The effect of Argania spinosa seed oil on diabetic nephropathy in streptozotocin-induced diabetes in Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes is a significant metabolic disease impacting many of the world's population. In Morocco, a wide range of medicinal plants has taken great importance in the treatment of diabetes, among these plants; we find Argania spinosa (L.) Skeels.

AIM

The objective of our work is based on the evaluation of the effect of roasted (Roil) and unroasted (UnRoil) Argan seed oil on diabetic nephropathy.

MATERIALS AND METHODS

Roasted and unroasted oils from Argania spinosa (L.) Skeels seeds were examined for their effects on diabetic nephropathy using an experimental streptozotocin-induced model. Biochemical and histopathological analyses were conducted on blood and kidney samples to assess renal function and tissue damage.

RESULTS

Both oils ameliorated significantly diabetic nephropathy symptoms. They limited the renal damage caused by streptozotocin and improved diabetes symptoms, including blood glucose levels, body weight, water intake, urinary volume, and kidney parameters. This activity could be elucidated by the antioxidant effect of Argan oil, enabling to neutralize free radicals and undertake a fundamental role in preventing the onset of these complications.

CONCLUSION

Based on our findings, Argan oil could be used as dietary supplement for people with diabetes as a preventive measure against the emergence of diabetic complications.

Fatty acids characterisation by GC-MS, antiglycation effect at multiple stages and protection of erythrocytes cells from oxidative damage induced by glycation of albumin of Opuntia ficus-indica (L.) Mill seed oil cultivated in Eastern Morocco: Experimental and computational approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Opuntia ficus-indica (L.) Mill is frequently observed in the Moroccan traditional medicinal system, where these approaches are employed to mitigate the onset of diabetes and the subsequent complications it may entail.

AIM OF THE STUDY

The aim of this research was to examine the effectiveness of Opuntia ficus-indica seed oil in preventing diabetic complications. Specifically, the study assessed its ability to counteract glycation at various stages, protected red blood cells from the harmful effects of glycated albumin, and inhibited pancreatic lipase digestive enzymes to understand its potential antihyperglycemic properties. Additionally, the study aimed to identify the chemical components responsible for these effects, evaluate antioxidant and anti-inflammatory properties, and conduct computational investigations such as molecular docking.

MATERIALS AND METHODS

The assessement of Opuntia ficus-indica seed oil antiglycation properties involved co-incubating the extract oil with a bovine serum albumin-glucose glycation model. The study investigated various stages of glycation, incorporating fructosamine (inceptive stage), protein carbonyls (intermediate stage), and AGEs (late stage). Additionally, measurement of β-amyloid aggregation of albumin was performed using Congo red, which is specific to amyloid structures. Additionally, the evaluation of oil's safeguarding effect on erythrocytes against toxicity induced by glycated albumin included the measurement of erythrocyte hemolysis, lipid peroxidation, reduced glutathione. The fatty acid of Opuntia ficus-indica seed oil were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The in vitro evaluation of antihyperglycemic activity involved the use of pancreatic lipase enzyme, while the assessement of antioxidant capability was carried out through the utilization of the ABTS and FRAP methods. The in vitro assessement of the denaturation of albumin activity was also conducted. In conjunction with the experimental outcomes, computational investigations were undertaken, specifically employing ADMET (absorption, distribution, metabolism, excretion, and toxicity) analysis. Furthermore, molecular docking was utilized to predict antioxidant and antiglycation mechanisms based on protein targets.

RESULTS

In vitro glycation assays, Opuntia ficus-indica seed oil displayed targeted inhibitory effects at multiple distinct stages. Within erythrocytes, in addition to mitigating hemolysis and lipid peroxidation induced by glycated albumin. GC-MS investigation revealed a richness of fatty acids and the most abundant compounds are Linoleic acid (36.59%), Palmitic acid (20.84%) and Oleic acid (19.33%) respectively. The findings of antioxidant ability showed a remarkable activity on FRAP and ABTS radicals. This oil showed a pronounced inhibitory impact (p < 0.001) on pancreatic lipase enzyme. It also exerted a notibale inhibition of albumin denaturation, in vitro.

CONCLUSION

The identified results were supported by the abundant compounds of fatty acids unveiled through GC-MS analysis, along with the computational investigation and molecular docking.

Antihyperglycemic potential of the Lavandula stoechas aqueous extract via inhibition of digestive enzymes and reduction of intestinal glucose absorption

BACKGROUND

Diabetes mellitus is a widespread metabolic disorder affecting global populations. Lavandula stoechas from Moroccan traditional medicine is used for its potential anti-diabetic effects.

OBJECTIVE

This study aims to evaluate the antihyperglycemic impact of the aqueous extract of L. stoechas (AqLs) and explore its mechanisms.

METHODS

The study employed a glucose tolerance test (OGTT) on normal and diabetic Wistar rats, administering AqLs at 150 mg/kg. In vitro, AqLs was tested against α-glucosidase and α-amylase activities, confirmed in vivo using normal and Allx-diabetic rats. The extract's impact on intestinal d-glucose absorption was assessed using the jejunum segment perfusion technique at 250 mg/kg in situ. Albino mice were used to assess toxicity.

RESULTS

AqLs significantly reduced postprandial hyperglycemia (P < 0.001) due to glucose overload. It inhibited pancreatic α-amylase (IC50: 0.485 mg/mL) and intestinal α-glucosidase (IC50: 168 µg/mL) in vitro. Oral AqLs at 150 mg/kg reduced hyperglycemia induced by sucrose and starch in normal and diabetic rats. It also lowered (P < 0.001) intestinal glucose absorption in situ at 250 mg/kg. Oral acute toxicity tests on Albino mice indicated no adverse effects at different doses.

CONCLUSION

to summarize, L. stoechas has evident antihyperglycemic effects attributed to inhibiting intestinal glucose absorption and key monosaccharide digestion enzymes like α-amylase and α-glucosidase.

Myorelaxant and antispasmodic effects of the essential oil of Artemisia campestris L., and the molecular docking of its major constituents with the muscarinic receptor and the L-type voltage-gated Ca2+channel

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrointestinal disorders are among the most common diseases that cause discomfort to people who are affected. In Morocco, aromatic and medicinal plants are widely used to calm these pains and eliminate their symptoms. Among these plants, Artemisia campestris L. which is used in eastern Morocco to treat digestive system problems.

AIM OF THE STUDY

Our study aimed to experimentally verify the traditional use of this plant by evaluating the myorelaxant and antispasmodic effects of the essential oil of Artemisia campestris L. (EOAc).

MATERIALS AND METHODS

Gas Chromatography-Mass Spectrometry analysis (GC-MS) was performed to identify the compounds present in the EOAc. Then, these molecules were subjected to the in silico study for molecular docking. The myorelaxant and antispasmodic evaluation of the EOAc were tested in vitro on an isolated rabbit and rat jejunum mounted on an organ bath. Then, an isotonic transducer connected to an amplifier recorded the graph related to intestinal contractility.

RESULTS

GC-MS analysis of the essential oil of Artemisia campestris L. showed the presence of m-Cymene (17.308%), Spathulenol (16.785%), β Pinene (15.623%), α Pinene (11.352%), α.-Campholenal (8.848%) as main constituents. The EOAc gave a dose-dependent and reversible myorelaxant effect on the spontaneous contractions of jejunum isolated from rabbits, with an IC₅₀ equal to 72.16 ± 15.93 μg/mL. This effect did not occur through adrenergic receptors. The EOAc has an antispasmodic effect on the contractions of rat jejunal induced by a medium with low (25 mM) or high concentration (75 mM) of KCl, and carbachol 10^-6 M. The obtained inhibitory effects are comparable to those of a non-competitive antagonist of cholinergic receptors. The major compounds of EOAc allowed the establishment of a relationship between these phytoconstituents and the antispasmodic effect found by the EOAc. The obtained results are also supported by a docking study.

CONCLUSION

The obtained results confirm favorably the use of Artemisia campestris L. in traditional Moroccan medicine for the treatment of digestive tract illness, which gives us a new route to valorize the effects obtained by a phytomedicine specific for the digestive tract.

