Antioxidant activities of ethanol extracts from different parts of the black raspberry (rubus occidentalis) obtained using ultra-sonication

This study was carried out to investigate the antioxidant effects of different parts (stems, leaves, and seeds) of the black raspberry for utilization as food materials. Different parts of the black raspberry were subjected to extraction via ultra-sonication extraction methods using water and ethanol at various concentrations (25, 50, 75, and 100%). Antioxidant capability of the extracts were determined by amounts of phenolic compounds, with flavonoid contents, radical scavenging activity, and reducing power. Irrespectively of ethanol concentration, extracts of stem showed the highest total phenolic compounds and antioxidant activities among different parts of black raspberry. The total phenolic compounds extracted from the black raspberry stem using 25 and 50% ethanol showed 348.21±5.40 and 343.39±5.94 mg/g, respectively. Fifty percent ethanol extracts of the black raspberry stem showed the highest DPPH (EC₅₀ value:60.89 μg/mL) and ABTS radical scavenging activities (EC₅₀ value:82.57 μg/mL). Further, 25% ethanol extacts of the black raspberry stem (0.263±0.004) was found to have the highest reducing power. The highest antioxidant activity of black raspberry stem indicates that black raspberry stem may be useful source for functional food.