STEROIDAL GLYCOSIDES IN PLANTS AND CELL-CULTURES OF DIOSCOREA (A REVIEW)

Five new steroid glycosides, deltonin, deltoside, diosgenin-3-O-beta-D-glucopyranozyl-(1-->4)-beta-D-glucopyranoside, glucosidodeltonin, and 4''-O-(3-hydroxy-3-methylglutaryl)dioscin acidic acylated, glycoside called deltofolin were isolated from Dioscorea deltoidea Wall. and D. caucasica Lipsky and then characterized. Oligofurostanosides deltonin (a glycoside from the rhizome) and protodioscin (a glycoside from the leaves) were extracted from a suspension culture of D. deltoidea cells, Institute of Plant Physiology (IPP) strain, DM-0.5. Protodeltofolin is produced in the leaves by acylating protodioscin with 3-hydroxy-3-methylglutaric acid. Prototriosides are synthesized in the cells through an intermediate stage of a protobioside. Oligofurostanoside-specific beta-glucosidase, which catalyzes the transformation into oligospirostanosides, was detected in the leaves and rhizomes of D. deltoidea for the first time. The rhizomes and cell culture of D. deltoidea can be used as a source of diosgenin and biologically active steroid glycosides.