Cardiovascular effect of Artemisia herba alba aqueous extract in spontaneously hypertensive rats.

This study aimed to evaluate the hypotensive activity of Artemisia herba alba aqueous extract (AHAE) in spontaneously hypertensive rats (SHR). AHAE was lyophilized and administered daily at a dose of 150 mg/kg for 20 days. AHAE administration produced a significant reduction in systolic blood pressure after 8 days of oral administration (P < 0.01), and a sustained reduction was observed at the end of treatment (P < 0.01). Heart rate remained unchanged during the 20 days of oral AHAE administration. In addition, AHAE administration produced a significant increase in urinary output (P < 0.01) and glomerular filtration rate (P < 0.01) on day 8 of treatment. Urinary electrolyte excretion was also modified during the 20 days of AHAE administration, and a significant increase in urinary sodium and potassium excretion was observed from day 4 (P < 0.01) to day 20 (P < 0.001). However, urinary chloride excretion was increased from day 8 (P < 0.01) to the end of treatment (P < 0.001). The hypotensive effect appeared to be independent of the renin-angiotensin system since AHAE did not affect plasma angiotensin-converting enzyme or renin activities (P > 0.05) after 20 days of oral administration. We conclude that AHAE possesses antihypertensive activity in SHR and that the underlying mechanism appears to involve, at least in part, an increase in urine and electrolyte output.

Cholesterol and triglycerides lowering activities of caraway fruits in normal and streptozotocin diabetic rats.

The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Carum carvi L. fruits at a dose of (20mg/kg) on lipid metabolism in normal and streptozotocin-induced diabetic rats (STZ). After a single oral administration, Carum carvi extract produced a significant decrease on triglycerides levels in normal rats (p<0.05). In STZ diabetic rats, cholesterol levels were decreased significantly 6h after Carum carvi treatment (p<0.05). On the other hand, repeated oral administration of Carum carvi extract exhibited a significant hypotriglyceridemic and hypocholesterolemic activities in both normal (p<0.01 and <0.001 respectively) and STZ diabetic rats (p<0.001) 15 days after Carum carvi treatment. We conclude that the aqueous extract of Carum carvi (20mg/kg) exhibits a potent lipid lowering activity in both normal and severe hyperglycemic rats after repeated oral administration of Carum carvi aqueous extract.

Study of hypoglycaemic and hypolipidemic effects of Inula viscosa L. aqueous extract in normal and diabetic rats.

The present study was designed to examine the hypoglycaemic and hypolipidemic activity of Inula viscsa aqueous extract on normal and diabetic rats. In normal rats, a significant reduction in blood glucose levels 2 h was observed after a single oral administration (p<0.001). Repeated daily oral administration significantly reduced blood glucose levels after 4 days of treatment (p<0.01). In diabetic rats, a significant reduction in blood glucose levels was observed 1 h after a single oral administration (p<0.001). Repeated oral administration reduced blood glucose levels at the 4th day (p<0.001). No change in total plasma cholesterol and triglyceride levels was observed after both a single and repeated oral administration in both normal and diabetic rats. In addition, plasma insulin levels and body weight remained unchanged after 15 days of repeated oral administration in normal and diabetic rats. We conclude that Inula viscosa possess a hypoglycaemic but not hypolipidemic activity in normal and diabetic rats. The observed hypoglycaemic activity seems to be independent of insulin secretion.

Pharmacological evidence of α-adrenergic receptors in the hypotensive effect of Chamaemulum nobile L.

This study aims to evaluate the underlying mechanism of action involved in the hypotensive effect of Chamaemulum nobile L. (Cn) aqueous extract and in anesthetized Wistar rats. Lyophilized aqueous extract was administered in the jugular vein, arterial blood pressure and heart rate were measured in the carotide artery over 120 min of injection throughout an invasive direct blood pressure measuring procedure. Intravenous bolus injection of aqueous Cn extract at the doses of 50, 100 and 200 mg/kg produced a dose dependent reduction in arterial blood pressure and heart rate (p<0.001). Specific receptor antagonists (Phentolamine, Terazosin and Atropine) and pharmacological agents (N(omega)-Nitro-L-Arginine Methyl Ester and Captopril) were used for determining the underlying mechanism involved in the hypotensive effect of Cn. Only Phentolamine treatment (2 mg/kg) reduced significantly the hypotensive effect of aqueous Cn extract at a dose of 200 mg/kg. Intravenous perfusion of aqueous Cn extract caused a significant reduction of arterial blood pressure (p<0.01) and reduced the hypertensive effect of intravenous injection of norepinephrine at a dose of 1 µg/kg. We conclude that aqueous Cn extract exhibits a hypotensive effect which may be probably due to an alpha adrenergic receptor blockade mechanism.

