Antioxidant and Antidiabetic Properties of the Water Extract from Sigoise Olive Cultivar (Olea europaea L.), El Oued Region (Algeria)

Olive tree leaves (Olea europaea L.) have been widely used in Mediterranean traditional medicine to prevent and treat various ailments. This study investigated the effects of consuming a water extract of Sigoise olive leaves on antioxidant levels and type II diabetes. The extract was prepared by steeping 10 g of dried olive leaves in 500 mL of boiling water and then given to 20 Algerian volunteers (10 diabetic subjects and 10 healthy controls), who consumed it twice a day for a month. The volunteers were screened by biochemical blood tests before and by the end of the experiment. The antioxidant activity was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl-based assay, 35.3 +/- 0.5 mg/mL) and FRAP assays (ferric reducing antioxidant power assay, 8.3 +/- 0.1 mg/mL). The quantitative analysis revealed high contents of total polyphenols (41.8 +/- 0.8 mg gallic acid equivalent per 1 g of extract) and total flavonoids (14.3 +/- 0.8 mg rutin equivalent per 1 g of extract). The hypoglycemic effect of the extract was shown, thus confirming that it helps improve renal function and prevents cardiovascular disorders in type II diabetic patients. No toxic effects on kidney or liver function were observed. Despite clear health-boosting benefits, further research is needed to fully validate them clinically.