Antihypertensive effect of a standardized aqueous extract of Cecropia glaziovii Sneth in rats: an in vivo approach to the hypotensive mechanism

Vasorelaxant effects of ellagitannins isolated from Cuphea carthagenensis

Cuphea carthagenensis (Jacq.) J. F. Macbr. is a popular plant in Brazilian folk medicine owing to its hypotensive and central nervous system depressant effects. This study aimed to validate the hypotensive effect of the plant's aqueous extract (AE) in rats and examine the vascular actions of three hydrolyzable tannins, oenothein B, woodfordin C, and eucalbanin B, isolated from AE. Systolic blood pressure in unanesthetized rats was determined using the non-invasive tail-cuff method. Oral treatment of normotensive rats with 0.5 and 1.0 g/kg/day AE induced a dose-related hypotensive effect after 1 week. In rat aortic rings pre-contracted with noradrenaline, all ellagitannins (20 - 180 µM) induced a concentration-related vasorelaxation. This effect was blocked by either removing the endothelium or pre-incubating with NG-nitro-l-arginine methyl ester (10 µM), an inhibitor of nitric oxide (NO) synthase. In KCl-depolarized rat portal vein preparations, the investigated compounds did not affect significantly the maximal contractile responses and pD2 values of the concentration-response curves to CaCl2. Our results demonstrated the hypotensive effect of C. carthagenensis AE in unanesthetized rats. All isolated ellagitannins induced vasorelaxation in vitro via activating NO synthesis/NO release from endothelial cells, without altering the Ca2+ influx in vascular smooth muscle preparations. Considering the low oral bioavailability of ellagitannins, the determined in vitro actions of these compounds are unlikely to account for the hypotensive effect of AE in vivo. It remains to be determined the role of the bioactive ellagitannin-derived metabolites in the hypotensive effect observed after oral treatment of unanesthetized rats with the plant extract.

The mechanisms of calcium mobilization by procyanidins, flavonols and flavonoids from Cecropia glaziovii Sneth in pulmonary endothelial cell cultures endorse its popular use as vasodilator phytomedicine

The hypotensive and antihypertensive activities of the aqueous extract (AE) and butanolic fraction (ButF) isolated from Cecropia glaziovii Sneth have been demonstrated in previous studies in animal models. This study aimed to evaluate the molecular mechanism of action responsible for the vasodilatory effect of procyanidins, flavanols, and flavonoids found in C. glaziovii in endothelial cell culture. For this purpose, we analyzed the effect of procyanidin B2 and B3 compounds, catechin, epicatechin, orientin, isoorientin, and isovitexin in the mobilization of Ca2+ in rat endothelial cell cultures. Parallel associations with different antagonists were examined by considering the following in vivo hypotensive mechanisms: blockage of L-type calcium channels, action on β-2 adrenergic receptors, and vasodilation via the nitric oxide pathway. All measurements of calcium mobilization were carried out by using the fluorescence measurement methodology in a Flexstation M3 spectrophotometer. The results indicate that some of the compounds have mixed actions, acting through different calcium mobilization pathways. The mobilization induced by such compounds significantly decreased when they were incubated with their corresponding antagonists. Taken together, our data suggest that the beneficial effects seen with the popular use of Cecropia glaziovii Sneth in pathological conditions, such as systemic arterial hypertension, seem to be related to the plant's hypotensive effect, very probably promoted by the actions of flavonols, flavonoids, and procyanidins, by different pathways of calcium mobilization.

Pharmacognostic Evaluation of Ten Species of Medicinal Importance of Cecropia: Current Knowledge and Therapeutic Perspectives

This work covers a systematic review of literature about the genus Cecropia from 1978 to 2020, emphasizing the analysis of 10 of the most relevant species and their associated biological activities. Cecropia is a neotropical genus, which comprises about 61 native species in the American continent where it is known to be part of the traditional medicine of numerous countries. Secondary metabolites described for this genus showed an elevated structural and functional diversity, where polyphenols have been the most abundant. Based on this diversity, Cecropia phytochemicals represent an important source of potential therapeutic agents yet to be exploited. This review also highlights the effectiveness of combining chemometrics and ultra-performance liquid chromatography-tandem mass spectrometry as a novel approach to successfully single out Cecropia species phytochemicals. While the medicinal use of Cecropia species is officially recognized in National Pharmacopoeias and Formularies of several Latin American countries, it is important to recognize that these phytomedicines are complex mixtures requiring a thorough understanding of their chemical composition and their correlation with biological activities to guarantee their quality, safety, and efficacy.

Ethnopharmacological investigations of the leaves of Cecropia pachystachya Trécul (Urticaceae): A native Brazilian tree species

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia pachystachya Trécul (Urticaceae) is a medicinal plant popularly known as 'embaúba'. In Brazil, the leaves of this species are used for the treatment of various kidney and cardiovascular diseases. However, there are no detailed studies on the renal and cardiovascular activities of this species. No studies on the anatomy or the quality control of this herbal drug is available thus far.

AIM

This study was aimed to investigate the ethnopharmacological properties of the leaves of C. pachystachya.

