Guava (Psidium guajava L.) and banaba (Lagerstroemia speciosa L.) are well known as medicinal plants for their antidiabetic effects. These contain a great deal of polyphenol compound and work on the treatment of diabetes mellitus effectively. In this study, the extracts of guava and banaba are consumed by streptozotocin (STZ) induced diabetic rats to compare the antidiabetic effects. According to the comparison result, the glucose level of those STZ-induced diabetic rats has decreased by

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... total cholesterol by 24-46%, triglyceride by 22-67% and free fatty acid by 49-71% approximately compared to the diabetic rats, while the generation of insulin and the recovery of beta cells have increased. However, the result showed that the antidiabetic effect of guava extracts was higher than that of banaba extracts. This is because the hydrophilic polyphenol compounds contained in banaba leaves were not extracted during the ethanol extraction process, and the antidiabetic activity of the extracted corosolic acid was low to surprise.