Potent hypoglycaemic activity of the aqueous extract of Chamaemelum nobile in normal and streptozotocin-induced diabetic rats.

The purpose of this study was to investigate the effect of both a single dose and daily oral administration for 15 days of the aqueous extract of the aerial part of Chamaemelum nobile (C. nobile) at a dose of 20mg/kg body weight on blood glucose concentrations and basal insulin levels in normal and streptozotocin-induced diabetic rats (STZ). Single oral administration of C. nobile aqueous extract reduced blood glucose levels from 6.0 +/- 0.3 mmol/l to 4.9 +/- 0.09 mmol/l (P < 0.05) 6h after administration in normal rats and from 21.1 +/- 1.3 mmol/l to 14.5 +/- 0.9 mmol/l (P < 0.001) in STZ diabetic rats. Furthermore, blood glucose levels were decreased from 6.1 +/- 0.06 mmol/l to 4.6 +/- 0.17 mmol/l (P < 0.01) and from 21.1 +/- 1.31 mmol/l to 13.7 +/- 0.9 mmol/l (P < 0.01) in normal and STZ diabetic rats, respectively, after 15 days of treatment. Basal plasma insulin concentrations remain unchanged after treatment in both normal and STZ diabetic rats so the mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of C. nobile exhibits a significant hypoglycaemic effect in normal and STZ diabetic rats without affecting basal plasma insulin concentrations and support, therefore, its traditional use by the Moroccan population.

Hypoglycaemic effect of Triticum repens P. Beauv. in normal and diabetic rats.

The hypoglycaemic effect of an aqueous extract of Triticum repens (TR) rhizomes was investigated in normal and streptozotocin (STZ) diabetic rats. After a single oral administration of the aqueous extract (20mg/kg) a significant decrease on blood glucose levels in STZ diabetic rats (p<0.001) was observed; the blood glucose levels were normalized after 2 weeks of daily oral administration of TR aqueous extract (20mg/kg) (p<0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p<0.001) and chronic treatment (p<0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of TR exhibits a potent hypoglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.

Hypolipidemic activity of aqueous extract of Capparis spinosa L. in normal and diabetic rats.

The purpose of this study was to examine the effect of single and repeated oral administrations of the aqueous extract of Capparis spinosa L. (CS) at a dose of 20mg/kg on lipid metabolism in normal and streptozotocin-induced diabetic rats. In normal rats, the aqueous extract of CS induced a significant decrease on plasma triglycerides concentrations 1 week (p<0.05) and 2 weeks (p<0.01) after once daily repeated oral administration. A significant decrease of plasma cholesterol levels was also observed 4 days (p<0.05) and 1 week (p<0.05) after repeated oral administration. In diabetic rats, CS treatment caused a significant decrease of plasma triglycerides levels after repeated oral administration. Four days after repeated oral administration of aqueous CS extract, the plasma cholesterol levels were significantly decreased (p<0.05) and still dropped after 2 weeks (p<0.01). On the other hand, the repeated oral administration of CS aqueous extract caused a significant decrease of body weight 4 days after repeated oral treatment in diabetic rats (p<0.05). We conclude that the aqueous extract of CS (20 mg/kg) exhibits a potent lipid lowering activity in both normal and severe hyperglycemic rats after repeated oral administration of CS aqueous extract.

Acute diuretic effect of aqueous extract of Retama raetam in normal rats.

The purpose of this study was to examine the acute diuretic effect of the water extract of the aerial parts of Retama raetam (RR) at a dose of 5 mg/kg/h in normal rats. The aqueous extract was administered intravenously and the diuresis was followed within 4 h after starting the treatment. Intravenous administration of the aqueous RR extract produced a significant increment on diuresis from the second hour (p<0.01) to the fourth hour (p<0.001). Furosemide at a dose of 0.1 mg/kg/h had a similar effect when compared to RR administration. Parallel, the noticed increase of diuresis was associated with an elevation of glomerular filtration rate (p<0.05) and a significant decrease of urinary osmolarity (p<0.001). However, RR extract did not affect plasma urea levels, urine pH, plasma osmolarity and hematocrite. It is then concluded that the water extract of the aerial parts of RR exhibited a significant diuretic effect in normal rat.

Study of the hypoglycaemic activity of Lepidium sativum L. aqueous extract in normal and diabetic rats.