MATERIAL AND METHODS

The leaves of C. pachystachya were analyzed by light and scanning electron microscopy for pharmacobotanical and anatomical characterization. The ethanol-soluble fraction of C. pachystachya leaf extract (ESCP) was characterized by high-performance liquid chromatograph equipped with diode array detector and mass spectrometry (HPLC-DAD-MS). The acute oral toxicity of ESCP on female Wistar rats was assessed. The acute and prolonged diuresis and antioxidant effects of ESCP (30, 100, and 300 mg/kg) were evaluated in male Wistar rats. In addition, the hypotensive effects of the ESCP as well as the vasodilatory activity in isolated and perfused mesenteric vascular beds were investigated.

RESULTS

The anatomical markers obtained in this study can help in the identification of C. pachystachya, as well as to distinguish it from the other 'embaúbas'. The metabolites found in the ESCP were phenolic compounds, mainly C- and O-glycosylated flavonoids. The ESCP did not exhibit any toxic effects at a dose of 2000 mg/kg. Significant diuretic activities were observed at the doses of 30, 100, and 300 mg/kg. In addition, a significant modulating activity of the tissue redox state was observed after prolonged treatment. On the other hand, no hypotensive or vasodilator activity was observed.

CONCLUSION

The key findings of the present study can contribute to the taxonomy, species identification and quality control of C. pachystachya. Chemical studies have shown the presence of glycosylated flavonoids, phenylpropanoid derivative and proanthocyanidins. The pharmacological studies showed significant diuretic and antioxidant effects of C. pachystachya leaf extract, indicating a possible validation of its popular medicinal use.

Hypotensive effect of Eugenia dysenterica leaf extract is primarily related to its vascular action: The possible underlying mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Eugenia dysenterica (ED) leaves are used in Brazil to treat cardiac diseases; however, there are no scientific data describing the effects of this species on cardiac activity.

AIM OF THE STUDY

To investigate the effect of ED aqueous leaf extract (EDLE) on hear rate (HR) and mean arterial pressure (MAP) of anaesthetised rats and its underlying mechanism of action.

MATERIAL AND METHODS

EDLE was analysed, and its proanthocyanidin composition was determined. After performing dose-effect curves for EDLE on HR and MAP, EDLE-induced hypotension was evaluated before and after atropine (AT), L-N(ω)-nitro-L-arginine methyl ester (L-NAME), hexamethonium (HXT), indomethacin (IND), carbenoxolone (CBX), or nifedipine (NFD) administration. The effect of proanthocyanidin-depleted extract (EDLE/P-) was also determined and compared to that of the EDLE with proanthocyanidins.

RESULTS

EDLE decreased the MAP in a dose-dependent manner; HR was decreased only with the highest and most toxic dose. Only CBX and NFD decreased EDLE-induced hypotension. Five polymeric series of proanthocyanidins were identified, which were mainly constituted by procyanidin and prodelphinidin units with B-type linkage and up to 12 flavan-3-ol units. EDLE/P- induced hypotension did not differ from that induced by EDLE.

CONCLUSIONS

The cardiovascular effects of EDLE were primarily related to its vascular action. EDLE-induced hypotensive effect appeared to involve L-type calcium channel blockage as well as myoendothelial gap junction signalling. The higher molecular weight proanthocyanidins from EDLE are unlikely to contribute to its cardiovascular effect.

Development of Caco-2 cells-based gene reporter assays and evaluation of herb-drug interactions involving CYP3A4 and CYP2D6 gene expression

The indiscriminate use of medicinal plants and herbal medicinal products concomitantly with conventional drugs may result in herb-drug interactions that may lead to fluctuations in drug bioavailability, therapeutic failure, and/or toxic effects. CYP450 enzymes play an important role in drug biotransformation and herb-drug interactions. Thus, the aim of this study was to develop and apply Caco-2 cells-based gene reporter assays to study in vitro the potential occurrence of CYP3A4 and CYP2D6 gene expression modulation by standardized extracts of selected medicinal plants. Reporter cell lines developed showed a significant increase in CYP3A4 and CYP2D6 reporter fluorescent emission, 4 and 16-fold respectively, when compared to the controls. The standardized extracts of Cecropia glaziovii, Bauhinia forficata and Echinacea sp. significantly increased CYP3A4 reporter fluorescence, and those of Ilex paraguariensis, Bauhinia forficata and Echinacea sp. significantly decreased CYP2D6 reporter fluorescence in Caco-2 cells-based gene reporter assays. The data obtained suggest that CYP3A4 and CYP2D6 gene expression seem to be modulated by the extracts tested. In addition, the reporter cell lines developed are functional assays that could be used to study drug-drug and herb-drug interactions during the research and development of new drugs.

Phytochemical characterization and comparative studies of four Cecropia species collected in Panama using multivariate data analysis

Plant species of the genus Cecropia (Urticaceae) are used as traditional medicine in Latin-America, and are commercially available as food supplements. The aim of this study was to characterize and compare the phytochemical constituents of four Cecropia species collected in Panama. The structures of 11 compounds isolated from leaves of C. obtusifolia were elucidated based on high resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopic analysis; the polyphenolic constituents of leaves of all four Cecropia species and commercial products were characterized using high performance liquid chromatography-diode array detection-quadrupole time of flight-tandem high resolution mass spectrometry (HPLC-DAD-QTOF). Forty-seven compounds were fully identified or tentatively characterized. Thirty-nine of these have not been previously reported for the species under investigation. Multivariate analysis revelead that C. obtusifolia and C. insignis are the most related species, while C. hispidissima is the most segregated one. Considering the importance of the description of novel chemical entities and the increasing interest and use of natural products, this study may be of great help for chemotaxonomic purposes, the interpretation of medicinal properties and for quality assessment of herbal supplements containing Cecropia leaves.

