Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: evidence for the inhibition of angiotensin converting enzyme

Aim of the study

Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic properties. In the present study, we assessed whether the hypotensive and/or antihypertensive mechanism of hydroethanolic extract (HETM), semi-purified fraction (TMLR) obtained from T. majus and the flavonoids isoquercitrin (ISQ) and kaempferol (KPF) can be mediated by their interaction with angiotensin converting enzyme (ACE).

Methods and methods

Firstly, to evaluate changes in mean arterial pressure (MAP), different groups of normotensive and spontaneously hypertensive rats (SHR) were orally and intraduodenally treated with HETM (10-300 mg/kg) and TMLR (12.5-100 mg/kg) and intravenously treated with ISQ and KPF being later anesthetized with ketamine (100 mg/kg) and xylazine (20 mg/kg). The left femoral vein and the right carotid artery were isolated, and polyethylene catheters were inserted for ISQ and KPF (0.5-4 mg/kg) administration and blood pressure recording, respectively. The plasmatic ACE activity was evaluated to indirect fluorimetry, in serum samples after orally treatment with HETM, TMLR, ISQ and KPF.

Results

The oral administration of the HETM and its TMLR significantly reduced, in a dose-dependent manner, the MAP in both normotensive and SHR. In addition, these preparations significantly decreased the MAP for up to 3 h after the administration of the extract. Additionally, the intravenous administration of ISQ, but not KPF, decreased MAP in rats. Otherwise, neither the extracts nor ISQ affected the heart rate. The oral administration of the HETM, TMLR or ISQ reduced ACE activity in serum samples at 90 min after administration. Finally, the intravenous administration of ISQ caused a significant reduction in the hypertensive response to angiotensin I, but not angiotensin II in normotensive rats.

Conclusion

Our results show that the hypotensive effects caused by the HETM, as well as by its TMLR, may be associated with the high levels of the flavonoid ISQ found in this plant. In addition, ISQ-induced hypotension in rats is an event dependent on the inhibition of angiotensin II generation by ACE.     

Diuretic and potassium-sparing effect of isoquercitrin-an active flavonoid of Tropaeolum majus L

Aim of the study

Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic effects supporting the ethnopharmacological use of this plant as diuretic. In the present work, phytochemical investigation, guided by bio-assay in spontaneously hypertensive rats (SHR), was carried out in order to identify the compounds responsible for diuretic action.

Material and methods

Chromatographic fractionation of the hydroethanolic extract yielded an active fraction (TMLR) rich in isoquercitrin. TMLR (25-100 mg/kg) and isoquercitrin (5-10 mg/kg), as well the reference drug hydrochlorothiazide (10 mg/kg) were orally administered in a single dose or daily for 7 days to SHR. The urine excretion rate, pH, density, conductivity and content of sodium (Na⁺) and potassium (K⁺) electrolytes were measured in the urine of saline-loaded animals.

Results

The urinary excretion rate was dose-dependently increased in both TMLR and isoquercitrin groups, as well as Na⁺. Despite the changes in urinary excretion of electrolytes, the plasmatic levels of Na⁺ and K⁺ had not been changed. In addition, we did not find any evidence of renal toxicity or other adverse effects in these animals, even after prolonged treatment with TMLR or isoquercitrin.

Conclusion

This research supports and extends the ethnomedicinal use of T. majus as diuretic. This activity seems to be associated to the presence of the flavonol isoquercitrin.     

Screening for in vivo (anti)estrogenic and (anti)androgenic activities of Tropaeolum majus L. and its effect on uterine contractility

Ethnopharmacological relevance

Tropaeolum majus L. (Tropaeolaceae) is a medicinal herb popularly used in Brazil for treatment of inflammatory and cardiovascular diseases. Despite some published data on its efficacy, there are still few toxicological data describing the safety of this plant. The aim of this study was to evaluate the (anti)estrogenic and (anti)androgenic activity of the hydroethanolic extract obtained from Tropaeolum majus L. (HETM), as well as its possible effects on uterine contractility.

Materials and methods

Three experimental protocols were performed, (a) uterotrophic assay, (b) Hershberger assay and (c) an ex vivo test to investigate the effects of maternal administration of HETM on uterine contractility at the end of pregnancy. In all protocols three doses of the HETM were administered to Wistar rats: 3, 30 and 300 mg/kg.

