16,24-Cyclo-13,14-secoergosta-2,5-diene-18,26-dioic acid, 14,17:14,27-diepoxy-13,20,22-trihydroxy-1,15-dioxo-, gamma-lactone delta-lactone, (14alpha,16beta,22alpha,25S)- 23133-56-4 NSC-287088 Physalin B