IN VITRO AND IN SILICO ASSESSMENT OF HDAC INHIBITORY ACTIVITY OF MORINGA OLEIFERA LEAF EXTRACT IN PHENYLEPHRINE-INDUCED H9c2 CARDIOMYOCYTE CELLS WITH RELEVANCE TO CARDIAC HYPERTROPHY

AbstractCardiac hypertrophy is a pathological remodelling process marked by an abnormal increasein cardiomyocyte size and progressive deterioration of cardiac function; it remains a majorrisk factor for heart failure. Class II histone deacetylases, particularly HDAC4 and HDAC5,participate in the transcriptional programmes that drive this maladaptive growth. Moringaoleifera, a plant rich in flavonoids and isothiocyanates, has been linked in earlier work toepigenetic modulation and cardioprotection. The present study examined the HDACassociated and cardioprotective activity of a hydroalcoholic leaf extract by molecular dockingand cell-based assays in phenylephrine-stimulated H9c2 cardiomyocytes. Leaves wereauthenticated, shade-dried and extracted with 70 % ethanol by successive cold maceration(72 h), yielding 13.7 % w/w of extract. Phytochemical screening indicated strong presence offlavonoids, phenolic compounds and isothiocyanate-related constituents. HPTLC showed amarker-compatible band (Rf 0.38–0.44) with marker-related content of 4.86 ± 0.21 % w/w.Docking against human HDAC4 (PDB 2VQJ) and HDAC5 (PDB 5W5K) ranked quercetin(8.9 kcal/mol against HDAC4) and kaempferol (8.6 kcal/mol) ahead of the referenceinhibitor trichostatin A (8.4 kcal/mol). The MTT-derived IC50 was 1124 µg/mL. At 500µg/mL the extract reduced HDAC activity to 42.3 ± 3.1 % of the hypertrophy control,lowered ROS to 68.4 ± 5.2 % and MDA to 5.8 ± 0.4 nmol/mg, raised SOD to 78.6 ± 4.9U/mg and CAT to 61.2 ± 3.8 U/mg, and attenuated relative ANP expression to 54.7 ± 4.2 %and cell surface area to 63.5 ± 3.6 % of the phenylephrine control. Trichostatin A producedparallel or stronger shifts. The data indicate that the leaf extract can produce concentrationlinked improvements in HDAC-related, oxidative-stress and hypertrophic parameters whilepreserving acceptable cell viability, and they supply a basis for further biochemical and invivo investigation.