Effects of Mucuna pruriens extract on activation of prothrombin by Echis carinatus venom

Mucuna pruriens (L.) DC has long been used as a medicinal plant by traditional healers. The validity of the claims made for this plant has also been tested scientifically. Some of its properties are probably linked to high concentrations of dopa since it is useful in the treatment of Parkinson's disease. The antisnake properties of an extract of Mucuna pruriens' seeds (MP101UJ) in vivo were recently demonstrated and one is now investigating its biochemical mechanism. Echis carinatus venom (EV) contains a mixture of proteins that affect the coagulative cascade, causing severe bleeding and haemorrhage. Here the effect of an extract of MP101UJ in prothrombin activation by EV in vitro by clotting and chromogenic assay is studied. An increase in procoagulant activity was found. This could explain the protective effect in vivo.     

The effect of Momordica charantia and Mucuna pruriens in experimental diabetes and their effect on key metabolic enzymes involved in carbohydrate metabolism

The Indian traditional system of medicine prescribed traditional plant therapies. Two such plants, i.e. Momordica charantia (MC) and Mucuna pruriens (MP), earlier shown to reduce hyperglycaemia, were assessed for their anti hyperglycaemic effect on varying degrees of hyperglycaemia and diabetic complications. Alcohol and aqueous extracts of MC (50, 100 and 200 mg/kg/day) and only an alcohol extract of MP (100, 200 and 400 mg/kg/day) were evaluated in a pilot study (plasma glucose >180 mg/dL, 21 days), a chronic study in alloxanized rats (plasma glucose >280mg/dL, 120 days) and streptozotocin (STZ) mice (plasma glucose >400 mg/dL, 60 days). In the pilot study, the maximum antihyperglycaemic effect occurred with an aqueous extract of MC at week 3 and an alcohol extract of MP at week 6 at a dose of 200 mg/kg/day. In chronic alloxanized rats, the selected dose of MC led to a significant fall of 64.33%, 66.96%, 69.7% and 70.53% in plasma glucose levels at 1, 2, 3 and 4 months, respectively. MP showed a decrease of 40.71%, 45.63%, 50.33% and 51.01% at the same time period. In chronic STZ diabetic mice, MC led to a mean reduction of 15.37%, 18.68% and 22.86% in plasma glucose levels on days 40, 50 and 60 of sampling while MP had no significant effect. The alteration in hepatic and skeletal muscle glycogen content and hepatic glucokinase, hexokinase, glucose-6-phosphate and phosphofructokinase levels in diabetic mice were partially restored by MC but not by MP. The mechanism of action of MC and MP is discussed.     

Prevention of experimental diabetic cataract by Indian Ayurvedic plant extracts

The efficacy of Momordica charantia (MC), Eugenia jambolana (EJ), Tinospora cordifolia (TC) and Mucuna pruriens (MP) was assessed in the prevention of murine alloxan dibetic cataract. Alloxan (120 mg/kg) was used as the diabetogenic agent. While controls and diabetic controls did not receive any plant extract, treated rats received lyophilized aqueous extract of MC and EJ (200 mg/kg p.o.), alcohol extract of TC (400 mg/kg) and MP (200 mg/kg p.o.) every day until 4 months. Serum glucose concentration was assessed and cataracts examined with both the naked eye and through a slit lamp. Of the eight animals in the diabetic control group, four developed cortical cataract (stage IV) by day 90 while the remaining four developed it by day 100. The incidence rate of cataract in MC, EJ, TC and MP treated groups at 120 days was only 0, 0, 1 and 2. Oral feeding of MC, EJ, TC and MP extracts for 1 month produced a fall of 64.33%, 55.62%, 38.01% and 40.17%, respectively, in the serum glucose levels in comparison with the 48 h level. After 2 months of treatment, the respective values were 66.96%, 59.85%, 40.41% and 45.63%. MC and EJ prevented the development of cataract while the protective effect was less with TC and MP along with a significant reduction of plasma glucose levels (p < 0.001).     

