On The Toxic Of Illicium Anisatum. The Isolation And Characterization Of A Convulsant Principle Anisatin

FIGURE 4.22 Pseudomajucin-type sesquiterpenes (compounds 148-149)

responsible for the convulsive toxicity. We have to wait for further investigation to prove this kind of problem associated with the relationship between the structure and the toxicity in the Illicium sesquiterpenes.

4.5 DITERPENES AND TRITERPENES

In contrast to the relatively wide distribution of anisatin-like sesquiterpenes in the genus Illicium, few reports concerning about diterpenes and triterpenes have been documented. Two Chinese groups have reported the occurrence of abietane diterpenes in Illicium plants. 4-epi-Isopimaricacid (158), oh ho oh oh ho oh

oh

150 151

FIGURE 4.23 Cycloparvifloralone-type sesquiterpenes (compounds 150-152)

O

,10

1

JS

9 13

12 O

v8 16

HO 13 157

156 R1 = R2 = H, R3 = OH 156a R1 = R2 = p-BrBz, R3 = OH

HO 13 157

FIGURE 4.24 New carbon skeletal sesquiterpenes (compounds 153-157)

15-hydroxydehydroabietic acid (159), and 8,11,13,15- abietatetran-19-oic acid (160) were isolated from the bark of I. jiadifengpi, which is indigenous to China (Huang et al., 1996). Eleven novel diterpenes (161-164, 166-170, and 172-174) and two known abietane diterpenes (165, 171) were found from the aerial part of I. angustisepalum (Sy and Brown, 1998) (Figure 4.25), but angustanoic acid E, reported as a new compound in this chapter, has to be the known diterpene 160. Sy and Brown (1998) emphasized that these abietane diterpenes are unusual in the points such that they are oxygenated at the axial C-19 methyl rather than at the equatorial C-18 methyl group. The same type of diterpenes found in I. jiadifengpi and I. angustisepalum seem to serve as a chemical proof supporting the closely taxonomic relationship between these two species, as both species have been taxonomically arguable.

Although triterpenes are widely distributed in nature, there are very few reports on the triter-penes found in Illicium plants. New seco-cycloartane triterpenes 175 was isolated together with the previously known schizandronic acid (176), schizandrolic acid (177), and magniferolic acid

(178) from I. dunnianum (Zhang, 1989; Sy et al., 1997). In addition to 178, magniferonic acid

(179), betulic acid (180), and a new cycloartane triterpene, 3-O-acetylmagniferolic acid (181) was obtained from the bark of I. difengpi (Huang et al., 1997) (Figure 4.26). Sy et al. (1997) suggested that these cycloartane-type triterpenes might become one of the phytochemical markers characteristic of the Illicium species.

QH b

QH b

QH

118a

118a

OH OH

SCHEME 4.9 Two plausible mechanisms for the base-catalyzed transformation of pseudoanisatin (118) to 118a

OH OH

SCHEME 4.9 Two plausible mechanisms for the base-catalyzed transformation of pseudoanisatin (118) to 118a

4.6 FLAVONOIDS AND TANNINS

The common flavonols widely occurring in the plant kingdom were also detected in the fruits of I. verum (Knacksted and Herrmann, 1981). They are kaempferol (182), and its glycosides 183-185, and quercetin (186), and its glycosides (187-191), as shown in Figure 4.27.

In addition to the flavonoids, the occurrence of tannins had been suggested in I. anisatum because of the astringency of its bark. In fact, (+)-catechin (192) was detected in I. anisatum (Morimoto et al., 1988) and I. henryi (Xie et al., 1990). Morimoto et al. (1988) investigated the polar parts of the bark of I. anisatum, resulting in the isolation of two new prenylated catechins (193) and (194) and a new trimeric procyanidin (195), along with procyanidins B-1 (196) and B-7 (197), epicatechin-(4p ^ 8)-epicatechin-(4p ^ 8)-catechin (198), epicatechin-(4p ^ 8)-epi-cathechin-(4p ^ 6)-catechin (199), and epicatechin-(4p ^ 6)-catechin-(4p ^ 8)-catechin (200) (Kashiwada et al., 1986) (Figure 4.28 and Figure 4.29). In contrast to the relatively wide distribution of prenylated flavones, prenylated catechins (193) and (194) are not often found and thus seem to be components characteristic of the Illicium plants.

