Some selected medicinal plants with antidiabetic potentials

Abstract

Diabetes mellitus is a metabolic disorder that is characterized by hyperglycemia associat‐ ed with impairment in insulin secretion and/or insulin action as well as aberrations in intermediary metabolism of carbohydrates, proteins and lipids. Several reports indicate that annual incidence rate of diabetes mellitus will increase in the future worldwide, especial‐ ly in the developing countries [1]. The effects of diabetes mellitus include long-term damage, dysfunction and failure of various organs. Diabetes mellitus may present with classical characteristic features such as blurring of vision, excessive thirst (polydypsia), excessive feeding (polyphagia) excessive urination (polyuria), and weight loss. In its most severe forms, ketoacidosis may develop leading to stupor, coma and, in absence of effective treatment death ensues [2]. Often symptoms are not severe, or may be absent, and consequently hyperglycaemia sufficient to cause pathological and functional changes may be present for a long time before the diagnosis is made. On the other hand, other chronic features of diabetes mellitus include progressive development of the specific complications of retinopathy with potential blindness. Nephropathy that may lead to renal failure with risk of foot ulcers, amputation, including reproductive dysfunction [3-6]. People with diabetes are at increased risk of developing cardiovascular, peripheral vascular and cerebrovascular disease [7-8]. These include processes which destroy the beta cells of the pancreas with consequent insulin deficiency and ultimately Insulin resistance was recently reported to be associated with obesity and type 2 diabetes[11]. Recent studies suggest that a complex interaction between inflammation, endoplasmic reticulum stress, oxidative stress, mitochondrial dysfunction and autophagy dysregulation play an important role in insulin resistance. The stress-activated c-Jun N-terminal kinase (JNK) has been increasingly recognized as a central mediator of insulin resistance [11] and suppres‐ sion of the JNK pathway has been shown to improve insulin resistance and glucose tolerance. Also, hyperhomocysteinemia (HHcy) was found to induce insulin resistance in adipose tissue via activation of JNK pathway [12].