Phenolic Compounds from Ruta chalepensis Var. angustifolia as Potential HMG-CoA Reductase Inhibitors: Bioactivity-Guided Fractionation and Preliminary Identification of Active Metabolites

Ruta chalepensis L. var. angustifolia (Pers.) Willk. (Rutaceae) has been traditionally associated with hypocholesterolemic effects, although the bioactive metabolites responsible for this activity remain largely unknown. This study aimed to fractionate the methanolic extract of R. chalepensis var. angustifolia, identify its major phenolic constituents, and evaluate their inhibitory activity against 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. The methanolic extract was fractionated by open column chromatography, and selected fractions were analyzed by thin layer chromatography and HPLC-DAD. Rutin was identified as one of the major flavonoids, while three chromatographically pure fractions corresponded to unidentified phenolic compounds. Their inhibitory activity was assessed using a commercial HMG-CoA reductase assay. Pravastatin showed 87.5% inhibition and served as the positive control. Among the isolated fractions, one unidentified phenolic fraction exhibited the highest inhibitory activity (66.0%), exceeding that of rutin (45.8%), whereas another fraction showed negligible activity (8.3%). These findings indicate that the HMG-CoA reductase inhibitory potential of R. chalepensis var. angustifolia cannot be attributed solely to rutin and suggest the presence of additional bioactive phenolic metabolites. Further structural characterization and mechanistic studies are required to identify the active compound and confirm its hypocholesterolemic potential in biological systems.