Investigation of in-vitro hypoglycaemic activity of the different fractions of black pepper (Piper nigrum)

The study involved extracting different fractions from black pepper using solvents of varying polarities. The three fractions obtained were the PEF, CHF, and AQF. The yield values of the fractions were determined, and it was found that PEF had the highest yield, while AQF had the lowest. Subsequently, three in vitro hypoglycemic tests were performed to evaluate the hypoglycaemic activity of black pepper. The IC50 value (the concentration required for 50 % inhibition) for the alpha-amylase inhibitory activity was found to be 1.191 for PEF and 3.591 for CHF where acarbose, a standard hypoglycaemic drug, was used as a reference in this test. The second test evaluated the alpha-glucosidase inhibitory activity, where PEF exhibited an IC50 value of 1.47, and CHF had an IC50 value of 2.95 and again acarbose was utilized as the standard for comparison. The third test involved assessing glucose uptake by yeast cells. At 5 Mm glucose concentration and 5 mg/ml extract concentration, the percentage of glucose uptake by yeast cell was 69 for CHF and 76 for PEF. At 10 Mm glucose concentration and 5 mg/ml extract concentration, the percentage of glucose uptake by yeast cell was 43 for CHF and 57 for PEF. At 25 Mm glucose concentration and 5 mg/ml extract concentration, the percentage of glucose uptake by yeast cell was 28 for CHF and 30 for PEF. It was concluded that the PEF fraction of black pepper exhibited better hypoglycaemic activity compared to the standard metronidazole from the tests. However, further research and studies are necessary to isolate and identify the specific bioactive compounds responsible for the observed hypoglycaemic effects and to evaluate their efficacy and safety.