J. Trop. Forest Prod., 5:32-38, 1999
Malaysian Tropical Forest Medicinal Plants: A Source of Natural Antioxidants
Vimala, S., Adenan, M.I.

A total of 70 samples of different plant parts from 45 species of Malaysian tropical forest medicinal plants was screened for antioxidant (free radical scavenging) activity against autoxidation (oxidation by direct combination with oxygen (such as air) at ordinary temperatures) of linoleic acid (an essential fatty acid which cannot be made in the body) in a water-alcohol system. The crude extracts were assayed, and some were found to exhibit potent antioxidant activity relative to a synthetic antioxidant. A total of 59 samples from 43 species exhibited high antioxidant activity (more than 90%), 9 showed moderate activity (50 to 90%) while 2 exhibited low activity (less than 50%). The antioxidant activity observed in this study indicates that many of the local tropical medicinal plants possess free radical scavenging compounds that form a natural defense mechanism against activated oxygen damage (free radical mediated damage in stress situations) in plants.