Antihypertensive effect of Eucommia ulmoides Oliv. extracts in spontaneously hypertensive rats

Aim of the study

To investigate the antihypertensive fractions of Eucommia ulmoides Oliv. and their underlying mechanisms in spontaneously hypertensive rats (SHRs).

Materials and methods

In vivo study, Eucommia ulmoides lignans (EuL) and Eucommia ulmoides iridoids (EuI) were administrated to Sprague–Dawley (SD) rats and SHRs, and their blood pressures were measured. Plasma level of nitric oxide (NO) was measured by colorimetric method, and renin activity (RA) and plasma concentration of angiotensin II (Ang II) were measured by radioimmunoassay. In vitro study, rat mesenteric artery was treated with EuL and the vessel relaxation responses were determined.

Results

EuL could lower blood pressures of both SD rats and SHR dose-dependently by either intravenous (i.v.) or intragastric (i.g.) administration, but EuI failed to affect blood pressure in the two kinds of rats. Meanwhile, no synergistic effect was observed with the combination of EuL and EuI. The plasma level of NO in SHR treated with EuL 300 mg/kg twice a day was markedly increased. Both plasma RA and Ang II level were decreased with long-term oral treatment of EuL 150 and 300 mg/kg twice a day. In perfusion experiment, EuL relaxed mesenteric artery quickly and dose-dependently and the effect on the artery with and without endothelium was the same.

Conclusions

EuL may be the effective fraction to lowering blood pressure and its antihypertensive effect is probably associated with regulating NO and renin–angiotensin system (RAS) and directly relaxing artery.     

苦木提取物对原发性高血压大鼠的降压作用研究

目的:探讨苦木提取物(PQB)对原发性高血压大鼠(SHR)的降压作用及其降压机制。方法:40只雄性SHR被随机分为5组,高血压对照组,卡托普利组,PQB高剂量组,PQB中剂量组,PQB低剂量组,每组8只。每日给予各组大鼠相应药物灌胃,高血压对照组给予等量蒸馏水。6周末,自大鼠颈动脉取血,用于测定血清一氧化氮(NO)及超氧化物歧化酶(SOD)含量,同时取胸主动脉组织2cm左右用中性甲醛固定,用免于免疫组织化学法测定内皮一氧化氮合酶(eNOS)表达。结果:与高血压对照组相比,PQB中剂量组(100 mg/kg/d)和高剂量组(200 mg/kg/d)NO及SOD及含量明显升高(分别为P<0.05和P<0.01);而卡托普利组(12.5 mg/kg/d)和小剂量组(50 mg/kg/d)效果不显著(P>0.05)。胸主动脉eNOS蛋白表达逐步增强。结论:PQB可显著升高SHR大鼠血清NO和SOD水平,使eNOS蛋白表达增强,推测其降压机制主要是通过影响胸主动脉eNOS蛋白表达,增加血管舒张因子NO的含量,从而使血管扩张,血压下降。     

Effects of osthol on blood pressure and lipid metabolism in stroke-prone spontaneously hypertensive rats

Osthol, a coumarin compound, was isolated from the dried fruits of Cnidium monnieri (Umbelliferae) and the effect of dietary osthol on hypertension and lipid metabolism was examined in stroke-prone spontaneously hypertensive rats (SHRSP). Six-week-old male SHRSP were fed the experimental diet containing 0.05% osthol by weight for 4 weeks with free access to the diet and water. Elevation of systolic blood pressure was significantly suppressed on and after 3 weeks. In addition, significant decreases in cholesterol and triglyceride contents in the liver were recognized without any significant changes in serum lipids profiles. A comparative study on hepatic mRNA expression indicated that osthol induced a significant increase in 3-hydroxy-3-methylglutaryl coenzymeA (HMG-CoA) reductase mRNA expression, which may lead to decrease in hepatic cholesterol pool through inhibition of the enzyme activity. Moreover, osthol induced a significant increase in acyl-CoA oxidase mRNA expression associated with an increase in carnitine palmitoyl transferase 1a mRNA expression, which suggests the acceleration of beta-oxidation of hepatic fatty acids. This may be responsible, at least in part, for the reduction of hepatic triglyceride content in SHRSP. These beneficial effects of osthol could be useful for both prevention of atherosclerosis and suppression of hepatic lipid accumulation.     

