Antioxidant Activity of Rhamnus prinoides and Herkule Hops for Barley Malt Beer Production in Ethiopia Ashine Fekadu*, Tolessa Amsalu** *Senior Researcher, Chemical and Construction Input Industry Development Institute, Addis Ababa, Ethiopia **Researcher, Ethiopian Environment and Forest Research Institute, Wood Technology Research Center, Addis Ababa, Ethiopia Online published on 11 October, 2019. Abstract The effects of antioxidant activity of the Gesho (Rhamnus prinoides) extract, its residual and Herkule were evaluated by using 2, 2-diphenyl-2-picryl-hydrazine (DPPH) assay. Extraction of well vented and dried samples of R. prinoides was performed by socking in 97% ethanol as an extracting agent. Free radical scavenging activities of R. prinoides extract and Herkule was read spectrophotometrically and inhibition of free radical DPPH in percent (I %) was calculated and compared against the standard ascorbic acid. From the study Herkule, R. prinoides and ascorbic acid showed a maximum radical scavenging as 80.87, 81.148 and 93.77% at concentrations of 0.24mg/ml, 0.24mg/ml and 0.160mg/ml, respectively. Inhibitory concentration (IC50) was calculated for herkule, R. prinoides extract and ascorbic acid to be 5.2, 5.2 and 0.2 mg/ml, respectively. Moreover, the effect of different concentration of R. prinoides extract with DPPH free radical on absorbance at 517 nm is similar to that of standard ascorbic acid with varying degree of inhibition and comparable to that of the Herkule activity. Thus, this study suggests that the ethanolic extract of R. prinoides has a good antioxidant activity like Herkule as a potential source of natural antioxidant. This study indicated that R. prinoide plant is a promising source of antioxidants for utilization in beer brewery fields as bittering agent. Top Keywords Antioxidant activity, DPPH assay, Herkules, Rhamnus prinoides, Scavenging activity. Top |