In vitro Modulation of Pancreatic MIN6 Insulin Secretion and Proliferation and Extrapancreatic Glucose Absorption by Paronychia argentea, Rheum ribes and Teucrium polium Extracts

The present study design investigated the effects of crude aqueous extracts (AE) of Paronychia argentea Lam.,Rheum ribes L. and Teucrium polium L., traditionally utilized in diabetes treatment in Jordan, on the pancreaticβ-cell MIN6 proliferation and insulin secretion and extrapancreatic glucose diffusion. In an ascending order, R.ribes, T. polium and P. argentea concentrations induced a MIN6 monolayers expansion by respective 118-136%,158-175% and 140-200% (P 0.001), thus exceeding GLP-1 (5 nM) pancreatic proliferative capacity. Like Lalanine(10 mM) insulinotropic efficacy and without exerting cytotoxicity, glucose stimulated insulin secretionwas potentiated by AEs of R. ribes (373-736%, P 0.001) and T. polium (503-1190% P 0.001). P. argentea AEwas inactive at used doses. The potent plants’ insulin secretory bioactivities were abolished in the depleted Ca2+conditions (P 0.001). Comparable to guar gum (50 mg/ml) diffusional hindrance in a simple dialysis model, P.argentea inhibited overnight glucose movement in vitro (by 38.1±1.9% AUC reductions, P 0.001), while R.ribes and T. polium AEs proved inactive. This in vitro evaluation has revealed that all three plants augmented β-cell expansion, P. argentea inhibited carbohydrate absorption and R. ribes and T. polium stimulated insulinsecretion. These actions depend on their intact absorption in vivo. Future directives may assess the use of P.argentea, R. ribes and T. polium as new potential sources with functional properties for food or nutraceuticalproducts or active leads into anti-diabetes pharmacotherapy