Cellular antioxidative and regenerative potentials of Clinacanthus nutans leaf fractions towards liver cells: An integrated in vitro and in silico study

Clinacanthus nutans (Burm.f.) Lindau is a medicinal plant used for treatment of liver cancer and jaundice by Chinese healers.This study aimed to determine the phytocompounds that contribute to the antioxidative and regenerative potentials of C. nutans leaves when examined on the HepG2 liver cells and the umbilical cord-derived mesenchymal stem cells, respectively.NMR-based metabolomics approach and molecular docking were employed to identify contributing phytocompounds.All fractions were found non-toxic towards both cell lines when tested at concentration up to 100 g/ml.It was shown that cells treated with hexane and ethyl acetate fractions were able to reduce ROS levels by 36% and 27.6% respectively, during oxidative stress when measured at 120 min as compared to untreated cells.Furthermore, hexane fraction increased glutathione levels in HepG2 cells by approximately 3-fold whereas ethyl acetate fraction treated cells showed 2.36-fold increment of glutathione in comparison to untreated control.Hexane fraction demonstrated slight regenerative potential towards mesenchymal stem cells.Ethyl acetate fraction, on the contrary, retarded this activity.Interestingly, phytocompounds: clinacoside B, clinacoside C and isoschaftoside which were postulated earlier to play important roles in C. nutans leaves antioxidative properties were detected in hexane fraction through NMR analysis.Amongst them, isoschaftoside formed interactions with important amino acid residues within the binding pocket of Keap1 in silico suggesting its strong inhibitory effect towards this protein.Isoschaftoside is thus a promising compound to be further investigated as a treatment for chronic liver problems such as non-alcoholic fatty liver disease.