Antidiabetic potential of gallic acid from Emblica officinalis: Improved glucose transporters and insulin sensitivity through PPAR-γ and Akt signaling

Background: Nature has gifted a variety of vital phytochemicals having potential therapeutic application against various ailments. Emblica officinalis (E. officinalis), an ancient plant, has long been used as a remedy for diabetes and cardiovascular complications, and presence of abundant amount of gallic acid could be accountable for its medicinal potential. Purpose: The study was aimed to determine the in-vivo and in-vitro anti-diabetic potential of gallic acid and fruit juice of E. officinalis. Molecular mechanism of gallic acid as well as fruit juice of E. officinalis for anti-diabetic potential has also been revealed. Experimental study design: Anti-diabetic potential of E. officinalis and gallic acid was evaluated in 3T3-L1 preadipocytes and various animal models like db/db mice and fructose administered rats. PPAR-gamma expression and glucose translocation were observed using western blot and PCR techniques. Results: Treatment of E. officinalis fruit juice and gallic acid facilitated their glucose homeostasis; improved insulin sensitivity; reduced obesity; abridged elevated blood pressure and declined cholesterol level, and also induced adipogenesis in 3T3-L1 adipocytes. Mechanistically, treatment increased expression of PPAR-gamma through activation of C/EBPs and simultaneously increased Glut4 translocation in 3T3-L1 adipocytes. Moreover, gallic acid treatment increased insulin sensitivity through activation of Akt rather than AMPK signaling pathway while fruit juice of E. officinalis showed dual activation, Akt and AMPK as well. Conclusion: These findings reveal the role of gallic acid in E. officinalis mediated antidiabetic potential, and delineate the upregulation of pAkt, PPAR-gamma and Glut4 in gallic acid mediated antidiabetic activity, thus providing potential therapy for diabetes and related disorders.