Physicochemical Characteristics and Physiological Activity of Bitter Melon (Momordica charantia L.) from Different Regions

This study was conducted to determine the physicochemical characteristics of dry bitter melons (Momordica charantia L.) harvested from different regions (Hamyang, Jungeup, and Gangjin). The moisture content in the dry bitter melons occurred in the order Gangjin (6.60%) greater than Jungeup (5.81%) greater than Hamyang (4.35%), and the ash content in all three regions ranged between 8.55~9.31%. The crude protein content in dry bitter melons occurred in the order Gangjin (17.88%) greater than Hamyang (16.25%) greater than Jungeup (13.66%), while the total minerals content occurred in the order Hamyang greater than Jungeup greater than Gangjin. Among the minerals, K content was the highest in all three regions, and P, Mg, Ca, Na content were higher than other minerals in bitter melons from different regions. The level of reducing sugar was significantly higher in dry bitter melons from Jungeup than from other regions. In addition, the reducing sugar content of extracts of bitter melon from different regions differed significantly as follows: water greater than 50% ethanol greater than 100% ethanol. The total polyphenol content, antioxidant activities, and xanthine oxidase (XO) inhibition activity were significantly higher in dry bitter melons from Hamyang than other regions, and these activities were not dependent on the nature of the extraction solvent. The alpha-glucosidase inhibition activity occurred in the order Jungeup Gangjin Hamyang, and increased in direct proportion to the ethanol ratio of the extraction solvent. Based on the results, distinct tendency were not found in the major components and physiological activities of bitter melon according to the origin and extraction solvent. However, the antioxidant activity and XO inhibition activity were well correlated with total polyphenol content, while the reducing sugar and glucosidase inhibitory activity had a low correlation with total polyphenol content.