Potential Ethanol Extract of Rhinachantus nasutus (L.) Kurz Stem Bark as Antioxidant and Inhibitor of Dipeptidyl Peptidase IV (DPP IV) Activity

Rhinachantus nasutus (L.) Kurz is a plant that has long been used by people in Southeast Asia, India, and China as traditional medicine. R. nasutus plant preparations have been used in traditional medicine to treat diabetes. This study aims to reveal: the content of a group of secondary metabolite compounds in the extract of the stem bark R. nasutus; The extract's potential as an antioxidant with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition parameters and ferric-reducing power, and it's potential as an antidiabetic by inhibiting dipeptidyl peptidase IV (DPP IV) activity. Phytochemical screening results on the ethanol extract of the stem bark of R. nasutus found the presence of steroid glycosides, phenolic, alkaloids, and tannins. The antioxidant activity test using the DPPH and ferric reducing antioxidant power (FRAP) methods gave an IC₅₀ valuesof 90.668±0.084 mg/L and 8.91±0.023mg/L, respectively. In addition, the ethanol extract of the stem bark can inhibit the activity of DPP IV with a % inhibition of 52.19±1.667. From this study, we can conclude that the ethanol extract of the stem bark R. nasutus can potentially be a source of antioxidants and antidiabetes.