Leaf extracts of the tropical “water apple” plant may help lower blood sugar levels in people with diabetes, according to a study published in Food Chemistry.
Researchers from University of Malaya and Monash University in Malaysia found that the ethanolic extracts of the medicinal S. aqueum leaf are strong antihyperglycaemic agents.
They found that the leaf extracts were significantly more effective than the commercial drug acarbose in stabilizing blood sugar.
Specifically, the leaf extracts inhibited the carbohydrate hydrolysing enzymes alpha glucosidase and alpha amylase, both of which breakdown starch into sugars.
The leaf extracts also inhibited the key enzyme in the polyol pathway called aldose reductase, which is believed to cause diabetic complications in the nerves, eyes, and kidneys.
What's more, the researchers found that the leaf extracts prevent the formation of advanced glycation end products (AGEs) by 89 percent. Evidence shows that AGEs play an important role in almost all diabetes complications, according to Diabetes Journal.
The study isolated six flavonoid compounds from the ethanolic leaf extracts. Two of the flavonoids, europetin-3-O-rhamnoside and phloretin, where highly effective in inhibiting alpha glucosidase and alpha amylase.
Diabetes is the leading cause of kidney failure, new cases of blindness, and nontraumatic lower-limb amputations among adults in the United States, according to the Centers for Disease Control. The disease is a major cause of heart disease and stroke, and is the seventh leading cause of death in the US.
Grown in tropical regions
Syzygium aqueum is grown in tropical regions like Malaysia, southern India, Indonesia, the Philippines, and Thailand. The tree requires low altitudes where there is steady rainfall throughout the year.
A species of brush cherry tree, the water apple is also known as “watery rose apple” or “water guava.”
The fruit of the water apple is pear shaped, shiny and crisp, with flesh that is white, light read or red. The bark of the tree is sometimes used in herbal medicines, while the leaves are edible and sometimes used to wrap food.