Phyllanthus muellerianus and Ficus exasperata exhibit anti-proliferative and pro-apoptotic activities in human prostate cancer PC-3 cells by modulating calcium influx and activating caspases

Phyllanthus muellerianus (PM) and Ficus exasperata (FE) are plants used against cancers. We evaluated the phytochemical profiles and in vitro antioxidant potentials of PM and FE, and investigate their effects on cell proliferation, intracellular calcium ([Ca]), caspases 3/9, apoptosis, oxidative stress markers, and Bax/cytochrome C expression in PC-3 cells. The phytochemical profiles were evaluated by liquid chromatography-mass spectrometry (LC‐MS), and the antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging method. The cells were incubated for 24 h with 3% tween 80, paclitaxel (5 nM), PM (800 and 1200 µg/ml), and FE (800 and 1200 µg/ml). After treatments, [Ca], caspases 3/9, apoptosis and oxidative stress parameters were measured using colorimetric kits, while the mRNA levels of Bax and cytochrome C were quantified by RT‐qPCR. Nitidine, phloridzin and linoleic acid were identified in PM, while docosane, cardanol and chlorogenic acid were revealed in FE. The in vitro antioxidant potential of PM was greater than that of FE. Both plants inhibited the growth of PC-3 cells in a dose-dependent manner, but significantly (p < 0.5–0.001) increased [Ca], apoptosis level, caspase 3/9 activities, reactive oxygen species production and lipid peroxidation, compared with control. Moreover, the activities of superoxide dismutase, catalase and glutathione peroxidase were significantly decreased in the cells incubated with the plant extracts, PM being the most effective. Paclitaxel, PM and FE upregulated Bax and cytochrome C genes in PC-3 cells. PM and FE inhibited the growth of PC-3 cells by modulating the [Ca] and inducing apoptosis through Bax/Cytochrome C/Caspase 3–9 signaling pathway.