Antidiabetic phytoconstituents and their mode of action on metabolic pathways

Diabetes Mellitus, characterized by persistent hyperglycaemia, is a heterogeneous group of disorders of multiple aetiologies. It affects the human body at multiple organ levels thus making it difficult to follow a particular line of the treatment protocol and requires a multimodal approach. The increasing medical burden on patients with diabetes-related complications results in an enormous economic burden, which could severely impair global economic growth in the near future. This shows that today's healthcare system has conventionally been poorly equipped towards confronting the mounting impact of diabetes on a global scale and demands an urgent need for newer and better options. The overall challenge of this field of diabetes treatment is to identify the individualized factors that can lead to improved glycaemic control. Plants are traditionally used worldwide as remedies for diabetes healing. They synthesize a diverse array of biologically active compounds having antidiabetic properties. This review is an endeavour to document the present armamentarium of antidiabetic herbal drug discovery and developments, highlighting mechanism-based antidiabetic properties of over 300 different phytoconstituents of various chemical categories from about 100 different plants modulating different metabolic pathways such as glycolysis, Krebs cycle, gluconeogenesis, glycogen synthesis and degradation, cholesterol synthesis, carbohydrate metabolism as well as peroxisome proliferator activated receptor activation, dipeptidyl peptidase inhibition and free radical scavenging action. The aim is to provide a rich reservoir of pharmacologically established antidiabetic phytoconstituents with specific references to the novel, cost-effective interventions, which might be of relevance to other low-income and middle-income countries of the world.