A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid: a potent antioxidant agent from Iphiona scabra.

A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid 1 has been isolated from leaves of Iphiona scabra DC. Its structure has been established on the basis of chemical and physical evidence (IR, ¹H NMR, ¹³C NMR, and MS) and further confirmed by single-crystal X-ray diffraction study. The in vitro antioxidant activities of isolated compound 1 and extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl method.