Selection of chemical markers for the quality control of medicinal plants of the genus Cecropia

CONTEXT

Several Cecropia (Cecropiaceae) species are traditionally used in Latin America for the treatment of a variety of diseases including diabetes, arterial hypertension, asthma, bronchitis, anxiety, and inflammation. At present, a number of commercial products based on these plants have been introduced into the market with very little information on methods for guaranteeing their quality and safety.

OBJECTIVE

This work proposes potential chemical markers for the quality control of the raw materials of Cecropia obtusifolia Bertol., Cecropia peltata L., Cecropia glaziovii Snethl., Cecropia pachystachya Trécul, and Cecropia hololeuca Miq.

METHODS

The Herbal Chemical Marker Ranking System (Herb MaRS) developed by the National Institute of Complementary Medicine (NICM) at the University of Western Sydney was used for selecting chemical markers for the quality control of selected medicinal species of Cecropia. This review covers the period from 1982 to 2016.

RESULTS

Chlorogenic acid, flavonoidal glycosides (orientin, isoorientin, vitexin, isovitexin, and rutin), catechin, epicatechin, procyanidins (B2, B5, and C1), steroids (β-sitosterol), and triterpenoids (α-amyrin, pomolic, tormentic and ursolic acids) were selected as chemical markers for the quality control of the leaves.

CONCLUSION

It is necessary to establish comprehensive standards for guaranteeing quality, safety and efficacy of herbal drugs. The selection of adequate chemical markers for quality control purposes requires a good knowledge about the chemical composition of medicinal plants and their associated biological properties. To the best of our knowledge this review article is the first to address the identification and quantitative determination of the chemical markers for the genus Cecropia.

Mechanism of antihypertensive effect of Mucuna pruriens L. seed extract and its isolated compounds

Background In the search of safe and effective lead molecules from natural sources, Mucuna pruriens (MP) L. (Fabaceae) seeds were utilized for exploring the antihypertensive potential. Traditionally, it is used as diuretic and hypotensive. Methods Bioassay-guided fractions were utilized for the isolation of active compounds by column chromatography. IC50 value, enzyme kinetics and inhibition mechanism were determined. In vivo time and dose-dependent hypotensive study followed by changes in mean arterial pressure (MAP) induced by angiotensin I (3 nmol/kg), angiotensin II (3 nmol/kg), and bradykinin (10 nmol/kg) in anesthetized rats was done. Plasma and tissue angiotensin I-converting enzyme (ACE) activities were also determined. Results Phytochemical analysis by spectroscopic techniques revealed the presence of known compounds like genistein, ursolic acid and L-DOPA from the ethyl acetate and water fraction, respectively. In vitro study revealed MP ethyl acetate (MPEA) fraction and genistein as the most active fraction (IC50 156.45 µg/mL) and compound (IC50 253.81 µM), respectively. Lineweaver-Burk plots revealed a non-competitive mode of inhibition. ACE protein precipitation was the suggested mechanism for inhibition. The extract showed a time- and dose-dependent decrease in MAP. Genistein was able to dose-dependently reduce the MAP, up to 53±1.5 mmHg (40 mg/kg, i.v.). As compared to control, it showed a dose-dependent decrease in plasma ACE activity of 40.61 % and 54.76 % at 10 mg/kg and 20 mg/kg, respectively. It also decreased the ACE activity in the aorta (107.67nM/ml min at 10 mg, p<0.001; 95.33nM/ml min at 20 mg p<0.001). Captopril was used as a standard for various in vitro and in vivo assays. Conclusions The study revealed the antihypertensive potential of MP seed compounds via ACE inhibition.

In vitro antiherpes effect of C-glycosyl flavonoid enriched fraction of Cecropia glaziovii encapsulated in PLGA nanoparticles

In this work is reported a novel and promising approach for the preparation of C-glycosylflavonoid enriched fraction of Cecropia glaziovii (EFF-Cg) loaded PLGA nanoparticles (NP) with antiherpes properties. The purpose of this study was to evaluate and to compare the effect of two nonionic surfactants (poloxamer 188 (PLU) and polyvinyl alcohol (PVA)), and also an emulsion stabilized by solid particles of cellulose nanocrystal (CNC) in place of surfactants. The characterization of these nanoparticles was in terms of size, polydispersity index, zeta potential, morphology, thermogravimetric analysis (TGA), loading capacity and percent yield. Since TGA analysis revealed thermo stability especially for NP-PLU, this formulation was selected for the evaluation of drug release profile, cytotoxicity and antiherpes activity. The drug delivery profile demonstrated a sustained release through the polymer structure and a significant reduction of the polymer molecular weight at 21-day period. The cytotoxicity of these nanoparticles was determined on Vero cells, and the selected formulation did not exhibit cytotoxicity even at the highest tested concentration. The results demonstrated a potential antiherpetic effect of the EFF-Cg loaded NP at 48h of testing. In summary, EFF-Cg loaded NP exhibited a promising system for the effective drug delivery in the treatment of herpes infections.

Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Hypertensive Effect of Protein Hydrolysate from Actinopyga lecanora (Sea Cucumber) in Rats

Food protein hydrolysates are known to exhibit angiotensin converting enzyme (ACE) inhibitory properties and can be used as a novel functional food for prevention of hypertension. This study evaluated the ACE inhibitory potentials of Actinopyga lecanora proteolysate (ALP) in vivo. The pre-fed rats with ALP at various doses (200, 400, 800 mg/kg body weight) exhibited a significant (p ≤ 0.05) suppression effect after inducing hypertension. To determine the optimum effective dose that will produce maximal reduction in blood pressure, ALP at three doses was fed to the rats after inducing hypertension. The results showed that the 800 mg/kg body weight dose significantly reduced blood pressure without noticeable negative physiological effect. In addition, there were no observable changes in the rats’ heart rate after oral administration of the ALP. It was concluded that Actinopyga lecanora proteolysate could potentially be used for the development of functional foods and nutraceuticals for prevention and treatment of hypertension.

Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families

Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

Anti-inflammatory and antioxidant activities of aqueous extract of Cecropia glaziovii leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia glaziovii Sneth leaves extract is widely used as a traditional folk medicine in Brazil, especially for the treatment of diabetes, and as an antihypertensive and antiinflammatory agent.

AIM OF THE STUDY

To investigate the anti-inflammatory and antioxidant properties of crude aqueous extract (CAE) of C. glaziovii leaves.

MATERIALS AND METHODS

The in vivo anti-inflammatory and antioxidant effect of the CAE (10-300mg/kg, intragastrically) was investigated in the animal model of pleurisy. The cell migration, proinflammatory cytokines (TNF-α, IL-1β and IL-6), nitrite/nitrate concentration, myeloperoxidase (MPO) activity, oxidative damage in lipids and proteins, lactate dehydrogenase (LDH) activity and total protein content were also analyzed. Furthermore, the in vitro antioxidant activity of CAE was evaluated by the inhibition of formation of thiobarbituric acid reactive substances (TBARS), induced by free radical generators (H2O2, FeSO4 and AAPH) on a lipid-rich substrate. Hence, the chemical characterizarion of CAE by HPLC was therefore performed. The results showed that the inflammatory process caused by the administration of carragenin (Cg) into the pleural cavity resulted in a substantial increase in inflammatory parameters and oxidative damage. These levels seems to be reversed after CAE treatment in animals with similar results to Dexamethasone (Dex) treatment. Further, the CAE was effective in reducing proinflammatory cytokines, cell infiltrate, MPO activity, nitrite/nitrate concentration, LDH activity, and total protein levels with concomitant attenuation of all parameters associated with oxidative damage induced by Cg. Finally, the CAE presented in vitro antioxidant activity induced by free radical generators at all the concentrations investigated. HPLC analysis confirmed the presence of chlorogenic acid and C-glycosylflavonoids (isoorientin and isovitexin) as the major compounds of the CAE.

CONCLUSION

CAE of C. glaziovii exerts significant antiinflammatory and antioxidant activities and this effect can be attributed, at least in part, to the presence of chlorogenic acid and the C-glycosylflavonoids.

Cecropia pachystachya extract attenuated the renal lesion in 5/6 nephrectomized rats by reducing inflammation and renal arginase activity

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Cecropia pachystachya Trécul has been used in Brazilian folk medicine to treat hypertension, bladder and kidney inflammation and renal diseases. The aim of this study was to evaluate the potential of the aqueous fraction from the ethanolic extract of Cecropia pachystachya (FCP) in the management of hypertension, inflammation and progressive renal disease in rats submitted to 5/6 nephrectomy.

MATERIALS AND METHODS

Thirty male Wistar rats submitted to 5/6 nephrectomy (5/6 NE) were untreated (NE) or treated (NE+FCP) with the FCP (0.5g/kg/day). The treatment started 15 days after surgery, and the rats were followed for a period of 60 days. Systolic blood pressure (SBP) and albuminuria were evaluated from 15-60 days after the surgical procedure. Function and estructural renal changes, TGF-β (transforming growth factor β), MCP-1 (monocyte chemoattractant protein-1) and nitric oxide (NO) urinary excretion were analyzed. Expression and activity of the renal enzymes arginase (ARG), angiotensin converting enzyme (ACE), and MAP kinase p-JNK expression also were analyzed.

RESULTS

The nephrectomized rats developed progressive albuminuria and increased SBP that was less intense in the treated group. There was a reduction in the glomerular filtration rate (GFR) in the nephrectomized rats, which was attenuated by treatment with FCP extract. The treatment with FCP also attenuated the histological changes, reduced the expression and activity of renal arginase, the number of macrophages (ED-1 positive cells) and the p-JNK expression in the renal cortex of the rats submitted to 5/6 NE. The urinary excretion of TGF-β was less intense in the treated group and was associated with the reduction of the expression and activity of the renal arginase.

CONCLUSIONS

These results suggest that the reduction of renal arginase activity, p-JNK and TGF-β expression can explain the mechanism by which the treatment with C. pachystachya reduced the inflammation and improved renal function. This study presents the potential use of Cecropia pachystachya in the treatment of chronic renal diseases.