Development of a Thin-Layer Chromatography-Enzymatic Test Combination Method for the Isolation of α-Glucosidase Inhibitors From Thymelaea hirsuta

A rapid, easy and simple method for the isolation and purification of α-glucosidase inhibitors of the ethyl acetate extract of Thymelaea hirsuta (EaTh) by a combination of thin layer chromatography (TLC) and enzymatic test has been developed. EaTh was demonstrated previously a potent α-glucosidase inhibitory effect. In this study, we developed a simple TLC-enzymatic test (TLC/EZ) combination to isolate α-glucosidase inhibitors present in EaTh.EaTh was extracted by Soxhlet from Thymelaea hirsuta (T. hirsuta). The EaTh was separated on a silica gel column and then on a TLC plate. After TLC separation, the TLC/EZ combination method was applied. α-glucosidase inhibitors were detected directly in the TLC plate using the glucose oxidase peroxidase method (GOD-POD). A good detection of active compounds was obtained in the TLC favoring the TLC/EZ method. Active compounds were then characterized using high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis. The main α-glucosidase inhibitors present in EaTh have a molecular ion [M + H]+ at m/z = 543. This proposed method is suitable for a reliable isolation and purification of α-glucosidase inhibitors present in EaTh. It could be proposed as an interesting alternative of the classical method for the isolation and purification of α-glucosidase inhibitors in plant extracts.

Antioxidant Activity and Inhibition of Carbohydrate Digestive Enzymes Activities of Artemisia campestris L

BACKGROUND

Carbohydrate digestive enzymes play a major role in the management of the postprandial hyperglycemia. A chronic hyperglycemia can lead to serious health problems due to excessive production of several reactive oxygen species. Therefore, the inhibition of carbohydrate digestive enzyme and the use of antioxidant natural product can be an important strategy to control the glycaemia level and prevent against the complication of diabetes.

AIM

The study aims to perform a phytochemical analysis, antioxidant activity, inhibitory effect on α -amylase, α -glucosidase (in vitro and in vivo) and the intestinal glucose absorption in Wistar rats of Artemisia campestris aqueous extract (AcAE) and hydro-ethanolic extract (AcEE).

RESULTS

The test of total phenolic content, show that the AcAE has the highest quantity of polyphenol (44.65 ± 0.54 μ g GAE/mg extract) compared to the AcEE (31.7 ± 0.53 μ g GAE/mg extract) significantly. The amount of flavonoid and condensed tannins content in AcAE is 24.41 ± 3.57 μ g QrE/mg extract, 14.31 ± 5.26 μ g CE/mg respectively. The AcAE has also exhibit a great antioxidant activity in DPPH-scavenging and Ferric reducing antioxidant power assay (FRAP) compared to AcEE with an IC 50 = 0.355 ± 0.057 mg/mL and IC 50 = 0.269 ± 0.025 mg/mL. However, in a β -carotene bleaching assay the AcEE has the highest effect with an IC 50 = 0.319 ± 0.097 mg/mL. The both extract of Artemisia campestris L. (250 mg/kg) decreased postprandial hyperglycemia in the normal and alloxane diabetic rats in a very significant manner after starch or sucrose administration as an α -amylase and α -glucosidase substrate respectively. This result is confirmed in vitro by a remarkable inhibitory effect on α -amylase digestive enzymes by an IC 50 = 1.259 ± 0.128 mg/mL and IC 50 = 0.602 ± 0.072 mg/mL receptively for AcAE and AcEE. For the α -glucosidase enzyme, the both extracts significantly inhibit α -glucosidase activity compared to the control and they are almost similar to each other. Using a jejunum perfusion technique (in situ), Artemisia campestris L. decrease the intestinal D-glucose absorption activity significantly compared to the control and comparable to the Phlorizin used as a positive control by an amount of glucose absorbed equal a 6.53 ± 0.57, 5.34 ± 0.64 and 4.71 ± 0.24 mg/10 cm/h, for AcAE, AcEE and Phlorizin respectively.

CONCLUSIONS

These results showed that the Artemisia campestris L. has highest phenolic content, antioxidant activity and demonstrated a postprandial anti-hyperglycemic effect via the inhibiting of the carbohydrate digestive enzyme ( α -amylase and α -glucosidase) and the intestinal glucose absorption.

Acute and Subchronic Treatment of Roasted and Unroasted Argan Oil on Postprandial Glycemia and Its Effect on Glucose Uptake by Isolated Rat Hemidiaphragm

Background:

In Morocco, Argan oil is one of the products used for antidiabetic purposes. Objective. This work aims to study the acute and subchronic effect treatment of the roasted (Roil) and unroasted (UnRoil) Argan oils on oral glucose tolerance test (OGTT) and body weight in normal and diabetic rats, evaluate the effect of these oils on glucose absorption by the diaphragm, and determine total polyphenol, flavonoids, tannins, chlorophyll and carotenoids amounts.

Methods:

The investigation of the anti-hyperglycemic effect of Roil and UnRoil was performed on normal and alloxane-diabetic rats, by treating orally the animals with 2 mLKg-1/day of oils for 1 day (Acute treatment) and 4 weeks (Subchronic treatment). Then, OGTT was carried out at the end of each treatment and the body weight was checked for each week. Besides, these oils (1 gL-1) were tested on glucose absorption by the diaphragm isolated from Wistar rats, in vitro.

Results:

This work shows that Roil and UnRoil decrease significantly the postprandial glycemia level in acute and subchronic treatments in normal and diabetic rats. Besides, the intake of these oils in diabetic rats attenuates significantly the postprandial glycemia, compared to the acute-treated group. In vitro glucose uptake by the hemidiaphragm study shows that Argan oils promote glucose consumption by the muscles.

Conclusion:

Argan oils showed a very important anti-hyperglycemic effect, and this effect could be explained by promoting peripheral glucose uptake. UnRoil shows a better effect than Roil towards glucose consumption which means that the roasting process influences the phytoconstituent responsible for this activity.

Myorelaxant and antispasmodic effect of an aqueous extract of Artemisia campestris L. via calcium channel blocking and anticholinergic pathways

Intestinal spasms are violent contractions that occur in the intestine, which cause discomfort to people who have them. Medicinal plants are widely used in traditional Moroccan medicine to treat these problems, among these being Artemisia campestris L. This study aims to evaluate the relaxant and antispasmodic effects of an aqueous extract of this plant (ACAE). It was performed in vitro on isolated segments of both isolated rat and rabbit jejunum mounted in an organ bath and tension recordings made via an isotonic transducer. ACAE caused a myorelaxant effect on baseline rabbit jejunum contractions in a dose-dependent and reversible manner with an IC₅₀ of 1.52 ± 0.12 mg/ml. This extract would not act via adrenergic receptors pathway. On the other hand, the extract caused a dose-dependent relaxation of the jejunum tone in rat jejenum segments pre-contracted with either Carbachol (CCh; 10^-6 M) or high K⁺ (KCl 75 mM) with an IC₅₀ = 0.49 ± 0.02 mg/ml and 0.36 ± 0.02 mg/ml respectively. In the presence of different doses of the extract, the maximum response to CCh and CaCl₂ was significantly reduced. This demonstrates that ACAE acts on both muscarinic receptors and voltage-dependent calcium channels. Thus, the plant extract acted on both muscarinic and nicotinic receptors and acts on the guanylate cyclase pathway, but not the nitric oxide pathway. These results indicate the mechanism by which Artemisia campestris L. acts as an effective antispasmodic agent in traditional Moroccan medicine.