The antiulcer activity of Garcinia cambogia extract against indomethacin-induced gastric ulcer in rats.

Garcinia cambogia extract is a herbal preparation that has been suggested as useful in the treatment of gastrointestinal disorders. In the present study this drug was tested for its antiulcerogenic effect. Oral pretreatment with Garcinia cambogia fruit extract (1 g/kg body wt/day) for 5, 10 or 15 days protected the gastric mucosa against the damage induced by indomethacin (20 mg/kg body wt). The volume and acidity of the gastric juice decreased in the pretreated rats. The glycoprotein levels of the gastric contents which were decreased in the untreated rats, maintained near normal levels in the pretreated rats. Protein which was elevated in the gastric juice of untreated rats, showed near normal levels in the pretreated rats. Garcinia cambogia was able to decrease the acidity and to increase the mucosal defence in the gastric areas, thereby justifying its use as an antiulcerogenic agent.     

Studies on the hypoglycaemic activity of Punica granatum seed in streptozotocin induced diabetic rats.

The hypoglycaemic activity of Punica granatum Linn. (Family Punicaceae) seed extract on rats made diabetic by streptozotocin (STZ) was investigated. The methanol extract of the seed at doses of 300 and 600 mg/kg, and chlorpropamide 200 mg/kg was administered to STZ diabetic rats. The seed extract (150, 300 and 600 mg/kg, orally) caused a significant reduction of blood glucose levels in STZ induced diabetic rats by 47% and 52%, respectively, at the end of 12 h.     

Nardostachys jatamansi protects against liver damage induced by thioacetamide in rats

Nardostachys jatamansi is a medically important herb of Indian origin used for centuries in Ayurvedic and Unani systems of medicine for the treatment of various ailments. In the present paper, a 50% ethanolic extract of the rhizomes of N. jatamansi is shown to possess hepatoprotective activity. Pretreatment of rats with the extract (800 mg/kg body wt, orally) for three consecutive days significantly ameliorated the liver damage in rats exposed to the hepatotoxic compound thioacetamide. Elevated levels of serum transaminases (aminotransferases) and alkaline phosphatase, observed in thioacetamide alone treated group of animals, were significantly lowered in N. jatamansi pretreated rats. Pretreatment of the animals with the extract also resulted in an increase in survival in rats intoxicated with LD90 dose of the hepatotoxic drug.     

Traditional Indian anti-diabetic plants attenuate progression of renal damage in streptozotocin induced diabetic mice.

The purpose of the study was to investigate the effects of daily oral feeding Momordica charantia (MC) (200 mg/kg), Eugenia jambolana (EJ) (200 mg/kg), Mucuna pruriens (MP) (200 mg/kg) and Tinospora cordifolia (TC) extracts for 40 days on blood glucose concentrations and kidney functions in streptozotocin (STZ)-diabetic rats. Plasma glucose levels, body weight, urine volume and urinary albumin levels were monitored on every 10th day over a 40-day period while plasma creatinine levels were assessed at the beginning and end of experiment. Renal hypertrophy was assessed as the ratio between the kidney weight and total body weight. Plasma glucose concentrations in STZ-diabetic mice were reduced by the administration of extracts of MC, EJ, TC and MP by 24.4, 20.84, 7.45 and 9.07%, respectively (P<0.005 for MC, EJ, MP and P<0.05 for TC). Urine volume was significantly higher (P<0.005) in diabetic controls and MC, EJ, MP and TC treatment prevented polyuria (P<0.001, 0.0001, 0.01 and 0.001, respectively). After 10 days of STZ administration urinary albumin levels (UAE) were over 6 fold higher in diabetic controls as compared to normal controls. Treatment with MC, EJ, MP and TC significantly prevented the rise in UAE levels from day 0 to 40 in comparison to diabetic controls (P<0.0001, 0.0001, 0.05, 0.05, respectively). Renal hypertrophy was significantly higher in diabetic controls as compared to non-diabetic controls. MC and EJ partially but significantly (P<0.05) prevented renal hypertrophy as compared to diabetic controls. TC and MP failed to modify renal hypertrophy. Results indicate that these plant drugs should be studied further.     