The hypoglycaemic effect of an aqueous extract of Lepidium sativum L. (LS) seeds was investigated in normal and streptozotocin (STZ)-induced diabetic rats. After a acute (single dose) or chronic (15 daily repeated administration) oral treatments, the aqueous LS extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (p < 0.001); the blood glucose levels were normalised 2 weeks after daily repeated oral administration of aqueous LS extract (20 mg/kg) (p < 0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p < 0.01) and chronic treatment (p < 0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment either in normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of LS exhibits a potent hypoglycaemic activity in rats without affecting basal plasma insulin concentrations.

Fraxinus excelsior L. evokes a hypotensive action in normal and spontaneously hypertensive rats.

The hypotensive effect of an aqueous extract of Fraxinus excelsior L. was investigated in both normotensive (WKY) and spontaneously hypertensive rats (SHR). Daily oral administration of Fraxinus excelsior (20 mg/kg) aqueous extract for 3 weeks produced a significant decrease in systolic blood pressure (SBP) with variation coefficient (Delta%) of 13.5% in SHR (p<0.01) and 9% in WKY rats (p<0.05). The aqueous extract of Fraxinus excelsior significantly enhanced the urination in both SHR (p<0.05 compared to control) and WKY (p<0.05 compared to control). Irbesartan (Avapro), an angiotensin II antagonist, was used as reference drug. Furthermore, oral administration of aqueous Fraxinus excelsior extract at a dose of 20 mg/kg produced a significant increase in urinary excretion of sodium (p<0.01 compared to control), potassium (p<0.001 compared to control) and chlorides (p<0.01) in SHR rats. In normal rats, the aqueous Fraxinus excelsior extract administration induced a significant increase of the urinary elimination of sodium (p<0.05 compared to control), chlorides (p<0.01 compared to control) and potassium (p<0.01 versus control). While there were no significant changes in heart rate (HR) after Fraxinus excelsior treatment in both SHR and WKY rats, glomerular filtration rate (GFR) showed a significant increase in SH rats (p<0.001) after Fraxinus excelsior treatment. These results suggest that oral administration of aqueous extract of Fraxinus excelsior exhibited hypotensive and diuretic actions.

Hypersensitivity to insulin during remissions in cyclosporin-treated IDDM patients.

OBJECTIVE: To test the sensitivity to insulin in recent-onset IDDM patients, its course according to treatment, and the advent of remissions. RESEARCH DESIGN AND METHODS: The euglycemic hyperinsulinemic clamp was used in 54 recent-onset IDDM patients and 14 healthy control subjects. Patients were tested after 1,2, and 4 wk of treatment with either insulin or insulin plus cyclosporin A, during cyclosporin A-associated long-lasting remissions, and during relapses. RESULTS: Insulin sensitivity was markedly decreased in all patients at onset. It was rapidly restored by insulin therapy, whether immunosuppression was associated with it or not. Insulin sensitivity was even higher than normal in the remission patients, who also were characterized by the reappearance of some endogenous insulin secretion and the sustained normalization of blood glucose profiles. During relapses, the deterioration of the blood glucose profiles was associated with some loss of insulin sensitivity. CONCLUSIONS: Cyclosporin A-associated remissions represent an original situation that associates euglycemia with the persistence of low endogenous insulin secretion. Cyclosporin A by itself had no influence on sensitivity to insulin, but allowed the reappearance of some insulin secretory capacity that contributed, with the improvement of insulin sensitivity, to the development of the diabetes honeymoon. The secretion of endogenous insulin, although lower than normal, was sufficient to secure a high sensitivity to insulin and the maintenance of normal blood glucose profiles, presumably because of the fact that insulin was released directly into the portal vein in these conditions. This metabolic state was precarious: the optimal sensitivity to insulin disappeared in patients who relapsed. These results have important clinical consequences: the preservation of islet residual secretory capacity by the use of newer nontoxic immunosuppressive protocols, combined with a minimal supportive insulin therapy in remission patients, may prolong remissions and maintain an optimal insulin sensitivity.

Hypoglycaemic effect of Calamintha officinalis Moench. in normal and streptozotocin-induced diabetic rats.

The purpose of this study was to investigate the effects of a water extract from the aerial parts of Calamintha officinalis Moench., after either a single dose or daily oral administration for 15 days, on plasma blood glucose concentrations and basal insulin levels in normal and streptozotocin-induced diabetic rats (STZ diabetic rats). The results clearly demonstrated the hypoglycaemic effect of this plant extract in both normal and STZ diabetic rats. In addition, no changes were observed in basal plasma insulin concentrations after treatment with this plant in normal or STZ diabetic rats, indicating that the underlying mechanism of the plant's pharmacological action seems to be independent of insulin secretion. We conclude that the aqueous C. officinalis extract exhibits a significant hypoglycaemic effect in normal and STZ diabetic rats without affecting basal plasma insulin concentrations, and supports, therefore, its traditional use by the Moroccan population.

