ABSTRACT
Aims: The leaves of Gmelina arborea (ROXB.) (Family Verbenaceae) are widely used in the folklore to treat various types of diseases. In this study, the antioxidant and cytotoxic activities of different methanolic extracts and the derived subfractions of 90% methanolic extract of this plant were evaluated. Methodology: The antioxidant activity was carried out via three different quantitative assays as well as qualitative one. Total phenolic was determined via Folin-Ciocalteu and total flavonoid via AlCl3 assays. The cytotoxic activity was carried out via brine shrimp test and toward human cancer cell line; HepG2 using Sulphorhodamine-B assay. The 90% methanolic extract was fractionated using pet. ether then the 90% defatted methanol undergoes fractionation using (CHCl3, EtOAc and n-BuOH). Results: The antioxidant results showed that the; DPPH antioxidant activity was (19.20, 14.10 and 28.94 μg/ml); total antioxidant capacity was (412.69, 518.45 and 390.41; mg AAE /g extract); reducing power was (0.649, 0.715 and 0.396; 200 mg/ml) and total phenolic was (330.22, 400.66 and 244.76; mg GAE/g extract), respectively for 90% methanol, n-BuOH and EtOAc. The cytotoxic results showed that the; mortality of brine shrimp larvae (LC50) against different dosages of defatted 90% methanol, n-BuOH and EtOAc respectively was (158.48, 39.81 and 199.52; μg/ml) and the results of HepG2 assay showed that n-BuOH fractions have cytotoxic activity with IC50 ≤ 20 μg/ml (IC50 = 17.3 μg/ml) which falls within the American Cancer Institute criteria followed by 90% methanol and EtOAc (IC50 = 22.1 μg/ml). Conclusion: It was concluded that Gmelina arborea extracts possess a powerful antioxidant and cytotoxic activities.