Antidiabetic activities of sesewanua (Clerodendrum squamatum Vahl.) leaves and flavonoids profiling of the bioactive extract

Abstract

Clerodendrum squamatum Vahl., locally known as “sesewanua,” is a traditional medicinal plant used by the Minahasa tribe, Indonesia. This study aimed to evaluate its antidiabetic potential and identify its flavonoid content. In vivo studies performed using a high-fat diet and streptozotocin-induced diabetic Wistar rats demonstrated that C. squamatum Vahl. extracts significantly lowered blood glucose, with effects comparable to metformin. In vitro α-glucosidase inhibition assays showed strong activity, particularly in the ethyl acetate extract (IC₅₀ = 42.19 µg/mL). The same extract displayed notable antioxidant activity with the DPPH radical scavenging assay (IC₅₀ = 40.07 mg/L). LC-MS/MS analysis identified three flavonoids in the ethyl acetate extract: hispidulin, kaempferol, and luteolin. Molecular docking simulation revealed strong binding affinities between the identified flavonoids and α-glucosidase (−7.5 to −7.6 kcal/mol). This study points out the potential of the ethyl acetate extract of C. squamatum Vahl, as a promising natural source for the development of novel antidiabetic agents.