Cytotoxicity of fig fruit latex against human cancer cells

Fig fruit latex (FFL) contains significant amounts of polyphenolic compounds and can serve as a source of antioxidants after human consumption. The purpose of this study is to confirm anticancer activity of FFL against human cancer cells and to further elucidate its mechanism of activity. Human glioblastoma, hepatocellular carcinoma, and normal liver cells were used for in vitro tests of FFL effects. Those tests included cytotoxicity, colony formation inhibition, Brdu incorporation, acridine orange/ethidium bromide (AO/EB) staining for apoptotic cells, cell cycle distribution through flow cytometry (FCM), and ADP-ribosyltransferase (NAD+; poly(ADP-ribose) polymerase)-like 1 (ADPERL1) mRNA expression through RT-PCR in response to FFL treatment. After FFL treatment, the proliferation, colony formation, and Brdu labeling indices of cancer cells decreased (P < 0.05), while the AO/EB stained apoptotic cells increased (P < 0.05). By FCM analysis, an increase of G0/G1 phase cell population and decrease of S and G2/M phase cells were observed (P < 0.01), while both ADPRTL1 mRNA expression and apoptotic indices increased (P < 0.01). The findings in these studies suggested that FFL exhibited potent cytotoxicity in some human cancer cells with little effect in normal cells at certain concentration. The mechanism for such effects might be associated with the inhibition of DNA synthesis, induction of apoptosis, and cell cycle arrest of cancer cells.