Phytochemical investigation and radical scavenging activities of Melia azedarach and its DNA protective effect in cultured lymphocytes.

CONTEXT: Melia azedarach Linn (Meliaceae) is an Ayurvedic medicinal plant which is native to India. It is traditionally used for the treatment of leprosy, inflammation, scrofula, anthelmintic, antilithic, diuretic, deobstruent and cardiac disorders.

OBJECTIVE: To evaluate the phytochemical constituents and antioxidant activities of the ethanol leaf extract of Melia azedarach (MA) and its protective effect against H2O2-induced cellular damage in cultured lymphocytes.

MATERIALS AND METHODS: The dose-dependent study of MA (20, 40, 60, 80, 100 µg/ml) was used to study in vitro radical scavenging assays. The effective dose of MA (60 µg/ml) was further used to study the H2O2-induced DNA damage (comet assay and DNA fragmentation assay) in cultured lymphocytes.

RESULTS: The ethanol extract of MA (20, 40, 60, 80, 100 µg/ml) exhibited a significant dose-dependent inhibition of in vitro radical scavenging assays and their corresponding IC50 values as follows: hydroxyl radical (26.50 ± 0.26 µg/ml), superoxide anion (30.00 ± 0.32 µg/ml), nitric oxide radical (48.00 ± 0.48 µg/ml), DPPH radical (30.55 ± 0.32 µg/ml) and reducing power (22.00 ± 0.22 µg/ml). The increase in the severity of DNA damage and TBARS was increased significantly (p<0.05) at 500 µM H2O2-treated cultured lymphocytes and RBC cellular membranes. The phytochemical screening studies identified 13 chemical constituents present in the leaf extract of MA.

DISCUSSION AND CONCLUSION: The results of this study demonstrate that MA offers protection against H2O2-induced cellular damage and it can be developed as an effective antioxidant during oxidative stress.