Antioxidant Capacity and Potential as an Alpha-Glucosidase Inhibitor in Phaleria macrocarpa (Scheff.) Boerl Fruit Peel Ultrasonic Extract

Phaleria macrocarpa (Scheff.) Boerl is native to the tropical region of Papua Island, Indonesia, and has traditionally been used as a herbal drink, either alone or in combination with other medicinal plants, to treat diseases such as cancer, hypertension, and diabetes mellitus. This study aimed to obtain the fruit peel extract of Phaleria macrocarpa (Scheff.) Boerl. through the application of ultrasound-assisted extraction (UAE) with variations in time and amplitude to produce optimal extraction conditions. The potential of the extract as an antioxidant using the cupric ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods, and its potential as an antidiabetic through alpha glucosidase inhibition. The optimum extract selected was extract C (extraction time was 45 minutes and amplitude 60%) with IC₅₀ values for antioxidant activity in the CUPRAC method of 39.63 ± 0.009 mg/L and the FRAP method of 77.37 ± 0.8 mg/L, while the inhibition of alpha glucosidase was 0.45 ± 0.007 mg/L. It can be concluded that the ethanol extract of Phaleria macrocarpa fruit peel has the potential as a source of antioxidants and anti-diabetic.