One of the earliest recorded chemical investigations of a Panax species was published in 1854 when Rafinesque commented on a camphor-like substance named panacene which he had isolated from an extract of the root of the American ginseng P. quinquefolium L. In the same year Garriques reported the occurrence of panaquilon, a yellowish amorphous compound with the molecular formula C32HJ6O14 also obtained from the roots of P. quinquefolium. Panaquilon demonstrated typically glycosidal characteristics being soluble in water and alcohol and possessing a sweetish taste. On acid hydrolysis panaquilon yielded a water-insoluble substance which he called panacon.
Investigating Manchurian ginseng roots in a similar manner in 1889, the Russian chemist Davydow also recovered a glycoside resembling panaquilon. Early in the 20th century Japanese scientists commenced the investigation of Japanese and Korean ginsengs. Inoue in 1902 isolated a saponin glycoside from Japanese ginseng (chikusetsu ninjin) and three years later Fujitani published an account of the recovery of a relatively pure, white, crystalline compound also called panaquilon from extracts of Japanese and Korean ginseng roots. Further progress was achieved in 1906 when Asahini and Taguchi described a noncrystalline compound obtained from an alcoholic root extract; this compound was found to be a saponin hydrolysing into an aglycone or sapogenin and a glycone identified as glucose (Hou, 1978).
A decade later Professor Kondo's research team studied aqueous, methanolic and ethereal extracts of ginseng roots. The aqueous fraction yielded mucilage and inorganic compounds, the methanolic extract sucrose, some nitrogenous substances and a saponin glycoside, and the ether extract an oily material. Steam distillation of this oily fraction yielded two products, a light, yellowish volatile oil and a brown non-volatile residue. From the volatile oil the camphor-like panacene was recovered, and the non-volatile fraction contained phytosterol and fatty acids. Study of the saponin fraction, using 7 per cent alcoholic hydrochloric acid as the hydrolysing agent, produced two compounds, a crystalline panax-sapogenol and an amorphous panaxsapogenol. Closer investigation confirmed that the saponin glycoside had a molecular weight of 876 and comprised a molecule of panax-sapogenol linked to two molecules of glucose and one molecule of pentose. Kondo's team also observed that cultivated Japanese and Korean ginsengs produced similar chemical compounds (Kondo and Tanaka, 1915; Kondo and Yamaguchi, 1918; Kondo and Amano, 1920).
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