Anisatin (107)

Anisatin (107)

Acorane

cis, trans-Farnesol PP

r2o ho

r2o ho

HO HO Pseudoanisatin (118)

Illicium Anisatum Images

Acorane

och3

Illicinolide A (155) and B (156)

SCHEME 4.10 Plausible biosynthesis for illicinolides A (155) and B (156), and tashironin (157)

162 R1, R2 = O

FIGURE 4.25 Diterpenes (Compounds 158-174)

CH3O2C

CH3O2C

COOH

FIGURE 4.26 Triterpenes (compounds 175-181)

FIGURE 4.26 Triterpenes (compounds 175-181)

OH O

OH O

OH O

OH O

183 R = 6-O-a-L-rhamnosyl-D-glucosyl

184 R = D-glucosyl

185 R = D-glactosyl

187 R = 6-O-a-L-rhamnosyl-D-glucosyl

188 R = D-glucosyl

189 R = D-glactosyl

190 R = D-xylosyl

191 R = L-rhamnosyl

FIGURE 4.27 Flavonoids 182 and 186 and their glycosides

Flava Lignan Glycoside

OH OH

FIGURE 4.29 Tannins 131 and 132 isolated from I. anisatum

Magniferonic Acid
OH

TABLE 4.1

Lethality Induced by Illicium Sesquiterpenes

Sesquiterpenes LD50 (mg/kg)

Anisatin (107) 1.03a

Neoanisatin (108) 1.62a

Majucin (137) >40a

Neomajucin (138) 12.2a

Pseudoanisatin (118) >100

Minwanensin (133) >50

2-oxo-6-dehydroxyneoanisatin (115) 1.46

(2S*)-hydroxyneomajucin (139) >40

2-oxoneomajucin (142) >40

(2R*)-hydroxy-3,4-dehydroneomajucin (144) >40

107a 180

107b Nontoxic

107c Nontoxic a Litchfield-Wilcoxon method.

References

Barton, D.H., Bhati, A., Mayo, P.D., and Morrison, G.A., The constitution and synthesis of anisoxide, J. Chem. Soc., 4393-4398, 1958.

Devon, T.K. and Scott, I.A., Handbook of Naturally Occurring Compounds, Vol. II, Terpenes, Academic Press, New York, 1972, p. 56.

Dictionary of Natural Products on CD-ROM, version 4.2, Chapman and Hall, London, 1996.

Fukuyama, Y., Okamoto, K., Kubo, Y., Shida, N., and Kodama, M., New chlorine-containing prenylated C6-C3 compounds increasing choline acetyltransferase (ChAT) activity in culture of postnatal rat spetal neurons from Illicium tashiroi, Chem. Pharm. Bull., 42, 2199-2201, 1994a.

Fukuyama, Y., Shida, N., Hata, Y., Anzaki, S., and Kodama, M., Prenylated C6-C3 compounds related to illicinone E from Illicium tashiroi, Phytochemistry, 37, 1653-1657, 1994b.

Fukuyama, Y., Shida, N., Hata, Y., and Kodama, M., Prenylated C6-C3 compounds from Illicium tashiroi, Phytochemistry, 36, 1497-1503, 1994c.

Fukuyama, Y., Shida, N., and Kodama, M., Structure of illicinolide A, a novel sesquiterpene lactone from the bark of Illicium tashiroi, Tetrahedron Lett., 31, 5621-5622, 1990.

