INHIBITION OF ALPHA-GLUCOSIDASE BY POLYSACCHARIDES FROM WATER LETTUCE (Pistia stratiotes) LEAF EXTRACTS WITH DIFFERENT EXTRACTION METHODS

Diabetes mellitus (DM) is a metabolic disorder that has a significant impact on the quality of life and health. This condition is indicated by high blood glucose or hyperglycemia.  Alpha-glucosidase is an important enzyme during carbohydrate digestion to obtain monosaccharides such as glucose. This study aimed to investigate the alpha-glucoside inhibitory activity of polysaccharides from water lettuce (Pistia stratiotes) leaf with different extraction methods. The leaf was extracted by hot water extraction (HWE) and ultrasound-assisted extraction (UAE). The total sugar, crude fiber, and alpha-glucosidase inhibitory activity were analysis by in vitro, then an independent-sample t-test was used to analyze the statistically different. The UAE method showed a high yield of crude extract than the HWE method. However, the total sugar of HWE is higher than UAE, whereas no different of crude fiber level. The extract from the HWE method more effectively inhibits the alpha-glucosidase activity when compared to UAE. Therefore, hot water extraction is the suitable method to extract polysaccharides from a water lettuce (Pistia stratiotes) leaf. This condition also indicated polysaccharides extract potential to develop as an antidiabetes agent.