| Budget Amount *help |
¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1988: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1987: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Research Abstract |
To know the active forms of saikosaponin a (sa), saikosaponin c (sc) and saikosaponin d (sd) after the oral administration, metabolites in alimentary tract were derived from sa, sc and sd chemically and studied their pharmacological activities. Since th aglycones of sa, sc and sd have ether ring which is unstable in acidic conditions, alcoholic alkali metal degradation of hlycosidic bond was studied to get intestinal metabolites which have genuine aglycones. The conditions of the reaction were as follows; solvent: notmal butanol for spectra analysis, metal: Na (> 10 equivalent mole). temperature: 60-80 c. alkaline degradation gave intestinal metabloites which were obtained by the partial hydrolysis at a high yield, although its reaction mechanism is unknown except that the alkaline degradation was the indirect cleavage of glycosidic bond due to the degradation of terminal sugars. This possibility was explained by the inactivity of the permethylate of sa against the alcoholic alkali metal.
The corticosterone-secretion activities of 30 kinds of gastric and intestinal metabolites of sa, sc and sd were studied in vivo. Sd and its intestinal product, prosaikogenin G (PSG), showed a remarkable activity. The activity of sa and its intestinal product, prosaikogenin F (psF), which have -OH at C-16 (sd and psG have -OH at C-16) were weaker than that of sd and psG. The gastric products which have diene structure in aglycone by the by the cleavage of ether ring showed a little or no corticosterone-secretion activity. These activities were corresponded with their hemolytic activities and the adsorbability to the cell membrane to some extent.
Consequently, the polar valance between the sugar moiety (polar part) and the aglycone moiety (nonpolar part) should be important for their pharmacological activities.
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