Computational assessment of chemicals from Morinda citrifolia as potential inhibitors of B-Raf kinase in hepatocellular carcinoma treatment.

Hepatocellular carcinoma (HCC) is a tumour pathology that lacks specific treatment and is predominantly resistant to chemotherapy. The inhibitory activity of Morinda citrifolia, an evergreen tree commonly called Noni, against various carcinomas especially HCC is widely acclaimed. This study was to assess the phytochemical constituents of the plant for inhibitory activity against B-Raf kinase (3C4C) in order to design drugs for HCC treatment. Molecular docking, pharmacophore modelling, induced-fit docking, molecular dynamics (MD) simulations and ADMET predictions were the computational techniques employed in this study to detect potential inhibitors of B-Raf kinase from 135 compounds of Morinda citrifolia. Soranjidiol, Thiamine, Lucidin, 2-Methyl-1,3,5-Trihydroxyanthraquinone and Rubiadin were the five top-scoring compounds ranging from -8.39 to -8.22 kcal/mol, however, the standard ligand, PLX4720, scored -11.26 kcal/mol. The five compounds, like PLX4720 demonstrated hydrogen bond interactions with active site amino acid residues such as GLN 530, CYS 532 and ASP 594. The main energy contributor to the interactions between the compounds and B-Raf kinase were pi-stacking, hydrogen bond, van der Waals and covalent energy. Better docking scores obtained in the induced-fit docking further validates the inhibitory potential of the Soranjidiol against the flexible protein. In MD simulations, Soranjidiol revealed good stability in the active site of the protein since significant conformational changes were not evident. These five compounds, unlike the standard compound, demonstrated adequate druglike properties and good safety profiles. Therefore, further studies should be undertaken so as to develop them into drugs against HCC.Communicated by Ramaswamy H. Sarma.