Figure 1.Basic skeleton of withanolides. Withaferin A R1 = OH, R2 = H, R3 = H; Withaferin D R1 = H, R2 = OH, R3 = H; 27-Deoxywithaferin A R1 = H, R2 = H, R3 = H; 27-hydroxywithanolide D R1 = OH, R2 = OH, R3 = H; Dihydrodeoxywithaferin A R1 = H, R2 = H, R3 = H; Dihydrowithaferin A R1 = H, R2 = OH, 17-hydroxywithaferin A, R1 = R3 = OH, R2 = H.
