Recent studies on glycosides from plant drugs of Himalaya and south-western China: chemo- geographical correlation of Panax species

The geographical relationship of saponin composition of Panax species has been studied extensively. Close similarity in saponin composition was observed for the plants in Eastern Himalaya, South-western China and Southern Japan. The exeptional saponin compositions were found for some plants growing near the western and southern limits of the distribution as well as that in Japan Island. Comparison of the chemical constitents of Ginseng with crude drugs which are used as a Ginseng substitute, was also presented. Ginseng, the famous plant drug, has been used as an expensive traditional medicine in oriental countries for more than 5,000 years. Our group has elaborated the chemical investigation of secondray metabolites of Ginseng, isolating a number of tetracyclic dammarane saponins named ginsenosidesRa-h. [ref.1,2] These dammarane saponins are first isolated from Ginseng, being characteristic of Panax species. The pharmacological studies on Ginseng have been centered on these saponins, disclosing a variety of physiological activities for the major dammarane saponins. [ref.2] Recently, Dr.Kitagawa et al. reported the isolation of unstable acidic malonyl-ginsenosides-Rbl , -Rb2 , -Rc and -Rd from Ginseng in relatively high yields. [ref.3,4] Ginsenoside-Ro (=chikusetsusaponin-V) which is an acidic glucuronide sapnoin of oleanolic acid (pentacyclic oleanane triterpene), has been also isolated from Ginseng. [ref.1,2] It has been wellknown that saponins of oleanolic acid occur widely in a variety of plants, being not characteristic of Panax species. In the biosynthesis of triterpenes, dammaranes are formed in the early stage of the cyclization of 2,3-oxido-squaleneI while oleananes are the terminal products. A number of Panax species are growing in the Northern hemisphere from Central Himayalas onward through China and Japan to North America. I would like to propose the chemo-geographical correlation of Panax species, mainly based on the differnece in sapogenin, secondarily on the variation in structures of sugar moieties. Ginseng and American Ginseng C.A.Meyer (Araliaceae) which grows wild extending from North Eastern China, Korea to Far Eastern Siberia. It was revealed that the saponin compositions of Ginseng and psuinsuefolium L. (American Ginseng) are very similar from each other. [ref.l,4] Roots of both the plants contain a variety of dammarane saponins and one oleanolic acid glucuronide saponin, ginsenoside Ro. Recently, Dr.Lee and Dr.Marderosian disclosed that saponin composition of p. trifolius L. (Dwarf-Ginseng) in North America is also similar to those of Ginseng and American Ginseng. Panax species in Eastern Himalaya and south-western China The close relationship of plants growing between Eastern Himalaya, South-western China and Japan, has been pointed out by many botanists. A variety of plants growing in these area are originated from a common ancestor in the Early Tertiary and now widely separated in the respective regions. Several Panax species are growing in Eastern Himalaya and designated as ppseudo-ginseng and its subspecies by late Professor Hara. [ref.5] pThe source plant of Ginseng is Panax ginseng