Biomedical subjects

Rosendo A Yunes

Publications and source records attributed to Rosendo A Yunes.

At least 19 recordsLinked to original sources

PubMed2006

Non-peptide antagonists for kinin B1 receptors: new insights into their therapeutic potential for the management of inflammation and pain.

Kinin B1 and B2 receptors are central to the aetiology of pain and inflammation. Constitutive B2 receptors are commonly associated with the acute phase of inflammation and nociception, whereas the inducible B1 receptors are mostly linked to the chronic or persistent phase (or both). Therefore, selective, orally active kinin B1 receptor antagonists could be potentially therapeutic. B1 receptor antagonists have long been exclusively peptides, but recently a few non-peptide representatives have been identified. The clinical potential of these non-peptide molecules has not yet been evaluated, but they might have a role in treating persistent inflammation and pain, especially when no satisfactory therapy is available. This review summarizes recent advances in the identification and the potential therapeutic properties of these molecules.

Animals↗

PubMed2006

Anti-edematogenic effects of velutinol A isolated from Mandevilla velutina: evidence for a selective inhibition of kinin B1 receptor-mediated responses.

This study assesses the effects of compound velutinol A obtained from M. velutina in the rat paw edema induced by several phlogistic agents. Attempts were made to analyze how velutinol A is able to inhibit kinin B(1) receptor-mediated inflammatory responses. Velutinol A (100 nmol/paw) partially reduced (about 30%) the edema evoked by carrageenan (300 microg/paw). However, velutinol A (100 nmol/paw) failed to affect the edema induced by histamine (200 nmol/paw), substance P (30 nmol/paw), PAF (10 nmol/paw) or BK (3 nmol/paw). Interestingly, the edema caused by the selective kinin B(1) receptor agonist des-Arg(9)-BK (100 nmol/paw) in animals pre-treated with PAF or LPS was significantly inhibited by velutinol A (100 nmol/paw) (48 and 46%, respectively). A similar inhibition of des-Arg(9)-BK-induced edema after pre-treatment with PAF was obtained with the non-peptidic and selective B(1) receptor antagonist SSR 240612 (60 nmol/paw) (46%). In addition, the systemic administration of velutinol A (10 mg/kg, i.p.) or SSR 240612 (1 mg/kg, i.p.) also caused a significant reduction of des-Arg(9)-BK (100 nmol/paw)-induced edema in PAF-treated rats (51 and 43%, respectively). The results provide convincing evidence that velutinol A selectively blocks the edema responses mediated by B(1) receptor activation in vivo. This compound might represent a new non-peptidic and selective antagonist for kinin B(1) receptors.

Animals↗

PubMed2006

Relationship between the lipophilicity of gallic acid n-alquil esters' derivatives and both myeloperoxidase activity and HOCl scavenging.

The gallic acid and several n-alkyl gallates, with the same number of hydroxyl substituents, varying only in the side carbonic chain length, with respective lipophilicity defined through the C log P, were studied. It evidenced the structure-activity relationship of the myeloperoxidase activity inhibition and the hypochlorous acid scavenger property, as well as its low toxicity in rat hepatic tissue. The gallates with C log P below 3.0 (compounds 2-7) were more active against the enzyme activity, what means that the addition of 1-6 carbons (C log P between 0.92 and 2.92) at the side chain increased approximately 50% the gallic acid effect. However, a relationship between the HOCl scavenging capability and the lipophilicity was not observed. With these results it is possible to suggest that the gallates protect the HOCl targets through two mechanisms: inhibiting its production by the enzyme and scavenging the reactive specie.

Animals↗

PubMed2006

Evaluation of antiviral activity of phenolic compounds and derivatives against rabies virus.

