Physalins Possessing an Endoperoxy Structure from Physalis alkekengi var. francheti. Structural Revision of Physalin K

Physalin K was isolated from Physalis alkekengi var. francheti. Spectroscopic studies and chemical correlations, however, revealed that the reported structure of physalin K at the AB ring moiety, namely, 4α,5α-epoxy-6α-hydroxy-2-en-1-one, should be revised to 2α,5α-epidioxy-6β-hydroxy-3-en-1-one. A new physalin, named physalin Q, was also isolated and identified as the 2β,5β-epidioxy diastereomer of physalin K.