Effect of Retama raetam on lipid metabolism in normal and recent-onset diabetic rats

The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Retama raetam (Forssk) Webb (RR) (20 mg/kg) on lipid metabolism in normal and streptozotocin-induced diabetic rats. In normal rats, the aqueous extract of RR induced a significant decrease of the plasma triglycerides concentrations one week after repeated oral administration (P<0.05). This reduction was maintained two weeks after once daily repeated oral administration (P<0.05). A significant decrease of plasma cholesterol levels was also observed one week (P<0.05) and two weeks (0.05) after repeated oral administration.

In diabetic rats, RR treatment caused a significant decrease of plasma triglycerides levels after a single (P<0.05) and repeated (P<0.001) oral administration. A significant decrease of cholesterol levels was observed four hours after a single oral administration of the RR aqueous extract (P<0.05). One week after repeated oral administration of RR aqueous extract, the plasma cholesterol levels were significantly decreased (P<0.05) and still dropped after two weeks (P<0.005).

On the other hand, the repeated oral administration of RR aqueous extract caused a significant decrease of body weight one week after repeated oral treatment in diabetic rats (P<0.05). We conclude that the aqueous extract of RR exhibits lipid and body weight lowering activities in both normal and severe hyperglycemic rats after repeated oral administration of RR aqueous extract at a dose of 20 mg/kg.     

Hypoglycaemic effect of the lyophilised aqueous extract of Ajuga iva in normal and streptozotocin diabetic rats

The purpose of this study was to examine the hypoglycaemic effect of the lyophilised aqueous extract of the whole plant of Ajuga iva (L.) Schreber (Labiatae) in normal and streptozotocin-induced diabetic rats. Single and repeated oral administration of the extract of Ajuga iva L (AI) at a dose of 10 mg/kg produced a slight and significant decrease in plasma glucose levels in normal rats 6 h after administration and after 3 weeks of treatment. AI reduced plasma glucose levels of streptozotocin diabetic rats from 337±9.3 to 102.2±17.7 mg/dl after 6 h of oral administration (P<0.001). Repeated oral administration of AI to streptozotocin diabetic rats significantly decreased the plasma glucose levels after 1 week of treatment (112±14.4 mg/dl at 1 week vs 337±9.3 mg/dl at the baseline values, (P<0.001). It continuously decreased thereafter and showed a rapid normalisation after 1 week of AI treatment. It is concluded that these results demonstrated that the water extract of the whole plant of AI possess a strong hypoglycaemic effect in diabetic rats, and support therefore, its traditional use in diabetes mellitus control.     

Cholesterol-lowering activity of the aqueous extract of Spergularia purpurea in normal and recent-onset diabetic rats

The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Spergularia purpurea (SP) at a dose of 10mg/kg in normal and streptozotocin-induced diabetic rats. In normal rats, the aqueous extract of SP induced a significant decrease of the plasma cholesterol concentrations 6h after a single oral administration (P<0.05) and 2 weeks after repeated oral administration (P<0.05). The plasma triglycerides levels increased significantly 6h after a single oral administration (P<0.05) and decreased 2 weeks after repeated oral administration (P<0.05). In diabetic rats, SP treatment caused a significant decrease of plasma cholesterol levels after a single (P<0.01) and repeated (P<0.01) oral administration. A significant increase of triglycerides levels was observed 6h after a single oral administration of the SP aqueous extract (P<0.01). One week after repeated oral administration of SP aqueous extract, the plasma triglycerides levels were significantly decreased (P<0.005) and still dropped after 2 weeks (P<0.01). On the other hand, the repeated oral administration of SP aqueous extract caused a significant decrease of body weight after 2 weeks of treatment in both normal (P<0.001) and diabetic (P<0.01) rats. We conclude that the aqueous extract of SP exhibits a cholesterol and body weight-lowering activities in both normal and severe hyperglycaemic rats.     

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.     

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.     

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.     

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.     

Effect of the desert plant Retama raetam on glycaemia in normal and streptozotocin-induced diabetic rats

The effect of the aqueous extract of Retama raetam (RR) on blood glucose levels was investigated in fasting normal and streptozotocin-induced diabetic rats after single and repeated oral administration. The aqueous extract of RR at a dose of 20mg/kg significantly reduced the blood glucose in normal rats 6h after a single oral administration (P<0.005) and two weeks after repeated oral administration (P<0.05). This hypoglycaemic effect is more pronounced in streptozotocin (STZ) diabetic rats (P<0.001). The aqueous extract of RR had no effect on basal plasma insulin levels indicating that the underlying mechanism of RR activity is extra-pancreatic. These findings suggest that the aqueous extract of RR possess significant hypoglycaemic effect in both normal and STZ diabetic rats.     

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.     

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.     

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.     

