The increasing population of Diabetes Mellitus (DM) in the world has always been concerned by physicians and scientists due to its life-threatening effects including heart diseases and premature death. Out of them, nearly 90-95% population is having type 2 diabetes mellitus (T2DM), characterised by insulin resistance. The available treatments for T2DM includes inhibition of α- glucosidase present on the brush border of human intestine that controls post-prandial hyperglycaemia by slower the releasing of glucose in the blood. Adverse effects of the available α- glucosidase inhibitors (AGI) such as abdominal discomfort and hypoglycaemia has prompted a search for the newer AGIs from natural compounds. The impact of various plant extracts on the management of medical disorders has recently aroused curiosity of researchers. Alstonia scholaris has set its hight reputation in ethnopharmacological world for treating major health issues including skin carcinoma, lung cancer and also T2DM. Though some research supports the antidiabetic activity of the plant, the mode of action responsible for it has yet to be discovered. At the same time, Catharanthus roseus has also been proved to be effective in diabetic conditions but in vitro study of antidiabetic activity of the plant is yet to be encountered. The presented study investigated different extracts of A. scholaris and C. roseus on α- glucosidase isolated from Saccharomyces cerevisiae. The presented research not only gives in-vitro proves of the plants as AGIs but also open ups new pathways in understanding the secondary metabolites as inhibitors.