Antioxidant activity of a new capsaicin derivative from Capsicum annuum.

A new capsaicin derivative, 6' ',7' '-dihydro-5',5' "-dicapsaicin (1), and a known capsaicin metabolite, omega-hydroxycapsaicin (2),(1) were isolated from the fruit of Capsicum annuum. Their structures were established on the basis of spectroscopic evidence. Compound 1 showed almost the same antioxidant activity as capsaicin, but did not have a pungent taste.