Fukuyama, Y., Shida, N., and Kodama, M., Isodunnianin: a new sesquiterpene enhancing neurite outgrowth in primary culture of fetal rat cerebral hemisphere from Illicium tashiroi, Planta Med., 59, 181-182, 1993.

Fukuyama, Y., Shida, N., and Kodama, M., Tashironin, a plausible biosynthetic precursor of anisatin-type sesquiterpens, Tetrahedron Lett., 36, 583-586, 1995a.

Fukuyama, Y., Hata, Y., and Kodama, M., Bicycloilliocinone asarone acetal: a novel prenylated C6-C3 compound increasing choline acetytransferase (ChAT) activity from Illicium tashiroi, Planta Med., 63, 2199-2201, 1997.

Fukuyama, Y., Shida, N., Kodama, M., Chaki, H., and Yugami, T., Tricycloillicinone, a novel prenylated C6-C3 compound increasing choline acetyltransferase (ChAT) activity, isolated from Illicium tashiroi, Chem. Pharm. Bull., 43, 2270-2272, 1995b.

Fukuyama, Y., Shida, N., Kodama, M., Kido, M., Nagasawa, M., and Sugawara, M., Illicinolides A and B, novel sesquiterpene lactones from the wood of Illicium tashiroi, Tetrahedron, 48, 5847-5854, 1992a.

Fukuyama, Y., Shida, N., Sakurai, T., and Kodama, M., Prenylated C6-C3 compounds from Illicium tashiroi, Phytochemistry, 31, 3975-3979, 1992b.

Furita, T.E. and Bellanca, N., Eds., Fenaroli's Handbook of Flavor Ingredients, 2nd ed., Vols. 1 and 2, CRC Press, Cleveland, OH, 1975.

Hano, Y., Kaku, H., and Nomura, T., The 112th Annual Meeting of Pharmaceutical Society of Japan, Fukuoka, abstract no. 2, 1992, p. 200.

Hatanaka, H., Tsukui, H., and Nihonmatsu, I., Developmental change in the nerve growth factor action from induction of choline acetyltransferase to promotion of cell survival in cultured basal forebrain cho-linergic neurons from postnatal rats, Dev. Brain Res., 39, 85-95, 1988.

Harada, N. and Nakanishi, K. Circular Dichroic Spectroscopy—Exciton Coupling in Organic Stereochemistry, University Science Books, New York, 1982.

Huang, J.-M., Wang J.-L., and Yang C.-S., Sesquiterpene lactones from the pericarp of Illicium dunnianum, Phytochemistry, 46, 777-780, 1997.

Huang, J.-M. and Yang C.-S. Pseudoanisatin-like sesquiterpene lactones from the pericarps of I. dunnianum. Phytochemistry, 42, 1375-1376, 1996.

Huang, J.-M., Yang, C.-S., Wang, H., Wu, Q.-M., Wang, J.-H., and Fukuyama, Y., Structures of novel sesquiterpenes from the pericarps of Illicium merrillianum, Chem. Pharm. Bull., 47, 1749-1752, 1999.

Huang, P., Xuezhong, Z., Mighi, H., and Nakanishi, T., Chemical studies on the bark of Illicium jiadifengipi, Zhongguo Zhongyao Zazhi, 21, 551-553, 1996a.

Huang, P., Yang, M., Lai, M.-X., Zheng, X.-Z., Nishi, M., and Nakanishi, T., Chemical studies on the barks of Illicium difengpi, Zhongguo Yaoxae Zazhi, 31, 278-281, 1996b.

Huang, P., Nishi, M., Zheng, X.-Z., Lai, M.-X., and Nakanishi, T., Triterpenoid acids from Illicium difengpi, Zhongguo Yaoxae Zazhi, 32, 704-707, 1997.

