Application of Ultrasound-Assisted Extraction on the Stem Bark of Rhinachantus Nasutus (L.) Kurz, Total Phenolic, and Its Potential as Antioxidant and Inhibitor of Alpha-Glucosidase Enzyme Activity

Aims: This study aims to obtain a stem bark extract of Rhinachantus nasutus (L.) Kurz through the application of ultrasound-assisted extraction (UAE) and reveal: the total phenolic content in the extract; The extract's potential as an antioxidant with copper-reducing strength parameters, and its potential as an antidiabetic by inhibiting alpha-glucosidase activity. Results: The crude ethanol extract of R. nasutus stem bark obtained from the UAE process was 7.4896 g with a yield of 4.99%. The high total phenolic content, namely 677.3343±0.0007 mg GAE / g sample, the antioxidant activity test using the CUPRAC method gave an IC₅₀ value of 18.43±0.20 mg / L. In addition, the ethanol extract of stem bark has a high ability to inhibit the activity of the alpha-glucosidase enzyme with an IC₅₀ value of 10.95±0.28 mg / L. Conclusion: The ethanol extract of the stem bark of R. nasutus from UAE has the potential as a source of antioxidants and antidiabetic.