Inclusive Metabolomic Profiling and Biological Evaluation of Leptodermis virgata (Family Rubiaceae): In Vitro and In Silico Characterization of High-Yield Terpenoid Extract Fractions

Despite its therapeutic potential, the metabolomic profile and biomedical efficacy of L. virgata remain entirely unexplored. This study was designed to comprehensively map the metabolomic profile of L. virgata leaves and evaluate their biomedical efficacy. The leaf extract was prepared in methanol (80%) and fractionated with hexane, ethyl acetate, acetone, and distilled water, and evaluated for biological activities, including antioxidant (DPPH), antimicrobial, and in vitro and in silico AChE inhibitory and cytotoxic effects. Phytochemical profiling was conducted using ATR-FTIR and UHPLC-ESI-QTOF-MS/MS (LC-MS). The crude extract showed the highest DPPH scavenging activity (88.11 ± 3.45%). Antibacterial and antifungal MIC values ranged from 375 ± 125 to 1500 ± 217 μg/mL. The acetone fraction showed strong AChE inhibition (IC50: 805.63 ± 5.87 μg/mL), while the hexane fraction showed notable anti-leukemic cytotoxic activity against U937 cells (GI50: 596.74 ± 2.24 μg/mL). Untargeted LC-MS profiling identified 194 compounds, dominated by terpenoids (69.32%), followed by lipids (7.93%), steroids (6.40%), flavonoids (4.13%), quinones (2.72%), coumarins (2.17%), and carbohydrates (1.87%). Oleanolic acid (15.84%) was the most abundant metabolite. In silico docking revealed strong binding affinities of 4,5-dicaffeoylquinic acid and Asperuloside for AChE, and Acanthoside B for DNA topoisomerase II. These findings indicate that L. virgata leaves are rich sources of bioactive Rubiaceae-specific metabolites, supporting their potential for developing natural therapeutic and nutraceutical products.