Cytotoxicity and Apoptosis-Induction Potential of Fraction F3 from Fruits of Bersama engleriana (Melanthaceae) against Human Cervical Cancer Cells

Abstract

Cervical cancer is one of the most life-threatening malignancies worldwide, despite intensive research for more efficacious chemotherapeutic agents. Recent efforts geared towards eradicating the scourge of cancer have embodied a major surge of interest in natural products as promising lead molecules in pharmaceutical development and therapeutic translation. Consequently, this study aimed to assess the cytotoxicity of a previously identified plant Fraction (F3) from Bersama engleriana against cervical cancer (HeLa) cells and non-cancerous normal human foreskin fibroblasts (HFF cells). Flow cytometric analysis via Annexin V/PI in HeLa cells was carried out to assess apoptosis induction. We report here the 50% Inhibitory Concentration (IC50) of fraction F3 to be 96.15 µg/mL and a 50% Cytotoxic Concentration (CC50) of 527.4 µg/mL, as well as a Selectivity Index (SI) of 5.48, thus confirming that fraction F3 is relatively non-toxic to the normal cells compared to the cancer cells evaluated. In addition, microscopic observations showed a higher reduction of cells, aggregated with dark color in HeLa cells treated with fraction F3 compared to control (cells only). The Annexin V/PI analysis showed the percentages of apoptotic cells were 4.6±0.05, 7.9±0.9 and 7.6±0.15, respectively, for the control and treatments of cells with 120 and 150 µg/mL fraction F3 in early apoptosis (Annexin V+/PI-) 48 h post-treatment. Percentages of apoptotic cells were 2.1±0.1, 8.9±0.2 and 7.7±0.2, respectively, for control, 120 and 150 µg/mL fraction F3 treatments in late apoptosis (Annexin V+/PI+) after 48 h posttreatment. Nevertheless, a comparison of the lowest percentage inhibition of apoptosis with the highest number of reduced cells observed with fluorescence microscopy suggests that fraction F3 may exert its growth inhibitory action on HeLa cells via another mechanism. The results established that fraction F3 from B. engleriana is a promising source for exploring antitumor activity.