Wentilactone B

3β,6β,17-Trihydroxy-13,14,15,16-tetranorlabda-7,9(11)-diene-12,19-dioic acid 12,17:19,6-dilactone

(3S)-1,2,3,3a,5aβ,7,10b,10cβ-Octahydro-3α-hydroxy-3aβ,10bα-dimethyl-4H,9H-furo[2',3',4':4,5]naphtho[2,1-c]pyran-4,9-dione