Fissisternoids A and B, two 2′,5′-quinodihydrochalcone-based meroterpenoid enantiomers with unusual carbon skeletons from Fissistigma bracteolatum

Compound 1 represents an unprecedented meroterpenoid featuring a unique tricyclo [3,3,1,0 1′,5′ ] decane central framework and 2 possesses a rare 6/6/5/4 tetracyclic carbon skeleton were isolated from Fissistigma bracteolatum.