Maria G.M.O. Henriques

Antiinflammatory effects of natural tetranortriterpenoids isolated from Carapa guianensis Aublet on zymosan-induced arthritis in mice

Abstract.ObjectiveWe investigated the antiinflammatory properties of a derived fraction of tetranortriterpenoids (TNTP) obtained from the seeds of Carapa guianensis Aublet.Material and methodsZymosan-induced arthritis and pleurisy in Swiss and C57/Bl6 mice (nxa0=xa010 per group). Western blot analysis was performed to analyze nuclear factor-κB (NFκB) translocation in mice peritoneal macrophages stimulated in vitro with zymosan (500xa0μg/ml). ELISA was performed to evaluate cytokine levels in knee joints. Values of pxa0≤xa00.05 were regarded as significant.ResultsZymosan intra-articular (i. a.) injection (500μg/ cavity) induced a significant increase in knee joint diameter within 6xa0h, peaked within 24xa0h and remained above control values for 20xa0days. Orally-given (p. o.) TNTP (100–200xa0mg/ kg) inhibited zymosan-induced increase in knee joint diameter and protein extravazation into synovial cavity within 6xa0h. TNTP (100–200xa0mg/kg, p. o.) also inhibited total leukocyte influx into the synovial space and tissue, as well as into the mice pleural cavity, due to neutrophil impairment 6xa0h after zymosan stimulation. The increase in TNF-α, IL-1β and CXCL8/IL-8 levels that were detected in knee synovial extracts obtained from zymosan-stimulated mice was also inhibited by TNTP (100xa0mg/kg, p. o.). Moreover, the incubation of mice peritoneal macrophages with TNTP (100xa0μg/ml) inhibited zymosan (500xa0μg/ml)-induced NFκB translocation into the nucleus 6xa0h after stimulation.ConclusionTaken together, these results indicate that TNTP present an important antiinflammatory effect, inhibiting zymosan-induced arthritis in mice via the impairment of TNF-α, IL-1β and CXCL8/IL-8 generation, as well as NFκB signaling pathway.

Pharmacological study of anti-allergic activity of Syzygium cumini (L.) Skeels

Myrtaceae is a plant family widely used in folk medicine and Syzygium and Eugenia are among the most important genera. We investigated the anti-allergic properties of an aqueous leaf extract of Syzygium cumini (L.) Skeels (SC). HPLC analysis revealed that hydrolyzable tannins and flavonoids are the major components of the extract. Oral administration of SC (25-100 mg/kg) in Swiss mice (20-25 g; N = 7/group) inhibited paw edema induced by compound 48/80 (50% inhibition, 100 mg/kg; P <or= 0.05) and, to a lesser extent, the allergic paw edema (23% inhibition, 100 mg/kg; P <or= 0.05). SC treatment also inhibited the edema induced by histamine (58% inhibition; P <or= 0.05) and 5-HT (52% inhibition; P <or= 0.05) but had no effect on platelet-aggregating factor-induced paw edema. SC prevented mast cell degranulation and the consequent histamine release in Wistar rat (180-200 g; N = 7/group) peritoneal mast cells (50% inhibition, 1 microg/mL; P <or= 0.05) induced by compound 48/80. Pre-treatment of BALB/c mice (18-20 g; N = 7/group) with 100 mg/kg of the extract significantly inhibited eosinophil accumulation in allergic pleurisy (from 7.662 +/- 1.524 to 1.89 +/- 0.336 x 10(6)/cavity; P <= 0.001). This effect was related to the inhibition of IL-5 (from 70.9 +/- 25.2 to 12.05 +/- 7.165 pg/mL) and CCL11/eotaxin levels (from 60.4 +/- 8.54 to 32.8 +/- 8.4 ng/mL) in pleural lavage fluid, using ELISA. These findings demonstrate an anti-allergic effect of SC, and indicate that its anti-edematogenic effect is due to the inhibition of mast cell degranulation and of histamine and serotonin effects, whereas the inhibition of eosinophil accumulation in the allergic pleurisy model is probably due to an impairment of CCL11/eotaxin and IL-5 production.

Differential inhibition by two hetrazepine PAF antagonists of acute inflammation in the mouse

1 The injection of 100 or 300 μg of carrageenin into the mouse paw or pleural cavity produced a delayed inflammatory reaction at 48 h while platelet activating factor (PAF)‐induced paw oedema and pleurisy were maximal 30 min after its injection. 2 The PAF antagonist, WEB 2086, failed to inhibit mouse paw oedema and pleurisy induced by PAF, but reduced the first phase of oedema (1–4 h) induced by carrageenin without interfering with the second one (48–72 h). In contrast, another structurally‐related PAF antagonist, WEB 2170, inhibited dose‐dependently both oedema and pleurisy induced by PAF and by carrageenin (48 h). 3 Repeated injections of PAF into the mouse paw or pleural cavity led to significant auto‐desensitization. The animals desensitized to PAF and injected with carrageenin also displayed a significantly reduced oedema. 4 Our results suggest that PAF may be involved in the inflammatory response to carrageenin in mice. Furthermore, because the different receptor antagonists displayed distinct effects against PAF itself, different sites for in vivo interaction of PAF are available and are species‐ and drug‐dependent.

