Agric. Biol. Chem., 47 (2), 411 -412, 1983 Note 411 ether as fine needles (113mg), mp 111-113°C. Amax Shikonin /?,/J-Dimethylacrylate: A Componentof Alkanna h irsu tissima M. Afzal* and Nazar Muhammad (MeOH): conj. ester; 275, 483, 1642 olifinic Received June 28, 1982 The shikonin species (Boraginaceae) of plants have long been known as folklore remedies for a number of ailments. The extracts of these plants are described to contain a number of pigments including Shikonin (1) (5,8-di- hydroxy-2-( 1 -hydroxy-4-methyl-3-pentenyl)1 -4-naphthoquinone), and a number of its ester derivatives. OH r 0 OR ]T OH Jj I (2) R=COCH=C(CH3)2 (5.75), 271 (23.64), vmaxcm-1 1710, C=C; 1618, bonded C=O; 1610 (3.46), (2.13), intensity): 270 (1.27), 370 (30.98), 253 (M+, 0.08%), 272 269 (1.16), 256 (3.96), 255 252 (2.65), 251 (1.22), 237 (6.66), (4.33), 228 199 (3.59), (1.64), 227 189 (4.28), (1.31), 216 187 (2.24), 230 214 (1.01), (2.34), 229 204 (1.39), 181 (1.55), 171 (1.25), 165 (1.44), 153 (1.24), 152 (1.80), 137 (3.80), 136 (2.46), 135 (1.40), 128 (1.17), 121 (1.54), 119 (1.22), 108 (4.61), 100 (16.34), 83 (100.00). Ester hydrolysis of the pure compound with aqueous 27V-sodium hydroxide for 12 hours, followed by working up the reaction in the usual way resulted in Shikonin and /?,/?dimethylacrylic acid, identical with an authentic sample (IR; MS.). Thus the compound was characterized as Shikonin-/?,/?-dimethylacrylate (2). This product showed strong antibacterial properties and inhibited Sarcina lutea, Bacillus subtilis and Staphylococcus aureus. Shikonin-/?,/?- dimethylacrylate has been previously reported as a me- 0 tabolite Shikonin (1) has been shown to exhibit antiamoebic, antifungal, antibacterial and antitumor activities.1 ~4) It is also reported to stimulate peroxidase from horseradish5* and inhibit alkaline phosphatase activity.6* Shikonin esters are reported to be effective as antipyretic,9* antimicrobial,7'10* anti-inflamatory8) and antitumor4* agents. Crude extracts of plants containing shikonin esters are also effective in preventing acne, freckles and sunburn of the skin.11* These extracts are also effective in leg ulcers connected with varicosis, and improve wound healing12'13* having an epithelialization tendency.12* During our work on Boraginaceae, we have previously the isolation of deoxyshikonin and shikonin from Alkanna hirsutissima (Boraginaceae) * a wild plant collected near the Tigris river in Mosul, Iraq in April 1972.17) In this report, the isolation and characterization of another component, shikonin-/?,/?-dimeth- ylacrylate (2) and its biological activity is described. Powdered Alkanna hirsutissima (500 g) was Soxhlet ex- tracted with light petroleum ether (40~60°) until the extracts were colourless, and the extract was concentrated under vacuum to give a dark red viscous mass. The crude extract was chromatographed on acid-washed silica gel columns as described previously.17* Gradient elution of the columns with petroleum ether and toluene gave a pure product (TLC) (5.92), 254 of a number of plants ginaceae.10 reported angelate 560nm, Ar-C = C. NMR (CDC13) 6: 1.56, s, 3H, -CH3; 1.74, s, 3H, -CH3; 1.90, s, 3H, -CH3; 2.14, s, 3H, -CH3; 2.55, m, 2H, RO CH-CH2-; 5.10, s, 1H, -CH: CMe2; 5.74, m, 2H, >CH CH2-&-COCH=; 6.98, d (/=3.5Hz), 1H, quinone ring-H at C3; 7.1, s, 2H, Ar-H. MS m/z (relative Department of Biochemistry, Kuwait University, Kuwait 520, which crystallized from the petroleum belonging to Bora- ~ 16) Acknowledgment. A financial grant No. SBO10 from the Research Management Unit, Kuwait University to carry out these investigations, is thankfully acknowledged. REFERENCES 1) M. A. Rubinchik, Chem. Abst., 83, 671h (1975). 2) L. R. Shcherbanovskii, G. I. Nilov, Z. D. Rabinovich and V. A. Gorina, Rast. Reur, 8, 112 (1972); Chem. Abst., 76, 136281u 3) L. P. Sherbanivs'kii, Chem. Abst., (1972). Ukr. 76, 68687d Bot. Zh, 28, 504 (1971); (1972). 4) Y. Ebizuka, T. Miyazaki, Y. Isomura, H. Otsuka, S. Shibata, M. Inomata and F. Fukuoka, Chem. Phar. Bull., 25, 2392 (1977). 5) L. N. Blagonravova and L. R. Shcherbanovskii, Prikl. Biokhim. Mikrobiol, 10, 666 (1974); Chem. Abst., 82, 2782b (1975). 6) S. N. Gorge fs, S. N. H. Naqvi, L. J. Rashan and S. H. Zakaria, Folia Histochem. Cytochem., 16, 51 (1978). 7) K. Kyogoku, H. Terayama, Y. Tachi, T. Suzuki and M. Komatsu, Shoyakugaku Zasshi, 27, 31 (1973). 8) Z. B. Lin,B. L. Chai,P.Wang,Q.X.Guo,F. S. Lu * The plant was characterized by Professor S. Mushtaq Hussain of the Department of Botany, University of Mosul, Iraq, and a sample has been submitted in the herbarium of the Agriculture College, Mosul University, for inspection. 412 M. Afzal and N. Muhammad and G. Q. Xiang, Pao, 12, 101 (1980); Pei-Ching I Hsueh Yuan Hsueh Chem. Abst., 93, 143008q (1980). 14) Y. Tanaka, T. Odani and T. 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