Phlorizin-like effect of Fraxinus excelsior in normal and diabetic rats.

The purpose of this study was to determine the underlying mechanism of the hypoglycaemic activity of the aqueous extract perfusion of Fraxinus excelsior L. (FE) in normal and streptozotocin-induced diabetic rats. The aqueous extract was administered intravenously and the blood glucose changes were determined within four hours after starting the treatment. Plasma insulin concentrations and glycosuria were determined. The aqueous extract at a dose of 10 mg/kg/h produced a significant decrease in blood glucose levels in normal rats (P < 0.001) and even more in diabetic rats (P < 0.001). This hypoglycaemic effect might be due to an extra-pancreatic action of the aqueous extract of FE, since the basal plasma insulin concentrations were unchanged after FE treatment. A potent increase of glycosuria was observed both in normal and diabetic rats (P < 0.001). We conclude that aqueous extract perfusion of FE caused a potent inhibition of renal glucose reabsorption. This renal effect might be at least one mechanism explaining the observed hypoglycaemic activity of this plant in normal and diabetic rats.

Hypoglycemic effect of Suaeda fruticosa in streptozotocin-induced diabetic rats.

The purpose of this study was to examine the hypoglycemic activity of the aqueous extract of the aerial part of Suaeda fruticosa (SF) in normal and streptozotocin-induced diabetic rats. The aqueous extract was administered intravenously (i.v.) and the blood glucose changes were determined within 4 h after starting the treatment. Plasma insulin, cholesterol and triglycerides levels were also determined. The aqueous extract at a dose of 192 mg/kg produced a significant decrease in blood glucose levels in normal rats (P < 0.05), and even more in diabetic rats (P < 0.001). This hypoglycemic effect might be due to an extra-pancreatic action of the aqueous extract of SF, since that the levels of plasma insulin were unchanged between the values before and after treatment. In the other hand, the effect of the aqueous extract on the plasma cholesterol were also significant in both normal and diabetic rats (P < 0.05). But, there is no significant effect of SF on plasma triglycerides in both groups. In order to characterize the active principle(s), which could be responsible for the therapeutic effect, preliminary phytochemical analysis of the aqueous extract of the plant has been investigated.

Chronic diuretic effect of the water extract of Spergularia purpurea in normal rats.

The purpose of this study was to examine the chronic diuretic effect of the water extract of the whole plant of Spergularia purpurea (SP) at different doses (100, 200 and 400 mg/kg) in normal rats. Daily oral administration of the water extract was tested for 4 weeks. Urinary water and electrolytes excretion were determined weekly. Oral administration of the water extract at different doses produced a significant and dose-dependent diuresis and increase in electrolytes excretion. The highest dose (400 mg/kg) of the water extract of SP enhanced urine output from 7.15 +/- 0.42 ml/24 h at the start to 23.01 +/- 0.75 ml/24 h after 4 weeks (p < 0.001). It also produced significant increase in urinary excretion of Na+ (P < 0.01), K+ (P < 0.01) and Cl(-) (P < 0.01). Chronic treatment with SP decreased significantly urine osmolality (P < 0.01 vs. control), while a slight increase in glomerular filtration rate was also observed (P < 0.05) for both doses of water extract (100 and 400 mg/kg). It is concluded that the water extract of whole plant of SP has a significant diuretic effect in rats.

Caraway and caper: potential anti-hyperglycaemic plants in diabetic rats.

The hypoglycaemic effect of aqueous extracts of Carum carvi (CC) and Capparis spinosa L. (CS) fruit were investigated in normal and streptozotocin (STZ) diabetic rats. After a single dose or 14 daily doses, oral administration of the aqueous CC and CS extracts (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (P < 0.001); the blood glucose levels were nearly normalised 2 weeks after daily repeated oral administration of both aqueous CC and CS extracts (20 mg/kg) (P < 0.001). No highly significant changes on blood glucose levels were noticed in normal rats after both acute and chronic treatments with CS and CC. In addition, no changes were observed in basal plasma insulin concentrations after treatment with these plants in either normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that aqueous extracts of CC and CS exhibit a potent anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.

Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region.