Leishmanicidal activity of Cecropia pachystachya flavonoids: arginase inhibition and altered mitochondrial DNA arrangement

The plant Cecropia pachystachya Trécul is widely used in Brazilian ethnomedicine to treat hypertension, asthma, and diabetes. Arginase is an enzyme with levels that are elevated in these disorders, and it is central to Leishmania polyamine biosynthesis. The aims of this study were to evaluate antileishmanial activity and inhibition of the arginase enzyme by C. pachystachya extracts, and to study changes in cellular organization using electron microscopy. The ethanol extract of C. pachystachya was tested on Leishmania (Leishmania) amazonensis promastigote survival/proliferation and arginase activity in vitro. Qualitative ultrastructural analysis was also used to observe changes in cell organization. The major bioactive molecules of the ethanol extract were characterized using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). The ethyl acetate fraction of the ethanol extract diminished promastigote axenic growth/survival, inhibited arginase activity, and altered a mitochondrial kinetoplast DNA (K-DNA) array. The bioactive compounds of C. pachystachya were characterized as glucoside flavonoids. Orientin (9) (luteolin-8-C-glucoside) was the main component of the methanol-soluble ethyl acetate fraction obtained from the ethanol extract and is an arginase inhibitor (IC50 15.9 μM). The ethyl acetate fraction was not cytotoxic to splenocytes at a concentration of 200 μg/mL. In conclusion, C. pachystachya contains bioactive compounds that reduce the growth of L. (L.) amazonensis promastigotes, altering mitochondrial K-DNA arrangement and inhibiting arginase.

Hepatoprotective effects and HSV-1 activity of the hydroethanolic extract of Cecropia glaziovii (embaúba-vermelha) against acyclovir-resistant strain

CONTEXT

Cecropia glaziovii Snethl. (Cecropiaceae), commonly known as "embaúba-vermelha", is widely distributed throughout Latin America and has been reported in Brazilian folk medicine to treat cough, asthma, high blood pressure and inflammation.

OBJECTIVE

Investigate the hepatoprotective properties of crude hydroethanolic extract of C. glaziovii as well as its in vitro antioxidant and antiviral (HSV-1 acyclovir resistant strain) activities.

MATERIALS AND METHODS

The hepatoprotective effect, the antioxidant properties and antiviral activity of crude hydroethanol extract (RCE40) from C. glaziovii leaves were evaluated by carbon-tetrachloride (CCl(4))-induced hepatotoxicity, by TBARS (thiobarbituric acid reactive species) and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assays, respectively.

RESULTS

The RCE40 extract (20 mg/kg) inhibited lipid peroxidation on liver in post injury treatment and decreased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, in this protocol the RCE40 (20 mg/kg) enhanced the activity of hepatic enzymes (SOD/CAT) which are involved in combating reactive oxygen species (ROS), suggesting that it possesses the capacity to attenuate the CCl(4)-induced liver damage. Moreover the RCE40 (20 mg/kg) inhibited TBARS formation induced by several different inductors of oxidative stress showing significant antioxidant activity, including physiologically relevant concentration, as low as 2 µg/mL. Concerning antiviral activity, the RCE40 was effective against herpes simplex virus type 1 replication (29R acyclovir resistant strain) with EC(50) = 40 µg/mL and selective index (SI) = 50.

DISCUSSION AND CONCLUSION

These results indicate that C. glaziovii could be a good source of antioxidant and anti-HSV-1 lead compounds.

Hypotensive mechanism of the extracts and artemetin isolated from Achillea millefolium L. (Asteraceae) in rats

Traditional uses of Achillea millefolium L. (Asteraceae) include the treatment of cardiovascular diseases. In the present study, we used anesthetized rats to assess the hypotensive effect of a hydroethanolic extract (HEAM), and its dichloromethane (DCM), ethyl acetate (EA), butanolic (BT), and dichloromethane-2 (DCM-2) fractions, besides the flavonoid artemetin, isolated from A. millefolium. The oral administration of HEAM (100-300 mg/kg), DCM (20mg/kg), DCM-2 (10-30 mg/kg), but not EA (10 mg/kg) and BT (50 mg/kg) fractions significantly reduced the mean arterial pressure (MAP) of normotensive rats. The phytochemical analysis by NMR (1)H of DCM and DCM-2 fractions revealed high amounts of artemetin, that was isolated and administered by either oral (1.5 mg/kg) or intravenous (0.15-1.5 mg/kg) routes in rats. This flavonoid was able to dose-dependently reduce the MAP, up to 11.47 ± 1.5 mmHg (1.5 mg/kg, i.v.). To investigate if artemetin-induced hypotension was related to angiotensin-converting enzyme inhibition, we evaluated the influence of this flavonoid on the vascular effects of both angiotensin I and bradykinin. Intravenous injection of artemetin (0.75 mg/kg) significantly reduced the hypertensive response to angiotensin I while increased the average length of bradykinin-induced hypotension. Artemetin (1.5 mg/kg, p.o.) was also able to reduce plasma (about 37%) and vascular (up to 63%) ACE activity in vitro, compared to control group. On the other hand, artemetin did not change angiotensin II-induced hypertension. Our study is the first showing the hypotensive effects induced by the extract and fractions obtained from A. millefollium. In addition, our results disclosed that this effect may be, at least in part, associated with high levels of artemetin and its ability to decrease angiotensin II generation in vivo, by ACE inhibition.

Chemical and Pharmacological Aspects of the Genus Cecropia

The Cecropia genus consists of about 60 species distributed throughout Latin America, mostly in Brazil. These species are widely used in traditional medicine to treat cough, asthma, bronchitis, high blood pressure, inflammation, heart disease, and as a diuretic. In recent years, there has been an increase in research on Cecropia species, with several phytochemical and pharmacological reports. Concerning its chemical composition, C-glycosylflavonoids and proanthocyanidins have been described as the main constituents of C. glaziovii, C. hololeuca and C. pachystachya, while terpenoids and steroids have been reported in several species, including C. adenopus and C. pachystachya. Among the pharmacological properties described for the genus, the most frequently reported are hypoglycemic activity for C. obtusifolia and C. peltata, and hypotensive and central nervous system activity for C. glaziovii. The present review compiles the information available on this genus because of its ethnopharmacological relevance and the potential therapeutic uses of these species.