地龙降压蛋白对自发性高血压大鼠降压作用及其机制的影响

目的:初步探讨地龙降压蛋白对自发性高血压大鼠(spontaneously hypertension rat,SHR)的降压作用及机制。方法:选择16周龄雄性SHR 24只随机分为3组:模型组、地龙降压蛋白低剂量组、地龙降压蛋白高剂量组,另纳入8只同龄雄性Wistar大鼠为正常对照组,干预持续28d。采用无创尾动脉套袖法观察地龙降压蛋白对SHR的降压作用;放射免疫分析法测定SHR血浆、肾脏局部醛固酮(aldosterone,Ald)、6-酮-前列腺素-F1α(6-Keto-PGF1α)含量。结果:地龙降压蛋白低、高剂量组均可明显降低SHR的血压,与模型组比较有显著性差异(P<0.05),可明显降低SHR血浆、肾脏Ald的水平(P<0.05);同时显著升高血浆、肾脏局部6-Keto-PGF1α的含量(P<0.05)。结论:地龙降压蛋白对SHR有降压作用,其降压机制可能与降低SHR血浆、肾脏Ald的水平,升高血浆、肾脏局部6-Keto-PGF1α的含量有关。     

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.     

银杏叶与山楂提取物配伍治疗SHR高血压的实验研究

目的:探讨银杏叶、山楂提取物配伍联用治疗高血压模型动物的作用和机制。方法:自发高血压大鼠(Spontaneously hypertensive rats,SHR)的基础血压值随机分成7组(模型对照、卡托普利、银杏叶提取物、山楂提取物、银杏叶/山楂提取物1:1、1:2和1:3配伍组),同时选用SD大鼠作为正常对照组,每组10只动物,按设计剂量(卡托普利35 mg/kg,银杏叶提取物150 mg/kg,山楂提取物组130 mg/kg,其他均为300 mg/kg)每日给予受试物,对照组给予蒸馏水,连续30天,以尾脉搏法测定血压。每周测量血压、心率和体重一次,实验末摘眼球采血并处死动物,计算心室指数,血液分离血清后测定血清中一氧化氮、丙二醛的含量以及总超氧化歧化酶的活力。结果:实验末,山楂提取物、银杏叶/山楂提取物1:2和1:3配伍组的动物收缩压明显低于模型对照组(P0.05或P0.01),而各组对动物的心率、体重无明显影响。山楂提取物和1:3配伍组的动物心室指数和血清中丙二醛含量明显降低,一氧化氮水平则显著升高,且1:3配伍组血清中总超氧化歧化酶的活力也明显升高;此外,银杏叶提取物组的动物血清中丙二醛含量也明显降低,而总超氧化歧化酶的活力则显著升高。结论:银杏叶和山楂提取物按1:3配伍联用能协同有效降低SHR的血压,保护累及的组织器官,其作用机制为通过调节内皮依赖性舒血管物质减少外周血管阻力,同时通过抗氧化作用来保护高血压诱发的重要组织器官损伤。     

Effect of Tulbaghia violacea on the blood pressure and heart rate in male spontaneously hypertensive Wistar rats

Ethnopharmacological relevance

Tulbaghia violacea Harv. (Alliaceae) is a small bulbous herb which belongs to the family Alliaceae, most commonly associated with onions and garlic. In South Africa, this herb has been traditionally used in the treatment of various ailments, including fever, colds, asthma, paralysis, hypertension and stomach problems. The aim of this study was to evaluate the effect of methanol leaf extracts (MLE) of Tulbaghia violacea on the blood pressure (BP) and heart rate (HR) in anaesthetized male spontaneously hypertensive rats; and to find out the mechanism(s) by which it acts.

Materials and methods

The MLE of Tulbaghia violacea (5–150 mg/kg), angiotensin I human acetate salt hydrate (ang I, 3.1–100 μg/kg), angiotensin II human (ang II, 3.1–50 μg/kg), phenylephrine hydrochloride (phenylephrine, 0.01–0.16 mg/kg) and dobutamine hydrochloride (dobutamine, 0.2–10.0 μg/kg) were infused intravenously, while the BP and HR were measured via a pressure transducer connecting the femoral artery and the Powerlab.