Results

In vivo tests for detection of (anti)androgenic and (anti)estrogenic activities did not show any significant alterations. Similarly, no alterations were observed on uterine contractility induced by oxytocin and arachidonic acid.

Conclusions

HETM was unable to produce (anti)estrogenic or (anti)androgenic activities in the short-term in vivo screening assays performed. In addition, there was no evidence that HETM can affect uterine contractility following gestational exposure of rats.     

Natriuretic and diuretic effects of Tropaeolum majus (Tropaeolaceae) in rats

Tropaeolum majus L. (Tropaeolaceae), popularly known as “chaguinha”, is well recognized in Brazilian traditional medicine as diuretic agent, although no scientific data have been published to support this effect.     

青蒿总香豆素解热作用及其机理初步研究

目的:研究青蒿总香豆素解热(降温)作用并探讨其作用机理。方法:从黄花蒿中提取总香豆素,利用内生致热原性家兔发热模型,观察青蒿总香豆素对发热家兔体温的影响并测定脑脊液、血清中前列腺素E₂(PGE₂)、环单磷酸腺苷(cAMP)水平以及肝脏、腓肠肌钠泵活性。结果:青蒿总香豆素可以显著降低正常及发热家兔体温,抑制肝脏、腓肠肌组织钠泵活性,降低发热家兔血液及脑脊液PGE₂水平,对血液及脑脊液cAMP水平变化无明显影响。结论:香豆素成分可能是青蒿解热降温的有效部位,其作用机制与抑制钠泵活性及降低中枢PGE₂水平有关。     

青蒿总香豆素抗热应激作用及其机理的研究

目的:研究青蒿抗热应激作用及其机理。方法:利用高温高湿环境造成家兔热应激模型,观察青蒿总香豆素对家兔肛温上升及血液、肺组织磷脂酶A₂活性和循环内皮细胞数目的变化,并测定其对脑、心脏、肾组织钠泵活性及小鼠抗脑缺氧能力的影响。结果:青蒿总香豆素可明显降低热应激家兔体温上升速度,并伴随血清、肺组织磷脂酶A₂活性降低,循环内皮细胞减少,显著抑制脑、心、肾组织钠泵活性,延长断头小鼠张口喘气时间几近1倍。结论:香豆素部位可能是青蒿祛暑功效的活性成分群之一。     

木犀草素对缺血再灌损伤神经元的保护作用及机制研究

目的:探讨黄酮类化合物木犀草素对缺血/再灌损伤神经元的作用以及可能的作用机制。方法:原代培养的海马神经元经2 h的氧糖剥夺和24 h的再灌处理,分别检测细胞活性,乳酸脱氢酶漏出率和细胞凋亡率,采用Pu lsinelli四动脉阻断法对SD大鼠施行10 m in全脑缺血和24 h再灌,检测钠泵活性。结果:经氧糖剥夺/再灌后,海马神经元的活性比未经氧糖剥夺/再灌组显著地降低,乳酸脱氢酶漏出率和细胞凋亡率均显著地增高。在氧糖剥夺期间给予的木犀草素,在10~100μmol.L-1能呈剂量依赖地逆转这些改变。进一步实验发现木犀草素能够显著地增强大鼠全脑缺血/再灌后的钠泵活性。在神经元氧糖剥夺/再灌模型上,利用钠泵抑制剂哇巴因能阻断木犀草素的神经元保护作用。结论:木犀草素能减轻缺血/再灌所致的神经元损伤,其保护机制可能与增强了神经元细胞膜上的钠泵活性有关。     

In vivo inhibition of gastric acid secretion by the aqueous extract of Scoparia dulcis L. in rodents

The freeze-dried aqueous extract (AE) from the aerial parts of Scoparia dulcis was tested for its effects on experimental gastric hypersecretion and ulcer in rodents. Administration of AE to animals with 4h pylorus ligature potently reduced the gastric secretion with ED(50)s of 195 mg/kg (rats) and 306 mg/kg (mice). The AE also inhibited the histamine- or bethanechol-stimulated gastric secretion in pylorus-ligated mice with similar potency suggesting inhibition of the proton pump. Bio-guided purification of the AE yielded a flavonoid-rich fraction (BuF), with a specific activity 4-8 times higher than the AE in the pylorus ligature model. BuF also inhibited the hydrolysis of ATP by H(+),K(+)-ATPase with an IC(50) of 500 microg/ml, indicating that the inhibition of gastric acid secretion of Scoparia dulcis is related to the inhibition of the proton pump. Furthermore, the AE inhibited the establishment of acute gastric lesions induced in rats by indomethacin (ED(50)=313 mg/kg, p.o.) and ethanol (ED(50)=490 mg/kg, p.o.). No influence of the AE on gastrointestinal transit allowed discarding a possible CNS or a cholinergic interaction in the inhibition of gastric secretion by the AE. Collectively, the present data pharmacologically validates the popular use of Scoparia dulcis in gastric disturbances.     

