Abstract:
Plants possess a self-defense mechanism to counteract the oxidative stress that
caused by the accumulation of reactive oxygen species (ROS). In plant, antioxidant
composed of enzymatic and non-enzymatic antioxidants. Enzymatic antioxidant includes
ascorbate peroxidase (APx), catalase (CAT), guaiacol peroxidase (G-POD) and
superoxide dismutase (SOD) while the non-enzymatic antioxidant comprise of ascorbic
acid, a-tocopherol, carotenoid and flavonoid. Stenochlaena palustris (paku midin) is a
type of fems that widely distributed in Malaysia. Objectives of this study are to determine
and compare the level of antioxidative compounds in S. palustris at different leaf stages,
i.e. stage 1 (frond), stage 2 Guvenile leaf), stage 3 (matured leaf). The antioxidant assayed
includes APx, CAT and G-POD specific activity as well as ascorbic acid, a-tocopherol
and carotenoid content. Among the three stages, juvenile leaf contained the highest
specific activities of APx and CAT as well as a-tocopherol and carotenoid content. On
the other hand, matured leaf exhibited highest specific activity of POD and ascorbic acid
concentration. The results suggest that juvenile leaf is a good source of dietary
antioxidants due to high concentrations of antioxidants compared to other stages.