Results

Tulbaghia violacea significantly (p < 0.01) reduced the systolic, diastolic, and mean arterial BP; and HR dose-dependently. Ang I, ang II, phenylephrine and dobutamine all increased the BP dose-dependently. The hypertensive effect of ang I and the HR-increasing effect of dobutamine were significantly (p < 0.01) decreased by their co-infusion with Tulbaghia violacea (60 mg/kg). However, the co-infusion of ang II or phenylephrine with Tulbaghia violacea (60 mg/kg) did not produce any significant change in BP or HR when compared to the infusion of either agent alone in the same animal.

Conclusions

Tulbaghia violacea reduced BP and HR in the SHR. The reduction in BP may be due to actions of the MLE on the ang I converting enzyme (ACE) and β₁ adrenoceptors.     

Evaluation of the anti-myocardial ischemia effect of individual and combined extracts of Panax notoginseng and Carthamus tinctorius in rats

Ethnopharmacological relevance

The decoction of combined Panax notoginseng (Burk) F.H. Chen and Carthamus tinctorius L. has a history of use in traditional medicine for the prevention and treatment of cardiovascular diseases such as angina pectoris and myocardial infarction.

Aim of the study

In this study, we investigated the effects of individual herbal extracts and combined extracts on anti-myocardial ischemia injuries in vivo, and determined the proper dosage of Panax notoginseng (EPN) combined with Carthamus tinctorius (ECT) that could strengthen their cardio-protective effects. Meanwhile, their potential anti-oxidative stress and anti-inflammation effect were assessed.

Material and Methods

SD rats were orally given individual EPN 50, 100 mg/kg, ECT 100, 200 mg/kg, and different combinations between them. Myocardial infarction was produced by occlusion of the left anterior descending coronary artery for 24 h. Infarct area was determined with 2,3,5-triphenyltetrazolium chloride (TTC) staining. The biomarkers related to myocardial ischemia injury were determined. Simultaneously, hemodynamic parameters were monitored as left ventricular systolic pressure (LVSP), LV end-diastolic pressure (LVEDP) and maximal rate of increase and decrease of left ventricular pressure (dP/dt_max). The oxidative stress indicators and inflammatory factors were also evaluated.

Results

The results showed EPN or ECT significantly reduced infarct size, improved cardiac function, decreased levels of creatine kinase (CK) and lactate dehydrogenase (LDH) (all P<0.05 vs. control ). EPN or ECT alone also restrained the oxidative stress related to myocardial ischemia injury as evidenced by decreased malondialdehyde (MDA) and elevated superoxide dismutase (SOD) activity (all P<0.05 vs. control). However, this cardio-protective effect was further strengthened by their combinations. Among all the combinations, EPN 50 mg/kg plus ECT 200 mg/kg showed predominant potential to reduce infarct size (22.21±1.72%, P<0.05 vs. each single, respectively), preserve cardiac function (P<0.05 vs. ECT 200 mg/kg for LVEDP and −dP/dt_max) after myocardial ischemia injury in rats. This heart protection was confirmed with the lowered cardiac troponin I (cTnI) (P<0.05 vs. ECT 200 mg/kg and EPN 50 mg/kg, respectively). Oxidative stress and inflammation are the two key factors in the pathogenesis of myocardial ischemia injury. In the present study, EPN 50 mg/kg plus ECT 200 mg/kg markedly increased SOD and GSH-Px activity (475.30±23.60 U/ml, P<0.05 vs. each single, respectively), while elevated MDA level was significantly depressed. Meanwhile, the inflammatory cascade was inhibited as evidenced by decreased cytokines such as tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) and interleukin-1β (IL-1β).

Conclusion

These results demonstrated EPN, ECT and their combinations exhibited significant cardio-protective effects. The findings suggest EPN combined with ECT may be therapeutically more useful for ameliorating anti-myocardial ischemia injuries than individual herbal extract, and EPN 50 mg/kg plus ECT 200 mg/kg is the appropriate combination in the present research. The cardio-protective effect of this combination was achieved partially by decreasing oxidative stress and repressing inflammatory cascade.     