Antiulcer and gastric antisecretory effects of dichloromethane fraction and piplartine obtained from fruits of Piper tuberculatum Jacq. in rats

Ethnopharmacological relevance

Piper tuberculatum Jacq. (Piperaceae) is medicinally used as an analgesic and as a treatment for gastric complaints. Thus, the current study aimed to investigate the gastroprotective and antisecretory properties of the dichloromethane fraction of the fruit of Piper tuberculatum (DFPT) and piplartine, a compound isolated from the DFPT, in rats.

Materials and methods

Gastric ulcers were induced in fasted rats by oral administration of absolute ethanol and then mucus content and glutathione (GSH) levels were measured. Mechanisms underlying the antisecretory action were studied through gastric H⁺,K⁺-ATPase activity of highly purified rabbit gastric microsomes and pylorus ligature method in rats.

Results

In the acute toxicity test the values of estimated LD₅₀ for oral and intraperitoneal administration of DFPT were 1.6266 and 0.2684 g/kg, respectively. The DFPT (ED₅₀=29 mg/kg, p.o.) and piplartine (4.5 mg/kg, p.o.) promoted gastroprotection against acute lesions induced by ethanol, effect that could be related with the maintenance of GSH levels in the gastric mucosa. However, only DFPT stimulated gastric mucus secretion. In vitro, the DFPT and piplartine inhibited the H⁺,K⁺-ATPase activity and, in vivo DFPT and piplartine also reduced basal gastric acid secretion, as well as that stimulated by pentagastrin.

Conclusions

These results demonstrate that DFPT and piplatine cause marked gastroprotective effects accompanied by the increase and maintenance of gastric mucus and GSH levels, as well as a reduction in gastric acid secretion through the gastrinergic pathway.     

Mechanisms of the anti-hypertensive effect of Hibiscus sabdariffa L. calyces

Previous studies have demonstrated the anti-hypertensive effects of Hibiscus sabdariffa L. (HS) in both humans and experimental animals. To explore the mechanisms of the anti-hypertensive effect of the HS, we examined the effects of a crude methanolic extract of the calyces of HS (HSE) on vascular reactivity in isolated aortas from spontaneously hypertensive rats. HSE relaxed, concentration-dependently, KCl (high K(+), 80 mM)- and phenylephrine (PE, 1 microM)-pre-contracted aortic rings, with a greater potency against the alpha(1)-adrenergic receptor agonist. The relaxant effect of HSE was partly dependent on the presence of a functional endothelium as the action was significantly reduced in endothelium-denuded aortic rings. Pretreatment with atropine (1 microM), L-NAME (10 microM) or methylene blue (10 microM), but not indomethacin (10 microM), significantly blocked the relaxant effects of HSE. Endothelium-dependent and -independent relaxations induced by acetylcholine and sodium nitroprusside, respectively, were significantly enhanced in aortic rings pretreated with HSE when compared to those observed in control aortic rings. The present results demonstrated that HSE has a vasodilator effect in the isolated aortic rings of hypertensive rats. These effects are probably mediated through the endothelium-derived nitric oxide-cGMP-relaxant pathway and inhibition of calcium (Ca(2+))-influx into vascular smooth muscle cells. The present data further supports previous in vivo findings and the traditional use of HS as an anti-hypertensive agent.     

Gastroprotective activity of ethanolic root extract of Potentilla fulgens Wall. ex Hook

Ethnopharmacological relevance

Potentilla fulgens (Wall.) ex Hook. (Rosaceae) is a potent medicinal plant of the Western Himalayas, known under the name “Himalayan Cinquefoil or Bajradanti”, and has been used traditionally to treat ailments including peptic ulcers, mouth ulcers, diarrhea, diabetes and cancer.