Hussain, R.A., Poveda, L.J., Pezzuto, J.M., Soejarto, D.D., and Kinghorn, A.D., Sweeting agents of plant origin: phenylpropanoid constituents of seven sweet-tasting plants, Econ. Bot., 44, 174-182, 1990.

Jackson, R.W. and Short, W.F., Anisol. Part I, J. Chem. Soc., 513, 1937.

Jiang, Z.-H., Tanaka, T., and Kouno, I., New phenylpropanoid glucosides from the fruits of Illicium anisatum, Chem. Pharm. Bull., 47, 421-422, 1999.

Kajimoto, Y., Fujimori, H., and Hirota, K., Study on the toxic components of "Sikimi." I. Chemical study, Tokushima J. Exp. Med., 2, 104-107, 1955a.

Kajimoto, Y., Fujimori, H., and Hirota, K., Study on the toxic components of "Sikimi." II. Chemical study, Tokushima J. Exp. Med., 2, 108-110, 1955b.

Kaku, H., Hano, Y., and Nomura, T., The 113th Annual Meeting of Pharmaceutical Society of Japan, Osaka, abstract no. 2, p. 216, 1993.

Kashiwada, Y., Nonaka, G., and Nishioka, I., Tannins and related compounds. XLVIII. Rhuharb. 7. Isolation and characterization of new dimeric and trimaric procyanidins, Chem. Pharm. Bull., 34, 4083-4091, 1986.

Kawano, N. and Matsuo, A., Studies on the toxic components of Illicium anisatum L. I, Yakugakuzasshi, 78, 1220-1223, 1958.

Kende, A.S. and Chen, J., Stereoselective total synthesis of 8-deoxyanisatin, J. Am. Chem. Soc., 107, 7184-7186, 1985.

Knackstedt, J. and Herrmann, K., Flavonol glycosides of bay leaves (Laurus nobilis L.) and star anise fruits (Illicium verum Hook. fil.), Z. Lebenm. Unters. Forsch, 173, 288-290, 1981.

Kouno, I., Akiyama, T., and Kawano, N., Minor constituents from the seeds of Japanese star-anise, Chem. Pharm. Bull., 36, 2990-2992, 1988.

Kouno, I., Baba, N., Hashimoto, M., Kawano, N., Takahashi, M., Kaneto, H., Yang, C.-S., and Sato, S., Isolation of three new sesquiterpene lactones from the pericarps of Illicium majus, Chem. Pharm. Bull., 37, 2448-2451, 1989a.

Kouno, I., Baba, N., Hashimoto, M., Kawano, N., Yang, C.-S., and Sato, Y., A new sesquiterpene lactone and its glucoside from the pericarps of Illicium majus, Chem. Pharm. Bull., 39, 1773-1778, 1989b.

Kouno, I., Baba, N., Hashimoto, M., Kawano, N., Takahashi, M., Kaneto, H., and Yang, C.-S., Sesquiterpene lactones from the pericarps of Illicium majus; 2-oxy derivatives of neomajucin and 3,4-dehydroxy-neomajucin, Chem. Pharm. Bull., 38, 422-425, 1990.

Kouno, I., Hashimoto, M., Enjoji, S., Takahashi, M., Kaneto, H., and Yang, C.-S., Isolation of neoanisatin derivatives from the pericarps of Illicium majus with other constituents, Chem. Pharm. Bull., 39, 1773-1778, 1991a.

Kouno, I., Hashimoto, A., Kawano, N., and Yang, C.-S., New sesquineolignan from the pericarps of Illicium macranthum, Chem. Pharm. Bull., 37, 1291-1292, 1989c.

Kouno, I., Irie, H., and Kawano, N., The structure of pseudoanisatin and its novel base-catalysed rearrangement product, J. Chem. Soc. Perkin Trans. I, 2511-2515, 1984.

Kouno, I., Irie, H., Kawano, N., and Katsube, Y., The revised structure of pseudoanistatin by x-ray crystal structure determination, Tetrahedron Lett., 24, 771-772, 1983.