Human rabies is a viral disease with a great impact on public health, mainly on account of its fatal course in the majority of cases. Despite the well-established prophylaxis by immunization, rabies is believed to be responsible for 40,000-70,000 human deaths per year, mostly in endemic areas. Palliative support and experimental protocols to avoid death have been employed with no expressive results, with the exception of a recent human case of recovery from rabies. No antiviral drugs are currently available to fight against this infection. In combination with the prophylaxis, an antiviral drug would be useful for human rabies treatment, providing enhanced protection against the encephalitis caused by the virus. Phenolic compounds are derived from the secondary plant metabolism, although they can also be obtained by synthetic processes. Many studies have shown a great range of pharmacological effects for these substances, including vasodilatation, antiallergenic, antiinflammatory and antiviral properties, among others. In this study, the potential in-vitro anti-rabies activity of 24 synthetic phenolic compounds was evaluated using McCoy cells and PV rabies strain. The cytotoxicity (CC50) was assayed by the MTT method and the antiviral activity (IC50) was estimated by the inhibition of viral cytopathic effects. Isoprinosine and ketamine were used as positive controls. The tested compounds showed selectivity indices (SI=CC50/IC50) ranging from 1.0 to 3.9. Six phenolic compounds failed to inhibit the cytopathic effect to any degree, and four showed SI > or = 3.0. According to these results, some probable structure-activity relationships are suggested. It was observed that the presence of free hydroxyl and ether groups influenced the anti-rabies activity. However, additional studies are required to establish these relationships.

Animals↗

PubMed2006

The sesquiterpenes polygodial and drimanial in vitro affect glutamatergic transport in rat brain.

Natural products including those derived from plants, have over the years greatly contributed to the development of therapeutic drugs. Polygodial and drimanial are sesquiterpenes isolated from the bark of the plant Drymis Winteri (Winteraceae) that exhibit antinociceptive properties. Since peripheral glutamate presents nociceptive actions, in this study it was investigated the effects of hydroalcooholic extracts from Drymis winteri (polygodial and drimanial) on the glutamatergic system in rat brain. Polygodial and drimanial inhibited glutamate uptake by astrocytes, as well as by cortical, hippocampal and striatal slices, and increased synaptosomal glutamate release. These concurrent effects would predispose to an increase in the extracellular glutamate concentrations, leading to possible neurotoxic effects (excitotoxicity) of these natural compounds, which would suggest the need for some caution in their therapeutic application.

Animals↗

PubMed2006

Antinociceptive properties produced by the pregnane compound velutinol A isolated from Mandevilla velutina.

Velutinol A is a pregnane compound isolated from the rhizomes of the Brazilian plant Mandevilla velutina that interferes with kinin actions and possesses anti-inflammatory action. Here, we investigate the effect produced by velutinol A in different models of inflammatory nociception. The nociceptive effect caused by the intraplantar injection of phorbol myristate acetate (PMA, 50 pmol/paw) in mice was practically abolished by coadministration of velutinol A (1-10 nmol/paw). In contrast, the coadministration of velutinol A (10 nmol/paw) failed to affect the nociceptive response elicited by either bradykinin (BK, 10 nmol/paw) or prostaglandin E(2) (PGE(2), 10 nmol/paw). Of note, velutinol A (10 nmol/paw) partially inhibited the nociceptive response caused by capsaicin (1 nmol/paw). However, velutinol A (10 microM) did not significantly interfere with the specific binding sites of [(3)H]resiniferatoxin or [(3)H]BK in vitro. Our data also suggest that these effects are related with its ability to interact with kinin B(1) receptor-mediated mechanisms, as the cotreatment of mice with velutinol A (10 nmol/paw) consistently blocked the nociceptive response induced by the selective B(1) receptor agonist des-Arg(9)-BK. Finally, the persistent hyperalgesia produced by intraplantar injection of carrageenan (300 microg/paw) was completely reversed by the coadministration of velutinol A (10 nmol/paw). Collectively, the present results show that the pregnane compound velutinol A produces peripheral antinociceptive action in some models of acute and persistent inflammatory pain by interacting with kinin B(1)-receptor mediated effects. Thus, velutinol A or its derivatives could constitute an attractive molecule of interest for the development of new analgesic drugs. Additional studies are now in progress in order to further explore its precise mechanism of action on B(1) receptor pathways.

Analgesics↗

PubMed2006

Pharmacological characterisation of the plant sesquiterpenes polygodial and drimanial as vanilloid receptor agonists.