In vitro and in vivo trypanocidal effect of lipophilic extracts of medicinal plants from Mali and Burkina Faso

AIM OF THE STUDY: To determine the in vitro and in vivo antitrypanosomal activity of extracts of traditionally used plants. MATERIALS AND METHODS: 47 dichloromethane extracts were tested in vitro in the Long-term Viability Assay (LtVA) on Trypanosoma brucei brucei. The most active ones were also tested in vivo using a standardised mouse test. RESULTS: 13 extracts (28%) were active in vitro with MIC-values相似文献   

The effect of Salvia divinorum and Mitragyna speciosa extracts,fraction and major constituents on place aversion and place preference in rats

Ethnopharmacological relevance

Consumer use of botanicals has increased despite, in many instances, the paucity of research demonstrating efficacy or identifying liabilities. This research employed the place preference/aversion paradigm to characterize the psychoactive properties of Salvia divinorum extract (10, 30, 100 mg/kg), salvinorin A (0.1, 0.3, 1.0 mg/kg), Mitragyna speciosa MeOH extract (50, 100, 300 mg/kg), Mitragyna speciosa alkaloid-enriched fraction (12.5, 25, 75 mg/kg) and mitragynine (5, 10, 30 mg/kg) in rats.

Material and methods

Following apparatus habituation and baseline preference scores, male Sprague-Dawley rats were given eight counter-balanced drug versus vehicle conditioning trials followed by a preference test conducted under drug-free states. S(+)-amphetamine (1 mg/kg) served as the positive control (in Exp. 2) and haloperidol (0.8, 1.0 mg/kg) served as the negative control in both studies.

Results

Rats displayed place aversion to both Salvia divinorum and salvinorin A that exceeded that of haloperidol. Rats showed place preference to mitragynine that was similar to that of S(+)-amphetamine. This CPP effect was much less pronounced with the Mitragyna speciosa extract and its fraction.

Conclusions

These findings suggest that both botanicals possess liabilities, albeit somewhat different, that warrant caution in their use.     

Vasorelaxant and antihypertensive effects of methanolic extracts from Hymenocardia acida Tul

Ethnopharmacological relevance

In Congolese traditional medicine, decoctions of Hymenocardia acida root bark (HaRB) and trunk bark (HaTrB) are used for the treatment of conditions assumed to be hypertension. In this work, we propose to study the vasorelaxant effect of HaRB and HaTrB methanolic extracts on isolated rat thoracic aorta, to characterize the group of molecules responsible for the observed vasorelaxant activity, to evaluate the in vitro antioxidant activity of these extracts and to determine the antihypertensive activity of the HaRB extract on spontaneously hypertensive rats (SHR).

Materials and methods

The vasorelaxant effect of the HaRB and HaTrB methanolic extracts was studied on endothelium-intact aortic rings pre-contracted with phenylephrine (PE, 1 μM). The mechanism of this vasorelaxant effect was investigated on endothelium-denuded vessels and on endothelium-intact aortic rings in the presence of three inhibitors: l-N^G-nitroarginine methyl ester (100 μM), indomethacin (10 μM) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 μM). To determine the nature of the compounds responsible for the vasorelaxant activity, we carried out a fractionation of the extracts and a thiolysis of the most active fraction followed by a liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) analysis. The extracts antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay. In vivo anti-hypertensive activity of the HaRB extract was conducted on SHR.

Results

HaRB and HaTrB methanolic extracts produced a concentration-dependent vasorelaxation on intact aortic rings pre-contracted with PE (1 μM). The vasorelaxant responses obtained were 95.3±1.5% (5 μg/ml) and 100.6±3.0% (1 μg/ml), respectively. The effect was markedly attenuated by removal of endothelium or pretreatment of aortic rings with all inhibitors except indomethacin. The LC/ESI-MS analysis of the thiolysis products indicated that the fraction which caused the most important vasorelaxation (97.9±2.5% at 3 μg/ml) was a mixture of procyanidins and prodelphinidins, with a predominance of procyanidins. Both extracts and all fractions from HaRB extract showed a DPPH scavenging activity, ranging from 0.4 to 0.8 quercetin-equivalents. The HaRB methanolic extract reduced the systolic blood pressure in SHR (from 214±3 mmHg to 194±4 mmHg) after a 5-week treatment.

Conclusions

The methanolic extracts of Hymenocardia acida root and trunk bark have vasorelaxant activity. The vasorelaxant effect observed is endothelium-dependent and seems mainly mediated through the NO-cGMP pathway. The COX pathway is not involved. The vasorelaxant activity appears to be due to polymeric procyanidins and prodelphinidins. These extracts also have an antioxidant effect. The extract of Hymenocardia acida root bark shows a significant but weak antihypertensive activity in SHR.     