Kouno, I., Iwamoto, C., Kameda, Y., Tanaka, T., and Yang C.-S., A new triphenyl-type neolignan and a biphenylneolignan from the bark of Illicium simonsii, Chem. Pharm. Bull., 42, 112-114, 1994.

Kouno, I. and Kawano, N., New pseudoanisatin-like sesquiterpene lactones from the bark of Illicium dunni-anum, J. Chem. Soc. Perkin Trans. I, 1537-1539, 1988.

Kouno, I., Mori, K., Akiyama, T., and Hashimoto, M., Two sesquiterpene lactones from Illicium anisatum, Phytochemistry, 30, 351-353, 1991b.

Kouno, I., Mori, K., Kawano, N., and Sato, S., Structure of anislactone A; a new skeletal type of sesquiterpene from the pericarps of Illicium anisatum, Tetrahedron Lett., 30, 7451-7452, 1989d.

Kouno, I., Mori, K., Okamoto, S., and Sato, S., Structure of anislactones A and B; novel type of sesquiterpene lactones from the pericarps of Illicium anisatum, Chem. Pharm. Bull., 38, 3060-3063, 1990.

Kouno, I., Morisaka, T., Hara, Y., and Yang, C.-S., Two new sesquineolignans from the bark of Illicium dunnianum, Chem. Pharm. Bull., 39, 2606-2608, 1991c.

Kouno, I., Shimamoto, S., Jiang, Z.-H., and Tanaka, T., Prenylated C6-C3 compounds from root bark of Illicium anisatum, Phytochemistry, 46, 1389-1392, 1997.

Kouno, I., Yanagida, Y., Shimamoto, S., Shintomo, M., Ito, Y., and Yang C.-S., Neolignans and a phenylpropanoid glucoside from Illicium difengpi, Phytochemistry, 32, 1573-1577, 1993.

Kouno, I., Yanagida, Y., Shimamoto, S., Shintomo, M., and Yang, C.-S., Phenylpropanoids from the barks of Illicium difengpi, Chem. Pharm. Bull., 40, 2461-2464, 1992.

Kudo, Y., Oka, J., and Yamada, K., Anisatin, a potent GABA antagonist, isolated from Illicium anisatum, Neurosci. Lett., 25, 83-88, 1981.

Lane, J.F., Koch, W.T., Leeds, N.S., and Gorin, G., On the toxin of Illicium anisatum. I. The isolation and characterization of a convulsant principle: Anisatin, J. Am. Chem. Soc., 74, 3211-3214, 1952.

Liu, H. and Yang, C.-S., Component analysis of essential oils from the fruits of seven species of Illicium (Illiciaceae) in China, Acta Phytotaxon. Sinica, 27, 317-320, 1989.

Lindner, D.L., Doherty, J.B., Shoham, G., and Woodward, R.B., Intermolecular ene reaction of glyoxylate esters: an anisatin model study, Tetrahedron Lett., 23, 5111-5114, 1982.

Luche, J.-L., Lanthanides in organic chemistry. 1. Selective 1,2 reductions of conjugated ketones, J. Am. Chem. Soc., 100, 2226-2227, 1978.

Miyazawa, M., Ota, H., Ishikawa, Y., and Kameoka, H., An insecticidal compound from Illicium vernum, Chem. Express., 8, 437-490, 1993.

Morimoto, S., Tanabe, H., Nonaka, G., and Nishioka, I., Prenylated flavan-3-ols and procyanidins from Illicium anisatum, Phytochemistry, 27, 907-910, 1988.

Nakamura, T., Okuyama, E., and Yamazaki, M., Neurotropic compounds from star anise, Chem. Pharm. Bull., 44, 1908-1914, 1996.

Niwa, H., Ito, S., Wakamatus, K., Mori, T., and Yamada, K., Synthesis of (-)-noranisatin, an oxidation product of neurotoxic sesquiterpene anisatin having a novel spiro P-lactone, Tetrahedron Lett., 32, 1329-1330, 1991.