This study was designed to assess the participation of transient receptor potential vanilloid 1 (TRPV1) in the biological effects induced by the plant-derived sesquiterpenes polygodial and drimanial. In rat isolated urinary bladder, polygodial and drimanial produced a tachykinin-mediated contraction that was inhibited by combination of NK(1) and NK(2) tachykinin receptor antagonists, SR 140333 and SR 48968. Furthermore, two different TRPV1 antagonists, capsazepine and ruthenium red prevented the contraction induced by both compounds. In addition, capsaicin, polygodial and drimanial displaced in a concentration-dependent manner the specific binding sites of [(3)H]-resiniferatoxin to rat spinal cord membranes, with a IC(50) values of 0.48, 4.2 and 3.2 microM, respectively. Likewise, capsaicin, polygodial and drimanial promoted an increase of [(45)Ca(2+)] uptake in rat spinal cord synaptosomes. In cultured rat trigeminal neurons, polygodial, drimanial and capsaicin were also able to significantly increase the intracellular Ca(2+) levels, effect that was significantly prevented by capsazepine. Together, the present results strongly suggest that the pharmacological actions of plant-derived sesquiterpenes polygodial and drimanial, seem to be partially mediated by activation of TRPV1. Additional investigations are needed to completely define the pharmacodynamic properties of these sesquiterpenes.

Animals↗

PubMed2006

Evaluation of the anti-proliferative effect the extracts of Allamanda blanchetti and A. schottii on the growth of leukemic and endothelial cells.

PURPOSE: To investigate the anti-proliferative effect of A. blanchetti and A. schottii extracts. METHODS: The anti-proliferative effect of A. blanchetti and A. schottii ethanolic extracts on K562 leukemic cells as well as on BMEC and HUVEC were evaluated. Phytochemical analysis to identify the possible active components was carried out. RESULTS: The root extract of A. schottii was the most active of them. At 80 microg/mL, the root extracts showed a cytostatic effect on K562, whereas at 400 microg/mL, there was a strong cytotoxic effect. Similar cytostatic and cytotoxic effects were seen in the endothelial cells, but at lower doses. The effect of A. schottii root extract on endothelial cells was seen at concentrations ten times lower (8 microg/mL) than the effect of the A. blanchetti root extract (80 microg/mL). Phytochemical investigation of different fractions and parts of the plant led to the isolation of several known compounds, some of which are described for the first time in the genus Allamanda, and with previous evidence of anticancer and antitumoral properties. CONCLUSIONS: Our results suggest that both plants studied exhibit cytostatic and cytotoxic activity, but the most active compounds are located in the roots.

Antineoplastic Agents↗

PubMed2005

Antifungal activity of drimane sesquiterpenes from Drimys brasiliensis using bioassay-guided fractionation.

PURPOSE: This study describes the antifungal effect of extracts and compounds isolated from Drimys brasiliensis acting against dermatophytes. METHODS: The activities were evaluated by using the microbroth dilution method. RESULTS: Bioassay-guided fractionation of the most active extract from the bark (CHCl3) led to the isolation of the sesquiterpene drimanes polygodial, 1-beta-(p-methoxycinnamoyl)-polygodial, drimanial and 1-beta-(p-cumaroyloxy)-polygodial, which were selectively active against Epidermophyton floccosum and Tricophyton rubrum. CONCLUSIONS: The selective antifungal activity reported in this paper for drimanes isolated from D. brasiliensis opens the possibility that they could be helpful for the developing of new antifungal agents for treating the difficult to eradicate dermatomycoses produced by E. floccosum.

Antifungal Agents↗

PubMed2005

The evolution of the human mind and logic--mathematics structures.

The evolution of the human mind is discussed based on: (i) the fact that living beings interchange matter, energy and information with their environment, (ii) an ontological interpretation of the "reality" of the quantum world, of which logic-mathematics structures are considered constitutive parts, (iii) recent theories according to which living beings are considered as dynamic complex systems organized by information, and (iv) the fact that the evolution of living beings is guided by information about the environment and by intrinsic information on living systems (auto-organization). Assuming the evolution of vision as a model we observe that the driving forces that directed the evolution of the eyes, as dynamic complex systems, are the information about the environment supplied by sunlight and the intrinsic information-gaining mechanism of living organisms. Thus, there exists a convergence toward a visual system with the greatest ability to obtain light information, like the human eye, and also a divergence that leads to the development of specific qualities in some species. As in the case of vision the evolution of the human mind-brain cannot be a consequence of factors unrelated to the object of its own functioning. The human mind was structured for the acquisition from reality of the logic-mathematics structures that underlie the whole universe and consequently of an internal representation of the external world and of its own self. Thus, these structures are, together with the intrinsic capacity for auto-organization of the human brain, the predominant driving force of the human mind evolution. Both factors are complementary.