Citrus limetta leaves extract antagonizes the hypertensive effect of angiotensin II

Ethnopharmacological relevance

Citrus limetta Risso (Rutaceae) is widely used in Mexico for healing purposes, among them as antihypertensive treatment.

Aim of the study

To assess the antihypertensive effect of C. limetta leaves as one of its ethnomedical uses.

Materials and methods

The acute response of blood pressure to angiotensin II administration was measured in mice. Additionally, the acute oral toxicity profiles were determined.

Results

The findings of the current investigation showed that different concentrations of the aqueous extract prevented the raise of systolic blood pressure (p ≤ 0.001 vs. vehicle), diastolic blood pressure (p ≤ 0.0002 vs. vehicle) and mean blood pressure (p ≤ 0.0000 vs. vehicle); with a dose dependent effect for diastolic pressures at 125–500 mg/kg dosages. The 500 and 1000 mg/kg doses inhibited the action of Ang II in similar extent to telmisartan. Toxic signs or deaths were not observed in mice treated at 2000 mg/kg of C. limetta extract.

Conclusions

All doses of C. limetta aqueous extract, used in this assay, were safe and effective.     

Antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. in sucrose-fed rats

The study was designed to investigate the antihypertensive effect of total flavones extracted from seed residues of Hippophae rhamnoides L. (TFH-SR) and its underlying mechanism in chronic sucrose-fed rats by evaluating its ability to regulate insulin and angiotensin || levels. Feeding of high-sucrose diet (HS: 77% of kcal from carbohydrate, 16% from protein and 6% from lipid, respectively) for 6 weeks resulted in significant rise in systolic blood pressure (SBP) by 25.60%, plasma insulin by 114.24%, triglycerides by 85.14% and activated angiotensin || contents in heart and kidney. However, TFH-SR treatment significantly suppressed the elevated hypertension, hyperinsulinemia and dyslipidemia. Furthermore, TFH-SR (especially at the dose of 150mg/kg/day) increased the circulatory blood angiotensin || level as effective as angiotensin || receptor blocker. These results indicated that TFH-SR exerted its antihypertensive effects at least in part by improving insulin sensitivity and blocking angiotensin || signal pathway. Findings of the present study suggested that TFH-SR might prove to be of potential use in the management of hyperinsulinemia in non-diabetic state with cardiovascular diseases.     

针刺“足三里”“太冲”对自发性高血压大鼠血压及心功能的影响

目的：观察针刺“足三里”“太冲”对自发性高血压大鼠(spontaneously hypertensive rat, SHR)血压指标、心脏超声指标及病理学检测的影响,探讨其作用机制。方法14只10周龄SHR大鼠按随机数字表法分为模型组6只、针刺组8只,6只同周龄SD大鼠为空白对照组。针刺组大鼠针刺双侧“足三里”“太冲”,留针20 min/次,连续4周,模型组及空白对照组无针刺干预。每周检测血压,连续5周。在针刺干预结束次日,使用彩色超声心动仪测量并记录各组大鼠左室舒张末期室间隔厚度、舒张末期左室内径、收缩末期左室后壁厚度、左室舒张末期后壁厚度。计算左室质量、左室质量指数、相对室壁厚度。采用HE染色法观察各组大鼠心脏病理学改变。结果与模型组比较,针刺干预第3、4周,针刺组大鼠收缩压[第3周：(178.38±9.47)mmHg比(190.00±13.90)mmHg;第4周：(167.96±23.47)mmHg比(195.47±11.36)mmHg]、舒张压[第3周：(139.33±13.20)mmHg比(159.56±12.89)mmHg;第4周：(132.92±18.02)mmHg比(165.61±13.36)mmHg]降低(P＜0.01或P＜0.05);针刺组大鼠左室舒张末期室间隔厚度[(0.96±0.07)mm 比(1.28±0.24)mm]、收缩末期左室后壁厚度[(1.15±0.08)mm 比(1.68±0.19)mm]、左室质量[(0.51±0.12)g 比(0.84±0.17)g]、左室质量指数[(14.96±1.53)比(23.65±5.04)]降低(P＜0.01)。HE 染色显示,模型组大鼠心肌外膜有慢性炎症伴肉芽组织增生及纤维化;针刺组大鼠心脏组织未见明显变化。结论针刺“足三里”“太冲”可有效降低 SHR 大鼠收缩压及舒张压,控制左室肥厚和心脏重构,对心肌细胞有保护作用。     

Antiplasmodial activity of extracts from seven medicinal plants used in malaria treatment in Cameroon

Aim of the study

In a search for new plant-derived biologically active compounds against malaria parasites, we have carried out an ethnopharmacological study to evaluate the susceptibility of cultured Plasmodium falciparum to extracts and fractions from seven Cameroonian medicinal plants used in malaria treatment. We have also explored the inhibition of the Plasmodium falciparum cysteine protease Falcipain-2.

