Chemical investigation on the ethyl acetate extract of the aerial parts of Begonia sp. afforded a new steroid glycoside, 9(11)α,16(17)α-dioxirane-20,25-dihydroxy-β-sitosterol-3-O-β-glucopyranoside (1) along with a known steroidal glycoside, β-sitosterol-3-O-β-D-glucopyranoside (2). The Chemical structures were elucidated by 1D and 2D NMR and mass spectroscopic analysis. Cytotoxicity against four different cancer cell lines (HeLa, T47D, WiDr and Vero) was assessed. Compound 1 was more potent and selective against breast cancer cell line (T47D) than other cell lines with an IC50 value of 0.16 µg/mL. Further docking study of 1 exhibited the preference of molecule to bind in the epidermal growth factor receptor tyrosine kinase (EGFR-TK) binding pockets with docking scores of -97.8800 (PLANTS) and -3.56 kcal/mol (AutoDock 4.2.6).
Keywords: Begonia sp.; breast cancer; molecular docking; spectroscopy; steroid glycoside.