Antiproliferative property of n-hexane and chloroform extracts of Anisomeles malabarica (L). R. Br. in HPV16-positive human cervical cancer cells.

To find the efficacy of serial extracts of Anisomeles malabarica in inhibiting proliferation of and inducing apoptosis in human cervical cancer cells, SiHa and ME 180, that are HPV 16-positive. The whole plant was extracted in n-hexane, chloroform, ethyl acetate, n-butanol, methanol, and water. The cells were treated with the extracts at increasing concentrations to find the IC(50), adopting MTT ([3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]) assay. Acridine orange (AO) and ethidium bromide (EB) and Hoechst 33258 staining were adopted to assess the mode of cell death, Annexin V-Cy3 staining to evaluate one of the early apoptotic features, JC-1 staining to assess the mitochondrial membrane depolarization, comet assay for DNA fragmentation, and cell cycle analysis for the distribution of cells after treatment. n-Hexane and chloroform extracts were cytotoxic to the cervical cancer cells in dose- and duration-dependent manner. The cells that responded to the treatments revealed typical apoptotic features. Early features of apoptosis, phosphatidyl serine translocation and loss of mitochondrial trans-membrane potential, were observed in the treated cells, and comet assay revealed DNA damage. In the FACS analysis, the cells accumulated in the sub-G0/G1 phase of the cell cycle, except in n-hexane- and chloroform extract-treated SiHa cells at 24 h, which showed arrest in S- and G2/M phases. n-Hexane and chloroform extracts of A. malabarica inhibit proliferation of and induce death in HPV16-positive cervical cancer cells, mostly by apoptosis and to some extent by necrosis.