Biological Evolution↗

PubMed2005

Antifungal activity and studies on mode of action of novel xanthoxyline-derived chalcones.

Chalcones and chalcone-like compounds, most of them new ones, prepared by base-catalyzed condensation of appropriate aldehydes and xanthoxyline, were tested for antifungal properties against a panel of yeasts, hialohyphomycetes as well as dermatophytes with the agar dilution assay. Results indicate that neither the sole presence of a "xanthoxyline-like" substitution pattern nor a 2'-OH substituent on ring A are sufficient for these compounds to have antifungal properties. The chalcone 3-(2-chlorophenyl)-1-(2'-hydroxy-4',6'-dimethoxyphenyl)prop-2-en-1-one, with a Cl atom in the ortho position of benzene ring B showed the best antifungal activity against standardized strains of Trichophyton rubrum (MIC = 12.5 microg/mL) and inhibited all of the ten clinical isolates of T. rubrum tested (MIC at which 50 % [MIC(50)] and 90 % [MIC(90)] of the isolates were inhibited = 12.5 and 25 microg/mL). Regarding its mode of action, the Neurospora crassa assay showed a blotchy appearance in the inhibition halo produced by this chalcone, strongly suggesting that it could act by inhibiting the fungal cell wall. This chalcone seems to be an hyphal malformation inducer, since a clear curling of the hypha was observed in this hazy zone at a magnification of x 400. This work strongly contributes to the knowledge of the antifungal properties of hydroxy-chalcones.

Acetophenones↗

PubMed2005

Evaluation of anti-herpetic and antioxidant activities, and cytotoxic and genotoxic effects of synthetic alkyl-esters of gallic acid.

The n-alkyl esters of gallic acid (CAS 13857-8) have a diverse range of uses as antioxidants in food, cosmetics and pharmaceutical industries. Pharmaceutical studies performed with these compounds have found that they have many therapeutic potentialities including anti-cancer, antiviral and antimicrobial properties. However, more interest has been devoted to their antioxidant activity due to the ability to scavenge and reduce reactive oxygen species (ROS) formation. In this study, gallic acid and 14 different alkyl gallates were tested. The cytotoxicity and anti-herpetic (HSV-1, KOS and 29-R strains) activity were studied by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) colorimetric assay and the cell viability by using the Trypan blue dye exclusion method. The genotoxicity was studied by the Comet assay and the antioxidant activity by using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and microsomal lipid peroxidation-inhibiting activities. The results showed that all the tested compounds have anti-herpetic activity at non cytotoxic concentrations with selectivity indices (SI = CC50/EC50) varying from 0.89 to 18.34, depending on the used HSV-1 strain. It was observed that all tested alkyl gallates showed some degree of genotoxicity, at the tested concentrations, except cetyl gallate, at 256.60 micromol/L (p <0.05, t-Student test), probably induced by ROS released by infected cells and/or by the alkyl gallates that were not antioxidants, at the tested concentrations, in which they demonstrated anti-herpetic activity. The hydroxyl groups can induce DNA damage due interactions with some metal ions, which are naturally present in the culture medium supplemented with fetal bovine serum, probably explaining the genotoxicity detected. However, the obtained results showed considerable antioxidant activity at smaller concentrations, when compared to quercetin which is considered as a reference drug due to its already described antioxidant potential: DPPH radical scavenging activity with IC50 values varying from 17 to 31 micromol/L; and microsomal lipid peroxidation-inhibiting activity with IC50 values varying from 21 to 59 micromol/L. It was observed that the presence of hydroxyl groups in these molecules is important for their pharmacological profile, but the length of the lateral carbonic chain does not have considerable influence.

