The genus Illicium belongs to the family Illiciaceae and is an evergreen shrub or tree. About 40 species have been disjunctively distributed in eastern North America, Mexico, the West Indies, and eastern Asia. The highest concentration of species is in northern Myanmar and southern China, where nearly 35 species have been described (Saunders, 1995). The genus is comparatively primitive and has close affinities with the Magnoliaceae. Therefore, Illicium was classified into the family Magnoliaceae in much of the early taxonomic literature (Torre et al., 1900) but was subsequently excluded from the Magnoliaceae by Smith on the basis of floral morphology and vegetative anatomy (Smith, 1947) and was assigned familial rank as the Illiciaceae.

The fruits of Illicium species are distinctive star-shaped follicles that emit a characteristic refreshing flavor. The fruits of I. verum Hook., in particular, are the source of the only economically important product derived from the genus: Chinese star anise, which is widely used as a spice for flavoring food and beverages. Hence, essential oils have been the primary subject of chemical research on Illicium species, and the presence of volatile phenols have been reported as constituents of various parts of all Illicium species so far studied. However, the fruits of I. anisatum, Japanese star anise, have been known to be very toxic for several centuries. Many researchers have been involved in the attempt to isolate the toxic substance since the struggle began in the middle of the nineteenth century. In 1952, Lane et al. succeeded in the isolation of the pure toxic principle named anisatin (Lane et al., 1952) for the first time, the complete structure of which was later established by Yamada and Hirata (Yamada et al., 1968). Since anistatin was first recognized as the unprecedented sesquiterpene dilactone containing an unusual P-lactone, several other members of the toxic Illicium species have also been the subject of chemical investigation mainly for the purpose of clarifying the relationship between structure and toxicity, resulting in the isolation of a number of unusual sesquiterpenes and neolignans. The chemical studies of Illicium have developed rapidly over the last 20 years as a result of more efficient methods of purification and of the use of modern spectroscopic techniques for structure elucidation.

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