Comparative In-Vitro Analysis on Anti-Diabetic Potential of Most prevalent medicinal herbs

18 samples (including seed and pulp of cumini syzygium) were taken on the basis of the prevalent medicinal herbs Inhibition of α-amylase activity Starch solution (0.5%w/v) was prepared by stirring potato starch (0.125 g) in 20 mM sodium phosphate buffer with 6.7 mM sodium chloride (pH 6.9; 25 mL) in a boiling water bath for 15 min. The 𝛼-amylase solution was prepared by mixing 1 U/mL of amylase in the same buffer. The colorimetric reagent was prepared by mixing equal volume of sodium potassium tartrate tetrahydrate solution and 96 mM 3, 5-dinitro salicylic acid (DNS) solution. Starch solution (1000𝜇L) was mixed with increasing concentration of an enzyme inhibitor i.e sample (100, 200, 400, 800, 1000𝜇g/mL) or acarbose (100–1000𝜇g/mL), and to this 1000𝜇L of 𝛼-amylase solution was added and incubated at 25∘C for 3min to react with the starch solution. A 1000𝜇L of 96 mM DNS reagent was added to the above solution, and the contents were heated for 15 min on a boiling water bath. The final volume was made up with distilled water, and the absorbance was measured at 540 nm using spectrophotometer (A. Kuppusamy et.al; 2011). The percentage inhibition and 50% inhibitory concentration (IC50) value was calculated. Inhibition of α-glucosidase activity The 𝛼-glucosidase enzyme inhibition activity was determined by incubating 100𝜇L of 𝛼glucosidase enzyme (1 U/mL) solution with 100𝜇L of phosphate buffer (pH 7.0) which contains 100𝜇L of enzyme inhibitor such a sample (100-1000µg/ml) or acarbose (1001000𝜇g/mL) at 37∘C for 60min in maltose solution. To stop the 𝛼-glucosidase action on maltose, the above reaction mixture was kept in boiling water for 2 min and cooled. To this, 2 mL of glucose reagent was added and its absorbance was measured at 540 nm to estimate the amount of liberated glucose by the action of 𝛼-glucosidase enzyme (Srinivasan and Ramaroa; 2007) .The percentage inhibition and 50% inhibitory concentration (IC50) value was calculated. Percentage inhibition was calculated using following equation: Percentage inhibition=(absorbance of control - absorbance of sample)/(absorbance of control)*100% Percentage inhibition is then transformed in the form of IC50 value using software prism 5. Those samples with IC50 value near to that of standard i.e. Acarbose were considered the best among the samples used. They showed highest inhibition potential in both the cases.