Animals↗

PubMed2005

In vitro antifungal properties structure-activity relationships and studies on the mode of action of N-phenyl, N-aryl, N-phenylalkyl maleimides and related compounds.

The synthesis, in vitro antifungal evaluation and structure-activity relationship studies of 14 compounds of the N-phenyl-, N-aryl-, N-phenylalkyl- maleimide and 3,4-dichloromaleimide series are reported. The compounds were evaluated against a panel of standardized yeasts and filamentous fungi as well as clinical isolates of Candida albicans. The activities of N-phenylalkyl-3,4-dichloromaleimide derivatives but not those of N-phenylalkyl-maleimide derivatives showed to be dependent on the length of the alkyl chain. N-Phenylpropyl-3,4-dichloromaleimide showed the broadest spectrum of action and lower minimal inhibitory concentrations (MIC) in all of the fungi tested. The nitrogen-carbon distance between the two rings seems to play an important role in the antifungal behavior of these compounds. The most active structure showed inhibited (1,3)beta-D-glucan and chitin synthases, enzymes that catalyze the synthesis of the major fungal cell-wall polymers.

Antifungal Agents↗

PubMed2005

Optimized modified topliss method: a tool for quantitative structure-activity relationship studies.

The structural variation of lead compounds often includes the variation of substituents at a particular site. A common difficulty, in quantitative structure-activity relationship (QSAR) studies, is to select the best substituents to obtain, with a minimum number of experiments, a major change in some impor. tant properties of the molecule. To improve a proposed modified Topliss method, 187 different substituted compounds belonging to 70 series were studied. A single linear regression was carried out between the experimental activity of each series of compounds and the molecular structure parameters pi, sigma, Es and MR, along with some combinations of them, in order to select the best substituents for constructing the "reduced" correlation. This selection considered the scaled smallest residue average of the substituent, the number of times that the substituent is inserted in the 70 series and its quadrant in the Craig graph. The results obtained in this study with this simple method showed a good predictive capacity when compared with the multiple regression analysis, using the Hansch method.

Algorithms↗

PubMed2004

Antinociceptive properties of mixture of alpha-amyrin and beta-amyrin triterpenes: evidence for participation of protein kinase C and protein kinase A pathways.

The mixture of the two pentacyclic triterpenes alpha-amyrin and beta-amyrin, isolated from the resin of Protium kleinii and given by intraperitoneal (i.p.) or oral (p.o.) routes, caused dose-related and significant antinociception against the visceral pain in mice produced by i.p. injection of acetic acid. Moreover, i.p., p.o., intracerebroventricular (i.c.v.), or intrathecal (i.t.) administration of alpha,beta-amyrin inhibited both neurogenic and inflammatory phases of the overt nociception caused by intraplantar (i.pl.) injection of formalin. Likewise, alpha,beta-amyrin given by i.p., p.o., i.t., or i.c.v. routes inhibits the neurogenic nociception induced by capsaicin. Moreover, i.p. treatment with alpha,beta-amyrin was able to reduce the nociception produced by 8-bromo-cAMP (8-Br-cAMP) and by 12-O-tetradecanoylphorbol-13-acetate (TPA) or the hyperalgesia caused by glutamate. On the other hand, in contrast to morphine, alpha,beta-amyrin failed to cause analgesia in thermal models of pain. The antinociception caused by the mixture of compounds seems to involve mechanisms independent of opioid, alpha-adrenergic, serotoninergic, and nitrergic system mediation, since it was not affected by naloxone, prazosin, yohimbine, DL-p-chlorophenylalanine methyl ester, or L-arginine. Interestingly, the i.p. administration of alpha,beta-amyrin reduced the mechanical hyperalgesia produced by i.pl. injection of carrageenan, capsaicin, bradykinin, substance P, prostaglandin E2, 8-Br-cAMP, and TPA in rats. However, the mixture of compounds failed to alter the binding sites of [3H]bradykinin, [3H]resiniferatoxin, or [3H]glutamate in vitro. It is concluded that the mixture of triterpene alpha-amyrin and beta-amyrin produced consistent peripheral, spinal, and supraspinal antinociception in rodents, especially when assessed in inflammatory models of pain. The mechanisms involved in their action are not completely understood but seem to involve the inhibition of protein kinase A- and protein kinase C-sensitive pathways.

