British Journal of Nutrition

Research Article

Insulin-releasing and insulin-like activity of the traditional anti-diabetic plant Coriandrum sativum (coriander)

Alison M. Graya1 c1 and Peter R. Flatta1

a1 School of Biomedical Sciences University of Ulster, Coleraine, BT52 1SA, UK

Abstract

Coriandrum sativum (coriander) has been documented as a traditional treatment of diabetes. In the present study, coriander incorporated into the diet (62·5 g/kg) and drinking water (2·5 g/l, prepared by 15 min decoction) reduced hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of coriander (1 mg/ml) increased 2-deoxyglucose transport (1·6-fold), glucose oxidation (1·4-fold) and incorporation of glucose into glycogen (1·7-fold) of isolated murine abdominal muscle comparable with 10−8 m-insulin. In acute 20 min tests, 0·25–10 mg/ml aqueous extract of coriander evoked a stepwise 1·3–5·7-fold stimulation of insulin secretion from a clonal B-cell line. This effect was abolished by 0·5 mm-diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion by 10 mm-l-alanine, thereby negating an effect due to detrimental cell damage. The effect of extract was potentiated by 16·7 mm-glucose and 10 mm-l-alanine but not by 1 mm-3-isobutyl-1-methylxanthine. Insulin secretion by hyperpolarized B-cells (16·7 mm-glucose, 25 mm-KCl) was further enhanced by the presence of extract. Activity of the extract was found to be heat stable, acetone soluble and unaltered by overnight exposure to acid (0·1 m-HCl) or dialysis to remove components with molecular mass < 2000 Da. Activity was reduced by overnight exposure to alkali (0·1 m-NaOH). Sequential extraction with solvents revealed insulin-releasing activity in hexane and water fractions indicating a possible cumulative effect of more than one extract constituent. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Coriandrum sativum.

(Received April 03 1998)

(Revised October 05 1998)

(Accepted October 08 1998)

Correspondence:

c1 *Corresponding author: Dr Alison Gray, present address: Young Hearts Project, Level 3 McKinney House, Musgrave Park Hospital, Belfast BT9 7JB, UK, fax +44 (0) 1232 382008, email youngheartsproject@hpsspop.n-i.nhs.uk

0Comments