Natural medicines from plant source used for therapy of diabetes mellitus: An overview of its pharmacological aspects

Diabetes mellitus is chronic metabolic disorders that affect human body in terms of physical, psychological and social health. It is defined as a group of disorders characterized by hyperglycemia, altered metabolism of lipids, carbohydrates and proteins[1,2]. It is becoming the third “killer” of the health of mankind along with cancer, cardiovascular and cerebrovascular diseases[3]. The prevalence of diabetes mellitus is expected to reach up to 4.4% in 2030, and the occurrence was found to be high in India, China, and USA. Historical accounts reveal that as early as 200 BC, diabetes mellitus was well recognized disease in India even as distinguished in two types: a genetically based disorder and a dietary related disorder[4]. Among all the cases of diabetes, type 2 diabetes was found to be more prevelent[5]. The pernicious effects of diabetes have been found to be mediated through oxidative stress. Oxidative stress is associated with increased production of reactive oxygen species and impaired antioxidant defense systems, which cause lipid peroxidation, alteration in antioxidant enzymes and impaired glutathione metabolism[6]. The increased production and ineffective scavenging of reactive oxygen species may play a critical role in diabetese mellitus. Disturbance of antioxidants defence system in diabetes is mainly because of alteration in antioxidant enzymes, impaired glutathione metabolism, and decreased ascorbic acid levels[7,8]. The principal diagnostic feature of diabetes mellitus is elevated blood glucose level, which leads to increased formation and accumulation of advanced glycation products (AGEs) and sorbitol concentration, which play an important role in diabetic complications, such as retinopathy, neuropathy, and renal dysfunction[9]. Knowledge about diabetes mellitus existed in ancient Egypt and Greece. The word “diabetes” is derived from the Greek word “Diab” (meaning to pass through, referring to the cycle of heavy thirst and frequent urination); “mellitus” is the Latin word for “sweetened with honey” (refers to the presence of sugar in the urine)[2]. According to ancient Hindu physicians, “Madhumeha” is a disease in which a patient passes sweet urine and exhibits sweetness all ARTICLE INFO ABSTRACT