Objective

The aim of the present study was to scientifically evaluate the gastric-ulcer protective effect of P. fulgens ethanolic root extract (EPF) on experimental rats.

Material and methods

The gastroprotective activity of EPF was evaluated on four gastric-ulcer models such as pyloric ligation (PL), ethanol (EtOH), cold restrain stress (CRS) and aspirin (ASP)-induced gastric ulcers. The gastric acid obtained from 4 h PL-induced gastric ulcer rats was determined for total volume content, pH and total acid–pepsin output. Total carbohydrates and protein ratio, expressed as index of mucin activity, and DNA content were estimated in the gastric juice and gastric mucosal tissue. The microvascular permeability, H⁺K⁺–ATPase activity, gastric mucus and histamine content were also determined. The levels of antioxidant enzymes (superoxide dismutase, catalase, and glutathione) and malondialdehyde in the stomach tissue (mucosal scrapings) were quantified. A histopathological study of the stomach was evaluated using eosin–haematoxylin stain.

Results

EPF (200–400 mg/kg, p.o.) showed significant protection against acute gastric-ulcer induced by EtOH, PL and CRS (400 mg/kg, p.o.), but was found to be ineffective against ASP-induced ulcerogens. The effect of EPF on gastric juice studies in 4 h PL rats significantly produced an increased level in gastric pH, whereas the effect on gastric volume and acid–pepsin output was observed to decrease significantly. However, EPF was found to have no significant effect on the defensive factors, thus revealing its antisecretory property by inhibiting the aggressive factors. EPF, significantly decreased the histamine level, inhibited the H⁺K⁺–ATPase activity and prevented the microvascular injury caused by ethanol in the rat stomach. Moreover, it was also observed to have antioxidant effects by producing a significant increase in the levels of SOD, CAT, and GSH and decreased the LPO activity. Histopathological studies showed that EPF significantly prevented gastric lesions caused by ethanol.

Conclusions

The present study showed that EPF has potent gastroprotective and antisecretory effects, thus justifying the traditional usage of this herb to treat gastric ulcers.     

Effects of strictosamide on mouse brain and kidney Na+, K+-ATPase and Mg2+-ATPase activities

Present study reports on the general bioactivity of strictosamide and on its effects on Na(+),K(+)-ATPase and Mg(2+)-ATPase activities of Charles River male mouse. Strictosamide is the main glycoalkaloid of Sarcocephalus latifolius (Rubiaceae) leaves and roots, used as medicinal plant in folk medicine. In this work, we studied the in vitro effects of various concentrations of strictosamide (0.25, 0.5, 1 or 2 mg/mL) and the in vivo effects of single doses (50, 100 or 200 mg/kg, i.p.) of this compound on kidney and brain Na(+),K(+)-ATPase and Mg(2+)-ATPase activities. Results of general study showed that strictosamide is slightly toxic to Charles River mouse (LD(50)=723.17 mg/kg), producing CNS depression and kidney toxicity, but the exact mechanism of these effects could not be defined. Strictosamide inhibited the in vitro and in vivo Mg(2+)-ATPase activity on kidney but had nonsignificant effect on brain. Furthermore, strictosamide had nonsignificant in vitro and in vivo effect on kidney Na(+),K(+)-ATPase activity but produced an in vivo increase of Na(+),K(+)-ATPase activity of brain, these findings suggesting that strictosamine may be related to the induction of alpha(2) isoform of Na(+),K(+)-ATPase and may account for the folk use of Sarcocephalus latifolius root infusion on hypertension.     

Mechanisms underlying the antispasmodic and bronchodilatory properties of Terminalia bellerica fruit

AIM OF THE STUDY: The present investigation was carried out to provide the pharmacological basis for the medicinal use of Terminalia bellerica in hyperactive gastrointestinal and respiratory disorders. MATERIALS AND METHODS: Crude extract of Terminalia bellerica fruit (Tb.Cr) was studied in in vitro and in vivo. RESULTS: Tb.Cr caused relaxation of spontaneous contractions in isolated rabbit jejunum at 0.1-3.0mg/mL. Tb.Cr inhibited the carbachol (CCh, 1microM) and K(+) (80mM)-induced contractions in a pattern similar to that of dicyclomine, but different from nifedipine and atropine. Tb.Cr shifted the Ca(++) concentration-response curves to right, like nifedipine and dicyclomine. In guinea-pig ileum, Tb.Cr produced rightward parallel shift of acetylcholine-curves, followed by non-parallel shift at higher concentration with the suppression of maximum response, similar to dicyclomine, but different from nifedipine and atropine. Tb.Cr exhibited protective effect against castor oil-induced diarrhea and carbachol-mediated bronchoconstriction in rodents. In guinea-pig trachea, Tb.Cr relaxed the CCh-induced contractions, shifted CCh-curves to right and inhibited the contractions of K(+). Anticholinergic effect was distributed both in organic and aqueous fractions, while CCB was present in the aqueous fraction. CONCLUSIONS: These results indicate that Terminalia bellerica fruit possess a combination of anticholinergic and Ca(++) antagonist effects, which explain its folkloric use in the colic, diarrhea and asthma.     

