scholarly journals Pancreatic and extra-pancreatic effects of the traditional anti-diabetic plant, Medicago sativa (lucerne)

1997 ◽  
Vol 78 (2) ◽  
pp. 325-334 ◽  
Author(s):  
Alison M Gray ◽  
Peter R Flatt

Medicago sativa (lucerne) is used as a traditional plant treatment of diabetes. In the present study, administration of lucerne in the diet (62·5 g/kg) and drinking water (2·5 g/l) reduced the hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of lucerne (1 mg/ml) stimulated 2-deoxy-glucose transport (1·8-fold), glucose oxidation (1·7-fold) and incorporation of glucose into glycogen (l·6-fold) in mouse abdominal muscle. In acute 20 min tests, 0·25–1 mg/ml aqueous extract of lucerne evoked a stepwise 2·5–6·3-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0·5 mM-diazoxide, and prior exposure to extract did not affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby negating a detrimental effect on cell viability. The effect of extract was potentiated by 16·7 mM-glucose and by 1 mM-3-isobutyl-1-methylxanthine. L-Alanine (10 mM) and a depolarizing concentration of KCI (25 mM) did not augment the insulin-releasing activity of lucerne. Activity of the extract was found to be heat stable and largely acetone insoluble, and was enhanced by exposure to acid and alkali (0·1 M-HCI and NaOH) but decreased 25% with dialysis to remove components with molecular mass <2000 Da. Sequential extraction with solvents revealed insulin-releasing activity in both methanol and water fractions indicating a cumulative effect of more than one extract constituent. The results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in the traditional antidiabetic plant, Medicago sativu.

1999 ◽  
Vol 81 (3) ◽  
pp. 203-209 ◽  
Author(s):  
Alison M. Gray ◽  
Peter R. Flatt

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.


1998 ◽  
Vol 157 (2) ◽  
pp. 259-266 ◽  
Author(s):  
AM Gray ◽  
PR Flatt

Agaricus campestris (mushroom) has been documented as a traditional treatment for diabetes. Here the administration of mushroom in the diet (62.5 g/kg) and drinking water (2.5 g/l) countered the hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of mushroom (1 mg/ml) stimulated 2-deoxyglucose transport (2.0-fold), glucose oxidation (1.5-fold) and incorporation of glucose into glycogen (1.8-fold) in mouse abdominal muscle. In acute 20 min tests, 0.25-1 mg/ml aqueous extract of mushroom evoked a stepwise 3.5- to 4.6-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0.5 mM diazoxide and prior exposure to extract did not affect subsequent stimulation of insulin secretion by 10 mM L-alanine, thereby negating a detrimental effect on cell viability. The effect of extract was potentiated by 16.7 mM glucose, L-alanine (10 mM) and IBMX (1 mM), and a depolarising concentration of KCl (25 mM) did not augment the insulin-releasing activity of mushroom. Activity of the extract was found to be heat stable, acetone soluble and unaltered by exposure to alkali, but decreased with exposure to acid. Dialysis to remove components with molecular mass < 2000 Da caused a 40% reduction in activity. Sequential extraction with solvents revealed insulin-releasing activity to be greatest in polar fractions. Lack of haemagglutinin activity with extract activity indicated that activity was unlikely to be due to a lectin-mediated event. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in A. campestris.


1998 ◽  
Vol 80 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Alison M. Gray ◽  
Peter R. Flatt

Agrimony eupatoria (agrimony) has been documented as a traditional treatment of diabetes. Here, the effects of dietary administration of agrimony on streptozotocin (STZ)-diabetic mice and on in vitro glucose uptake and glucose metabolism, and on insulin secretion by BRIN-BD11 cells were investigated. Agrimony incorporated into the diet (62·5 g/kg) and drinking water (2·5 g/l) countered the weight loss, polydipsia, hyperphagia and hyperglycaemia of STZ-diabetic mice. Aqueous extract of agrimony (1 mg/ml) stimulated 2-deoxy-glucose transport (1·4-fold), glucose oxidation (1·4-fold) and incorporation of glucose into glycogen (2·0-fold) in mouse abdominal muscle comparable with 0·1 μM-insulin. In acute 20 min tests, 0·25-1 mg/ml aqueous extract of agrimony evoked a stepwise 1·9–3·8-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0·5mM-diazoxide and previous exposure to extract did not adversely affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby indicating that there was no detrimental effect of the extract on cell viability. The effect of extract was glucose-independent and was not evident in BRIN-BD11 cells exposed to a depolarizing concentration of KCl. The ability of agrimony extract to enhance insulin secretion was dependent on use of heat during extract preparation. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Agrimony eupatoria.


