Alpha-amylase and Alpha-glucosidase enzymes inhibition and antioxidant potential of selected medicinal plants used as anti-diabetes by Sundanese community in West Java, Indonesia

Plants provide an excellent alternative for managing diabetes and are widely utilized in many developing countries including Indonesia. This study aimed to provide comprehensive scientific information on the α-amylase and α-glucosidase inhibitory of the selected medicinal plants used by Sundanese community in West Java. Twelve medicinal plants were extracted individually in ethanol and their total phenolic content (TPC) and total flavonoid content (TFC) were quantified by Folin-Ciocalteu and AlCl₃ colorimetric assays, respectively. Concentration-dependent inhibition of α-amylase and α-glucosidase, as well as DPPH scavenging, were measured in 96-well plates. IC₅₀ values were obtained by non-linear regression. Data were compared by one-way ANOVA (P < 0.001). Autoscaled principal-component analysis (PCA) explored multivariate relationships among TPC, TFC and the bioactivity variables. Among the twelve selected medicinal plants, TPC and TFC varied 20.3-61.9 mgGAE/g and 15.0-64.9 mg/QE g, respectively. S. mahagoni seeds possessed the highest TPC, whereas A. muricata leaves led in TFC. Only S. mahagoni (IC₅₀ = 214 ± 4 µg/mL) and M. charantia (274 ± 5 µg/mL) reached 50% α-amylase inhibition. P. angulata provided the sole measurable α-glucosidase IC₅₀ (438 µg/mL). Furthermore, S. mahagoni exhibited the strongest DPPH scavenging (IC₅₀ = 138.6 µg/mL). PCA explained 69.9% of variance with PC1 (39.5%) loaded positively on α-amylase inhibition (+ 0.83) and TPC (+ 0.81) and PC2 (30.4%) associated with α-glucosidase inhibition (+ 0.81) and TFC (+ 0.62). These data validate Sundanese ethnomedicine and prioritize S.mahagoni and P.angulata for bioactivity-guided isolation and in vivo antidiabetic evaluation.