Vasoactive effects of different fractions from two Panamanians plants used in Amerindian traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia obtusifolia (Cecropiaceae) and Psychotria poeppigiana (Synonym: Cephaelis elata, Rubiaceae) are two Latin American plants broadly used in traditional Amerindian medicine. The former, together with many other species of the genus Cecropia, share the folk reputation of curing heart failure, cough, asthma and bronchitis. The latter is used in Panama by Kuna and Ngäbe Buglé (Guaymies) native Indians for the treatment of dyspnea.

AIM OF THE STUDY

Based on screening of selected medicinal Panamanian plants by radioligand-binding techniques by Caballero-George et al. (2001), the present study was carried out in order to investigate the vasoactive effects of different fractions from both P. poeppigiana and C. obtusifolia on rat thoracic aorta and identify active fractions and their chemical constituents.

MATERIALS AND METHODS

Both acid and neutral methanol fractions (P-AMeOH and P-NMeOH) and acid and neutral dichlorometane fractions (P-ADCM and P-NDCM) were obtained from P. poeppigiana crude methanolic and dichlorometane extracts, respectively. Identical fractionation was carried out for C. obtusifolia (C-AMeOH, C-NMeOH, C-ADCM and C-NDCM. Vasorelaxant effect of all fractions, and their inhibition of contractile responses to angiotensin II were evaluated in isolated aortic rings.

RESULTS

P-AMeOH, P-NMeOH and P-ADCM fractions induced a concentration-dependent relaxation (43.9+/-1.8%, 35.3+/-4.7% and 52.9+/-3.5%, respectively) in the endothelium-intact aorta precontracted by phenylephrine (PE, 10(-6)M). The relaxation produced by C-AMeOH and C-NMeOH (57.3+/-2.5% and 53.3+/-3.3%, respectively) was greater than the effect produced by C-ADCM and C-NDCM (42.2+/-3.4% and 21.8+/-0.8%, respectively). Only the incubation of the aortic rings with P-AMeOH reduced the maximum contraction induced by angiotensin II at 20.08+/-0.55%.

CONCLUSIONS

The direct vasorelaxation effect observed could explain in part the ethnomedical use of these plants in Amerindian traditional medicine. The most active fractions contain phenolic and aromatic acid compounds. Furthermore, P-AMeOH, the only fraction that showed both vasorelaxant effect and inhibition of contractile responses to angiotensin II, is the most rich in aromatic acids compounds and the only one that contains scopoletin.

Inhibitory effects of Schizandrae Fructus on eotaxin secretion in A549 human epithelial cells and eosinophil migration

Eosinophilia have been implicated in a broad range of diseases, most notably allergic conditions (e.g. asthma, rhinitis and atopic dermatitis) and inflammatory diseases. These diseases are characterized by an accumulation of eosinophils in the affected tissue. Defining the mechanisms that control the recruitment of eosinophil is fundamental to understanding how these diseases progress and identifying a novel target for drug therapy. Accordingly, this study was conducted to evaluate the regulatory effect of Schizandrae Fructus (SF) on the expression of eotaxin, an eosinophil-specific chemokine released in respiratory epithelium following allergic stimulation, as well as its effects on eosinophil migration. To accomplish this, human epithelial lung cells (A549 cell) were stimulated with a combination of TNF-alpha (100ng/ml) and IL-4 (100ng/ml) for 24h. The cells were then restimulated with TNF-alpha (100ng/ml) and IL-1beta (10ng/ml) to induce the expression of chemokines and adhesion molecules involved in eosinophil chemotaxis for another 24h. Next, the samples were treated with various concentrations of Schizandrae Fructus (SF) (1, 10, 100, 1000microg/ml) or one of the major constituents of SF, schizandrin (0.1, 1, 10, 100microg/ml), after which following inhibition effect assay was performed triplicates in three independence. The levels of eotaxin in secreted proteins were suppressed significantly by SF (100 and 1000microg/ml, p<0.01) and schizandrin (10 and 100microg/ml, p<0.01). In addition, SF (1, 10, 100 and 1000microg/ml) decreased mRNA expression levels in A549 cells significantly (p<0.01). Eosinophil recruitment to lung epithelial cells was also reduced by SF, which indicates that eotaxin plays a role in eosinophil recruitment. Furthermore, treatment with SF suppressed the expression of another chemokine, IL-8 (0.1 and 1microg/ml SF, p<0.01), as well as intercellular adhesion molecule-1 (10 and 100microg/ml SF, p<0.01) and vascular cell adhesion molecule-1 (0.1 and 1microg/ml SF, p<0.05), which are all related to eosinophil migration. Taken together, these findings indicate that SF may be a desirable medicinal plant for the treatment of allergic diseases.