Comparative pharmacokinetic study of paeoniflorin after oral administration of decoction of Radix Paeoniae Rubra and Radix Paeoniae Alba in rats

An investigation was designed and conducted to compare the pharmacokinetics difference of paeoniflorin after oral administration of the extracts of Radix Paeoniae Rubra and Radix Paeoniae Alba to rats on separate occasions. Quantification of paeoniflorin in rat plasma was achieved using a simple and rapid HPLC method for pharmacokinetic study. After oral administration of decoctions of Radix Paeoniae Rubra and Radix Paeoniae Alba, paeoniflorin was absorbed and reached a maximum concentration of 3.69 ± 1.46 and 1.46 ± 0.29 (p < 0.05) μg/ml at 1.67 ± 0.43 and 0.80 ± 0.35 h (p < 0.05), respectively. Compared to the AUC (18.85 ± 7.54 μg h/ml) after oral administration of the paeoniflorin solution, a smaller AUC (10.61 ± 1.51 μg h/ml, p < 0.05) and a larger AUC (24.89 ± 7.41 μg h/ml) of paeoniflorin after oral administration of the decoctions of Radix Paeoniae Alba and Radix Paeoniae Rubra were obtained, respectively. There were statistically significant differences in pharmacokinetic parameters of paeoniflorin including the t_max, C_max, AUC, t_1/2, CL, and V_d among the animals orally administered the decoctions of Radix Paeoniae Rubra and Radix Paeoniae Alba. In particular, the parameters of t_max, C_max, and AUC of paeoniflorin were remarkably increased (P < 0.05, P < 0.001) when oral administering paeoniflorin in the decoctions of Radix Paeoniae Rubra, but t_1/2, V_d, and CL were decreased (P < 0.05 or P < 0.01), in comparison of the decoction of Radix Paeoniae Alba.     

Hypolipidemic effects of acute and sub-chronic administration of an aqueous extract of Ajuga iva L. whole plant in normal and diabetic rats

Diabetes is often accompanied by lipid abnormalities, which contribute significantly to cardiovascular (CV) morbidity and mortality in diabetic patients. The plant Ajuga iva (L.) Schreiber (Labiatea) is used in the treatment of diabetes in Moroccan folk medicine. Previously, we have demonstrated potent hypoglycemic activity and relatively non-toxic nature of a lyophilized aqueous extract of the whole plant (AI-extract) in normal (normoglycemic) and streptozotocin (STZ)-diabetic rats. In this study, we examined the AI-extract for its possible lipid-lowering activity in normal and STZ-diabetic rats. Taurine (TR) and glibenclamide (GLB) were used as reference substances. As shown previously, the AI-extract (10 mg/kg; oral) reduced plasma glucose levels after acute (single) and sub-chronic (3 weeks) dosing both in normal and diabetic rats. In normal rats, single and repeated oral administration of the AI-extract, at a dose of 10 mg/kg produced a small but significant decrease in plasma CHL levels (P<0.05). A single dose of the AI-extract did not produce a significant change in plasma TG, but sub-chronic dosing (for up to 21 days) caused a significant decrease in plasma TG (P<0.05). In STZ-diabetic rats, a single dose as well as repeated (3 weeks) treatment with the AI-extract produced a significant decrease in plasma CHL (P<0.01), and triglyceride (P<0.01) levels. The AI-extract also prevented weight loss in the diabetic animals. In summary, an aqueous extract of the Ajuga iva whole plant showed hypolipidemic activity, in addition to its hypoglycemic effect in normoglycemic and diabetic rats. In view of the hypoglycemic and hypolipidemic activity, and its relatively non-toxic nature (shown previously), Ajuga iva may be a candidate for development as an anti-diabetic agent in humans. Further studies are warranted to confirm our results and fractionate the AI-extract to isolate and identify the active principle(s), and to determine the exact mechanism(s) of action.     

Comparison between ethanolic and aqueous extracts from Chinese juniper berries for hypoglycaemic and hypolipidemic effects in alloxan-induced diabetic rats

AIM OF THE STUDY: Hypoglycaemic and hypolipidemic properties of the ethanolic and aqueous extracts, respectively, from Chinese juniper (Juniperus chinensis L.) berries were investigated in alloxan-induced diabetic rats. MATERIALS AND METHODS: After oral administration of each extract singly or repeatedly to alloxan-induced diabetic rats, the blood glucose, glutamate-pyruvate transferase (GPT), glutamate-oxaloacetate transaminase (GOT), total cholesterol (TC) and triglyceride (TG) levels were assayed. RESULTS: The blood glucose levels after a single oral administration of the ethanolic extract significantly reduced in a time-dependent manner, which is much faster and more than that of glibenclamide. The blood glucose levels of alloxan-induced diabetic rats treated with the ethanolic extract were reduced to 94, 81%, 66%, 45% and 40% at 1, 3, 5, 7 and 9h, respectively (p<0.05), while the aqueous extract had no effect at all. Repeated oral administration of the ethanolic extract also effectively reduced the GPT value to 58% of the diabetic rats, but slightly reduced the GOT value to 87% of the diabetic rats (p<0.05). On the other hand, the repeated oral administration of aqueous extract effectively reduced the GOT value to 43% of the diabetic rats, without affecting the GPT level. Effects of both extracts on the TC and TG levels were different. There was no significant difference in the TC and TG levels between diabetic control and diabetic groups when repeatedly administered orally with ethanolic extract. On the other hand, the aqueous extract brought down the TC value to 57% and the TG value to 37% of the diabetic control rats (p<0.05). CONCLUSIONS: The results suggested that the ethanolic extract of Chinese juniper berries possesses a potential hypoglycaemic effect while the aqueous extract has a potential hypolipidemic effect.     

