Ameliorative Effects of Essential Oils on Diabetes Mellitus: A Review

Diabetes mellitus (DM) is a metabolic disorder and is responsible for the death of more than 4.2 million people in 2019. Synthetic drugs for DM like metformin have been reported to induce numerous complications and side effects. Reports suggested that essential plant oil has been used as an herbal remedy to lower blood glucose levels. Essential oils (EOs) are complex combinations of small molecules obtained from plants via the process of steam distillation and several solvents. EOs have already shown great efficacy as antimicrobials, anti-inflammatory, hepatoprotective, and anti-hypertensive. This review aims to summarize some potential EOs that have been reported to have anti-diabetic activity both in preclinical and clinical aspects while summarizing the probable mechanism of action. The authors went through a vast number of articles from various scientific databases like Google Scholar, PubMed, and Web of Science. It was found that EO from a total of 20 plants has been pre-clinically investigated to have anti-diabetic potential. Besides this, clinical studies have reported the antidiabetic efficacy of EOs from Nigella sativa and Cuminum cyminum at different concentrations. Bioactive phytoconstituents like carvacrol, thymol, α- pinene, via . obtained from EOs ameliorate DM by inhibiting α-GLUC, α-amylase, lipase enzymes and increasing GLUT-4 expression, AKT phosphorylation, via . Although fewer in number, EOs from plant sources have demonstrated significant efficacy in DM. Proper elucidation of the anti-diabetic efficacy of the EOs may open up new avenues for drug discovery and development subjected to clinical studies.