Steroidal constituents of Physalis minima(Solanaceae)

Abstract

Four new steroidal lactones have been isolated from the leaves of Physalis minima(Solanaceae), along with the known physalin B (1)(major constituent). 5β,6β-Epoxyphysalin B (2b) is a 16α,24-cyclo-13,14-seco-steroid whose structure was established by comparison with the 5α,6α- and 5β,6β-epoxy-derivatives (2a and 6) and obtained by epoxidation of physalin B (1). Withaphysalins A (3) and B (7a) belong to the withanolide group, the first containing an 18,20-lactone and the latter an 18,20-lactol ring. The structure of withaphysalin C, C₂₈H₃₆O₇, is still under investigation.