Inhibition of gastric acid secretion by a standardized aqueous extract of Cecropia glaziovii Sneth and underlying mechanism

Cecropia glazioui Sneth (Cecropiaceae) is used in folk medicine in tropical and subtropical Latin America as cardiotonic, diuretic, hypotensive, anti-inflammatory and anti-asthmatic. The hypotensive/antihypertensive activity of the plant aqueous extract (AE) and isolated butanolic fraction (BuF) has been confirmed and putatively related to calcium channels blockade in vascular smooth musculature [Lapa, A.J., Lima-Landman, M.T.R., Cysneiros, R.M, Borges, A.C.R., Souccar, C., Barreta, I.P., Lima, T.C.M., 1999. The Brazilian folk medicine program to validate medicinal plants - a topic in new antihypertensive drug research. In: Hostettman, K., Gupta, M.P., Marston, A. (Eds.), Proceedings Volume, IOCD/CYTED Symposium, Panamá City, Panamá, 23-26 February 1997. Chemistry, Biological and Pharmacological Properties of Medicinal Plants from the Americas. Harwood Academic Publishers, Amsterdam, pp. 185-196; Lima-Landman, M.T., Borges, A.C., Cysneiros, R.M., De Lima, T.C., Souccar, C., Lapa, A.J., 2007. Antihypertensive effect of a standardized aqueous extract of Cecropia glaziovii Sneth in rats: an in vivo approach to the hypotensive mechanism. Phytomedicine 14, 314-320]. Bronchodilation and antidepressant-like activities of both AE and BuF have been also shown [Delarcina, S., Lima-Landman, M.T., Souccar, C., Cysneiros, R.M., Tanae, M.M., Lapa, A.J., 2007. Inhibition of histamine-induced bronchospasm in guinea pigs treated with Cecropia glaziovi Sneth and correlation with the in vitro activity in tracheal muscles. Phytomedicine 14, 328-332; Rocha, F.F., Lima-Landman, M.T., Souccar, C., Tanae, M.M., De Lima, T.C., Lapa, A.J., 2007. Antidepressant-like effect of Cecropia glazioui Sneth and its constituents -in vivo and in vitro characterization of the underlying mechanism. Phytomedicine 14, 396-402]. This study reports the antiulcer and antisecretory gastric acid activities of the plant AE, its BuF and isolated compounds with the possible mechanism involved. Both AE and BuF were assayed on gastric acid secretion of pylorus-ligated mice, on acute models of gastric mucosal lesions, and on rabbit gastric H(+), K(+)-ATPase preparations. Intraduodenal injection of AE or BuF (0.5-2.0g/kg, i.d) produced a dose-related decrease of the basal gastric acid secretion in 4-h pylorus-ligated mice. At 1.0g/kg, BuF decreased the volume (28%) and total acidity (33%) of the basal acid secretion, and reversed the histamine (2.5mg/kg, s.c.)- or bethanecol (1.0mg/kg, s.c.)-induced acid secretion to basal values, indicating inhibition of the gastric proton pump. Pretreatment of mice with the BuF (0.05-0.5g/kg, p.o.) protected against gastric mucosal lesions induced by 75% ethanol, indomethacin (30mg/kg, s.c.) or restraint at 4 degrees C. BuF also decreased the gastric H(+), K(+)-ATPase activity in vitro proportionately to the concentration (IC(50)=58.8microg/ml). The compounds isolated from BuF, consisting mainly of cathechins, procyanidins and flavonoids [Tanae, M.M., Lima-Landman, M.T.R., De Lima, T.C.M., Souccar, C., Lapa, A.J., 2007. Chemical standardization of the aqueous extract of Cecropia glaziovii Sneth endowed with antihypertensive, bronchodilator, antacid secretion and antidepressant-like activities. Phytomedicine 14, 309-313], inhibited the in vitro gastric H(+), K(+)-ATPase activity at equieffective concentrations to that of BuF. The results indicate that C. glazioui constituents inhibit the gastric proton pump; this effect may account for the effective antisecretory and antiulcer activities of the standardized plant extract.

Antihyperlipemic and antihypertensive effects of Spirulina maxima in an open sample of Mexican population: a preliminary report

Background

Spirulina maxima is a filamentous cyanobacterium used as food supplement because of its high nutrient contents. It has been experimentally proven, in vivo and in vitro that posses several pharmacological properties. The purpose of this study was to evaluate the effects of Spirulina maxima orally supplied (4.5 g/day, for 6 weeks) to a sample of 36 subjects (16 men and 20 women, with ages between 18–65 years) on serum lipids, glucose, aminotransferases and on blood pressure. The volunteers did not modify their dietary habits or lifestyle during the whole experimental period. From each subject, a sample of blood was drawn in fasting state of 12 hours to determi the plasma concentrations of glucose, triacylglycerols (TAG), total cholesterol (TC), cholesterol associated to high density lipoprotein (HDL-C) and aspartate aminotransferase (AST). Anthropometric measurements including systolic (SYST-P) and diastolic (DIAST-P) blood pressure, height, weight and Body Mass Index (BMI) were also recorded.

Results

Comparing initial and final data, the results showed that there were no significant changes in the values of glucose and AST, but significant differences in TAG, TC, and HDL-C, were observed: TAG 233.7 ± 177.8 vs. 167.7 ± 100.7 mg/dL (p < 0.001), TC 181.7 ± 37.5 vs. 163.5 ± 34.4 mg/dL (p < 0.001), C-HDL 43.5 ± 14.4 vs. 50 ± 18.8 mg/dL (p < 0.01). The univariated analysis showed that the changes in the HDL-C and TC concentrations were dependent on TAG concentration (p = 0.247 and p = 0.108, respectively); nevertheless the calculated values for cholesterol associated to low density lipoprotein (LDL-C) were significantly reduced by the Spirulina maxima treatment but independently of the TAG changes. In addition, significant differences were found comparing initial and final SYST-P and DIAST-P blood pressure in both male and female: SYST-P male 121 ± 9 vs. 111 ± 8 mm Hg (p < 0.01), DIAST-P male 85 ± 6.5 vs. 77 ± 9 mm Hg (p < 0.01); SYST-P female 120 ± 9.5 vs. 109 ± 11 mm Hg (p < 0.002), DIAST-P female 85 ± 11 vs. 79 ± 7.5 mm Hg (p < 0.03).

