Exploring the Medicinal Potency of Uncaria gambir (W. Hunter) Roxb. Cv. Cubadak: Antioxidant Activity, Catechin Content, Metabolite Profiling, and Antimicrobial Testing as a Basis for Potential Therapeutic Use

Recent research has focused on examining the metabolite diversity of U. gambir Roxb. cv. Cubadak to assess its antioxidant and catechin content across various plant organs, processing methods, and extract types. The antioxidant ability is further tested on pathogenic microbes. U. gambir samples were prepared in the forms of catechu-2 (G2), catechu-1 (G1), dried leaves (D), fresh leaves (FL), fresh twigs (FS), and fresh roots (FR). Extractions were performed using methanol, ethyl acetate, and n-hexane. The resulting extracts underwent metabolite profiling via LC-MS/MS, DPPH assay, total phenolic content (TPC), total flavonoid content (TFC), and total catechin content. Antimicrobial testing was performed on Escherichia coli, Staphylococcus aureus and Candida albicans. U. gambir Roxb. cv. Cubadak contains lipids, terpenoids, benzene derivatives, flavonoids, and alkaloids. Both solvent polarity and type of raw material significantly impacted antioxidant activity, TPC, TFC, and total catechin content. Among samples, the best antioxidant activity was observed in the following order: G2 > G1 > D > FL > FS > FR. Pearson correlation analysis confirmed a positive association between high antioxidant capacity and increased levels of TPC, TFC, and total catechin. U. gambir showed antimicrobial activity on fungal pathogen compared to bacteria. Taken together, the combination of G2 processed with ethyl acetate extraction demonstrated superior antioxidant activity (IC₅₀ = 8.82µg/mL), along with high levels of TPC (1420mg GAE/g DW), TFC (1902 mg QE/g DW), and total catechin (784.45µg/mL), highlighting its potential as a natural antioxidant source. This antioxidant exhibited fair antimicrobial.