Acute and Subacute Toxicity and Cytotoxicity of Opuntia Dillenii (Ker-Gawl) Haw. Seed Oil and Its Impact on the Isolated Rat Diaphragm Glucose Absorption

This study aims to assess the safety of the Opuntia dillenii (Ker-Gawl) haw. seed oil (ODSO) and its effect on the glucose absorption activity of the isolated rat hemidiaphragm. This oil's safety was studied by exploring its acute (doses 1, 3, 5, and 7 mL/kg) and subacute (doses 1 and 2 mL/kg) toxicities in albino mice and Wistar rats, respectively. The safety of the ODSO was also assessed by studying its effect on the HepG2 cell viability in vitro. The effect of ODSO, or combined with the insulin, on the glucose absorption activity of isolated rat hemidiaphragm was evaluated at the dose 1 g/L in vitro. The results demonstrated the safety of ODSO. Indeed, this study showed that this oil does not produce any mortality or signs of toxicity after the single-dose administration in mice. Additionally, the daily intake of the ODSO during four weeks does not induce a significant variation in the biochemical parameters and body weight of rats compared with the control group. Besides, the cell viability of HepG2 did not change in the presence of ODSO. On the other hand, the ODSO increased the glucose absorption activity of the isolated rat hemidiaphragm, and this activity was significantly enhanced when combined with insulin. This study confirms, on one side, the safety of this oil and its efficacy and, on the other side, encourages its potential use as a complement to treat diabetes.

Opuntia dillenii (Ker Gawl.) Haw., Seeds Oil Antidiabetic Potential Using In Vivo, In Vitro, In Situ, and Ex Vivo Approaches to Reveal Its Underlying Mechanism of Action

Opuntia dillenii Ker Gawl. is one of the medicinal plants used for the prevention and treatment of diabetes mellitus (DM) in Morocco. This study aims to investigate the antihyperglycemic effect of Opuntia dillenii seed oil (ODSO), its mechanism of action, and any hypoglycemic risk and toxic effects. The antihyperglycemic effect was assessed using the OGTT test in normal and streptozotocin (STZ)-diabetic rats. The mechanisms of action were explored by studying the effect of ODSO on the intestinal absorption of d-glucose using the intestinal in situ single-pass perfusion technique. An Ussing chamber was used to explore the effects of ODSO on intestinal sodium-glucose cotransporter 1 (SGLT1). Additionally, ODSO’s effect on carbohydrate degrading enzymes, pancreatic α-amylase, and intestinal α-glucosidase was evaluated in vitro and in vivo using STZ-diabetic rats. The acute toxicity test on mice was performed, along with a single-dose hypoglycemic effect test. The results showed that ODSO significantly attenuated the postprandial hyperglycemia in normal and STZ-diabetic rats. Indeed, ODSO significantly decreased the intestinal d-glucose absorption in situ. The ex vivo test (Ussing chamber) showed that the ODSO significantly blocks the SGLT1 (IC₅₀ = 60.24 µg/mL). Moreover, ODSO indu\ced a significant inhibition of intestinal α-glucosidase (IC₅₀ = 278 ± 0.01 µg/mL) and pancreatic α-amylase (IC₅₀ = 0.81 ± 0.09 mg/mL) in vitro. A significant decrease of postprandial hyperglycemia was observed in sucrose/starch-loaded normal and STZ-diabetic ODSO-treated rats. On the other hand, ODSO had no risk of hypoglycemia on the basal glucose levels in normal rats. Therefore, no toxic effect was observed in ODSO-treated mice up to 7 mL/kg. The results of this study suggest that ODSO could be suitable as an antidiabetic functional food.

Beneficial Effect of Thymelaea hirsuta on Pancreatic Islet Degeneration, Renal Fibrosis, and Liver Damages as Demonstrated in Streptozotocin-Induced Diabetic Rat

OBJECTIVE

In Morocco, Thymelaea hirsuta (T. hirsuta) (Thymelaeacea) is a medicinal plant widely used to treat and prevent diabetes. The present study aimed to evaluate the medium-term antidiabetic effect of aqueous extract (AqTh) and ethyl acetate fraction (EaTh) of Th and to investigate their putative protective effect on pancreatic islet degeneration, diabetic nephropathy, and liver damages in streptozotocin (STZ)-diabetic rats.

METHODS

Experimental diabetes in rats was induced by a single intraperitoneal injection of 50 mg/kg of STZ. During the treatment period (4 weeks), 200 mg/kg AqTh and 50 mg/kg EaTh were orally administrated daily to STZ-diabetic rats. A group of parameters including fasting blood glucose, biochemical parameters, and intestinal α-glucosidase inhibition were studied. Furthermore, histological study of the pancreas, kidney, liver, and aorta was also realized.

RESULTS

At the end of the treatment, both AqTh and EaTh had normalized fasting blood glucose to 1.08 and 1.25 g/l, respectively. AqTh has also reduced urinary creatinine and HbAc1. The EaTh showed inhibitory activity against intestinal α-glucosidase, whereas AqTh did not have this inhibitory effect. Furthermore, pancreas hematoxylin and eosin staining showed that AqTh or EaTh prevents pancreatic islet cell degeneration. As the same kidney, Masson's trichrome staining has shown a significant prevention of renal fibrosis in AqTh- or EaTh-treated diabetic rats. On the other hand, liver hematoxylin and eosin staining showed that AqTh and EaTh prevent liver damage.

CONCLUSION

We conclude that medium-term administration of AqTh and EaTh exerts significant antihyperglycemic effect in STZ-diabetic rats possibly through intestinal α-glucosidase inhibition and protection against pancreatic islet cell damage. Moreover, AqTh and EaTh treatment prevent nephropathy and liver complications in STZ-diabetic rats.

Origanum majorana L. extract exhibit positive cooperative effects on the main mechanisms involved in acute infectious diarrhea

ETHNOPHARMACOLOGICAL RELEVANCE

Origanum majorana L. (Lamiaceae) is commonly used in Moroccan folk medicine to treat infantile colic, abdominal discomfort and diarrhea. Liquid stools and abdominal discomfort observed in acute infectious diarrhea are the consequences of imbalance between intestinal water secretion and absorption in the lumen, and relaxation of smooth muscle surrounding the intestinal mucosa.

AIM OF THE STUDY

The objective of our study was to see if aqueous extract of Origanum majorana L. (AEOM) may exhibit an effect on those deleterious mechanisms.

MATERIALS AND METHODS

The effect of AEOM on electrogenic Cl^- secretion and Na⁺ absorption, the two main mechanisms underlying water movement in the intestine, was assessed on intestinal pieces of mice intestine mounted, in vitro, in Ussing chambers. AEOM effect on muscle relaxation was measured on rat intestinal smooth muscle mounted in an isotonic transducer.

RESULTS

1) AEOM placed on the serosal (i.e. blood) side of the piece of jejunum entirely inhibited in a concentration-dependent manner the Forskolin-induced electrogenic chloride secretion, with an IC₅₀ = 654 ± 8 µg/mL. 2) AEOM placed on the mucosal (i.e. luminal) side stimulated in a concentration-dependent manner an electrogenic Na⁺ absorption, with an IC₅₀ = 476.9 ± 1 µg/mL. 3) AEOM (1 mg/mL) inhibition of Forskolin-induced electrogenic secretion was almost entirely prevented by prior exposure to Ca⁺⁺ channels or neurotransmitters inhibitors. 4) AEOM (1 mg/mL) proabsorptive effect was greater in the ileum and progressively declined in the jejunum, distal colon and proximal colon (minimal). 5) AEOM inhibited in a concentration-dependent manner smooth muscle Carbachol or KCl induced contraction, with an IC₅₀ = 1.64 ± 0.2 mg/mL or 1.92 ± 0.8 mg/mL, respectively.

CONCLUSION

the present results indicate that aqueous extract of Origanum majorana L. exhibit positive cooperative effects on the main mechanisms that are involved in acute infectious diarrhea.

Myorelaxant Activity of essential oil from Origanum majorana L. on rat and rabbit

ETHNOPHARMACOLOGICAL RELEVANCE

Origanum majorana L. (Lamiaceae) was usually used in Moroccan folk medicine to treat infantile colic and abdominal discomfort.

MATERIALS AND METHODS

The essential oil from the aerial part of the dry Origanum majorana L. (EOOM) was obtained through hydro distillation and analyzed by gas chromatography/mass spectrometry (GC/MS). The effect of EOOM on muscle relaxation was measured on rabbit and rat intestinal smooth muscle mounted in an isotonic transducer.

