Perbandingan Uji Aktivitas Antioksidan Isolat Flavonoid Kulit Buah Durian (Durio Zibethinus Murr.) Dengan Metode DPPH Dan Frap

Antioxidants are compounds capable of inhibiting oxidation processes and neutralizing free radicals. Durian peel, an agricultural waste product, has the potential to serve as a source of flavonoid compounds that possess antioxidant activity. This study aimed to compare the antioxidant activity of flavonoid isolates from durian peel using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the ferric reducing antioxidant power (FRAP) assay, as well as to compare the validation parameters for both methods. This experimental study utilized durian peels of the 'Monthong' variety, obtained from Gunungpati, Semarang, Central Java. The samples were extracted via the reflux method using 96% ethanol as a solvent for 6 hours, followed by phytochemical screening, thin-layer chromatography, and column chromatography to obtain flavonoid isolates. Antioxidant activity was assessed using UV-Vis spectrophotometry and expressed as the half-maximal inhibitory concentration (IC₅₀). Method validation parameters included precision, accuracy, linearity, limit of detection (LOD), and limit of quantification (LOQ). The results indicated that the flavonoid content in the durian peel extract was 3.77%. The IC₅₀ value for the flavonoid isolates was 29.22 ppm using the DPPH method and 459.00 ppm using the FRAP method. The DPPH method demonstrated a precision of 98.15%, an accuracy of 0.27%, a coefficient of determination (R²) of 0.9982, an LOD of 0.189 ppm, and an LOQ of 0.631 ppm. Meanwhile, the FRAP method showed a precision of 73.65%, an accuracy of 0.11%, an R² of 0.9538, an LOD of 0.207 ppm, and an LOQ of 0.690 ppm. Based on the IC₅₀ values ​​obtained, the DPPH method demonstrated higher antioxidant activity compared to the FRAP method under the test conditions employed. It can be concluded that flavonoid isolates from durian peel possess antioxidant activity, with test results varying between the DPPH and FRAP methods