Isolation and Characterization of Anticancer Properties of Compounds from the Leaf Extracts of Vitex negundo

Vitex negundo belongs to the family of Lamiaceae and is popularly known as sambhaloo or Chinese chaste tree. It is widely used as Indian medicinal shrub to prevent a variety of ailments including cancer. The aim of the study was to investigate the anticancer activity of solvent extracts and fractionates of Vitex negundo (VN) leaves against human lung carcinoma epithelial cells A549 by MTT assay. The leaves were extracted with various solvents by ultrasonic-assisted extraction method, in the sequel of non-polar to polar solvents from n-hexane, chloroform, ethyl acetate and ethanol:water (1:1). Among the four solvent extracts, the ethanol:water (1:1) extract has shown the significant anticancer activity (IC50 = 44.31 ± 0.61 at 5 to 300 µg/mL). Four components were isolated from ethanol:water (1:1) extract. The structure of these compounds were elucidated and identified as 4-OH benzoic acid (VN-EtOH+H2O-P1), negundoside (VN-EtOH+H2O-P2), isoorientin (VN-EtOH+H2O-P3) and agnuside (VN-EtOH+H2O-P4) by NMR, LCMS, FTIR and melting point. Among the four fractionated products, isoorientin showed the significant cytotoxic activity against A549 cells with IC50 value 18.50 ± 0.76 µM/mL. The standard drug, cisplatin IC50 values for anticancer activity of crude extracts (IC50 value 13.45 ± 0.084 µM/mL) were compared with that of pure compounds (IC50 value 14.27 ± 0.143 µM/mL). The bioactive compound, isoorientin (VN-EtOH+H2O-P3) as well as the standard drug, doxorubicin treated with normal human dermal fibroblast (HDF) cells after 48 h, with an IC50 values of 416.57 ± 0.01µM/mL and 19.8 ± 0.01 µM/mL).