Acetic Acid↗

PubMed2004

Topical antiinflammatory effects of the ether extract from Protium kleinii and alpha-amyrin pentacyclic triterpene.

Protium kleinii (Burseraceae), a native Brazilian medicinal plant is claimed to be useful to treat some inflammatory states. Now we reported that topical application of either the ether extract or the main active constituent from P. kleinii the pentacyclic triterpene alpha-amyrin, all caused a dose-related inhibition of both ear oedema (ID50 values are 0.55 and 0.31 mg/ear, respectively) and influx of polymorphonuclear cells (ID50 values are 0.72 and 0.45 mg/ear, respectively) in response to topical application of 12-O-tetradecanoylphorbol-acetate (TPA) in the of mice ear. In terms of the efficacy, the maximal obtained inhibition for both ear oedema and neutrophil influx was very similar to that produced by the topical application of the steroidal antiinflammatory drug dexamethasone (DE; with inhibition of 70+/-5%, 66+/-3%, and 87+/-4% for oedema and 83+/-6%, 73+/-5%, and 91+/-3% for neutrophil influx, for the ether extract, alpha-amyrin, and dexamethasone, respectively). Likewise, both the ether extract and alpha-amyrin given topically dose-dependently prevented the increase of the proinflammatory cytokine interleukin-1beta levels in response to topical application of TPA. The calculated mean ID50 values are 1.81 and 0.53 mg/ear, respectively. Again, the efficacy of the extract and alpha-amyrin was very similar to that produced by dexamethasone (63+/-6%, 61+/-5%, and 74+/-5%, respectively). In marked contrast to phenidone, a lipo and cyclooxygenase inhibitor, neither the ether extract nor the alpha-amyrin inhibited arachidonic acid-mediated ear oedema in mice. Collectively, these results indicate that the active constituents present in the ether extract of P. kleinii including the pentacyclic triterpene alpha-amyrin are good candidates to develop a skin permeable antiinflammatory drug.

Administration, Topical↗

PubMed2004

Evidence for the involvement of vanilloid receptor in the antinociception produced by the dialdeydes unsaturated sesquiterpenes polygodial and drimanial in rats.

This study investigated whether or not the neonatal treatment of rats with the sesquiterpenes polygodial or drimanial could cause persistent antinociception similar to that induced by capsaicin. Rats were injected subcutaneously 48 h after birth with capsaicin (50 mg/kg), polygodial (150 mg/kg), drimanial (150 mg/kg) or vehicle (1ml/kg). Six to eight weeks later, rats were tested in models of nociception. Treatment of rats with capsaicin, polygodial or drimanial produced significant inhibition of the first phase and, to a lesser extent, the second phase of formalin-induced nociception. A significant reduction in Complete Freund's Adjuvant and capsaicin-induced hyperalgesia was observed in the animals neonatally treated with capsaicin, polygodial or drimanial compared with vehicle-treated rats. Moreover, both sesquiterpenes caused inhibition of plasma extravasation induced by injection of capsaicin. The neonatal treatment with capsaicin, polygodial or drimanial significantly decreased [3H]-resiniferatoxin binding sites in the rat spinal cord, but only capsaicin neonatal treatment significantly reduced the expression of TRPV1 in dorsal root ganglia (DRG) when assessed by Western blot. These results extend our previous findings demonstrating that the neonatal treatment of rats with polygodial or drimanial, similar to that reported for capsaicin, produced persistent antinociception in adult animals associated with TRPV1 down-regulation in the spinal cord, but not TRPV1 expression in DRG.

Analgesics↗

PubMed2004

Paludolactone: a new eudesmanolide lactone from Wedelia paludosa DC. (Acmela brasiliensis).

Phytochemical investigation of the whole plant of Wedelia paludosa (Acmela brasiliensis) furnished a new eudesmanolide lactone, named paludolactone (2), in addition to the known eudesmanolide (1), stigmasterol, kaurenoic and oleanolic acids. 1H- and 13C-NMR, and MS spectroscopic and elemental analyses were used for the structural elucidation of these compounds.

Humans↗