Insulin secretory actions of extracts of Asparagus racemosus root in perfused pancreas, isolated islets and clonal pancreatic beta-cells.
Asparagus racemosus root has previously been reported to reduce blood glucose in rats and rabbits. In the present study, the effects of the ethanol extract and five partition fractions of the root of A. racemosus were evaluated on insulin secretion together with exploration of their mechanisms of action. The ethanol extract and each of the hexane, chloroform and ethyl acetate partition fractions concentration-dependently stimulated insulin secretion in isolated perfused rat pancreas, isolated rat islet cells and clonal beta-cells. The stimulatory effects of the ethanol extract, hexane, chloroform and ethyl acetate partition fractions were potentiated by glucose, 3-isobutyl-1-methyl xanthine IBMX, tolbutamide and depolarizing concentration of KCl. Inhibition of A. racemosus-induced insulin release was observed with diazoxide and verapamil. Ethanol extract and five fractions increased intracellular Ca(2+), consistent with the observed abolition of insulin secretory effects under Ca(2+) -free conditions. These findings reveal that constituents of A. racemosus root extracts have wide-ranging stimulatory effects on physiological insulinotropic pathways. Future work assessing the use of this plant as a source of active components may provide new opportunities for diabetes therapy.
Hannan
J M A
JM
Diabetes Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
Marenah
Lamin
L
Ali
Liaquat
L
Rokeya
Begum
B
Flatt
Peter R
PR
Abdel-Wahab
Yasser H
YH
D000818:Animals; D027761:Asparagus Plant; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002999:Clone Cells; D003920:Diabetes Mellitus / Q000628:therapy; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010477:Perfusion; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D007328:Insulin; D010936:Plant Extracts; D002118:Calcium