Endothelium-independent vasorelaxant effect of Asphodelus tenuifolius Cav. via inhibition of myosin light chain kinase activity in the porcine coronary artery

ETHNOPHARMACOLOGICAL RELEVANCE

Asphodelus tenuifolius Cav. (Asphodelaceae), a wild, terrestrial, annual stemless herb, is widely used in traditional medicine for the treatment of hypertension, diabetes, atherosclerosis and circulatory problems. A previous research study from our laboratory revealed that A. tenuifolius has beneficial effects in reducing blood pressure and improves aortic endothelial dysfunction in chronically glucose fed rats. Despite the fact that A. tenuifolius reduces blood pressure and improves endothelial function in vivo, there are no detailed studies about its possible mechanism of action.

AIM OF THE STUDY

This study was designed to provide pharmacological basis and mechanism of action for the traditional use of A. tenuifolius in hypertension and circulatory problems. We explored the vasorelaxant effect of A. tenuifolius and its underlying vasorelaxation mechanism in porcine coronary artery rings.

MATERIALS AND METHODS

Aqueous methanolic crude extract of A. tenuifolius was prepared by maceration process and then activity guided fractionation was carried out by using different polarity based solvents. Phytochemical studies were carried out using LC-DAD-MS. Segments of porcine distal coronary artery were set up in a wire myograph for isometric force measurements. Extract/fractions of A. tenuifolius seeds were tested for vasodilator activity by measurement of changes in tone after pre-contraction with the thromboxane mimetic U46619 in the presence or absence of inhibitors of intracellular signaling cascades.

RESULTS

Crude extract/fractions of A. tenuifolius produced dose dependent endothelium independent vasorelaxant response in coronary rings, whereas, the butanol fraction of A. tenuifolius (BS-AT) produced the largest relaxation response with 100% relaxation at 1 mg/ml, therefore the mechanism of relaxation of this fraction was determined. The relaxation to BS-AT was unaffected by removal of the endothelium, pre-contraction with KCl, or the presence of the non-selective potassium channel blocker tetraethylammonium, indicating that the relaxation was endothelium-independent, and does not involve activation of potassium channels. BS-AT (1 mg/ml) inhibited the contractile response to calcium,the L-type calcium channel activator BAY K8664,and ionomycin, indicating that it inhibits calcium-induced contractions. The relaxation response to BS-AT was attenuated in the absence of extracellular calcium. However, relaxations to BS-AT were also reduced after deletion of calcium from intracellular stores with cyclopiazonic acid. Incubation with 1 mg/ml BS-AT also inhibited phosphorylation of myosin light chains in homogenates of coronary artery.

CONCLUSION

The butanol extract of Asphodelus tenuifolius produces a large endothelium-independent relaxation of the porcine coronary artery through inhibition of calcium-induced contractions. The effect appears to be downstream of calcium influx, possibly through inhibition of myosin light chain kinase. This study supports previous studies demonstrating that A. tenuifolius reduces blood pressure. Future studies will aim to determine the active compounds underlying this response.

From general toxicology to DNA disruption: A safety assessment of Plinia cauliflora (Mart.) Kausel

ETHNOPHARMACOLOGICAL RELEVANCE

Plinia cauliflora (Mart.) Kausel (Myrtaceae) is popularly known as "jaboticaba" or "jaboticaba". The fruit is appreciated for both fresh consumption and the manufacture of jelly, juice, ice cream, fermented beverages, and liqueurs. The more widespread traditional use of the plant involves the treatment of diarrhea, which utilizes all parts of the plant, including the fruit peels.

AIM OF THE STUDY

We sought to elucidate possible risks of the administration of an ethanol-soluble fraction that was obtained from an infusion of P. cauliflora fruit peels (SEIPC). We performed a series of experiments to evaluate possible toxicity, in which we administered SEIPC orally both acutely and repeatedly for 28 days. We also evaluated possible endocrine-disruptive and genotoxic effects in eukaryotic cells. The possible mutagenic activity of SEIPC was evaluated using reverse mutation (Ames) assays.

MATERIALS AND METHODS

SEIPC was produced and chemically characterized by LC-DAD-MS. Acute toxicity and behavioral and physiological alterations were evaluated in the modified Irwin test. Respiratory rate, arterial blood gas, electrocardiography, respiratory rate, heart rate, and blood pressure were evaluated, and hematological, biochemical, and histopathological analyses were performed after 28 days of oral treatment. The comet assay, mammalian erythrocyte micronucleus test, uterotrophic test, Hershberger bioassay, and AMES test were performed using appropriate protocols.

RESULTS

From SEIPC, ellagic acid and derivatives, flavonols and anthocyanidins, as well as citric acid and gallic acid, were annotated by LC-DAD-MS. We did not observed any significant toxic effects after acute or prolonged SEIPC treatment. No endocrine-disruptive or mutagenic effects were observed.

