Butea monosperma (Lam.) Taub. is an ethnomedicinal tree of remedial value in the treatment of diabetes, bone fractures, and liver and neurological disorders. However, the information available on DNA-protective and anti-proliferative potential of bark of this tree is scarce. In the present study, the extract/fractions obtained from bark of B. monosperma were evaluated for antioxidant, DNA-protective, and anti-proliferative activities, along with their phytochemical profiling for identifying major constituents present in them. Different extract/fractions, namely, Bmth (methanol), Bhex (hexane), Bchl (chloroform), and Beac (ethyl acetate), were prepared and evaluated for antioxidant activity using in vitro assays. Extract/fractions were also evaluated for anti-proliferative and apoptotic activity in human breast carcinoma cell line MCF-7, using in vitro assays, namely, MTT, clonogenic, and neutral comet assay, along with confocal microscopy and flow cytometry. Among all extract/fractions, a pronounced antioxidant activity was exhibited by Bchl and Beac fractions, in DPPH· (EC50 213.2 and 161.5 µg/mL, respectively), ABTS+· (EC50 139.3 and 44.1 µg/mL, respectively), and reducing power assay (EC50 86.7 and 84.5 µg/mL, respectively). Both fractions protected plasmid DNA against hydroxyl radical induced damage in plasmid nicking assay. Bchl and Beac were also observed to inhibit the growth of MCF-7 cells (GI50 203.7 and 246.5 µg/mL, respectively). Both fractions induced apoptosis in MCF-7 cells, by arresting the cell cycle in G1 and sub-G1 phase, respectively, enhancing ROS levels, decreasing mitochondrial membrane potential, and inducing double-strand DNA breaks. HPLC analysis revealed high kaempferol content in Bchl, and catechin, epicatechin, and gallic acid in Beac.
Keywords: Butea monosperma; MCF-7; ROS; antioxidant; apoptosis; cell cycle.