Flavonoid-rich fraction of Maytenus ilicifolia Mart. ex. Reiss protects the gastric mucosa of rodents through inhibition of both H+,K+ -ATPase activity and formation of nitric oxide

Maytenus ilicifolia Mart. ex. Reissek (Celastraceae), a medicinal plant known in Brazil as "espinheira-santa" is commonly used to treat gastric disorders. The effect of the flavonoid-rich fraction separated from the leaves was evaluated for its gastroprotective properties and the mechanism(s) involved in this activity. Intraperitoneal administration of the flavonoid-rich fraction potently protected rats from experimentally induced chronic (ED(50)=79 mg/kg) and acute gastric lesions by ethanol (ED(50)=25mg/kg) and indomethacin (ED(50)=4 mg/kg) without altering the decreased amount of cytoprotective glutathione and mucus amount in the injured gastric mucosa. A potent reduction of gastric acid hypersecretion (ED(50)=7 mg/kg, i.p.) was accompanied by a reduction of nitric oxide release (ED(50)=1.6 mg/kg, i.p.) in the gastric secretion of 2h pylorus ligated rats which suggests an important role for nitric oxide-dependent mechanisms. Inhibition of gastric acid secretion in vivo was correlated with the in vitro inhibition of rabbit gastric H(+),K(+)-ATPase activity (IC(50)=41 microg/mL). Chemical investigation of the fraction showed galactitol (25%), epicatechin (3.1%) and catechin (2%) as the majoritary components. Collectively, the results show that the flavonoid-rich fraction of Maytenus ilicifolia potently protects animals from gastric lesions with high potency through inhibition of gastric acid secretion.     

Hepatotoxic constituents and toxicological mechanism of Xanthium strumarium L. fruits

Ethnopharmacological relevance

In the recent years, the international community has attached increasing importance to possible toxicity associated with Traditional Chinese Medicine (TCM). And hepatotoxicity is one of the major concerns, a fundamental pathological process induced by toxicant. This paper is in an attempt to identify the hepatotoxic components in Xanthium strumarium L. fruits (XSF) and interpret the toxicological mechanism induced by XSF.

Materials and methods

XSF extract was prepared and seven characteristic components were isolated and identi?ed in XSF water extracts. We evaluated their hepatotoxicity effect on cell proliferation and lactate dehydrogenase (LDH) activity in L-02 and BRL liver cell line. An integrated metabonomics study using high-resolution ¹H nuclear magnetic resonance (¹H NMR) spectroscopy combined with multivariate statistical analysis was undertake to elucidate the hepatotoxicity mechanism induced in rats by XSF. The urine and serum metabolites were measured after treatment of rats with XSF (7.5, 15.0 and 30.0 g/kg/day) for 5 days.

Results

The results showed that atractyloside, carboxyatractyloside, 4'-desulphate-atractyloside and XSF induced significant cytotoxic effects in both L-02 and BRL liver cell lines, indicating that atractyloside, carboxyatractyloside, and 4'-desulphate-atractyloside were the toxic components of XSF. When rats were treated with XSF at 30.0 g/kg the hepatotoxicity was reflected in the changes observed in serum biochemical profiles and by the histopathological examination of the liver. The levels of VLDL/LDL, 3-HB, lactate, acetate, acetone and glutamate in serum were increased in this group, while d-glucose, choline and valine were decreased. The elevation in the levels of succinate, citrate, 2-oxo-glutamate, glycine, 3-HB, acetate, lactate, hippurate, dimethylglycine, methylamine, dimethylamine, phenylalanine and tryptophan was observed in urine, in contrast a reduction in the intensities of taurine, d-glucose, N-acetyl-glucoprotein and trimethylamine-N-oxide (TMAO) was observed.

