Abstract

Oleracein E and oleracein L are the major bioactive isoquinoline alkaloids in Portulaca oleracea. Here, the effects of these alkaloids on cell survival, the activity of superoxide dismutase, catalase, and glutathione peroxidase, factors associated with oxidative stress such as malondialdehyde and dityrosine, carbohydrate-hydrolyzing enzymes alpha-amylase and alpha-glucosidase, insulin secretion levels and glucose uptake ability were investigated. The beta-TC-6 pancreatic cell line was incubated with oleracein E and L at concentrations of 0, 50, 100, 200 and 400 µM and tested separately. All biological assays were based on UV/Vis spectrophotometric and/or high performance liquid chromatography methods. Oleracein E and L at 100 μM concentrations increased antioxidant activity of enzymes. In addition, the total oxidative damage biomarkers ablated significantly in 50 and 100 μM concentrations, which could be due to the positive effect of antioxidant enzymes on biomarker level. Similar inhibition properties were shown by alpha-amylase and α-glucosidase and consequently, the investigated alkaloids could exhibit the high hypoglycemic effect. Furthermore, glucose uptake and insulin secretion were enhanced by these compounds. Hence, these alkaloids have considerable antioxidant and potential hypoglycemic effects on the pancreatic cell line and they could be suggested for future studies in the treatment of diabetes mellitus.