ABSTRACT

Oxidative stress is caused by an imbalance between oxidants and antioxidants. Overwhelming evidence indicates that oxidative stress can lead to cell and tissue injury. However the same free radicals that are generated during oxidative stress are produced during normal metabolism and as well involved in both human health and disease. Plants however have been assayed to be a rich source of antioxidants. This study evaluated the antioxidant components (total phenolic, flavonoid, 13- carotene, lycopene and Ascorbic acid) and in vitro antioxidant activities of the methanol extract of Senna alata and Asystasia gangetica respectively. The antioxidant activity was determined using DPPH, FRAP, Nitric oxide scavenging activity respectively. The results from the study showed that the methanol extract of Senna alata and Asystasia gangetica possessed low antioxidant components lycopene, Ascorbic acid and f3-carotene, however both leaves possessed high phenolic (172.1 ± 3.97 and 186.9 ± 4.73mg1g) and flavonoid (2303.64 + 30.6 and 1051.56±18mg/bOg) contents respectively. The ferric reducing antioxidant power (FRAP) of the two extracts at low concentrations was observed to be high. Furthermore there was a dose dependent increase in the percentage inhibition of 2,2-Diphenyl- 1-picrylhydrazyl radical (DPPH) and percentage nitric oxide scavenging activity of the two extracts respectively. Antioxidant component present in methanol extract of Senna alata and Asystasia gangetica leaves respectively enables them to effectively scavenge the free radicals generated from various sources and hence can be used in the treatment and management of various health condition associated with free radical generation. Furthermore, it also suggests that proper screening of the bioactive components of these extracts is recommended to further project the antioxidant activities of the extract.