Antioxidant and In-vitro Antidiabetic Activities of Fermented Peels of Citrus x Sinensis (l.) Osbeck (Rutaceae)

The various parts of Citrus sinensis plant have been employed over the years for medicinal purposes. As part of the concept of waste to wealth, the medicinal importance of the peels was exploited. This study aimed at determining the antioxidant and in vitro antidiabetic activities of fermented peel extracts of C. sinensis. Fermentation of the peels was carried out, and phytochemical tests were done. DPPH free radical scavenging activity, anti-lipid peroxidation and Antidiabetic assay method were performed in vitro using standard procedures. C. sinensis were rich in polyphenols and reducing sugars. Radical scavenging assay showed an IC50 of 0.57μg/ml and 1.60μg/ml for fresh peels and dried peels respectively for DPPH assay, and 0.67μg/ml (fresh) and 0.72μg/ml (dried) for anti-lipid peroxidation assay. The α-amylase inhibition assay showed that the fermented fresh peels and fermented dried peels had IC50 values of 2.23μg/ml and 2.73μg/ml respectively. The α-glucosidase assay showed better inhibition by the extracts. Fermented fresh and dried peels had IC50 values of 0.03μg/ml and 0.03μg/ml respectively. Fermented fresh peels of C. sinensis expressed relatively stronger protection in the antioxidant and antidiabetic assays than the fermented dried peels. This study revealed that extracts can be considered as an important addition to the therapeutic management for diabetes.