Comparative In-Vitro Analysis on Anti-Diabetic Potential of Selected Medicinal Herbs of Nepal
Description
18 samples (including seed and pulp of Syzygium cumini) were taken on the basis of the prevalent medicinal herbs Inhibition of the ฮฑ-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 ๐ผ-amylase solution was prepared by mixing 1 U/mL of amylase in the same buffer. The colorimetric reagent was prepared by mixing an equal volume of sodium potassium tartrate tetrahydrate solution and 96 mM 3, 5-dinitro salicylic acid (DNS) solution. Starch solution (1000๐L) was mixed with increasing concentration of an enzyme inhibitor i.e sample (100, 200, 400, 800, 1000๐g/mL) or acarbose (100โ1000๐g/mL), and to this 1000๐L of ๐ผ-amylase solution was added and incubated at 25โC for 3min to react with the starch solution. A 1000๐L 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 of distilled water, and the absorbance was measured at 540 nm using a spectrophotometer (A. Kuppusamy et.al; 2011). The percentage inhibition and 50% inhibitory concentration (IC50) values were calculated. Inhibition of ฮฑ-glucosidase activity The ๐ผ-glucosidase enzyme inhibition activity was determined by incubating 100๐L of ๐ผglucosidase enzyme (1 U/mL) solution with 100๐L of phosphate buffer (pH 7.0) which contains 100๐L of enzyme inhibitor such a sample (100-1000ยตg/ml) or acarbose (1001000๐g/mL) at 37โC for 60min in maltose solution. To stop the ๐ผ-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 a ๐ผ-glucosidase enzyme (Srinivasan and Ramaroa; 2007) . The percentage inhibition and 50% inhibitory concentration (IC50) values were calculated. Percentage inhibition was calculated using the 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 an IC50 value near to that of standard i.e. Acarbose were considered the best among the samples used. They showed the highest inhibition potential in both cases.