RESULTS

1) The main compounds obtained from the aqueous extract of this plant were alpha Terpineol, L-terpinen-4-ol and Beta.-Linalool. 2) EOOM inhibited in a concentration-dependent manner spontaneous contraction of rabbit jejunum, with an IC₅₀ = 64.08 ± 2.42 μg/mL. 3) In rat intestine, EOOM induced the relaxation of the tissue in concentration-dependent manner with an IC₅₀ = 39.70 ± 2.29 μg/mL when the tissue was pre-contracted with CCh 10^-6 M, and 48.70 ± 2.26 μg/mL when the tissue was pre-contracted with 25 mM KCl. 4) The relaxation effect induced by EOOM was more important than that obtained in the presence of atropine, hexamethonium, Nifedipine, L-NAME and Blue of methylene.

CONCLUSION

the present result indicates that essential oil of Origanum majorana L. exhibit an effect on intestinal relaxation in vitro. This effect further validates the traditional use of Origanum majorana L. to treat infantile colic and abdominal discomfort.

Inhibition of α-Glucosidase, Intestinal Glucose Absorption, and Antidiabetic Properties by Caralluma europaea

Many medicinal plants around the world are used for therapeutic purposes against several diseases, including diabetes mellitus. Due to their composition of natural substances that are effective and do not represent side effects for users, unlike synthetic drugs, in this study, we investigated the inhibitory effect of Caralluma europaea (CE) on α-glucosidase activity in vitro; then the kinetics of the enzyme were studied with increasing concentrations of sucrose in order to determine the inhibition type of the enzyme. In addition, this effect of Caralluma europaea (CE) was confirmed in vivo using rats as an experimental animal model. Among the five fractions of CE, only the ethyl acetate fraction of C. europaea (EACe) induced a significant inhibition of α-glucosidase and its inhibition mode was competitive. The in vivo studies were conducted on mice and rats using glucose and sucrose as a substrate, respectively, to determine the oral glucose tolerance test (OGTT). The results obtained showed that the EACe and the aqueous extract of C. europaea (AECe) have significantly reduced the postprandial hyperglycemia after sucrose and glucose loading in normal and diabetic rats. AECe, also, significantly decreased intestinal glucose absorption, in situ. The results obtained showed that Caralluma europaea has a significant antihyperglycemic activity, which could be due to the inhibition of α-glucosidase activity and enteric absorption of glucose.

Antihypertensive and vasorelaxant effects of aqueous extract of Artemisia campestris L. from Eastern Morocco

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia campestris L. (Asteraceae) has many traditional uses, among which treatment of diabetes and hypertension.

AIM OF THE STUDY

This study was conducted in order to confirm the antihypertensive and hypotensive effects of A. campestris L. aqueous extract (AcAE) and to explore the underlying mechanism of action of its vasorelaxant effect, besides the acute toxicity. Also, the chemical composition of AcAE was investigated.

MATERIAL AND METHODS

the chemical content of AcAE was determined by using HPLC and NMR techniques. The antihypertensive effect was assessed indirectly by tail-cuff method on L-NAME induced hypertensive rats, while the hypotensive action was monitored intravenously by invasive method on normotensive rats. The vasorelaxant effect and vascular mechanism of action were studied in the presence of antagonists and blockers on aorta isolated from normotensive rats. On the other side, the acute toxicity was studied by oral feeding of extract to the mice.

RESULTS

The global phytochemical profile of AcAE reveals the presence of several polyphenols as main components. A. campestris L. infusion was characterized by mono- and di-cinnamoyl compounds, with 3,5-dicaffeoylquinic (isochlorogenic A) acid being the main compound, followed by 5-caffeoylquinic (chlorogenic) acid. Vicenin-2 (apigenin 6,8-di-C-glucoside) appeared to be the most abundant compound among flavonoids. The daily treatment with AcAE at 150mg/kg/day prevented the installation of hypertension on L-NAME hypertensive rats, and reduced SBP from 172mmHg up to 144mmHg. At the dose 40mg/kg, AcAE provoked reduction of systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP), without affecting the heart rate. Also, AcAE (10^-2-2mg/ml) relaxed the precontracted aorta by 95.8±1.3%. The denudation and preincubation of aorta with atropine, calmidazolium, L-NAME, hydroxycobalamin, ODQ, 8-RP-Br-PET-cGMP, thapsigargin and verapamil attenuated the vasorelaxant response, while the pre-treatment with 4-AP, TEA, glibenclamide and BaCl₂ did not alter this effect. The oral administration of AcAE (0-6g/kg) reveals no mortality or toxicity.

CONCLUSIONS

our study proved that AcAE possess an important antihypertensive, hypotensive and vasorelaxant effect, which is mediated via calmodulin-NO-cGC-PKG pathway, and via inhibition of calcium influx through voltage-operated calcium channels and activation of intracellular calcium mobilization into sarcoplasmic reticulum. Therefore, our findings give first evidence about the traditional use of A. campestris L. as antihypertensive plant.

Antihypertensive and vasodilator effects of methanolic extract of Inula viscosa: Biological evaluation and POM analysis of cynarin, chlorogenic acid as potential hypertensive

BACKGROUND

Inula viscosa L. (Asteraceae) is a medicinal plant widely used as a folk medicine in oriental Morocco, to treat hypertension. The antihypertensive effect of the methanolic extract obtained from I. viscosa leaves was evaluated in hypertensive L-NAME rats. Systolic blood pressure (SBP) was measured using a non-invasive indirect tail-cuff plethysmographic method. Four groups of rats were used: a control group; a hypertensive group treated with L-NAME (32mg/kg/day); a positive control group treated with L-NAME plus enalapril (15mg/kg/day) as a reference antihypertensive agent; and a group treated with L-NAME plus MeOH-extract (40mg/kg/day).

METHODS

Treatment with L-NAME alone caused a progressive increase in SBP. After 4 weeks, the value of SBP reached 160±2mmHg which shows the installation of hypertension. Enalapril prevented the increase in SBP, which remained normal at 123±1mmHg after 4 weeks of treatment. The administration of MeOH-extract along with L-NAME prevented the increase in SBP as well, which remained constant at 115±1mmHg after 4 weeks of treatment. In ex-vivo models, MeOH-extract produced a relaxation of pre-contracted ring aorta (54 ± 2% of relaxation at 3g/L). But, when the rings were denuded, MeOH-extract failed to relax pre-contracted rings of aorta. Phytochemical study of I. viscosa MeOH-extract revealed the presence of phenolic compounds, such as cynarin and chlorogenic acid.

RESULTS

The present results suggest that I. viscosa MeOH-extract has an antihypertensive, predominantly mediated by an endothelium-dependent vasodilatory effect. Cynarin and chlorogenic acid, which have a strong vasorelaxant effect may be involved in the antihypertensive effect of the plant extract. The bioinformatic POM analysis confirms the therapeutic potential of cynarin and chlorogenic acids as inhibitors of various biotargets. Based on the results, the coordination of these phytochemicals with calcium and transition metals should be studied, for better scope at antihypertensive drug development.

Chemical composition, vasorelaxant, antioxidant and antiplatelet effects of essential oil of Artemisia campestris L. from Oriental Morocco

BACKGROUND

Artemisia campestris L. (Asteraceae) is a medicinal herb traditionally used to treat hypertension and many other diseases. Hence, this study is aimed to analyze the essential oil of A. campestris L (AcEO) and to investigate the antiplatelet, antioxidant effects and the mechanisms of its vasorelaxant effect.

METHODS

The chemical composition of AcEO was elucidated using GC/MS analysis. Then, the antioxidant effect was tested on DPPH radical scavenging and on the prevention of β-carotene bleaching. The antiplatelet effect was performed on the presence of the platelet agonists: thrombin and ADP. The mechanism of action of the vasorelaxant effect was studied by using the cellular blockers specified to explore the involvement of NO/GC pathway and in the presence of calcium channels blockers and potassium channels blockers.

RESULTS

AcEO is predominated by the volatiles: spathulenol, ß-eudesmol and p-cymene. The maximal antioxidant effect was obtained with the dose 2 mg/ml of AcEO. The dose 1 mg/ml of AcEO showed a maximum antiplatelet effect of, respectively 49.73% ±9.54 and 48.20% ±8.49 on thrombin and ADP. The vasorelaxation seems not to be mediated via NOS/GC pathway neither via the potassium channels. However, pretreatment with calcium channels blockers attenuated this effect, suggesting that the vasorelaxation is mediated via inhibition of L-type Ca²⁺ channels and the activation of SERCA pumps of reticulum plasma.

