclusions and prospective

Prangos species have been extensively used as food and medicine in Asia. Prangos species have been the subject of intense phytochemical examination in the past few decades. From the 30 Prangos species existing worldwide, 15 and 17 species have been investigated for non-volatile components and EO compositions, respectively. Furthermore, biological activities of 14 plant species have been evaluated. In these studies, crude extracts, EOs, and pure compounds isolated from Prangos species have been tested.

Phytochemical investigations of the genus revealed that coumarins, flavonoids and terpenoids are the major components of the plants. Coumarin derivatives, including aglycones and glycosylated simple coumarins, aglycones and glycosylated linear and angular furocoumarins, and condensed furocoumarins are the main constituents of this genus. There are no quantitative data on the non-volatile secondary metabolites, and their occurrence in different plant parts has not been studied extensively. Different plant parts of this genus are fragrant and produce EO with remarkable yield. Monoterpene hydrocarbons, especially α- and β-pinenes, γ-terpinene, (E)-β-ocimene, and δ-3-carene have been identified as the major volatile oil components.

Since coumarins have a wide range of pharmacological effects (e.g. anti-neurodegenerative, antiviral, antimicrobial, antioxidant, antidiabetic, anti-inflammatory, and anticancer activities), the genus is a promising source of new bioactive compounds. However, considering the toxic effects of certain furocoumarins, including their cytotoxic and carcinogenic effects (Mullen et al. 1984), there is a need for further studies to support the safe use of Prangos species or their extracts. All the phytochemical studies reporting furocoumarins were preparative experiments and there are no quantitative data on the occurrence of furocoumarins in different species and plant parts. Moreover, the toxicological profiles of Prangos species is unknown, since no scientific studies focused on this aspect. The majority of the studies reported antimicrobial and antioxidant effects, and with one exception all the experiments were carried out in vitro.

Further pharmacological studies, including in vivo studies would be indispensable in determining and assessing the pharmacological potential of the isolated compounds and the species of the genus. The available experimental evidence does not support the rationale folk medicinal use of Prangos species. Although the antimicrobial activities may explain some of the uses, no human studies were carried out to assess efficacy and safety. The application as spice might be related to the essential oil and coumarin content of the species; however, the safety of these food is yet to be studied.