Sclerocarya birrea and Terminalia prunioides: Phytochemical screening and synergistic inhibition of cervical cancer cells proliferation through modulation of EGFR, VEGF, MACC1, CYFRA 21-1, and CD 95 gene expressions

Abstract

Cancer is one of the leading causes of death globally. Conventional drugs are expensive and have been reported to have side effects. This directs efforts in cancer research to search for inexpensive solutions with less or no side effects. This study aimed at screening for phytochemicals and the antiproliferative effects of Sclerocarya birrea fruit exocarp (SBFE) and Terminalia prunioides pods extracts (TPPE) on human cervical cancer cell line (HeLa). Extracts were qualitatively evaluated for their phytochemicals using HPLC and LC-MS/MS, and the antiproliferative effects by 4-[-3(4-Iodophenyl)-2-(4-nitro-phenyl)-2H-5-tetrazolio]-1,3-benzene sulfonate (WST-1) assay. HPLC and LC-MS/MS analysis led to identification and quantification of 24 polyphenolic metabolites amongst which shikimic acid (3.6014 mg g^-1), gallic acid (40.8283 mg g^-1), and quercetin-3-d-xyloside (3.4677 mg g^-1) as the major metabolites. Results from antiproliferative effects of extracts were used to make 3 potential anticancer formulations. Furthermore, effects of extracts and formulations on the expressions of cervical cancer markers: Epidermal Growth Factor Receptor (EGFR), Metastasis-Associated in Colon Cancer 1 (MACC1), Vascular Endothelial Growth Factor (VEGF), Cytokeratin Fragment (CYFRA 21-1), and Cluster differentiation 95 (CD95) were evaluated by Reverse transcription quantitative Polymerase Chain Reaction (RT-qPCR). Methanol and ethyl acetate extracts of both plants tested positive for saponins, tannins, flavonoids, phenols, terpenoids, cardiac glycoside and steroids. Methanol extracts were the most effective with IC₅₀ values of 75 µg/mL and 190 µg/mL for SBFE and TPPE respectively. The formulations: M1E1M2E2 and M1M2 had IC₅₀ values of 77 µg/mL and 83 µg/mL respectively. All treatments downregulated mRNA expression of EGFR, VEGF, MACC1, CYFRA 21-1, and upregulated CD 95 mRNA expression. Formulations were more effective than individual extracts against HeLa cells. However, there is need for further testing for other possible mechanisms of action and isolation of phytocompounds.