Conclusion

The Spirulina maxima showed a hypolipemic effect, especially on the TAG and the LDL-C concentrations but indirectly on TC and HDL-C values. It also reduces systolic and diastolic blood pressure.

ACE activity during the hypotension produced by standardized aqueous extract of Cecropia glaziovii Sneth: a comparative study to captopril effects in rats

To evaluate the effect of the standardized aqueous extract (AE) of Cecropia glaziovii Sneth on the plasma angiotensin I converting enzyme (ACE-EC 3.4.15.1) activity, rats were treated with a single dose of AE (1 g/kg, p.o.) or repeatedly (0.5 g/kg/bid, p.o.) for 60 days. Captopril (50 mg/kg, p.o.) was used as positive control on the same animals. The effects on the blood pressure were recorded directly from the femoral artery (single dose), or indirectly by the tail cuff method (repeated doses) in conscious rats. The plasma ACE activity was determined spectrofluorimetrically using Hypuril-Hystidine-Leucine as substrate. The arterial blood pressure, heart rate and plasma ACE activity were not significantly modified within 24 h after a single dose administration of AE. Comparatively, blood pressure in captopril treated rats was reduced by 7-16% and heart rate was increased by 10-20% from 30 min to 24 h after drug administration. ACE activity after captopril presented a dual response: an immediate inhibition peaking at 30 min and a slow reversal to 32% up-regulation after 24 h. To correlate the drug effects upon repeated administration of either compound, normotensive rats were separated in three groups: animals with high ACE (48.8+/-2.6 nmol/min/ml), intermediate ACE (39.4+/-1.4 nmol/min/ml) and low ACE (23.5+/-0.6 nmol/min/ml) activity, significantly different among them. Repeated treatment with AE reduced the mean systolic blood pressure (121.7+/-0.5 mm Hg) by 20 mm Hg after 14 days. The hypotension was reversed upon washout 60 days afterwards. Likely, repeated captopril administration decreased blood pressure by 20 mm Hg throughout treatment in all groups. After 30 days treatment with AE (0.5 g/kg/bid, p.o.) the plasma ACE activity was unchanged in any experimental group. After captopril (50 mg/kg/bid, p.o.) administration the plasma ACE activity was inhibited by 50% within 1 h treatment but it was up-regulated by 120% after 12 h in all groups. It is concluded that the hypotension produced by prolonged treatment with AE of C. glaziovii is unrelated to ACE inhibition.

Chemical standardization of the aqueous extract of Cecropia glaziovii Sneth endowed with antihypertensive, bronchodilator, antiacid secretion and antidepressant-like activities

This study reports the extraction process and standardization of the aqueous extract (AE) of a Cecropia species aiming its pharmacological characterization as a phytomedicine to be used in primary health care. The plant was originally collected in its environment, and was thereafter specially cultivated for the present work. To standardize the plant AE, several 2.0% tea of the dried leaves were prepared under controlled conditions and freeze dried. The AE (20% yield) was partitioned with n-butanol yielding the butanolic fraction (BuF; 1% yield). The activity of AE on vital organ functions (cardiovascular, respiratory, gastrointestinal and central nervous system) was determined in vivo. The effects of AE were compared to those of BuF in the same models and the relative potency determined. BuF was further evaluated in representative in vitro models to assess possible mechanisms of action. Chemical constituents of BuF were isolated in preparative HPLC columns yielding 10 highly purified compounds chemically identified as catechins (2), procyanidins (4), flavonoids (2), mixed sugars (1) and chlorogenic acid. All the compounds were identified by chemical analytic instrumentation (13C-NMR, 1H-NMR, LC-MS). Their relative concentrations in AE were ca 12% catechins, 19% procyanidins and 19% flavonoids. The pharmacological activity of the standardized AE is reported in accompanying papers.

Inhibition of histamine-induced bronchospasm in guinea pigs treated with Cecropia glaziovi Sneth and correlation with the in vitro activity in tracheal muscles

A standardized aqueous extract (AE) and a purified fraction (BuF) of Cecropia glaziovi Sneth leaves were tested in unrestrained guinea pigs challenged with histamine. Changes of the respiratory pressure and rate were recorded in a whole body plethysmograph before and after treatment. The concentration of histamine necessary to produce bronchospasm was increased by five-fold following administration of AE (1.0 g/kg p.o.), and by two-fold after treatment with the semi-purified procyanidin/flavonoids enriched BuF (0.1 g/kg p.o.). Both effects were blocked by previous treatment with propranolol (10.0 mg/kg i.p.). In vitro incubation of BuF (0.1-1.0 mg/ml) decreased by 13-55% the maximal response of guinea pig tracheal muscle to histamine, without significant change of EC50. The results confirmed old reports on the useful pulmonary effects of Cecropia extracts. The bronchodilation observed in vivo seems to be related to beta-adrenergic activity observed in vitro only with high concentrations of the purified extract.