The traditional plant treatment, Sambucus nigra (elder), exhibits insulin-like and insulin-releasing actions in vitro.
Sambucus nigra (elder) has been documented as a traditional treatment of diabetes. In the present study, an aqueous extract of elder (AEE, 1 g/L) significantly increased 2-deoxy-glucose transport, glucose oxidation and glycogenesis of mouse abdominal muscle in the absence of added insulin (2 x 2 factorial design). in acute 20-min tests, 0.25-1 g/L AEE evoked a stepwise stimulation of insulin secretion from clonal pancreatic beta-cells. The insulin releasing effect of AEE (0.5 g/L) was significantly potentiated by 16.7 mmol/L of glucose and significantly reduced by 0.5 mmol/L of diazoxide. AEE did not further enhance insulin secretion in cells stimulated by 10 mmol/L of L-alanine, 1 mmol/L of 3-isobutyl-1-methylxanthine or a depolarizing concentration of KCl (25 mmol/L). Prior exposure of clonal pancreatic beta-cells to AEE did not alter subsequent stimulation of insulin secretion induced by 10 mmol/L of L-alanine, thereby precluding a detrimental effect on cell viability. The insulinotropic action of AEE was partially dependent upon use of heat during extract preparation. Activity of AEE was heat-stable, acetone-insoluble and unaltered by prolonged exposure to acid/alkali (0.1 mol/L of HCl and NaOH). However, activity was significantly decreased 41% by dialysis to remove components with molecular mass <2000 Da. Sequential extraction with solvents revealed activity in both methanol and water fractions, indicating a cumulative effect of more than one extract constituent. Known constituents of elder, including lectin, rutin and the lipophilic triterpenoid (lupeol) and sterol (beta-sitosterol), did not stimulate insulin secretion. The results demonstrate the presence of insulin-releasing and insulin-like activity in the traditional antidiabetic plant, Sambucus nigra.
Gray
A M
AM
School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, United Kingdom.
Abdel-Wahab
Y H
YH
Flatt
P R
PR
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000409:Alanine / Q000494:pharmacology; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D005943:Gluconeogenesis / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D009699:N-Glycosyl Hydrolases; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010940:Plant Proteins / Q000627:therapeutic use*; D011500:Protein Synthesis Inhibitors / Q000627:therapeutic use*; D051381:Rats; D054790:Ribosome Inactivating Proteins, Type 2; D013311:Streptozocin
D007328:Insulin; D010726:Phosphodiesterase Inhibitors; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D054790:Ribosome Inactivating Proteins, Type 2; D013311:Streptozocin; D009699:N-Glycosyl Hydrolases; D005947:Glucose; D000409:Alanine; D015056:1-Methyl-3-isobutylxanthine