Niwa, H., Nishiwaki, M., Tsukada, I., Ishigaki, T., Ito, S., Wakamatsu, K., Mori, T., Ikagawa, M., and Yamada, K., Stereocontrolled total synthesis of (-)-anisatin: a neurotoxic sesquiterpenoid possessing a novel spiro P-lactone, J. Am. Chem. Soc., 112, 9001-9003, 1990.

Niwa, H. and Yamada, K., Synthesis of plant neurotoxin, anisatin, Pharmacia, 27, 924-927, 1991.

Okely, H.M. and Grundon, M.F., Anisoxide: an artifact from star anise oil formed by Claisen rearrangement, Chem. Commun., 1157-1158, 1971.

Okely, H.M. and Grundon, M.F., Thermal rearrangement of 1-(3-methylbut-2-enyloxy)-4-prop-1-enyl-benzene (Feniculin): a new synthesis of anisoxide and re-investigation of the constituents of star anise oil, J. Chem. Soc. Perkin I, 897-899, 1981.

Okigawa, M. and Kawano, N., The structure of pseudoanisatin, Tetrahedron Lett., 75-78, 1971.

Okuyama, E., Nakamura, T., and Yamazaki, M., Convulsants from star anise (Illicium vernum Hook. f.), Chem. Pharm. Bull., 41, 1670-1671, 1993.

Saunders, R.M.K., Systematics of the genus Illicium L. (Illiciaceae) in Meleasia, Bot. J. Linn. Soc., 117, 333-352, 1995.

Sakabe, N., Hirata, Y., Furusaki, A., Tomiie, Y., and Nitta, I., X-ray structure determination of bromonorani-satinone, a derivative of anisatin, Tetrahedron Lett., 4795-4796, 1965.

Schmidt, T.J., Novel seco-prezizaane sesquiterpene from North American Illicium species, J. Nat. Prod., 62, 684-687, 1999.

Schmidt, T.J. and Peters, W., Revision of the structure of dunnianin and related sesquiterpene lactone from Illicium species, J. Nat. Prod, 60, 783-787, 1997.

Schmidt, T.J., Schmidt, H.M., Muller, E., and Peters, W., New sesquiterpene lactones from Illicium floridanum, J. Nat. Prod., 61, 230-236, 1998.

Shibuya, M., Abe, K., Nakahashi, Y., and Kubota, S., Phenolic components from leaf oil of Illicium anisatum L, Chem. Pharm. Bull., 26, 2671-2673, 1978.

Smith, A.C., The families Illiciaceae Schisandraceae, Sargentia, 7, 1-224, 1947.

Sy, L.-K. and Brown, G. D., A sesquilignan from Illicium dunnianum, Phytochemistry, 45, 1417-1419, 1996.

Sy, L.-K. and Brown, G.D., Abietane diterpenes from Illicium angustisepalum, J. Nat. Prod., 61, 907-912, 1998a.

Sy, L.-K. and Brown, G.D., Novel pheylpropanoids and lignans from Illicium verum, J. Nat. Prod, 61, 987-992, 1998b.

Sy, L.-K. and Brown, G.D., A prezizaane sesquiterpene from Illicium angustisepalum, Phytochemistry, 49, 1715-1717, 1998c.

Sy, L.-K., Saunders, R.M.K., and Brown, G.D., Phytochemistry of Illicium dunnianum and the systematic position of the Illiciaceae, Phytochemistry, 44, 1099-1108, 1997.

Tanaka, T., Ueda, K., Kawojiri, M., Yamasa, H., and Kouno, I., The chemical constituents of the leaf of Illicium anisatum, The 118th Annual Meeting of Pharmaceutical Society of Japan, Kyoto, Abstract No. 2, 1998, p. 153.