Neutralization potential of Viper russelli russelli (Russell's viper) venom by ethanol leaf extract of Acalypha indica

The study aims to examine the Viper russelli russelli venom neutralization potential of the ethanol leaf extract (250, 500 and 750 mg/kg) of Acalypha indica (Euphorbiaceae). Administration of the ethanol leaf extract at i.p. dose levels of 500 and 750 mg/kg significantly inhibited, in a dose dependent manner, the Viper russelli venom-induced lethality, haemorrhage, necrotizing and mast cell degranulation in rats and the cardiotoxic and neurotoxic effects in isolated frog tissue. Administration of the extract also significantly inhibited venom-induced lipid peroxidation in RBC, decreased GSH and catalase levels of rat kidney tissue. The observations confirmed that the ethanol leaf extract of Acalypha indica possesses potent snake venom neutralizing properties.     

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.     

Protective effect of the aqueous leaf and seed extract of Phyllanthus amarus on gentamicin and acetaminophen-induced nephrotoxic rats

AIM OF THE STUDY: In African traditional medicine, different parts of Phyllanthus amarus Schum. and Thonn. (family: Euphorbiaceae) are highly valued for the treatment of array of human diseases including hepatic and urolithic and/or other renal diseases. In the present study, single oral 100-400mg/kg/day of the leaf and seed aqueous extract of Phyllanthus amarus (PA) were studied for their protective effects in acetaminophen- and gentamicin-induced nephrotoxic Wistar rats for 14 days. MATERIALS AND METHODS: In each model of nephrotoxicities, thirty adult male Wistar rats were evenly divided into 5 groups. Groups I and II served as untreated and model controls, respectively while groups III-V were the treatment groups which were pretreated with 100-400mg/kg/day of PA 1hr before each dose of the nephrotoxicants for 14 days. On the 15th day, blood samples for serum urea and creatinine while the rat kidneys for histology were obtained under inhaled diethyl ether anesthesia. RESULTS: In the acetaminophen nephrotoxic rats, 100-400mg/kg/day significantly (p<0.05, p<0.01, p<0.001) attenuated elevations in the serum creatinine and blood urea nitrogen levels in dose related fashion, as well as, attenuation of acetaminophen-induced tubulonephrosis. Similar effects were also recorded in the gentamicin model of acute renal injury. Results suggest that the nephroprotective effect of PA could be due to the inherent antioxidant and free-radical-scavanging principle(s) contained in the extract. CONCLUSIONS: In the near future, PA could constitute a lead to discovery of a novel drug for the treatment of drug-induced nephrotoxicity.     

Mitigation of thyroxine-induced hyperglycaemia by two plant extracts

Extracts of Trigonella foenum-graecum (TFG) seed and Allium sativum (AS) bulb were evaluated for their efficacy to ameliorate l-thyroxine (l-T4) induced hyperglycaemia in rats. Simultaneously, the serum cholesterol concentration, a supporting parameter for thyroid function, was also estimated. Thyroxine treatment in rats (300 microg/kg b. wt./day) increased the levels of both the thyroid hormones, namely thyroxine (T4) and tri-iodothyronine (T3) with a concomitant elevation in serum glucose concentration and a reduction in serum cholesterol level. Administration of TFG (220 mg/kg/day) and AS (500 mg/kg/day) extracts in hyperthyroid animals decreased the serum glucose concentration as well as the serum thyroid hormones. For comparison, propyl thiouracil (PTU), an antithyroid compound, was used as the standard at a daily dose of 10 mg/kg. The reductions in serum glucose and thyroid hormone concentrations in the plant extract treated groups were comparable to that in PTU treated animals. Our findings indicate that TFG seed and AS bulb extracts may prove to be effective in the treatment of thyroxine-induced hyperglycaemia.     