The effect of an aqueous extract of Origanum vulgare (OV) leaves on blood glucose levels was investigated in normal and streptozotocin (STZ) diabetic rats. In normal rats, the blood glucose levels were slightly decreased 6 h after a single oral administration (P<0.05) as well as 15 days after once daily repeated oral administration of aqueous OV extract (P<0.05) (20 mg/kg). After a single dose or 15 daily doses, oral administration of the aqueous extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (P<0.001). In STZ rats, the blood glucose levels were normalised from the fourth day after daily repeated oral administration of aqueous OV extract (20 mg/kg) (P<0.001). However, this effect was less pronounced 2 weeks after daily repeated oral administration of OV extract. In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the aqueous OV extract acted without changing insulin secretion. We conclude that an aqueous extract of OV exhibits an anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.

Ethnobotanical survey of medicinal plants used for the treatment of diabetes, cardiac and renal diseases in the North centre region of Morocco (Fez-Boulemane).

In order to make an inventory of herbal remedies commonly used in the treatment of diabetes, hypertension and renal diseases in the North centre region of Morocco, 1527 patients (1095 diabetic patients, 274 with renal disorders and 158 with cardiac disorders) and 25 traditional herbal healers were interviewed in four different areas of Fez-Boulemane region. More than 1153 of the total patients interviewed (76%) used regularly medicinal plants to treat diabetes, cardiac and renal diseases. These data showed that phytotherapy has always be practiced in this region. All the persons interviewed have indicated that the reasons of using phytotherapy is that the plant medicines are cheapest (54%) and more efficient (38%) than modern medicine. They also reported that the result of phytotherapy is better (72%). Our survey started at May 1997. About 90 plants were cited (54 plants for diabetes, 11 for cardiac diseases, 19 for hypertension and 33 for renal diseases). The plants reported have been identified and are presented in a table with the vernacular name, useful parts, ecological distribution and medicinal uses. Only 12% of the total patients have a relative knowledge of the toxic plants. The result indicated that nine plants are extremely toxic at high doses and chronic treatment. Fifty nine percent of the interviewers have indicated that they used medicinal plants from the experience of the other.

Effects of the flavonoids extracted from Spergularia purpurea Pers. on arterial blood pressure and renal function in normal and hypertensive rats.

The antihypertensive and diuretic effects of the flavonoids extracted from Spergularia purpurea Pers. (SP) were studied both in normotensive (NTR) and spontaneously hypertensive conscious rats (SHR). Daily oral administration of the flavonoid mixture (5 mg/kg for 1 week) exhibited a significant decrease in blood pressure with variation coefficient (Delta) of 20 in SHR rats and 11 in NTR rats. The systolic and diastolic blood pressure decreased significantly and respectively with 17 and 24% in SHR, and with 11 and 16% in NTR. The flavonoid mixture enhanced significantly the water excretion in hypertensive (P<0.001) and normal rats (P<0.001). Furthermore, oral administration of flavonoids mixture at a dose of 5 mg/kg produced a significant increase of urinary excretion of sodium (P<0.01), potassium (P<0.05) and chlorides (P<0.05) in SHR. Similarly, the flavonoid administration induced a significant increase of urinary electrolytes elimination in NTR (P<0.01 versus controls). No significant changes were noted on heart rate after flavonoids treatment in SHR as well as in NTR. While, glomerular filtration rate showed a significant increase after administration of flavonoids in all groups (P<0.05). These results suggest that oral administration of flavonoids obtained from Spergularia purpurea exhibited antihypertensive and diuretic actions.

Hypoglycaemic effect of spergularia purpurea in normal and streptozotocin-induced diabetic rats.

Single and repeated oral administration of the water extracts of Spergularia purpurea (SP) at a dose of 10 mg/kg were tested on hypoglycaemic activity in normal and streptozotocin-induced diabetic rats. In normal rats, the water extract of SP decreased significantly the plasma glucose levels 4 h after single oral administration (P<0.01), and one week after repeated oral administration (P<0.05). A significant decrease of plasma glucose levels was observed 6 h after a single oral administration of the water extract of S. purpurea in severe hyperglycaemic rats (n=6) from 22.78+/-0.60 to 11.21+/-0.49 mmol/l (P<0.001). On other hand, water extract of S. purpurea normalised plasma glucose levels after two weeks of repeated oral administration in diabetic rats; 24.05+/-1.16 versus 7.18+/-0.51 mmol/l (P<0.001) at the start and 2 weeks after water extract administration, respectively. We conclude that the water extract of SP induces hypoglycaemic activity when administered orally in normal and STZ diabetic rats. In order to determine the active principle (s) responsible of the hypoglycaemic effect, preliminary phytochemical analysis of the water extract has been investigated.