Anti-diabetic activity of alcoholic extract of Aerva lanata (L.) Juss. ex Schultes in rats

Aerva lanata (L.) Juss. ex Schultes commonly known as ‘Sunny khur’ is widely used in Indian folk medicine for the treatment of Diabetes mellitus. This study was undertaken to evaluate the effect of an alcoholic extract of A. lanata (AAL) on blood glucose and other biochemical parameters in alloxan-induced diabetic rats. AAL was found to reduce the increase of blood sugar in alloxan-induced diabetic rats (42% at 375 mg/kg and 48% at 500 mg/kg body weight). Chronic administration of AAL significantly (P<0.001) reduced the blood sugar of alloxan induced diabetic rats for 2 weeks. Also the extract prevented a decrease in body weight and reduced the increased lipid peroxides in alloxan induced diabetic rats. These results suggest that the AAL posseses anti-diabetic activity and is able to ameliorate biochemical damages in alloxan induced diabetic 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.     

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.     

Anti-inflammatory,analgesic activity and acute toxicity of Glaucium grandiflorum extract

The species of Glaucium have been used in Iranian herbal medicine as laxative, hypnotic, antidiabetic agents and also in the treatment of dermatitis. The anti-inflammatory and analgesic effects of the aerial parts of Glaucium grandiflorum Boiss & Huet (Papaveraceae), a native plant of Iran, were studied using carrageenan induced edema, formalin and hot plate tests. The G. grandiflorum extract at the dose of 200 mg/kg had more edema inhibition than indomethacin at the doses of 10 (P<0.01) and 8 mg/kg (P<0.001) in the carrageenan test. The ED₅₀ (i.p.) in the edema induced by carrageenan was 13.59 mg/kg. In formalin test, the extract (60–90 mg/kg, i.p.) caused graded inhibition of both phases of formalin-induced pain. In hot plate test, the i.p. administration of the extract at the doses of 60, 70, 80 and 90 mg/kg significantly raised the pain threshold at a observation time of 45 min in comparison with control (P<0.001). The extract, at the antinociceptive doses, did not affect motor coordination of animals when assessed in the rotarod model. The 72 h acute LD₅₀ value of this extract after i.p. administration in mice was 797.94 mg/kg.     

Antihypertensive effect of Lepidium sativum L. in spontaneously hypertensive rats

The antihypertensive and diuretic effects of the aqueous extract of Lepidium sativum L. (LS) were studied both in normotensive (WKY) and spontaneously hypertensive rats (SHR). Daily oral administration of the aqueous LS extract (20mg/kg for 3 weeks) exhibited a significant decrease in blood pressure (p<0.01) in SHR rats while in WKY rats, no significant change was noted during the period of treatment. The systolic blood pressure was decreased significantly from the 7th day (p<0.05) to the end of treatment (p<0.01) in SHR rats. The aqueous LS extract enhanced significantly the water excretion in WKY rats (p<0.001) but no statistically significant change was observed in SHR rats. Furthermore, oral administration of aqueous LS extract at a dose of 20mg/kg produced a significant increase of urinary excretion of sodium (p<0.05), potassium (p<0.01) and chlorides (p<0.01) in WKY rats. In spontaneously hypertensive rats, the aqueous LS extract administration induced a significant increase of urinary elimination of sodium (p<0.01), potassium (p<0.001) and chlorides (p<0.001). Glomerular filtration rate showed a significant increase after oral administration of LS in normal rats (p<0.001) while in SHR rats, no significant change was noted during the period of treatment. Furthermore, no significant changes were noted on heart rate after LS treatment in SHR as well as in WKY rats. Our results suggest that daily oral administration of aqueous LS extract for 3 weeks exhibited antihypertensive and diuretic activities.     

Hypoglycaemic effect of Helicteres isora bark extract in rats

The hypoglycaemic effect of the aqueous extract of the bark of Helicteres isora L. (Sterculiaceae) was investigated in normal, glucose load conditions and streptozotocin (STZ)-induced diabetic rats. In normal rats, the aqueous extract of the bark of Helicteres isora L. (100 and 200 mg/kg/p.o.) significantly (P<0.001) reduced the blood glucose levels from 64.5-48.5 and 67-47 mg% 2h after oral administration of bark extract and also significantly lowered the blood glucose in STZ diabetic rats from 68-105 and 66-85.5 mg% 21 days after daily oral administration of the extract (P<0.001). The results suggested that the aqueous extract of bark of Helicteres isora L. possesses a potential hypoglycaemic effect in diabetic rats.