Anti-allergic effects of natural tetranortriterpenoids isolated from Carapa guianensis Aublet on allergen-induced vascular permeability and hyperalgesia.

Abstract.Objective: We investigated the anti-allergic and analgesic properties of an oil and a derived fraction of tetranortriterpenoids (TNTP) obtained from the seeds of Carapa guianensis Aublet.Materials and methods: Pleurisy, paw and ear edema were induced in Swiss and C57/Bl10 mice mice, whereas thermal hyperalgesia was assessed in Wistar rats (n = 6−10 per group). Values of p < 0.05 were regarded as significant.Results:C. guianensis oil (100 to 400xa0mg/kg, p.o.) and TNTP (12.5 to 100xa0mg/kg, p.o.) inhibited pleural exudation, paw and ear edema induced by ovalbumin (OVA) in sensitized mice. TNTP (12.5 to 100xa0mg/kg, p.o.) also inhibited paw edema induced by histamine, PAF and bradykinin. TNTP (100xa0mg/kg, p.o.) inhibited prostaglandin E2 generation in the pleural cavity in response to antigenic challenge. Moreover, C. guianensis oil (100 to 400xa0mg/kg) and TNTP (12.5 to 100xa0mg/kg) decreased OVA- and histamine-induced hyperalgesia.Conclusion: Taken together, these findings demonstrate the anti-edematogenic and analgesic effects of C. guianensis oil, and points out TNTP as the responsible bioactive compounds.

Synthesis, antichagasic in vitro evaluation, cytotoxicity assays, molecular modeling and SAR/QSAR studies of a 2-phenyl-3-(1-phenyl-1H-pyrazol-4-yl)-acrylic acid benzylidene-carbohydrazide series.

Chagas disease (American trypanosomiasis) is one of the most important parasitic diseases with serious social and economic impacts mainly on Latin America. This work reports the synthesis, in vitro trypanocidal evaluation, cytotoxicity assays, and molecular modeling and SAR/QSAR studies of a new series of N-phenylpyrazole benzylidene-carbohydrazides. The results pointed 6k (X=H, Y=p-NO2, pIC(50)=4.55 M) and 6l (X=F, Y=p-CN, pIC(50)=4.27 M) as the most potent derivatives compared to crystal violet (pIC(50)=3.77 M). The halogen-benzylidene-carbohydrazide presented the lowest potency whereas 6l showed the most promising profile with low toxicity (0% of cell death). The best equation from the 4D-QSAR analysis (Model 1) was able to explain 85% of the activity variability. The QSAR graphical representation revealed that bulky X-substituents decreased the potency whereas hydrophobic and hydrogen bond acceptor Y-substituents increased it.

Lipoxin A4 attenuates zymosan-induced arthritis by modulating endothelin-1 and its effects

BACKGROUND AND PURPOSE Lipoxin A4 (LXA4) is a lipid mediator involved in the resolution of inflammation. Increased levels of LXA4 in synovial fluid and enhanced expression of the formyl peptide receptor 2/lipoxin A4 receptor (FPR2/ALX) in the synovial tissues of rheumatoid arthritis patients have been reported. Endothelins (ETs) play a pivotal pro‐inflammatory role in acute articular inflammatory responses. Here, we evaluated the anti‐inflammatory role of LXA4, during the acute phase of zymosan‐induced arthritis, focusing on the modulation of ET‐1 expression and its effects.

Endothelins contribute towards nociception induced by antigen in ovalbumin-sensitised mice

