Inhibitory Effect of Extracts of Syzygium Cumini and Psidium Guajava on Glycosidases

Diabetes mellitus is one of the most common endocrine diseases and its type 2 is the major form of diabetes, accounting for 90% of cases worldwide. One of the complications of diabetes is post-prandial hyperglycemia (PPHG). The inhibition of carbohydrate hydrolyzing enzymes such as α-amylase can be an important in the control of blood glucose levels and managing PPHG in patients with type 2 diabetes. Amylase inhibitors have been shown to decrease intestinal absorption of carbohydrates by reducing intestinal amylase activity. However, there are few high-quality human studies that support the use of amylase inhibitors for any indication. Herbal alpha-amylase inhibitors have the ability to lower postprandial blood glucose level and should be used in the supplementary treatment of diabetes. Two herbal plants namely, Syzygium cumini (Eugenia jambolana or Jambul ) and Psidium guajava (Guava) were tested for their ability to inhibit α-amylase activity and to comment on the use in anti-diabetic treatment. The chloroform, aqueous and methanol extracts were prepared sequentially from leaves of guava and seeds of jambul. It was tested against human salivary amylase and it was observed that aqueous and methanolic extracts of both plants showed significant inhibition of alpha amylase. Plants extracts were further tested against rat pancreatic, liver and intestinal enzyme preparations for amylase inhibitory activity. The aqueous and methanolic extracts of both the plants showed high inhibition of rat pancreatic, liver and intestinal glucosidases.