CONCLUSION

This study confirms the antioxidant, antiplatelet and vasorelaxant effects of A.campestris L essential oil. However, the antihypertensive use of this oil should be further confirmed by the chemical fractionation and subsequent bio-guided assays.

Chemical composition, vasorelaxant, antioxidant and antiplatelet effects of essential oil of Artemisia campestris L. from Oriental Morocco

BACKGROUND

Artemisia campestris L. (Asteraceae) is a medicinal herb traditionally used to treat hypertension and many other diseases. Hence, this study is aimed to analyze the essential oil of A. campestris L (AcEO) and to investigate the antiplatelet, antioxidant effects and the mechanisms of its vasorelaxant effect.

METHODS

The chemical composition of AcEO was elucidated using GC/MS analysis. Then, the antioxidant effect was tested on DPPH radical scavenging and on the prevention of β-carotene bleaching. The antiplatelet effect was performed on the presence of the platelet agonists: thrombin and ADP. The mechanism of action of the vasorelaxant effect was studied by using the cellular blockers specified to explore the involvement of NO/GC pathway and in the presence of calcium channels blockers and potassium channels blockers.

RESULTS

AcEO is predominated by the volatiles: spathulenol, ß-eudesmol and p-cymene. The maximal antioxidant effect was obtained with the dose 2 mg/ml of AcEO. The dose 1 mg/ml of AcEO showed a maximum antiplatelet effect of, respectively 49.73% ±9.54 and 48.20% ±8.49 on thrombin and ADP. The vasorelaxation seems not to be mediated via NOS/GC pathway neither via the potassium channels. However, pretreatment with calcium channels blockers attenuated this effect, suggesting that the vasorelaxation is mediated via inhibition of L-type Ca2+ channels and the activation of SERCA pumps of reticulum plasma.

CONCLUSION

This study confirms the antioxidant, antiplatelet and vasorelaxant effects of A.campestris L essential oil. However, the antihypertensive use of this oil should be further confirmed by the chemical fractionation and subsequent bio-guided assays.

Epidemiology of hypertension and its relationship with type 2 diabetes and obesity in eastern Morocco

The major objectives of this work are to estimate the hypertension (HT) frequency in the east of Morocco and to study the relationship between HT, type 2 diabetes and obesity. Our sample is composed of 1628 adults aged 40 years and older, recruited voluntarily by using the convenience sampling method through 26 screening campaigns in urban and rural areas of the east of Morocco. We enumerated 516 hypertensive people (31.7%), without significant difference between women (32.5%) and men (30.2%). The known hypertensive people represent 10.1% of the whole sample. The frequency of HT, increases with age and it is more marked in rural (39.9%) than in urban areas (29%) (p < 0.001). It is significantly very high in diabetic subjects (69.9%) than among the non-diabetic ones (27.4%) (p < 0.001). The odd ratio (OR) of the diabetics to HT is 6.16 (IC95% [4.33-8.74]). Among the obese persons, HT is present at (40.8%) vs. (30.2%) among the subjects of normal weight (p < 0.05). The OR of the obese to HT is 1.6 (IC95% [1.26 - 2.04]). In conclusion, our results show a high frequency of HT in the east of Morocco; it affects nearly one third of the adult population aged 40 years and older. The relations between type 2 diabetes and obesity have also been identified and estimated.

Evaluation of antidiabetic properties of cactus pear seed oil in rats

CONTEXT

Cactus pear (Opuntia ficus-indica (L.) Mill. (Cactaceae)) is a medicinal plant widely used to treat diabetes.

OBJECTIVE

This work investigates the hypoglycemic and antihyperglycemic effect of cactus pear seed oil (CPSO), its mechanism of action, and any toxic effects.

MATERIALS AND METHODS

The hypoglycemic effect of CPSO was evaluated in groups of six healthy Wistar rats given 1 or 2 ml kg(-1) orally and compared with groups receiving glibenclamide (2 mg kg(-1)) or water. Glycemia was determined after 30, 60, 120, 240, and 360 min. The antihyperglycemic effect of CPSO was determined in healthy rats and in streptozotocin-induced diabetic rats (STZ); normal rats received 0.8 ml kg(-1) CPSO, while diabetic rats received 1 ml kg(-1) CPSO, their controls received water or 2 mg kg(-1) glibenclamide. For the antihyperglycemic effect evaluation, all the animals were fasted for 16 h before treatment and received glucose orally at 1 g kg(-1) 30 min after treatment; blood was taken after 30, 90, 150, and 210 min. Intestinal glucose absorption was estimated in rat jejunum perfused with a solution containing 5.55 mmol l(-1) glucose. Acute toxicity was determined in albino mice that received oral or intraperitoneal doses of 1, 3, or 5 ml kg(-1) CPSO.

RESULTS

CPSO (p.o.) decreased postprandial hyperglycemia (60 min after glucose loading), 40.33% and 16.01%, in healthy and STZ-diabetic glucose-loaded rats, respectively. CPSO, also, significantly decreased intestinal glucose absorption by 25.42%. No adverse effects were seen in mice administered CPSO at up to 5 ml kg(-1).

CONCLUSION

CPSO is antihyperglycemic. The effect can be explained partly by inhibition of intestinal glucose absorption.

Inhibition of α-glucosidase and glucose intestinal absorption by Thymelaea hirsuta fractions

BACKGROUND

Thymelaea hirsuta (L.) Endl. (Thymelaeaceae) is a medicinal plant used in Morocco to treat diabetes. In previous studies T. hirsuta has shown a potent antihyperglycemic effect. Our aim was to study the effect of the plant on α-glucosidase inhibition and intestinal glucose absorption.

METHODS

Five fractions of T. hirsuta were tested, in vitro, in vivo and, in situ, to elucidate the inhibition of α-glucosidase and intestinal glucose uptake.

RESULTS

The fractions induced, in vitro, a significant inhibition of α-glucosidase. The ethyl acetate fraction (EATh) had high activity and its inhibition mode was non-competitive. The EATh at 50 and 100 mg/kg doses, decreased significantly, in vivo, the postprandial hyperglycemia after sucrose loading in normal and diabetic mice. Moreover, 50 mg/kg of EATh significantly decreased intestinal glucose uptake, in situ, in rats.

CONCLUSION

The antihyperglycemic effect of T. hirsuta can be explained, in part, by the inhibition of intestinal α-glucosidase and intestinal glucose absorption.

Hypotensive property of Chenopodium ambrosioides in anesthetized normotensive rats

BACKGROUND

The leaves of Chenopodium ambrosioides L. (Chenopodiaceae) are widely used in Moroccan traditional medicine to treat diabetes and hypertension. The goal of the present work is to investigate the hypotensive properties of different extract and fractions of the plant in anesthetized normotensive rats and to elucidate the mechanism underlying this effect.

METHODS

The hypotensive effect of aqueous extract (AqE) of the leaves of C. ambrosioides L., methanolic (MF), ethyl acetate (AcF), and aqueous (AqF) Soxhlet fractions, administrated intravenously, was evaluated in anesthetized rats. The recorded signals of blood pressure and heart rate were visualized and analyzed by using an acquisition card "National Instrument" and software Labview 6.1.

RESULTS

Intravenous administration of AqE of the leaves of C. ambrosioides L. induces a dose-dependent hypotension. A similar effect was obtained with MF, AcF, and AqF. Atropine (1 mg/kg), used to block cholinergic system, significantly reduced the hypotensive response to MF and AcF suggesting the presence of the cholinomimetic-muscarinic components in these fractions. However, the blood pressure lowering effect of MF and AcF in rats pretreated with L-NAME 20 mg/kg was unchanged showing that the release of NO is not implicated in the hypotensive action of this plant.

CONCLUSIONS

The present study demonstrates that extracts from leaves of C. ambrosioides induce hypotensive effect that may be partially associated with its cardiac effects. These results may partly explain the traditional use of leaves of C. ambrosioides L. for the treatment of disorders such as hypertension.