Antidepressant-like effect of Tagetes lucida Cav. extract in rats: involvement of the serotonergic system

It has been demonstrated that the decoction of the aerial parts of Tagetes lucida Cav. produces an antidepressant effect during the forced swimming test (FST) in rats. The aim of this study was to evaluate the effect of different organic extracts and one aqueous extract of the aerial parts of T. lucida on the FST. In addition, the possible involvement of the serotonergic system in the antidepressant-like effect of T. lucida in the FST was evaluated, as was its potential toxicological effect. The different extracts of T. lucida (methanol, hexane, dichloromethane and aqueous, 10 and 50 mg/kg), as well as fluoxetine (FLX, 5 mg/kg), were administered per os (p.o.) to rats for 14 days. All animals were subjected to the FST. Only the aqueous extract of T. lucida at a dose of 50 mg/kg significantly reduced immobility behavior and increased swimming in the FST, similar to FLX. Later, the aqueous extract of T. lucida (50mg/kg) was administered for 1, 7 and 14 days. An antidepressant effect was observed after 7 days of treatment. To evaluate the participation of the serotoninergic system, the animals were pretreated with PCPA, an inhibitor of serotonin synthesis (100 mg/kg/day for 4 consecutive days). The animals were treated with the aqueous extract of T. lucida (50 mg/kg) and FLX (5 mg/kg) 24 h after the final injection and were then subjected to the FST. Pretreatment with PCPA inhibited the antidepressant effect of both T. lucida and FLX. Finally, T. lucida was administered p.o. and intraperitoneal route to evaluate its acute toxicological effect. The aqueous extract of T. lucida, administered p.o., did not produce lethality or any significant changes in behavior. In conclusion, the aqueous extract of T. lucida manifested an antidepressant-like effect in the FST mediated by the serotonergic system, with no adverse effects when administered p.o.     

Evaluation of the analgesic, anti-inflammatory and anti-diabetic properties of Sclerocarya birrea (A. Rich.) Hochst. stem-bark aqueous extract in mice and rats

In order to appraise some of the ethnomedical uses of Sclerocarya birrea (A. Rich.) Hochst., subspecies caffra (Sond.) Kokwaro [family: Anacardiaceae], the present study was undertaken to investigate the analgesic, anti-inflammatory and anti-diabetic properties of the plant's stem-bark aqueous extract in experimental models of pain, inflammation and diabetes mellitus. The analgesic effect of Sclerocarya birrea stem-bark aqueous extract was evaluated in mice, while its anti-inflammatory and anti-diabetic effects were investigated in rats. Diclofenac (DIC, 100 mg/kg p. o.) and chlorpropamide (250 mg/kg p. o.) were used respectively as reference analgesic, anti-inflammatory and anti-diabetic agents for comparison. Like diclofenac (DIC, 100 mg/kg p. o.), Sclerocarya birrea stem-bark aqueous extract (SBE, 100-800 mg/kg p. o.) produced dose-dependent, significant protection (p < 0.05-0.001) against electrical heat-induced pain. The plant extract (SBE, 25-800 mg/kg p. o.) also produced dose- and time-related, sustained and significant reductions (p < 0.05-0.001) in the fresh egg albumin-induced acute inflammation of the rat hind paw oedema. However, the analgesic and anti-inflammatory effects of the plant's extract were found to be approximately 10-15 times less than that of diclofenac. In one set of experiments involving hypoglycaemic/antidiabetic evaluation of the plant's extract, graded doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) were separately administered to groups of fasted normal and fasted diabetic rats. In another set of experiments, a single dose of the plant's aqueous extract (SBE, 800 mg/kg p. o.) was used. The hypoglycaemic effect of this single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) was compared with that of chlorpropamide (250 mg/kg p. o.) in both fasted normal and fasted streptozotocin (STZ)-treated diabetic rats. Following acute treatment, relatively moderate to high doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) produced dose-dependent, significant reductions (p < 0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. Chlorpropamide (250 mg/kg p. o.) also produced significant reductions (p < 0.05-0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. Administration of the single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) significantly reduced (p < 0.01-0.001) the blood glucose levels of both fasted normal (normoglycaemic) and fasted STZ-treated, diabetic rats. The results of this experimental animal study indicate that Sclerocarya birrea stem-bark aqueous extract possesses analgesic, anti-inflammatory and hypoglycaemic properties. These experimental findings lend pharmacological support to the suggested folkloric uses of the plant's stem-bark in the management and/or control of pain, inflammatory conditions, and adult-onset, type-2 diabetes mellitus in some communities of South Africa.     

