Application of Nigella sativa as a functional food in diabetes and related complications: Insights on molecular, cellular, and metabolic effects

• Nigella sativa attenuates diabetes-induced oxidative stress and inflammation. • Nigella sativa reduces diabetes-induced apoptosis and oxidative DNA damage. • Nigella sativa combats diabetes-induced micro and macro vascular damages. • Nigella sativa alleviates the adverse effects of diabetes complications. Various studies have been conducted on the effect of medicinal plants in the treatment of different diseases, including diabetes. Nigella Sativa (N. sativa) is a plant with edible and medicinal properties that are of interest to scientists in traditional and complementary medicine, and much research has been conducted on this plant. Comprehensive reports are used to investigate the effect of N. sativa in vitro , animal models, and clinical trials in the treatment of diabetic diseases. An online database search was conducted to investigate the potential anti-diabetic effect of N. sativa . The results of various studies indicate that this plant can act as hypoglycemic, and due to antioxidant properties, it can have positive results in reducing blood sugar and glycosylated hemoglobin levels and controlling insulin secretion and glucose homeostasis. The effect of N. sativa in animal models has shown that N. sativa oil can eliminate oxygen-free radical species similar to hydroxyl free radicals and superoxide radical anions. Therefore, in this review study, we intend to address all the therapeutic aspects and effects of the black seed plant in the cellular and animal environment and clinical trial studies for the optimal use of this medicinal plant. In conclusion, the antidiabetic activities of N. sativa are indeed well established. However, in some cases, the molecular modulation underlying these activities remains unknown. N. sativa has been demonstrated to improve blood glucose and insulin levels, mitigate diabetes complications, and stimulate glucose absorption. Its antioxidant function, flavonoid and triterpenoid components, and potency to modulate insulin secretion in pancreatic cells introduced it as a safe medicinal herb for dietary adjuvant with antidiabetic medications. However, it has been declared to a decline in blood lipid profiles, and risk factors for cardiovascular diseases in Type 2 Diabetes patients. Further research must concentrate on patients unresponsive to available anti-diabetic drugs and hyperlipidemia T2D. Thus, further studies into its medicinal effects are recommended.