Antidiabetic and antihypertensive effect of Virgin Argan Oil in model of neonatal streptozotocin-induced diabetic and l-nitroarginine methylester (l-NAME) hypertensive rats

BACKGROUND

The goal of this study was to examine the effect of Virgin Argan Oil (VAO) obtained from the fruit of Argania spinosa in a model of type 2 diabetes and hypertensive rats. Neonatal diabetes was induced by a single i.p. injection of streptozotocin (90 mg/kg) 2 days after birth. To induce NO-deficient hypertension, the adult diabetic animals were treated with l-nitroarginine methylester (l-NAME) (30 mg/kg/day) given orally for 21 days.

METHODS

Following treatment with VAO (21 days), the hyperglycemia decreased to 1.3 ± 0.07 g/l compared with 1.92 ± 0.09 g/l (p < 0.01) in the untreated diabetic-hypertensive rats. The simultaneous administration of VAO with l-NAME prevented the increase in blood pressure during the 3 weeks of treatment. Blood pressure remained constant at 131 ± 1 mm Hg after 21 days - vs 157 ± 0.64 mm Hg in untreated animals (p < 0.001).

RESULTS

The treatment with VAO to diabetic-hypertensive rats caused a significant increase of hepatic glycogen levels (13.3 ± 1.8 vs 6.34 ± 0.75 mg/g tissue in untreated diabetic-hypertensive control group; p < 0.01).

CONCLUSIONS

In conclusion, the overall findings indicate that VAO possesses antidiabetic and antihypertensive activity in n-stz/l-NAME rats. This effect may be related to its high content of tocopherols, phenolic compounds, and unsaturated fatty acids.

Antidiabetic and antihypertensive effect of a polyphenol-rich fraction of Thymelaea hirsuta L. in a model of neonatal streptozotocin-diabetic and N(G) -nitro-l-arginine methyl ester-hypertensive rats

BACKGROUND

  The present study examined the effect of the polyphenol-rich fraction from Thymelaea hirsuta (PRF-Th) in a rat model of streptozotocin (STZ)-diabetes and nitric oxide (NO)-deficient hypertension.

METHODS

  Diabetes was induced by a single dose of STZ (90 mg/kg, i.p.). To induce NO-deficient hypertension, rats were treated with the NO synthase inhibitor N(G) -nitro-l-arginine methyl ester; l-NAME; 30 mg/kg per day, p.o. for 3 weeks. The effects of 21 days treatment with 80 mg/kg per day PRF-Th in the drinking water were evaluated in diabetic-hypertensive (DH) rats. In all groups (n = 6 in each), glycemia and systolic blood pressure were determined weekly. At the end of the experiment, hepatic glycogen was determined.

RESULTS

  Blood glucose levels decreased gradually from baseline until the end of the experiment in untreated DH rats (from 1.92 ± 0.09 to 1.3 ± 0.1 g/L; P < 0.05). Administration of PRF-Th concomitantly with l-NAME prevented the blood pressure increase in rats. After 21 days, blood pressure in PRF-Th + l-NAME- and l-NAME-treated rats was 132 ± 1 and 157 ± 1 mmHg, respectively (P < 0.001). Administration of 2 mL/kg per day PRF-Th to DH rats significantly increased hepatic glycogen levels compared with levels in untreated DH rats (13.65 ± 1.84 vs 6.34 ± 0.75 mg/g tissue, respectively; P < 0.01). Moreover, PRF-Th significantly reduced the amount of glucose absorbed in in situ perfused jejunum segments compared with control (by 33.6%; P <0.001). This effect of PRF-Th was comparable with that of acarbose, an α-glucosidase inhibitor.

CONCLUSIONS

  The findings of the present study indicate that T. hirsuta has antidiabetic and antihypertensive activity in STZ-diabetic, NO-deficient hypertensive rats. This effect seems to be due to its rich polyphenol content. Therefore, T. hirsuta may be useful as a food supplement for the prevention of type 2 diabetes and hypertension.

Relaxant Effect of Essential Oil of Artemisia herba-alba Asso. on Rodent Jejunum Contractions

Artemisia herba-alba Asso. is a shrub commonly encountered in Morocco. It is used in traditional medicine for treating intestinal disorders. The essential oil extracted from the plant's aerial parts reversibly relaxed the spontaneous tonus of the rabbit jejunum in a reversible concentration dependent manner with an IC(50) value of 97.33 ± 2.59 ng/ml and reversed the tonic contraction of rat jejunum induced by 75 mM KCl and 10(-6) M carbachol with IC(50) values of 115.5 ± 3.05 and 119.4 ± 20.86 ng/ml, respectively. The pre-treatment of the latter isolated intestine with this essential oil produced a dose-dependent shift of the Ca(++) and CCh dose-response curve to the right, with suppression of the maximal effect, similar to the non-competitive antagonist effect on muscarinic receptors and calcium channel, respectively.

Prevention of chemically induced diabetes mellitus in experimental animals by virgin argan oil

The argan tree plays an important socioeconomic and ecologic role in South Morocco. Moreover, there is much evidence for the beneficial effects of virgin argan oil (VAO) on human health. Thus, this study investigated whether administering VAO to rats can prevent the development of diabetes. VAO extracted by a traditional method from the almonds of Argania spinosa (2 mL/kg) was administered orally (for 7 consecutive days) to rats before and during intraperitoneal alloxan administration (75 mg/kg for 5 consecutive days). An alloxan diabetic-induced untreated group and treated by table oil were used as control groups. Body mass, blood glucose and hepatic glycogen were evaluated. In the present study, subchronic treatment with VAO at a dose of 2 mL/kg, before the experimental induction of diabetes, prevented the body mass loss, induced a significant reduction of blood glucose and a significant increase of hepatic glycogen level (p < 0.001) compared with the untreated diabetic group. In conclusion, the present study shows that argan oil should be further investigated in a human study to clarify its possible role in reducing weight loss in diabetics, and even in inhibiting the development or progression of diabetes. This antidiabetic effect could be due to the richness of VAO in tocopherols, phenolic compounds and unsaturated fatty acids.

Artemisia herba-alba Asso relaxes the rat aorta through activation of NO/cGMP pathway and K(ATP) channels

Artemisia herba-alba Asso (Compositae) is used in oriental Morocco to treat diabetes and arterial hypertension. The present work evaluated the vasorelaxant effect of Artemisia herba-alba aqueous extract (AHAE) in isolated rat aorta and the mechanism underlying this effect. In endothelium-containing aorta preparations, AHAE (10(-3), 10(-2), 10(-1), 1 and 2 mg/mL) relaxed the contraction elicited by noradrenaline in a concentration-dependent manner. This effect is dependent upon integrity of the vascular endothelium as it was fully abolished in endothelium-denuded preparations. The vasorelaxant effect of AHAE (2 mg/mL) was also inhibited by N(G)-nitro-L-arginine methyl-ester (100 microM), methylene blue (10 microM) or 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (50 microM) but not by 10 microM atropine. This effect remained unchanged by tetraethylammonium (5 mM) or indomethacin (10 microM) whereas it was significantly attenuated by glibenclamide (10 microM). These results suggest that AHAE produces an endothelium-dependent relaxation of the isolated rat aorta, an effect that seems mainly mediated through stimulation of the endothelial nitric oxide synthase by mechanisms other than activation of muscarinic receptors. Activation of ATP-dependent potassium channels partly contributes in the mediation of AHAE-induced endothelium-dependent relaxation.

