Researchers have known that free radical-mediated neurodegenerative diseases can be prevented through the consumption of food rich in antioxidants. Researchers have shown that aqueous extracts of ripe and unripe Capsicum annum, Tepin (CAT) and Capsicum chinese, Habanero (CCH) can prevent lipid peroxidation induced by sodium nitroprusside and quinolinic acid in rat brain in vitro.  In fact, unripe CAT caused the highest inhibition of sodium nitroprusside-induced lipid peroxidation, while unripe CCH caused the least inhibition. The unripe CAT and CCH peppers had a significantly higher inhibitory effect on quinolinic acid-induced lipid peroxidation in rat brain than the ripe pepper (CAT and CCH). They concluded that the protection of the brain tissues by hot pepper depends on the total phenol content in sodium nitroprusside-nduced ipid peroxidation and that ripening would reduce the protective properties of hot pepper against quinolinic acid-induced lipid peroxidation.

Ref: Journal of Medicinal Food 11.2 (June 2008): p349(7)