CONCLUSIONS

The present study found that SEIPC did not cause any significant alterations of various corporeal systems, including cardiac electrical activity, body temperature, respiratory rate, and arterial pressure. No alterations of biochemical, hematological, or blood gas parameters were observed. SEIPC did not cause any perturbations of the endocrine system or mutagenic, cytotoxic, or genotoxic effects. These findings substantiate the safe clinical use of P. cauliflora.

Cardioprotective effects of Plinia cauliflora (Mart.) Kausel in a rabbit model of doxorubicin-induced heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

In Brazil, the fruit of a native species that is popularly known as "jabuticaba" (Plinia cauliflora [Mart.] Kausel) is widely consumed fresh or used for the production of liqueur, juice, and jelly. In Brazilian folk medicine, this species is used to treat asthma, throat inflammation, and gastrointestinal and cardiovascular disturbances. However, no previous studies have reported its cardioprotective effects.

AIM

To evaluate the possible cardioprotective effects of a hydroethanolic extract of Plinia cauliflora (EEPC) in female rabbits in a model of doxorubicin-induced heart failure.

MATERIAL AND METHODS

EEPC was obtained and fractionated by solid phase extraction, and its constituents were determined by liquid chromatography coupled to diode array detector and mass spectrometry (LC-DAD-MS). Thirty female New Zealand rabbits received doxorubicin administration for 6 weeks to induce heart failure. EEPC was orally administered at doses of 75 and 150 mg/kg daily for 42 days. Enalapril (5 mg/kg) was used as a reference cardioprotective drug. At the end of the experimental period, blood pressure and heart rate were recorded. Serum parameters, including lipid profile, troponin, creatinine, nitrotyrosine, malondialdehyde, nitrite, and brain natriuretic peptide, were measured. The electrocardiographic profile and renal vascular reactivity were evaluated. Cardiac histopathology and ventricular morphometry were performed, and the tissue enzymatic antioxidant system was investigated.

RESULTS

A total of 37 compounds were detected in EEPC, including organic acids, phenolic acid derivatives, flavonoids, anthocyanins, and hydrolysable tannins (gallotannins and ellagitannins). EEPC treatment induced a cardiorenal protective response, prevented hemodynamic and functional alterations, and prevented ventricle remodeling. These effects were associated with the normalization of creatinine and brain natriuretic peptide levels and modulation of the tecidual antioxidant defense system.

CONCLUSION

The present study demonstrated that EEPC may prevent doxorubicin-induced heart failure by modulating the antioxidant defense system, reducing reactive oxygen species-induced damage, preventing alterations of hemodynamic and endothelial function, and preventing damage to the cardiac structure. EEPC, especially at the highest dose tested, may be considered a cardioprotective coadjuvant to prevent doxorubicin-induced cardiotoxicity.

Pharmacological safety of Plinia cauliflora (Mart.) Kausel in rabbits

•

Fruit peels of Plinia cauliflora are widely used in Brazilian traditional medicine.

•

No studies have proved the safety of its pharmacological effects.

•

We assessed the safety pharmacology of P. cauliflora extract (EEPC) in rabbits.

•

EEPC did not cause any significant changes in several physiological systems.

•

These data provide important safety data for its clinical use.

Fruit peels of Plinia cauliflora (Mart.) Kausel are widely used in Brazilian traditional medicine, but no studies have proved the safety of its pharmacological effects on the respiratory, cardiovascular, and central nervous systems. The present study assessed the safety pharmacology of P. cauliflora in New Zealand rabbits. First, an ethanol extract (EEPC) was selected for the pharmacological experiments and chemical characterization. Then, different groups of rabbits were orally treated with EEPC (200 and 2000 mg/kg) or vehicle. Acute behavioral and physiological alterations in the modified Irwin test, respiratory rate, arterial blood gas, and various cardiovascular parameters (i.e., heart rate, blood pressure, and electrocardiography) were evaluated. The main secondary metabolites that were identified in EEPC were ellagic acid, gallic acid, O-deoxyhexosyl quercetin, and the anthocyanin O-hexosyl cyanidin. No significant behavioral or physiological changes were observed in any of the groups. None of the doses of EEPC affected respiratory rate or arterial blood gas, with no changes on blood pressure or electrocardiographic parameters. The present study showed that EEPC did not cause any significant changes in respiratory, cardiovascular, or central nervous system function. These data provide scientific evidence of the effects of this species and important safety data for its clinical use.

Parthenolide Influences Herpes simplex virus 1 Replication in vitro

BACKGROUND/AIMS

Parthenolide is a sesquiterpene lactone that is present in plants of the Tanacetum genus, for which many biological effects have already been reported, including antiherpetic activity. Although the effectiveness of parthenolide against Herpes simplex virus 1 (HSV-1) has already been demonstrated, such findings are still controversial. The objective of this study was to investigate the ways in which parthenolide exerts anti-HSV-1 activity.