Antidiabetic effect of some medicinal plants of Oriental Morocco in neonatal non-insulin-dependent diabetes mellitus rats

The goal of the present study is to test the effect of water extract (WE) of four medicinal plants used as antidiabetics in Eastern Morocco (Arbutus unedo: Au, Ammoïdes pusilla: Ap, Thymelaea hirsuta: Th, and Urtica dioïca: Ud). These plants are used in cooking to bring out the flavor in a dish or to complement it. The first experiment was realized in order to determine the antidiabetic effect of the WE of these plants during 5 weeks' treatment. Seven groups of Wistar rats were used: Healthy controls, neonatal streptozotocin (n-stz) induced-diabetic rats (90 mg/kg; intraperitoneally [i.p.]), n-stz + tolbutamide (400 mg/l), and 4 groups n-stz + WE of plants (400 mg/l, drink water). The percentages of Plasma glucose lowering effect were, respectively for Au, Ap, Th, Ud and tolbutamide: 31.6 % p<0.01, 27.4 % p<0.05, 38.2 % p<0.01, 13 % and 33.9 % p<0.05 when compared with untreated diabetic controls. In a second experiment, oral glucose tolerance tests were carried out in n-stz induced-diabetic rats. The i.p. administration of the water extract (WE) of Ap and Ud (150 mg/kg) 30 minutes before the glucose overload (2 g/kg) showed a significant reduction glycemia, respectively of 36 % at 60 min (p<0.05) and 50 % at 180 min (p<0.05) after glucose overload compared with controls. In contrast, the effect of WE of Au and Th (150 mg/kg, i.p.) was not significant. The in vitro study of glucose utilization by isolated rat hemidiaphragm suggests that these extracts in combination with insulin potentiate its activity and enhance the utilization of glucose. In conclusion, it seems that these plants possess antidiabetic activity.

Antihypertensive and endothelium-dependent vasodilator effects of aqueous extract of Cistus ladaniferus

Cistus ladaniferus L. (Cistaceae) is a medicinal plant originated from the Mediterranean region which exerts different pharmacological effects. In the present study, our goal was to examine whether the plant possessed antihypertensive properties. Aqueous extract of Cistus leaves (AEC, 500mg/kg/day) reduced systemic blood pressure (SBP) in two animal models of hypertension, the l-NAME and renovascular two kidney-one clip (2K-1C) hypertensive rats. In the former, AEC prevented the increase in SBP when co-administered with l-NAME during four weeks (164+/-3mm Hg in l-NAME vs. 146+/-1mm Hg in l-NAME+AEC, p<0.001). In the latter, AEC reversed the increase in SBP when administered during four weeks after installation of the hypertension (146+/-5mm Hg with AEC vs. 179+/-6mm Hg without, p<0.05). AEC treatment also reversed the endothelial dysfunction observed in both animal models of hypertension. A direct effect on cardiac and vascular tissue was also tested by examining the contractile effects of AEC in rat isolated aortic rings and Langendorff perfused hearts. AEC (10mg/L) had no effect on left ventricular developed pressure and heart rate in isolated perfused heart. However, AEC produced a strong relaxation of pre-contracted rat aortic rings (80+/-2% relaxation, n=25). When the rings were denuded from endothelium or were incubated with 1mM Nomega-nitro-l-arginine (l-NNA), the relaxant effect of AEC was lost. We conclude that C. ladaniferus possesses antihypertensive properties which are mainly due to an endothelium-dependent vasodilatory action.

Vasorelaxant and anti-platelet aggregation effects of aqueous Ocimum basilicum extract

AIM OF THE STUDY

In this work the endothelium-dependant vasorelaxant and anti-platelet aggregation activities of an aqueous extract from Ocimum basilicum were studied.

MATERIALS AND METHODS

The vasorelaxant effect was undertaken in thoracic aorta from three experimental groups of rats: one of them (NCG) fed with standard diet, the second (HCG) with hypercholesterolemic diet (HCD) and the third (BTG) with hypercholesterolemic diet together with an intragastric administration of Ocimum basilicum extract at a dose of 0.5 g/kg body weight for a period of 10 weeks. The in vitro anti-platelet aggregation of Ocimum basilicum extract was studied using thrombin (0.5 U/ml) and ADP (5 microM) as agonists.

RESULTS

The results show that the HCD statistically decreases vascular relaxation in HCG compared to NCG (p<0.001) and increases the vascular responses to phenylephrine (p<0.02). Ocimum basilicum extract exerts a significant vasorelaxant effect at 10(-5) M (p<0.01) and 10(-4) M carbachol (p=0.001). The plant extract also tends to suppress the elevated contractions induced by HCD (p=0.05). The extract inhibits ADP-induced platelet aggregation by 13%, 28.2%, 30.5%, 44.7% and 53% at a dose of 1, 2, 3, 4 and 5 g/l, respectively. Thrombin-induced platelet activation was also reduced by 15%, 23%, 40%, 38.4%, and 42% at the same doses of extract described above.

CONCLUSION

The use of Ocimum basilicum as medicinal plant could be beneficial for cardiovascular system.

Parsley extract inhibits in vitro and ex vivo platelet aggregation and prolongs bleeding time in rats

Many cardiovascular diseases are associated with an increase in blood platelet activity. In Morocco, parsley (Petroselinum crispum, Apiaceae) is one of the medicinal herbs used to treat cardiovascular diseases such as arterial hypertension. In this study, crude aqueous extract (CAE) of parsley was evaluated for its anti-platelet activity in experimental animals on platelet aggregation in vitro and ex vivo; and on bleeding time in vivo. The in vitro aggregation was monitored after pre-incubation of platelets with CAE. The bleeding time and ex vivo aggregation were performed after oral treatment. CAE inhibited dose dependently platelet aggregation in vitro induced by thrombin, ADP, collagen and epinephrine. The oral administration of CAE (3g/kg) inhibited significantly (p<0.001) platelet aggregation ex vivo and prolonged bleeding time (p<0.001) without changes in the platelet amount. The prolongation of bleeding time by CAE may be attributed to the observed inhibition of platelet aggregation. These effects could be related in part to the polyphenolic compounds present in the extract. These results support the hypothesis that the dietary intake of parsley may be benefit in the normalization of platelet hyperactivation, in the nutritional prevention of cardiovascular diseases and are potentially interesting in the development of new prevention strategies.

Hypertensive effects of oral administration of the aqueous extract of Solanum torvum fruits in L-NAME treated rats: evidence from in vivo and in vitro studies

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum torvum fruits are commonly used in Cameroonian traditional medicine for treatment of arterial hypertension. It has been previously shown that intravenous administration of aqueous extract from dried fruits (AEST) reduced blood pressure.

AIM

The present work evaluates acute toxicity and effects of oral administration of AEST in chronic arterial hypertension induced by L-NAME. Effects of AEST were also evaluated on isolated aorta.

MATERIALS AND METHODS

AEST (200 mg/kg/day, p.o.) was given solely or concomitantly with L-NAME (40 mg/kg/day, p.o.) for 30 consecutive days. Animal body weight, systolic blood pressure and heart rate were measured before stating the treatment and at the end of each week. Urinary volume and urinary sodium and potassium contents were quantified before and at days 1, 15 and 30 of the treatment. Aorta from treated animals was tested for their sensitivity to noradrenaline and carbachol. Aorta from normal untreated rats was used to evaluate the in vitro vascular effect of AEST.

RESULTS

The results showed that AEST did induce neither mortality nor visible signs of toxicity. When given solely or in co-administration with L-NAME, AEST significantly reduced animal's body weight. It amplified the hypertensive and cardiac hypertrophy effect of L-NAME and did not affect these parameters in normotensive animals. AEST increased the sensitivity to noradrenaline in normotensive and significantly reduced it in hypertensive animals. AEST significantly increased urinary volume and sodium excretion in L-NAME treated animals while reducing the sodium excretion in normotensive. In vitro, AEST induced a potent partial endothelium-dependent contraction of aortic ring; contractions that were partially antagonized by prazosin and verapamil and were not relaxed by carbachol.

CONCLUSION

These results suggest that oral chronic administration of AEST induced potentiation of arterial hypertension and cardiac hypertrophy in L-NAME treated rats. These effects may result from a reduction in sensitivity to vasorelaxant agents and increase in hypersensitivity to contractile factors. AEST possess potent in vitro vasocontractile activity that may result from activation of both alpha(1)-adrenergic pathway and calcium influx.