Theander, O., Lundgren, L.N., and Shen, Z., The constituents of conifer needles. Dilignol glycosides from Pinus massoniena Lamb., Acta Chem. Scan. Ser. B, 39, 241, 1985.

Tomita, B. and Hirose, Y., A//o-Cedrol: a new tricarbocyclic sesquiterpene alcohol, Phytochemistry, 12, 1409-1414, 1973.

de Torre, D.C.G. and Harms, H., Genera Siphonogamarum ad Systema Eng/erianum Conscripta, Wilhelm Engelmann, Leipzig, 1900.

Wang, J.-L., Yang, C.-S., Yan, R.-N., Yao, B., and Yang, X.-B., Study on the chemical constituents of the fruits of I/licium minwanense, Zhongguo Yaoxue Zazhi, 29, 693-696, 1994.

Wong, M.G., Gulbis, J.M., Mackay, M.F., Crail, D.J., and Andrews, P.R., Anisatin: a crystallographic, N.M.R. and theoretical conformation study, Aust. J. Chem., 41, 1071-1086, 1988.

Xie, D.-L., Wang, S., Cheng, Z.-W., Song, Y.-S., and Kong, D.-Y., Chemical constituents of the root-cortex of I/licium henryi, Zhong Caoya., 21, 447-449, 1990.

Yakushijin, K., Furukawa, H., and McPhall, A.T., Studies on the constituents of the plants of I//icium species. IV. Thermal and photochemical reactions of illicinone A, a novel phytoquinoid from I//icium plants, Chem. Pharm. Bu//., 32, 23-30, 1984a.

Yakushijin, K., Sekikawa, J., Suzuki, R., Morishita, Furukawa, H., and Murata, H., Novel phytoquinoids from I//icium tashiroi MAXIM, Chem. Pharm. Bu//., 28, 1951-1954, 1980.

Yakushijin, K., Tohshima, Kitagawa, E., Suzuki, R., Sekikawa, J., Morishita, T., and Furukawa, H., Studies on the constituents of the plants of I//icium species. III. structure elucidations of novel phytoquinoids, illicinones and illifunones from I//icium tashiroi MAXIM. and I. arborescens HATAYA, Chem. Pharm. Bu//., 32, 11-22, 1984b.

Yakushijin, K., Tohshima, T., Suzuki, R., Murata, H., Lu, S.-T., and Furukawa, H., Studies on the constituents of the plants of I//icium species. II. Structures of phenolic components, Chem. Pharm. Bu//., 31, 2879-2983, 1983.

Yamada, T., Takada, S., Nakamura, S., and Hirata, Y., The structure of noranisatin, an oxidation product of anisatin. Tetrahedron Lett., 4785-4794, 1965.

Yamada, K., Takada, S., Nakamura, S., and Hirata, Y., The structure of anisatin and neoanisatin, toxic sesquiterpenes from I//icium anisatum L., Tetrahedron, 24, 199-229, 1968.

Yang, C.-S., Hashimoto, M., Baba, N., Takahashi, M., Kaneto, H., Kouno, I., and Kawano, N., A new toxic neoanisatin derivative from the pericarps of I//icium majus, Chem. Pharm. Bu//., 38, 291-292, 1990.

Yang, C.-S., Kouno, I., Kawano, N., and Sato, S., New anisatin-like sesquiterpene lactones from pericarps of I//icium majus, Tetrahedron Lett., 29, 1165-1168, 1988.

Yang C.-S., Liu, H., and Wu, X.-G., GC-MS analysis of essential oils of the fruits of I//icium plants in China, Zhongguo Yaoxue Zazhi, 27, 206-209, 1992.

Zhang, J., Chemical constituents of the stems and leaves of I//icium dunnianum, Zhonngguo Zhongyao Zazhi, 14, 36-37, 1989.

0 0

Responses

  • William
    What is magniferonic acid?
    6 years ago

Post a comment