METHODS

The cytotoxicity and antiviral activity of parthenolide were determined by the MTT method and plaque reduction assay, respectively. The expression of cell and viral proteins during the treatment of infected cells was investigated by Western blot.

RESULTS

Both strains of HSV-1 were sensitive to parthenolide, and parthenolide was active only after penetration of the virus into the host cell. The expression of p65 protein decreased, the expression of caspases 8 and 9 increased, and the expression of c-Jun N-terminal kinase (JNK) and p38 protein was altered in infected cells after parthenolide treatment, resulting in lower cell survival. The low expression of viral proteins gB, gD, and ICP0 confirmed the reduction of HSV-1 particle production.

CONCLUSION

Parthenolide exerts anti-HSV-1 activity by impairing cell viability, which consequently interferes with the efficient infection and production of new viral particles.

Antiviral Activity of Crude Hydroethanolic Extract from Schinus terebinthifolia against Herpes simplex Virus Type 1

Herpes simplex virus infections persist throughout the lifetime of the host and affect more than 80 % of the humans worldwide. The intensive use of available therapeutic drugs has led to undesirable effects, such as drug-resistant strains, prompting the search for new antiherpetic agents. Although diverse bioactivities have been identified in Schinus terebinthifolia, its antiviral activity has not attracted much attention. The present study evaluated the antiherpetic effects of a crude hydroethanolic extract from the stem bark of S. terebinthifolia against Herpes simplex virus type 1 in vitro and in vivo as well as its genotoxicity in bone marrow in mammals and established the chemical composition of the crude hydroethanolic extract based on liquid chromatography-diode array detector-mass spectrometry and MS/MS. The crude hydroethanolic extract inhibited all of the tested Herpes simplex virus type 1 strains in vitro and was effective in the attachment and penetration stages, and showed virucidal activity, which was confirmed by transmission electron microscopy. The micronucleus test showed that the crude hydroethanolic extract had no genotoxic effect at the concentrations tested. The crude hydroethanolic extract afforded protection against lesions that were caused by Herpes simplex virus type 1 in vivo. Liquid chromatography-diode array detector-mass spectrometry and MS/MS identified 25 substances, which are condensed tannins mainly produced by a B-type linkage and prodelphinidin and procyanidin units.

In vitro Cytotoxicity and Anti-herpes Simplex Virus Type 1 Activity of Hydroethanolic Extract, Fractions, and Isolated Compounds from Stem Bark of Schinus terebinthifolius Raddi

Background:

Herpes simplex virus type 1 (HSV-1) is associated with orofacial infections and is transmitted by direct contact with infected secretions. Several efforts have been expended in the search for drugs to the treatment for herpes. Schinus terebinthifolius is used in several illnesses and among them, for the topical treatment of skin wounds, especially wounds of mucous membranes, whether infected or not.

Objective:

To evaluate the cytotoxicity and anti-HSV-1 activity of the crude hydroethanolic extract (CHE) from the stem bark of S. terebinthifolius, as well as its fractions and isolated compounds.

Materials and Methods:

The CHE was subjected to bioguided fractionation. The anti-HSV-1 activity and the cytotoxicity of the CHE, its fractions, and isolated compounds were evaluated in vitro by SRB method. A preliminar investigation of the action of CHE in the virus–host interaction was conducted by the same assay.

Results:

CHE presented flavan-3-ols and showed anti-HSV-1 activity, better than its fractions and isolated compounds. The class of substances found in CHE can bind to proteins to form unstable complexes and enveloped viruses, as HSV-1 may be vulnerable to this action. Our results suggest that the CHE interfered with virion envelope structures, masking viral receptors that are necessary for adsorption or entry into host cells.

Conclusion:

The plant investigated exhibited potential for future development treatment against HSV-1, but further tests are necessary, especially to elucidate the mechanism of action of CHE, as well as preclinical and clinical studies to confirm its safety and efficacy.

SUMMARY

Crude hydroethanolic extract (CHE) presents promising activity against herpes simplex virus type 1 (HSV 1), with selectivity index (SI) = 22.50

CHE has flavan-3-ols in its composition, such as catechin and gallocatechin

The fractions and isolated compounds obtained from CHE by bioguided fractionation are less active than the CHE against HSV-1

CHE interferes with viral entry process in the host cell and acts directly on the viral particle.

Abbreviations used: HSV: Herpes simplex virus, CHE: Crude hydroethanolic extract, WF: Water fraction, AF: Ethyl-acetate fraction, MPLC: Medium-performance liquid chromatography, TLC: Thin-layer chromatography, NMR: Nuclear magnetic resonance, ESI-MS: Electrospray ionization mass spectrometry, SRB: Sulforhodamine B, CPE: Cytopathic effect, CC50: 50% cytotoxic concentration, EC50: 50% effective concentration, PBS: Phosphate-buffered saline.