Methanolic Root Extract of Calotropis gigantea Induces Apoptosis in Human Hepatocellular Carcinoma by Altering Bax/Bcl-2 Expression

Abstract

Calotropis gigantea, family apocynaceae, is a milkweed traditionally used in ayurveda for its anti-helminthic, anti-pyretic, and anti-malarial activities. It has also been studied widely for its anticancer potential. In the present study, the antioxidant, antibacterial, antifungal and antitumor potential of its three root extracts viz. chloroform extract (CE), ethyl acetate extract (EE) and methanolic extract (ME) were investigate. Antiproliferative activity of the extracts was examined on human hepatocellular carcinoma cells, HepG2 and human breast cancer cells, MCF-7. Maximum cytotoxicity was obtained with ME on HepG2 cells with IC50 value of 85 µg/mL. ME was further investigated at 85 µg/mL, for cell DNA damage using agarose gel electrophoresis and nuclear staining. RT-PCR analysis was done to study expression of bcl-2 family of genes viz., bax, bcl-2, and p53. Bax expression significantly (p < 0.05) increased following ME treatment, whereas bcl-2 expression was significantly (p < 0.05) lowered. Significant (p < 0.05) increase of p53 expression suggested damage to DNA of HepG2 cells. The study showed that methanolic root extract induces apoptosis in HepG2 cells by altering bax/bcl-2 expression. Further studies are required to obtain knowledge about the complete mechanism of its apoptosis inducing activity.