Arbutus unedo prevents cardiovascular and morphological alterations in L-NAME-induced hypertensive rats Part I: cardiovascular and renal hemodynamic effects of Arbutus unedo in L-NAME-induced hypertensive rats

Hypertension induced by nitric oxide synthase inhibition is associated with functional abnormalities of the heart and kidney. The aim of the present study was to investigate whether chronic treatment with Arbutus unedo leaf (AuL) or root (AuR) aqueous extracts can prevent these alterations. Six groups of rats were used: control group received tap water; N(G)-nitro-l-arginine methyl-ester (L-NAME) group treated with L-NAME at 40 mg/kg/day; AuL and AuR groups received simultaneously L-NAME (40 mg/kg/day) and Au leaves or roots extract at the same concentration 250 mg/kg/day; l-arginine and enalapril groups received simultaneously L-NAME (40 mg/kg/day) and l-arginine at 50mg/kg/day or enalapril at 15 mg/kg/day. Treatment of rats during 4 weeks with L-NAME caused an increase of the systolic blood pressure (SBP) accompanied by a ventricular hypertrophy, an impairment of endothelium-dependent vasorelaxation, an increase of the cardiac baroreflex sensitivity and a decrease of water, sodium and potassium excretion. The co-administration of AuL or AuR extracts with L-NAME reduces the development of increased SBP, ameliorates the vascular reactivity as well as the baroreflex sensitivity and normalizes the renal function. AuR reduces the ventricular hypertrophy but AuL do not. Enalapril associated with L-NAME reverses the majority of alterations induced by L-NAME while l-arginine only lightly ameliorates the vascular reactivity. These results show that chronic treatment with Arbutus extract regress the development of hypertension and ameliorate cardiovascular and renal functions in NO deficient hypertension.

Antiaggregant effects of Arbutus unedo extracts in human platelets

Platelet hyperaggregability plays a pivotal role in the pathogenesis of cardiovascular diseases. Thrombin evokes aggregation through Ca(2+) mobilization, tyrosine phosphorylation and generation of reactive oxygen species (ROS). We have investigated the antiaggregant properties of Arbutus unedo extracts in human platelets. Changes in cytosolic Ca(2+) concentration and intracellular oxidants production were registered by espectrofluorimetry using fura-2 and dichlorodihydrofluorescein, respectively, platelet aggregation was assessed by aggregometry and protein tyrosine phosphorylation was detected by Western blotting. Platelet treatment with increasing concentrations (0.015-1.5mg/mL) of crude aqueous, ethyl acetate or diethyl ether extracts reduced platelet aggregation evoked by thrombin (0.5 U/mL) and show a potent ROS scavenger activity, preventing thrombin-evoked endogenous generation of ROS. Treatment with Arbutus unedo extracts did not alter thrombin-evoked Ca(2+) release from the intracellular stores but reduced store-operated Ca(2+) entry induced by thrombin or by selective depletion of the two Ca(2+) stores in platelets, the dense tubular system and the acidic stores. In addition, platelet treatment with extracts reduced both basal and thrombin-stimulated protein tyrosine phosphorylation. We conclude that Arbutus unedo extracts show antiaggregant actions due to attenuation of Ca(2+) mobilization, ROS production and protein tyrosine phosphorylation and might be used for the treatment and/or prevention of cardiovascular diseases.

Antihyperglycemic activity of Arbutus unedo, Ammoides pusilla and Thymelaea hirsuta

The effect of the water extract (WE) of three medicinal plants used as antidiabetic medication in Eastern Morocco (Arbutus unedo: Au, Ammoides pusilla: Ap and Thymelaea hirsuta: Th) was tested in rats with the Oral Glucose Tolerance Test (OGTT) and Intravenous Glucose Tolerance Test (IVGTT). In the OGTT the rats received water, glibenclamide (2 mg/kg) or WE (500 mg/kg for Au and 250 mg/kg for Th and Ap) 30 min before glucose loading (glucose: 1 g/kg). The WE of Au, Ap and Th produced a significant decrease in glycemia after glucose loading. In the IVGTT the WE of Ap and Th produced a significant decrease in glycemia 60 min after i.v. glucose loading (0.5 g/kg). The addition of the WE of Au (500 mg/kg), Ap or Th (250 mg/kg) induced a significant inhibition of jejunal glucose absorption, (31.6%, 28.5% and 40.5% respectively). This effect could explain in part the significant antihyperglycemic effect observed in the OGTT model but it does not exclude other effects on glucose homeostasis, particularly for Ap and Th. Toxicity tests (high LD50 value) suggest no adverse effect of the use of these plants.

Relaxant effect of aqueous extract of Cistus ladaniferus on rodent intestinal contractions

The effects of the aqueous extract of Cistus ladaniferus leaves and stems were studied on the rodent isolated jejunum. The extract produced a reversible concentration dose-dependent (0.1-3 mg/ml) inhibition of the spontaneous motility of the rabbit jejunum. The inhibitory effects of the extract were not affected by pretreatment with the inhibitors of the alpha and beta adrenergic receptors yohimbine, prazosin or propranolol. The extract also inhibited K(+)-induced contractions in rabbit and rat jejunum at a similar concentration range. This result suggests that the antispasmodic action of the extract is mediated through calcium channel blockade. The results confirm the traditional use of C. ladaniferus in treating intestinal ache.

Effects of extracts and tannins from Arbutus unedo leaves on rat platelet aggregation

Many cardiovascular diseases such as arterial hypertension are associated with an increase in blood platelet activity. Arbutus unedo (Ericaceae) is a medicinal plant reputed to treat arterial hypertension, so the present study was undertaken in order to determine the antiaggregant effect. The crude aqueous extract showed an inhibition of thrombin-induced platelet aggregation (IC50 = 1.8 +/- 0.09 g/L, n = 10). The subsequent extraction of Arbutus unedo leaves by successive solvents showed that the methanol and ethyl acetate extracts accounted for most of the antiaggregant activity (IC50 = 0.7 +/- 0.08, n = 9; 0.6 +/- 0.05; n = 9, respectively). The tannins isolated from the methanol extract exhibited a strong antiplatelet effect (% of inhibition = 75.3 +/- 1.4, n = 8) and may be the major chemical compounds responsible for this action. Our results support the traditional use of this plant in the preventive or therapeutic treatment of platelet aggregation linked to arterial hypertension.

Inhibition of Rat Platelet Aggregation byUrtica dioica Leaves Extracts

Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was undertaken to investigate the effects of different extracts of Urtica dioica leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different concentrations of the tested extracts and aggregation was induced by different agonists including thrombin (0.5 U/mL), ADP (10 microm), epinephrine (100 microm) and collagen (5 mg/mL). The crude aqueous extract inhibited thrombin-induced platelet aggregation in a dose-dependent manner. At 1 mg/mL, the percent inhibition was 17.1 +/- 4.2%. Soxhlet extraction of the plant leaves with different successive solvents showed that the ethyl acetate extract exhibited the most antiaggregant effect with an inhibition of 76.8 +/- 6.1% at 1 mg/mL. Flavonoids isolated from the plant leaves, produced a strong inhibitory effect on thrombin-induced platelet aggregation with an IC(50) of 0.25 +/- 0.05 and 0.40 +/- 0.04 mg/mL for genins and heterosidic flavonoids, respectively. Flavonoids also markedly inhibited platelet aggregation induced by ADP, collagen and epinephrine. It is concluded that Urtica dioica has an antiplatelet action in which flavonoids are mainly implicated. These results support the traditional use of Urtica dioica in the treatment and/or prevention of cardiovascular disease.

Platelet anti-aggregant property of some Moroccan medicinal plants

It is known that blood platelets may present some dysfunction linked to cardiovascular pathologies such as arterial hypertension. The aim of this work is to examine the in vitro anti-aggregant effect of five medicinal plants among which three were reported as antihypertensive in oriental Morocco: Arbutus unedo (Ericaceae), Urtica dioïca (Urticaceae), and Petroselinum crispum (Apiaceae). The two other plants were Cistus ladaniferus (Cistaceae) and Equisetum arvense (Equisetaceae). The results obtained showed that all extracts produced a dose-dependent inhibition of thrombin and ADP-induced aggregation. The calculated IC50 (half-maximal inhibition of thrombin and ADP-induced aggregation) was found to be identical in all plant extracts while Urtica dioïca had a higher IC50 value. The effect of plants could be related in part to the polyphenolic compounds present in their extracts suggesting their involvement in the treatment or prevention of platelet aggregation complications linked to cardiovascular diseases. Phytochemical separation must be carried out to identify the active principles responsible for the anti-aggregant effect and elucidate their mechanisms of action.