Hypoglycaemic activity of Anthocleista vogelii (Planch) aqueous extract in rodents

The hypoglycaemic effect of Anthocleista vogelii was studied in mice, rats and rabbits. Aqueous extract of the plant obtained by infusion from finely pulverized root was used. The extract (100, 400 and 800 mg/kg) induced significant hypoglycaemic activity in a dose-related fashion at 2 h after oral administration in mice and rats with ED₂₅ of 250 mg/kg and 350 mg/kg respectively. The extract (800 mg/kg, orally) similarly induced statistically significant lowering of blood glucose levels at 8 h in normoglycaemic rabbits. The extract (400 mg/kg and 800 mg/kg, orally) also caused reduction of blood glucose levels in alloxan-induced diabetic animals. The results of this study indicate that the aqueous extract of the roots of Anthocleista vogelii possess favourable hypoglycaemic activity both in normo and hyperglycaemic animals compared to chlorpropamide as a standard.     

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.     

Anti-diabetic activity of green tea polyphenols and their role in reducing oxidative stress in experimental diabetes

An aqueous solution of green tea polyphenols (GTP) was found to inhibit lipid peroxidation (LP), scavenge hydroxyl and superoxide radicals in vitro. Concentration needed for 50% inhibition of superoxide, hydroxyl and LP radicals were 10, 52.5 and 136 micro g/ml, respectively. Administration of GTP (500 mg/kg b.wt.) to normal rats increased glucose tolerance significantly (P<0.005) at 60 min. GTP was also found to reduce serum glucose level in alloxan diabetic rats significantly at a dose level of 100 mg/kg b.wt. Continued daily administration (15 days) of the extract 50, 100 mg/kg b.wt. produced 29 and 44% reduction in the elevated serum glucose level produced by alloxan administration. Elevated hepatic and renal enzymes produced by alloxan were found to be reduced (P<0.001) by GTP. The serum LP levels which was increased by alloxan and was reduced by significantly (P<0.001) by the administration of 100 mg/kg b.wt. of GTP. Decreased liver glycogen, after alloxan administration showed a significant (P<0.001) increase after GTP treatment. GTP treated group showed increased antioxidant potential as seen from improvements in superoxide dismutase and glutathione levels. However catalase, LP and glutathione peroxidase levels were unchanged. These results indicate that alterations in the glucose utilizing system and oxidation status in rats increased by alloxan were partially reversed by the administration of the glutamate pyruvate transaminase.     

Evaluation of antidiabetic, antioxidant and vasoprotective effects of Posidonia oceanica extract

The aim of this study is to evaluate antidiabetic, antioxidant and vasoprotective effects of Posidonia oceanica extract (POE) in alloxan diabetic rats. Posidonia oceanica (L) Delile (Posidoniaceae), is a widely allocated phanerogam in Mediterranean and Aegean Sea. Up to date, no published data relevant to use of the plant in traditional medicine are available. However, decoction of the leaves has been quoted to be used as a remedy for diabetes mellitus and hypertension by villagers living by the sea coast of Western Anatolia. Oral administration of extract for 15 days (50, 150, and 250 mg/kg b.wt.) resulted in a dose-dependent decrease in blood glucose. Relaxant responses to acetylcholine (ACh) in diabetic thoracic aorta were restored by POE treatment (50, 150, and 250 mg/kg b.wt.). POE also attenuated the augmented phenylephrine (PE) and serotonin (5-HT) contractions. At concentration levels of 150 and 250 mg/kg b.wt., POE exerted a protective effect on the significantly decreased levels of antioxidants namely, glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase and nitric oxide (NO). POE (50mg/kg b.wt.) produced no effect on alloxan-induced alterations in the antioxidant status while possessing glucose lowering and vasoprotective activities. Furthermore, liver and kidney function markers, leucocyte counts, body weight and liver glycogen content remained unchanged at dose level of 50mg/kg b.wt., when compared with diabetic control group. These results suggest that antidiabetic and vasoprotective effects of POE may be unrelated to its antioxidant properties.     