Materials and methods

Plant materials were extracted by maceration in organic solvents, and subsequently partitioned or fractionated to afford test fractions. The susceptibility of erythrocytes and the W2 strain of Plasmodium falciparum to plant extracts was evaluated in culture. In addition, the ability of annonaceous extracts to inhibit recombinant cysteine protease Falcipain-2 was also assessed.

Results and discussion

The extracts showed no toxicity against erythrocytes. The majority of plant extracts were highly active against Plasmodium falciparumin vitro, with IC₅₀ values lower than 5 μg/ml. Annonaceous extracts (acetogenin-rich fractions and interface precipitates) exhibited the highest potency. Some of these extracts exhibited modest inhibition of Falcipain-2.

Conclusion

These results support continued investigation of components of traditional medicines as potential new antimalarial agents.     

Antioxidant and anti-inflammatory effects of Urtica pilulifera extracts in type2 diabetic rats

Ethnopharmacological relevance

"Urtica pilulifera has been traditionally used in Egyptian system as an herbal remedy to be a diuretic, antiasthmatic, anti-inflammatory, hypoglycemic, hemostatic, antidandruff and astringent"

Aim of the study

To evaluate the potential effects of ethyl acetate (EA), chloroform (CHLOR) and hexane (HEXA) extracts of Urtica piluliferaas oral anti-diabetic agents as well as to evaluate their possible anti-oxidant and anti-inflammatory effects in type2 diabetic rat model.

Material and methods

Type2 diabetes was induced by a high fat diet and low dose streptozotocin (STZ). Diabetic adult male albino rats were allocated into groups and treated according to the following schedule; Pioglitazone HCL (PIO), EA, CHLOR and HEXA extracts of Urtica pilulifera at two doses of 250 and 500 mg/kg were used. In addition, a normal control group and a diabetic control one were used for comparison. Blood glucose, insulin resistance, antioxidant enzymes, 8-hydroxy-2-deoxyguanosine (8-OHdG) as well as C-reactive protein and tumor necrosis factor-α levels were evaluated.

Results

EA and CHLOR extracts of Urtica pilulifera exhibited a significant hypoglycemia associated with antioxidant and anti-inflammatory effects in diabetic rats; however, HEXA extract showed no beneficial effect. These activities are responsible, at least partly, for improvements that have been seen in hyperglycemia and insulin resistance of diabetic rats.

Conclusion

Our results encourage the traditional use of Urtica pilulifera extract as an antioxidant and anti-inflammatory agent as an additional therapy of diabetes.     

Effect of the flavonoid fraction of Lithocarpus polystachyus Rehd. on spontaneously hypertensive and normotensive rats

Ethnopharmacological relevance

Lilhocarpus polystachys Rehd. (Sweet Tea, ST) is a folk herbal medicine that has been traditionally used as a natural remedy for hypertension in China, whose mechanism remains unveiled. Flavonoid fraction is considered as the major active components in ST. This study aimed to provide experimental evidence for the anti-hypertension activity of flavonoid fraction of ST (ST-F) and investigate the underlying mechanism. The effect of ST-F on the blood pressure of normotensive rats was also to be determined.

Materials and methods

Spontaneously hypertensive rats (SHRs) were treated with ST-F daily for 10 weeks. Blood pressure of SHRs was measured before and biweekly during ST-F treatment. Subsequently, animals were sacrificed either immediately at the end of treatment or 2 weeks after ST-F treatment discontinuance. The activities of plasma rennin (PRA), angiotensin II (Ang-I), endothelin (ET), nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured as well as skin microcirculatory flux. In normotensive rats, blood pressure was determined after six months' treatment of ST-F.

