ABSTRACT
Psidium guajava L. (guava), a small medicinal tree in tropical and subtropical areas, has been widely used in indigenous medicinal systems for the management of several diseases, including diabetes mellitus. To date, different extracts of plant parts of P. guajava and their isolated phytoconstituents have been screened for different bioactivities through preclinical and clinical studies. The present chapter highlights the botanical identity, distribution, phytochemical constituents, pharmacological studies, antidiabetic response, traditional, and other potential uses, safety issues, and cultivation practices of P. guajava. Active constituents such as quercetin, kaempferol, guaijaverin, avicularin, myricetin, hyperin, gallic acid, ellagic acid, citric acid, catechin, beta-sitosterol, oleanolic acid, and ursolic acid are responsible for the antidiabetic activity of P. guajava. Underlined molecular mechanisms of the antidiabetic activity of P. guajava include inhibition of glucose absorption from the small intestine, enhancement of secretion of insulin, and facilitation of the controlled release of glucose from the liver. More studies are warranted to isolate bioactive compounds with an aim of developing novel drug leads for the management of diabetes mellitus.
