RESUMO
Objective To find the microorganisms which hydrolyze sugar residues of steroidal saponins at C-3 position and to obtain their glucosyl-derivatives.Methods The enzymes secreted by fermentation of Curvularia lunata((3.438 1)) in the culture medium were employed to transform polyphyllin Ⅴ(compound Ⅰ) and polyphyllin Ⅵ(compound Ⅱ).The products were separated by means of chromatography on C_(18) column and their structures were elucidated on the basis of spectral analyses.Results Compounds Ⅰ and Ⅱ could be transformed by C.lunata((3.438 1)) and the main products were identified as diosgenin-3-O-?-D-glucopyranoside,named trillin(compound Ⅲ) and pennogenin-3-O-?-D-glucopyranoside(compound Ⅳ),respectively.Conclusion The terminal rhamnosyls of polyphyllin Ⅴ and polyphyllin Ⅵ at C-3 position could be hydrolyzed selectively by C.lunata((3.438 1)) for the first time.