Results

ST-F treatment significantly reduced the blood pressure of SHRs along with decreasing plasma levels of PRA and Ang II. ST-F did not show obvious effects on plasma levels of ET, NO or SOD, but it significantly decreased the plasma level of MDA and improved skin microcirculatory flux. Compared to the anti-hypertensive drug enalapril, ST-F showed a modest effect on lowering blood pressure of SHRs without obvious withdrawal reactions. But long-term intake of ST-F did not change the blood pressure in normotensive rats.

Conclusion

ST-F had an antihypertensive effect on SHRs. The underlying mechanism could be related to modulation on the rennin–angiotensin–aldosterone system (RAAS) and antioxidation system, as well as regulation of skin microcirculation. Compared to its anti-hypertensive effect on SHRs, ST-F did not cause hypotension in normotensive rats. The results indicated that ST-F could potentially be used as natural drugs or functional foods for preventing hypertension.     

Investigation of plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts

Aim of the study

To investigate the activities of the 217 plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts.

Materials and methods

Plant extracts were prepared by the method of maceration using solvents of different polarities. The growth inhibition of chloroquine-resistant Plasmodium falciparum strain (FcB1) was determined by measuring the radioactivity of the tritiated hypoxanthine incorporated. Activity against Leishmania (Leishmania) chagasi and Trypanosoma cruzi was measured by the MTT colorimetric assay. The antifungal tests were carried out by using the CLSI method. The active extracts were tested also by cytotoxicity assay using NIH-3T3 cells of mammalian fibroblasts.

Results

Two hundred and seventeen extracts of plants were tested against Plasmodium falciparum. The eleven active extracts, belonging to eight plant species were evaluated against L. (L.) chagasi, Trypanosoma cruzi, yeasts and in NIH-3T3 cells. The results found in these biological models are consistent with the ethnopharmacological data of these plants. The ethyl acetate extract of Diospyros hispida root showed IC₅₀ values of 1 μg/mL against Plasmodium falciparum. This extract demonstrated no toxicity against mammalian cells, resulting in a significant selectivity index (SI) of 435.8. The dichloromethane extract of Calophyllum brasiliense root wood was active against Cryptococcus gattii LMGO 01 with MIC of 1.95 μg/mL; and Candida albicans ATCC 10231 and Candida krusei LMGO 174, both with MIC of 7.81 μg/mL. The same extract was also active against Plasmodium falciparum and L. (L.) chagasi with IC₅₀ of 6.7 and 27.6 μg/mL respectively. The ethyl acetate extract of Spiranthera odoratissima leaves was active against Cryptococcus gattii LMGO 01 with MIC of 31.25 μg/mL, and against Plasmodium falciparum with IC₅₀ of 9.2 μg/mL and Trypanosoma cruzi with IC₅₀ of 56.3 μg/mL.

Conclusion

The active extracts for protozoans and human pathogenic yeasts are considered promising to continue the search for the identification and development of leading compounds.     

Anti-inflammatory activity of dried flower extracts of Aegle marmelos in Wistar rats

Ethnopharmacological relevance

Almost all part of the plant Aegle marmelos (Bael tree) has been used in the traditional medicine systems of Asian countries to treat various diseases over many centuries. The water extract of the dried flowers of Aegle marmelos is a commonly used beverage among Sri Lankan population in rural areas. Although extensive investigations done on many parts of the plant there are no experimental data available on the extracts of flowers. Anti-inflammatory effect of the water extract of dried flowers of Aegle marmelos (WEAM) was evaluated in the present study.

Materials and methods

The anti-inflammatory effect of the WEAM was evaluated by inhibition of the rat paw oedema, induced by carrageenan. The mechanism of the anti-inflammatory effect was assessed by the inhibition of production of nitric oxide (NO) by rat peritoneal cells, infiltration of rat peritoneal cells, anti-histamine effect, membrane stabilization activity, the antioxidant capacity and inhibition of lipid peroxidation by the WEAM.

Results

The maximum percentage inhibition of paw oedema was exhibited by the dose of 200 mg/kg at 2 h. The WEAM showed a significant increment of rat peritoneal cell infiltration, inhibition of NO production by rat peritoneal cells and inhibition of wheal formation on the skin of the rat after injection of histamine. The WEAM protected the erythrocyte membrane from heat-induced lysis in a dose-dependent manner and showed a significant anti-oxidant effect and lipid peroxidation inhibition activity.

Conclusion

The WEAM possesses significant anti-inflammatory effect by multiple mechanisms in Wistar rats.