Saponins neutral

Y. Nagai, O. Tanaka, and S. Shibata, Chemical studies on the Oriental plant drugs — XXTV Structure of ginsenoside Rgj, a neutral saponin of ginseng root. Tetrahedron 27, 811, 1971. 

Jenkins, K.J. and Atwal, A.S. 1994. Effects of dietary saponins on fecal bile acids and neutral sterols, and availability of vitamins A and E in the chick. J. Nutr. Biochem. 5, 134-137. 

Acid hydrolysis of the saponin. The saponin (5mg)was refluxed with 5ml 5% HCl-MeOH on a steam bath for 6 hr. The product was diluted with HjO and extracted with CHCI3 in a separatory funnel, and therespective aglycones were sepd. The aq. Filtrate was neutralized... 

IiDA, Y., O. Tanaka, and S. Shibata Studies on Saponins of Ginseng The Structure of Ginsenoside-Rgi. Tetrahedron Letters 1968, 5449 Nagai (n ee Iida), Y., O. Tanaka, and S. Shibata Chemical Studies on the Oriental Plant Drugs XXIV. Structure of Ginsenoside-Rgi, a Neutral Saponin of Ginseng Roots. Tetrahedron 27, 881 (1971). 

Nabata, H., H. Saito, and K. Takagi Pharmacological Studies of Neutral Saponins (GNS) of Panax ginseng Root. Japan. J. Pharmacol. 23, 29 (1973). 

There seems little point in subdividing the triterpenes into classes according to polarity, as done with the 10 -derivatives. With a view to preliminary separation of the substances during isolation, a division into neutral and acid triterpene derivatives is to be recommended. The hydrophilic triterpene glycosides can then profitably be separated from these ( bitter principles and saponins ). 

Two classes are recognized, the so-called neutral saponins (digitalis saponins), which have as aglycons substances derived from cyclopentano-perhydrophenanthrene, and the acid saponins, which have as aglycons substances derived from triterpene. The aglycons are called sapogenins. Most of the investigations have been devoted to the determination of the structures of the neutral saponins. 

The formulas of a typical neutral saponin, sarsasaponin from Radix sarsaparillae 25), and the acid saponin of sugar beets Beta vulgaris), the glucuronide of oleanolic acid 26), are given. 

Saponins contribute to the characteristic taste of soybeans and other legumes. They are heat stable in the neutral pH range. Since a considerable portion of the saponins occurs in the seed coat and in the hypocotyl, the taste of soybean products, e. g., tofu, improves when these parts are removed. 

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