1999 ◽  
Vol 160 (3) ◽  
pp. 409-414 ◽  
Author(s):  
AM Gray ◽  
PR Flatt

Viscum album (mistletoe) has been documented as a traditional treatment of diabetes. In acute 20-min tests, 1-10 mg/ml aqueous extract of mistletoe evoked a stepwise 1.1- to 12.2-fold stimulation of insulin secretion from clonal pancreatic B-cells. This effect was abolished by 0.5 mM diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion induced by 10 mM L-alanine, thereby negating a detrimental effect on cell viability. The insulin-releasing effect of mistletoe extract was unaltered by 16.7 mM glucose, l-alanine (10 mM), 3-isobutyl-1-methylxanthine (IBMX) (1 mM), or a depolarising concentration of KCl (25 mM). The ability of extract to enhance insulin secretion did not depend upon the use of heat during extract preparation and was not mediated by lectins. These results demonstrate the presence of insulin-releasing natural product(s) in Viscum album which may contribute to the reported antidiabetic property of the plant.


2010 ◽  
Vol 13 (1) ◽  
pp. 50-54
Author(s):  
Tatiana Ivanovna Romantsova ◽  
Nadezhda Viktorovna Maksimova

Type 2 diabetes is believed to develop as a result of lowered insulin secretion and insulin resistance leading to hyperglycemia. Sulfonylureas stimulateinsulin secretion and thereby decrease blood glucose level which accounts for their wide application in the treatment of diabetes. However, manyagents of this class produce side effects (increased body mass, hypoglycemia, resistance to therapy, etc.) attributable to excess stimulation of insulinsecretion. Glimepiride is as efficient as traditionally used sulfonylureas but causes a smaller rise in insulin secretion. Sulfonylurea receptors showlower affinity for glimepiride than for glibenclamide. Formation and dissociation of glimepiride-receptor complexes occur faster than those of glibenclamide-receptor complexes. In addition, therapeutic effect of glimepiride was shown to be associated with improved insulin sensitivity. It is concludedthat glimepiride is an efficacious agent for the treatment of type 2 diabetes.


1980 ◽  
Vol 95 (3) ◽  
pp. 372-375 ◽  
Author(s):  
B. J. Burke ◽  
R. J. Sherriff

Abstract. Residual insulin secretion, reflected by the presence of C-peptide in serum and urine, has been demonstrated in 5 of 10 insulin-requiring diabetics of less than 10 years' duration tested. The C-peptide response, in the C-peptide secretors, showed a significant increase in both serum and urine after 4 weeks' treatment with 15 mg glibenclamide daily in addition to their usual insulin regime although no beneficial effects in metabolic control were detected. It is suggested that glibenclamide might be a useful adjunct to insulin therapy in insulinrequiring diabetics who still secrete C-peptide.


Diabetes ◽  
1985 ◽  
Vol 34 (6) ◽  
pp. 548-552 ◽  
Author(s):  
R. L. Hanson ◽  
C. M. Isaacson ◽  
L. D. Boyajy

Diabetes ◽  
2007 ◽  
Vol 56 (4) ◽  
pp. 1087-1094 ◽  
Author(s):  
M. G. Latour ◽  
T. Alquier ◽  
E. Oseid ◽  
C. Tremblay ◽  
T. L. Jetton ◽  
...  

1983 ◽  
Vol 38 (9-10) ◽  
pp. 711-718 ◽  
Author(s):  
U. Margna ◽  
T. Vainjärv

A short treatment of excised buckwheat cotyledons with a solution of kinetin lead to an up to 9-fold stimulation of anthocyanin biosynthesis, to an about 50 percent increase in the accumula­tion of rutin, and to an about 30 percent increase, on the average, in the accumulation of C-glycosylflavones in the treated material during its posttreatment incubation in the dark. When the treated cotyledons were incubated in a solution of ʟ--phenylalanine anthocyanin accumulation in the dark practically attained the same high level as it was observed in the illuminated cotyledons fed with exogenous ʟ--phenylalanine. In experiments with l4C-labelled L-phenylalanine kinetin induced a sharp rise in the labelling (resp. in the utilization of exogenous substrate for biosynthesis) of anthocyanins and rutin in the dark and a slight increase in the radioactivity of C-glycosylflavones. Similar labelling changes occurred in the illuminated cotyledons. However, both kinetin and light still more effectively promoted biosynthetic use of the endogenous sub­strate. As a result the relative portion of flavonoids formed from exogenous L-phenylalanine under these conditions showed a decrease as compared with the ratio of precursor use in the un­treated cotyledons. The results show that low accumulation rates of anthocyanins and other flavo­noids in the dark are conditioned by the limited access of substrate (ʟ--phenylalanine) molecules to the flavonoid enzymes lending further support to the idea that flavonoid biosynthesis is normally controlled at the substrate rather than at the enzymic level.


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