Conclusions

The results demonstrate that the major hepatotoxicity constituents are atractyloside, carboxyatractyloside and 4'-desulphate-atractyloside, and the hepatotoxicity of XSF involves mitochondrial inability, fatty acid metabolism, and some amino acids metabolism. This integrated ¹H NMR -based metabolic profiling approach has been able to capture and probe the metabolic alterations associated with the onset and progression of hepatotoxicity induced by XSF, and permits a comprehensive understanding of systemic toxicity for phytochemicals and other types of xenobiotic agents.     

Dual effects of crude extracts obtained from Petiveria alliacea L. (Phytolaccaceae) on experimental anxiety in mice

Aim of the study

Different preparations obtained from P. alliacea have been traditionally used in South America and Brazil for many medical conditions.To investigate the effects of fresh whole plant (WP) extract, aerial part (AP) extract, and root (R) extract obtained from Petiveria alliacea using the elevated plus maze (EPM) model of anxiety in mice. Total flavonoid content present in Petiveria alliacea extracts was also determined.

Materials and methods

WP, AP, or R (300–900 mg/kg) extracts were orally administered to mice 30 min before they were subjected to the EPM and open field test. Total flavonoid content present in the extracts was determined by spectrophotometry.

Results

The WP extract (300 and 900 mg/kg) caused anxiolytic-like effects, and the AP extract (300 mg/kg) induced anxiogenic-like effects in mice subjected to the EPM. No effect on anxiety-like behavior was observed with acute administration of the R extract. The content of flavonoids present in the AP extract (1.34%) was almost threefold higher than the flavonoid content present in the WP extract (0.52%).

Conclusions

Preparations using different fresh parts of Petiveria alliacea caused opposite effects on experimental anxiety in mice. However, predicting the extent to which flavonoid content present in Petiveria alliacea extracts differentially induces anxiolysis or anxiogenesis in mice was not possible. Further studies will be necessary to elucidate the effects of flavonoids or other substances present in Petiveria alliacea extracts on experimental anxiety.     

Gastroprotective effect of swallow root (Decalepis hamiltonii) extract: possible involvement of H(+)-K(+)-ATPase inhibition and antioxidative mechanism

The present study reports the antiulcer potentials of aqueous extract of swallow root (Decalepis hamiltonii Wight & Arn, SRAE) belonging to the family Asclepiadaceae. Swim stress-induced ulcers with an ulcer index (UI) of 6.0+/-0.01 was protected up to 43% and 72% at 100 and 200mg/kg b.w. of SRAE, respectively, similar to protection offered by ranitidine (79%) at 30mg/kg b.w. Depletion in antioxidant enzymes and increased Thiobarbituric Acid Reactive Substances (TBARS) were observed in ulcer-induced rats while SRAE fed rats showed normal levels. SRAE also normalized approximately 3.1 and 2.4 folds of increased H(+)-K(+)-ATPase and gastric mucin, respectively, in ulcerous animals, similar to the levels found in healthy controls. SRAE also possessed reducing power, free radical scavenging ability with an IC(50) of 0.17microg/mL gallic acid equivalent (GAE), comparable to that of BHA (IC(50)-0.08microg/mL). DNA protection up to 80% at 0.2microg was also observed. Toxicity studies indicated no lethal effects in rats fed up to 5g/kg b.w. Antioxidant, proton pump inhibition as well as boosting of gastric mucin effects of SRAE have been implicated to be responsible for antiulcer property of SRAE.     

Mechanisms of action underlying the gastric antiulcer activity of the Rhizophora mangle L

Ethnopharmacological relevance

Rhizophora mangle, the red mangrove, has long been known as a traditional antiulcer medicine. The present work evaluated the mechanisms of action involved in the anti-ulcer properties of the Rhizophora mangle bark extracts.

Materials and methods

Gastroprotection of Rhizophora mangle was evaluated in rodent experimental models (ethanol). To elucidate the mechanisms of action the antisecretory action and involvement of NO, SH, mucus and PGE₂ were evaluated. The acetic acid-induced gastric ulcer model, Western blotting assay (COX-1, COX-2 and EGF) and immunohistochemical localization of HSP-70, PCNA and COX-2 were also used to evaluate the Rhizophora mangle healing properties.

