Diabetes mellitus is one of the most commonly occurring endocrinological diseases in today’s world. To circumvent the problem, the age old, described plant products with action on the specific problem of Type II diabetes mellitus is worthy. Costus igneus is commonly known as insulin plant and has an antidiabetic effect and there are many animal studies performed reflecting the antidiabetic property of the Costus species on dexamethasone induced diabetes mellitus. Alpha amylase and Alpha glucosidase are important enzymes that are responsible for the breakdown of starch into oligosaccharides during the absorption from intestine. By accessing the Alpha amylase inhibition and Alpha glucosidase inhibition activity one can assess the antidiabetic action of the study substance. The objective of the study was to compare the α-amylase and α-glucosidase inhibition activity of aqueous extracts of Costus igneus with that of Metformin in in-vitro studies. The study plant (Costus igneus) and control drug (Metformin) were taken and subjected to evaluation of their antidiabetic effects. 10 gm of fresh leaves sample was weighed and soaked in 100 ml of aqueous solution (Distilled Water). The extract was allowed to stand overnight and filtered using sterile filter paper. The filtrate was used for the study. Different concentrations of the aqueous extract of the leaf from the plant Costus igneus and the solution of drug Metformin (100-500 µl) and standard drug (Acarbose) were taken and assessed for the antidiabetic activity based on their α-amylase and α-glucosidase inhibition. The alpha-amylase inhibition action of Costus igneus was 89% of that of Metformin at a concentration of 500 µg. The alpha-glucosidase inhibition action of Costus igneus was 66.6% of that of Metformin at a concentration of 500 µg. The aqueous extract of the leaves of Costus igneus could serve as an alternative to the commonly used antidiabetic drug Metformin. 
Keywords: Acarbose, Alpha-amylase, Alpha-glucosidase, Costus igneus, Metformin