Polyphenolic-rich extracts of Andrographis paniculata mitigate hyperglycemia via attenuating [beta]-cell dysfunction, pro-inflammatory cytokines and oxidative stress in alloxan-induced diabetic Wistar albino rat

Background This study sought to investigate anti-hyperglycemic potentials of free and bound phenolic-rich extracts of Andrographis paniculata (A. paniculata) leaves, commonly called "king of the bitter", a plant locally employed in folkloric alternative medicine. Method In vitro antioxidant potentials such as total phenolic and flavonoid contents were evaluated in addition to phosphomolybdenum reducing total antioxidant activity in bound and free polyphenol-rich extracts of A. paniculata. Also, following induction of diabetes through a single intraperitoneal injection of freshly prepared alloxan monohydrate (150 mg/kg body weight, b.w), diabetic rats were divided into seven (7) treatment groups with six rats each (n = 6) i.e. group 1 (normal control), 2 (diabetic untreated), 3 (5 mg/kg glibenclamide -treated control), while 4-7 were administered 50 and 100 mg/kg b.w of free and bound phenolic extracts of A. paniculata, respectively for twenty-one (21) days. Results There was a significant (p < 0.05) difference in hematological indices, hepatic biomarkers, total protein, antioxidant enzymes activities, total thiol and fasting blood glucose levels of diabetic groups administered polyphenolic-rich extracts of A. paniculata compared to diabetic untreated control. Similarly, serum insulin levels, hexokinase and glucose-6-phoshatase activities were significantly (p < 0.05) improved in phenolic-rich extracts of A. paniculata-treated diabetic groups compared to diabetic untreated control. A significant (p < 0.05) reduction was as well observed in the levels of inflammatory biomarkers such as interleukin-6 (IL-6) and tumor necrosis factor (TNF[alpha]) among extract of A. paniculata administered diabetic groups compared diabetic untreated group. Conclusions Anti-hyperglycemic activities demonstrated by polyphenolic-rich extracts of A. paniculata when compared to glibenclamide and normal control, could possibly have been occasioned by [beta]-cell protection, restoration of glycolytic enzymes as well as mitigation of inflammatory markers via antioxidant defensive/protective properties of the extracts. Keywords: Andrographis paniculata, TNF[alpha], IL-6, Phenolic-rich extracts, Diabetes mellitus