Results

Results showed that Rhizophora mangle bark crude extract (CE), as well as ethyl acetate (EtOAc) and butanolic fractions (BuOH) provided significant gastroprotection at all the tested doses. Thereby, the following protocols were performed using the lowest dose capable of producing the most effective gastroprotection, which was the BuOH 0.5 mg/kg (P < 0.001). Several mechanisms are involved in the antiulcer activity of Rhizophora mangle, such as, participation of NO, SH and mucus. The enhancement of PGE₂ levels and the upregulation of COX-2 and EGF seem to be directly linked to the antisecretory, cytoprotective and healing effects of BuOH. HSP-70 and PCNA are also involved in this cicatrisation process. No sign of toxicity was observed in this study, considering the analyzed parameters.

Conclusion

Our study reinforces its traditional medicinal use. Considering that the current therapies are based on the use of antisecretory or cytoprotective drugs, the Rhizophora mangle arises as a promising alternative antiulcer therapy.     

Vascular effects of Tanacetum vulgare L. leaf extract: in vitro pharmacological study

Aim of the study

Tanacetum vulgare L. (Asteraceae/Compositae) is principally used in traditional Moroccan medicine as antihypertensive remedy. The aim of the present study was to investigate the in vitro vascular activity of the aqueous extract of Tanacetum vulgare L.

Materials and Methods

The activity of Tanacetum vulgare L. extract was tested on contractile response of Wistar rat aorta to high KCl and noradrenaline and on endothelium-dependent relaxation evoked by acetylcholine.

Results

The addition of Tanacetum extract during the plateau phase of noradrenaline-evoked contraction produced a rapid relaxation that reached a maximum of 30% of the contraction and was suppressed by the NO synthase inhibitor N^G-nitro-l-arginine. At higher extract concentrations this rapid relaxation was followed by a slowly developing, N^G-nitro-l-arginine-resistant, relaxing effect. Tanacetum extract also depressed KCl-evoked contraction by 30% at maximum. This effect was abolished in the presence of N^G-nitro-l-arginine. The endothelium-dependent relaxation induced by acetylcholine was depressed in the presence of Tanacetum extract in the bathing solution.

Conclusion

:This study indicates that the aqueous extract of Tanacetum possesses NO-mediated and NO-independent vasorelaxing properties in vitro.     

Anti-tumor and pro-apoptotic activity of ethanolic extract and its various fractions from Polytrichum commune L.ex Hedw in L1210 cells

Ethnopharmacological relevance

Polytrichum commune L.ex Hedw is a traditional Chinese herb for treatment of fever, hemostatic, uterine prolapse and especially for lymphocytic leukemia, but the antitumor effect and its potential mechanism remains unclear.

Aims of the study

The present study was to investigate the possible anti-proliferative activity of ethanolic extract and the organic fractions from P. commune on murine leukemia L1210 cells.

Materials and methods

The content of ethanolic extract and its fractions was performed on HPLC analysis with gradient elution. L1210 cells were treated with different concentrations of ethanolic extract and its fractions at different time intervals. Cell viability was evaluated using MTT assay. Apoptotic cell death was monitored by nuclear condensation and confirmed by exposure of phosphatidylserine to outer leaflet of plasma membrane. Loss of mitochondrial membrane potential was analyzed by flow cytometry using rhodamine 123 staining.

Results

The obtained results showed that the cell viability of L1210 cells was reduced by ethanolic extract of P. commune in a concentration-dependent manner, and the IC₅₀ value was about 77.22 μg/ml at 24 h post treatment. The ethylacetate fraction displayed higher anti-tumor effect than that of chloroform and butanol fractions with 32.29 μg/ml (IC₅₀ value, 48 h). Microscopy studies revealed that ethanolic extract and ethylacetate fraction treated cells showed morphological characteristics of apoptosis such as chromatin condensation and DNA aggregation. Further, Annexin V-PE/ 7-AAD double staining showing the out leaflet of phosphatidylserine and the decline of mitochondrial membrane potential by flow cytometry confirmed that the extracts do, in fact, induce apoptosis in L1210 cells.

Conclusion

This is the first report on anti-tumor and pro-apoptotic effect of P. commune in cultured leukemia cells, which provides scientific basis for its usefulness as traditional medicine. Further studies are needed to confirm the precise mechanism not only the crude extract but as well the monomeric chemical substances of Polytrichum commune L.ex Hedw.