Effect of Black Seed Oil on Markers of Endothelial Dysfunction in Patients with Type 2 Diabetes Mellitus

Abstract

Diabetes mellitus has been defined as a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes mellitus is associated with long term damage, dysfunction, and failure of different organs, especially the eyes, kidneys, nerves, heart, and blood vessel. Glucotoxicity, lipotoxicity, insulin resistance, oxidative stress and inflammation associated with diabetes can negatively impact the endothelium through diminishing nitric oxide bioavailability and the excessive production of reactive oxygen and nitrogen species, thus increasing the susceptibility of the vasculature to oxidative damage. In recent times, endothelial dysfunction (ED) gained a focused attention due to its critical role in the initiation and progression of atherosclerosis as well as being an early predictive factor for cardiovascular events. Extensive data from the literature demonstrated the benefits of targeting ED in reducing cardiovascular morbidity and mortality. With the long-term use of the currently available antidiabetic medications, most of them failed to achieve a consistent glycemic control and their use are associated with many undesirable side effects. Therefore, Putting in consideration novel therapies that can not only improve hyperglycemia but also prevent or at least delay the initiation and progression of diabetic complications is a need. Being back to nature, several experimental and clinical studies demonstrated the positive effect of herbal medicine such as Traditional Chinese Medicines on ED. Nigella sativa L. (NS), commonly known as black seed or black cumin in English ,and " Al Habbah El Sawda" or "Habbtul-Barakah " in Arabic, is a herbaceous plant that belongs to a big family called Ranunculaceae. A large body of literature demonstrated the miraculous healing properties of NS including anti-diabetic, anti-microbial, anti-obesity, anti-hyperlipidemic, anti-convulsant, analgesic, cardioprotective, anti-cancer, neuroprotective, gastroprotective, anti-rheumatic, anti-asthmatic, renoprotective, hepatoprotective, anti-toxicity, sexual and reproductive health, as well as wound healing properties. Experimental animal research has increasingly shown that NS has a potential ameliorative effect on ED. This might be accomplished by increasing endothelial nitric oxide synthase while decreasing cell adhesion molecules and the expression of oxidized low density lipoprotein receptor-1. Also, by replenishing vasodilating substances such endogenous nitric oxide and endothelium-derived hyperpolarizing factor, NS can increase endothelium-mediated vasorelaxant action. The current study was designed to evaluate the effect of black seed oil as an adjuvant therapy on the clinical outcome of type 2 diabetic patients. This was accomplished by assessing its effect on ED, glycemic control, lipid profile, inflammation, kidney functions, liver functions and patients' quality of life. The study was conducted on 50 type 2 diabetic patients. These patients were randomized to one