Biochemometric approach to reveal Terminalia bentzoë cytotoxic effect against HepG2 cells in relation to its different organs and extraction solvents as analysed via UPLC-MS

Numerous Terminalia species from the Combretaceae family have been well characterised for their potential anticancer, antioxidant and anti-inflammatory activities mediated in part by the plethora of phytochemicals they harbour. This study assessed the cytotoxicity of T. bentzoë crude extracts prepared from its different organs namely, flower, leaf and bark. The activities of the derived fractions obtained from solvents of different polarities were tested against HepG2 cells. The effect on intracellular reactive oxygen species (ROS), as well as intrinsic antioxidant enzyme activity, were also investigated. T. bentzoë crude extracts triggered HepG2 cell death by inducing loss of mitochondrial membrane potential (> 40% versus untreated control cells, p < 0.0001), upregulating intracellular ROS generation (2 folds higher than untreated control cells, p < 0.0001), and suppressing intrinsic catalase activity (> 28% lower than untreated control cells). The positive control etoposide showed higher cytotoxicity against HepG2 cells as opposed to crude extracts. Ethyl acetate fractions were the most active, compared to butanol and aqueous residual fractions. The metabolome heterogeneity among the different T. bentzoë crude extracts/fractions, was explored using ultra-performance liquid chromatography coupled to mass spectroscopy (UPLC-MS) aided by unsupervised principal component analysis (PCA) and supervised analysis i.e., orthogonal partial least squares discriminate analysis (OPLS-DA). The discriminating metabolites were identified by OPLS-DA to be phenolic compounds with tetrahydroxyflavone, gallate derivatives i.e. methyl gallate, gallic and ellagic acid, tri- and tetra-galloyl hexose and tercatain.