Antidiabetic and antioxidant effects of Annona muricata (Annonaceae), aqueous extract on streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Annona muricata are used in Cameroon to manage diabetes and its complications. The aim of this study was to evaluate the antidiabetic, antioxidant activities and the potential toxicity of aqueous extract of Annona muricata in streptozotocin-induced diabetic rats.

Material and methods

Oral administration of Annona muricata aqueous extract (100 mg/kg or 200 mg/kg) was studied in normal and streptozotocin-induced diabetic rats. In long term treatment, 2 weeks after streptozotocin-induced diabetic rats, animals received plant extract during 28 consecutive days. For a protective effect, extract was administered 3 days prior to streptozotocin exposure and animals were observed 2 weeks without treatment.

Results

The plant extract was not effective in normal rats. In diabetic rats, single administration of the extract significantly reduced blood glucose levels by 75% and 58.22% respectively at the dose of 100 mg/kg and 200 mg/kg as compared to the initial value. Treatment of normal rats 3 days prior to diabetes induction showed that, Annona muricata extract has no effect within 72 h following STZ injection. However, after 14 days post-treatment, the extract at the dose of 100 mg/kg significantly reduced blood glucose levels as compared with initial value and diabetic control rats. Immunohistochemical staining of pancreatic β-cells of diabetic rats treated with the dose of 100 mg/kg expressed strong staining for β-cell compared to diabetic control. In a long-term study daily administration of Annona muricata aqueous extract for 28 days to diabetic rats, reduced blood glucose levels, serum creatinine, MDA, AST, ALT activity, and nitrite levels LDL-cholesterol. Total cholesterol, triglycerides, SOD, and CAT activity contents were restored.

Conclusion

These different results show that the antidiabetic activity of Annona muricata aqueous extract can be explained by its hypolipidaemic effect, its antioxidant and protective action on pancreatic β-cells, which in turn improve glucose metabolism.     

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.     

Effect of Lepidium sativum L. on renal glucose reabsorption and urinary TGF-beta 1 levels in diabetic rats

The purpose of this study was to determine the mechanism underlying the hypoglycaemic activity of the aqueous extract perfusion of Lepidium sativum L. (LS) in normal and streptozotocin-induced diabetic rats. The aqueous LS extract was administered intravenously and the blood glucose levels were determined within 4 h of treatment. Plasma insulin concentrations and glycosuria were determined. The 24 h urinary transforming growth factor-beta1 (ELISA) was evaluated in diabetic and control rats 15 days after oral treatment with the aqueous LS extract at a dose of 20 mg/kg. The study showed that LS at a dose of 10 mg/kg/h reduced blood glucose levels both in normal and diabetic rats (p < 0.001). At the same time as a potent increase of glycosuria was observed both in normal and diabetic rats (p < 0.001). In addition, oral administration of LS for 15 days normalized glycaemia (p < 0.001), enhanced glycosuria (p < 0.05 vs diabetic control) and decreased the amount of urinary TGF-beta1 (p < 0.01) in diabetic rats. It is concluded that the aqueous LS extract caused a potent inhibition of renal glucose reabsorption which in turn reduced blood sugar. This renal effect is at least one mechanism explaining the observed hypoglycaemic activity of this plant in normal and diabetic rats.