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

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.

Anti-hyperglycemic activities demonstrated by polyphenolic-rich extracts of A. paniculata when compared to glibenclamide and normal control, could possibly have been occasioned by β-cell protection, restoration of glycolytic enzymes as well as mitigation of inflammatory markers via antioxidant defensive/protective properties of the extracts.

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 (TNFα) 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 β-cell protection, restoration of glycolytic enzymes as well as mitigation of inflammatory markers via antioxidant defensive/protective properties of the extracts.