Phytochemicals, Antioxidant and Inhibitory Activity against α-Glucosidase in Uncaria sclerophylla Twigs and Stems

The medicinal plant Uncaria sclerophylla Roxb has been used as a traditional antidiabetic drug by the people of Kalimantan, Indonesia. However, scientific data on this plant as an antidiabetic has never been reported. This research aims to investigate the antidiabetic activity of the twigs and stems of U. sclerophylla as an inhibitor of α-glucosidase, and its antioxidant activity, including phytochemical screening. Four-graded maceration was used as the extraction method, thin-layer chromatography was used as a screening method, and all bioassays were conducted by spectrophotometric principles to determine inhibition of α-glucosidase and antioxidant activity from n-hexane, dichloromethane, ethyl acetate and methanol extracts of twigs and stems. The research results showed that U. sclerophylla twigs and stems contain alkaloids, phenols, and flavonoids. Inhibitory activity against α-glucosidase was shown from both twigs and stems of the plant, with the most active extract being n-hexane extract from twigs with an IC₅₀ of 84.44 μg/mL. The best antioxidant activity was shown by methanol extract from both twigs (IC₅₀ 28.76 μg/mL) and stems (IC₅₀ 27.76 μg/mL). The assay results have underlined that the twigs and stems of this species have the potential to be developed in the treatment of diabetes mellitus through α-glucosidase inhibition and antioxidant activity.