The contribution of endogenous endothelins to nociceptive responses elicited by ovalbumin (OVA) in the hind‐paw of mice sensitised to this antigen (50 μg OVA+5 mg Al(OH)3, s.c., 14 days beforehand) was investigated. Sensitised mice exhibited greater nocifensive responsiveness to intraplantar (i.pl.) OVA (total licking time over first 30 min: 85.2±14.6 s at 0.3 μg; 152.6±35.6 s at 1 μg) than nonsensitised animals (29.3±7.4 s at 1 μg). Nocifensive responses of sensitised mice to 0.3 μg OVA were inhibited by morphine (3 mg kg−1, s.c.) or local depletion of mast cells (four daily i.pl. injections of compound 48/80). Pretreatment with i.v. bosentan (mixed ETA/ETB receptor antagonist; 52 μmol kg−1) or A‐122722.5 (selective ETA receptor antagonist; 6 μmol kg−1) reduced OVA‐induced licking from 124.8±20.6 s to 45.7±13.0 s and 64.2±12.1 s, respectively, whereas A‐192621.1 (selective ETB receptor antagonist; 25 μmol kg−1) enhanced them to 259.2±39.6 s. Local i.pl. pretreatment with BQ‐123 or BQ‐788 (selective ETA or ETB receptor antagonists, respectively, each at 3 nmol) reduced OVA‐induced licking (from 106.2±15.2 to 57.0±9.4 s and from 118.6±10.5 to 76.8±14.7 s, respectively). Sarafotoxin S6c (selective ETB receptor agonist, 30 pmol, i.pl., 30 min after OVA) induced nocifensive responses in OVA‐sensitised, but not in nonsensitised, animals. Compound 48/80 (0.3 μg, i.pl.) induced nocifensive responses per se and potentiated those induced by i.pl. capsaicin (0.1 μg). Treatment with BQ‐123 (3 nmol, i.pl.) reduced only the hyperalgesic effect of compound 48/80, whereas BQ‐788 (3 nmol) was ineffective. Thus, immune‐mediated Type I hypersensitivity reactions elicit mast cell‐ and endothelin‐dependent nociception in the mouse hind‐paw, which are mediated locally by both ETA and ETB receptors. The nocifensive response to antigen is amenable to blockade by systemic treatment with dual ETA/ETB or selective ETA receptor antagonists, but is sharply potentiated by systemic selective ETB receptor antagonist treatment. The apparently distinct roles played by ETB receptors in this phenomenon at local and other sites remain to be characterised.

Participation of endogenous endothelins in delayed eosinophil and neutrophil recruitment in mouse pleurisy.

Abstract.Objective: Investigate the role of endothelins in leukocyte recruitment in allergic and non allergic inflammation.¶Methods: Pleurisy was induced in mice by intrathoracic injection of ovalbumin (OVA; in sensitized animals), E. coli LPS, carrageenan, Mycobacterium bovis (BCG) or zymosan. Animals were treated with BQ-123 or BQ-788 (1.5-150 pmol/cavity), or intravenously with bosentan (30 mg/kg).¶Results: None of the ET receptor antagonists modified early neutrophil recruitment (at 4h) induced by OVA, LPS, carrageenan, BCG or zymosan or plasma leakage caused by carrageenan or zymosan. Mononuclear and eosinophil accumulation triggered by OVA were reduced by BQ-123 (150 pmol/cavity) or bosentan (68 and 43% inhibition of eosinophilia), but unaffected by BQ-788. BQ-123 and bosentan also inhibited LPS increases in neutrophil (by 67 and 40%) and eosinophil (by 63 and 74%) at 24 h.¶Conclusions: Endothelins, acting via ETA receptors, play a role in late eosinophil and neutrophil accumulation (24h), but not in the acute (4h) neutrophilic response.

Synthesis and antimalarial activity of hydroxyethylpiperazine derivatives

The antimalarial activity of hydroxyethylpiperazine derivatives, synthesized from the reaction of (2S,3S)Boc-phenylalanine epoxide with benzylpiperazines in good yields (76-96%), has been evaluated in vitro against the Plasmodium falciparum W2 clone (chloroquine resistant). The results show that some compounds have moderate activity against this parasite and none of the active compounds showed cytotoxicity at high concentration (100 microg/ml).

Endothelin-1 inhibits PAF-induced paw oedema and pleurisy in the mouse

1 The current study analyses the effects of endothelin‐1 (ET‐1) on paw oedema and pleurisy induced by platelet activating factor (PAF) and other inflammatory agents in the mouse. 2 Combined subplantar injection of ET‐1 (0.5 pmol/paw) did not modify oedema caused by histamine (1 to 100 μmol/paw), 5‐hydroxytryptamine (1 to 100 μmol/paw) or bradykinin (1 to 100 nmol/paw) but markedly inhibited the response to PAF (0.95 to 3.8 nmol/paw). The selective action of ET‐1 against PAF‐induced (1.9 nmol/paw) oedema was dose‐dependent, reaching a maximum at 0.5 pmol/paw and lasted up to 2 h. 3 ET‐1 (0.5 pmol/paw) also inhibited paw oedema (3–4 h) caused by zymosan (500 μg/paw). In contrast, it did not modify either the early (1–4h) or late (48–72 h) phases of the oedematogenic response to carrageenin (300 μg/paw), when given either together with or 24 h after the carrageenin. 4 Intrathoracic injection of PAF (1.9 nmol/cavity) induced pleurisy characterized by an increase in pleural exudate volume, and in accumulation of Evans Blue which was maximal at 30 min and lasted up to 4h. When injected together with PAF, ET‐1 (0.5 pmol/cavity) virtually abolished PAF‐induced pleurisy. 5 It is concluded that ET‐1 is a potent inhibitor of PAF‐induced inflammation in the mouse. Its mechanism of anti‐inflammatory action in this species, in contrast to what has been found in other species, does not appear to derive from its potent vasoconstrictor properties as ET‐1, at the doses used, failed to affect oedematogenic responses to other inflammatory mediators.