Extract of Solidago chilensis Meyen inflorescences: cytotoxicity and inhibitory activity on nitric oxide synthesis in activated macrophage cell line J774A. 1

Solidago chilensis Meyen (= Solidago microglossa) popularly known as "Brazilian arnica" is used to treat of inflammatory disorders. S. chilensis is constant in the Therapeutic Memento of the Rio de Janeiro city and belongs to the medicinal species of Brazilian National List of Medicinal Plants of Interest of the Unified National Health System (SUS). There are no studies in the literature showing the direct activity of this plant species on immune system cells. The present study evaluated the chemical composition as well as the cytotoxic and pharmacological activity of the ether-ethanol extract from S. chilensis inflorescences (SCIE) in murine macrophage cell line J774A.1. The results showed that higher concentrations (50 to 200 µg/mL) of SCIE had significant cytotoxicity on J774A.1 cells, however, lower concentrations (from 10 to 0.1 µg/mL) did not produce significant cytotoxic effects and exhibited an inhibitory effect on nitric oxide production in LPS-stimulated J774A.1 cell line. The chemical analysis by HPLC-UV-PDA indicated that the SCIE contains flavonoid derived from quercetin and kaempferol; and diterpenes, probably labdanes. These findings complement data in the literature regarding the activity of this plant species on an important cell from the immune system involved in the innate and acquired immune response, the macrophages.

Role of P2 Receptors as Modulators of Rat Eosinophil Recruitment in Allergic Inflammation.

ATP and other nucleotides are released from cells through regulated pathways or following the loss of plasma membrane integrity. Once outside the cell, these compounds can activate P2 receptors: P2X ionotropic receptors and G protein-coupled P2Y receptors. Eosinophils represent major effector cells in the allergic inflammatory response and they are, in fact, associated with several physiological and pathological processes. Here we investigate the expression of P2 receptors and roles of those receptors in murine eosinophils. In this context, our first step was to investigate the expression and functionality of the P2X receptors by patch clamping, our results showed a potency ranking order of ATP>ATPγS> 2meSATP> ADP> αßmeATP> ßγmeATP>BzATP> UTP> UDP>cAMP. This data suggest the presence of P2X1, P2X2 and P2X7. Next we evaluate by microfluorimetry the expression of P2Y receptors, our results based in the ranking order of potency (UTP>ATPγS> ATP > UDP> ADP >2meSATP > αßmeATP) suggests the presence of P2Y2, P2Y4, P2Y6 and P2Y11. Moreover, we confirmed our findings by immunofluorescence assays. We also did chemotaxis assays to verify whether nucleotides could induce migration. After 1 or 2 hours of incubation, ATP increased migration of eosinophils, as well as ATPγS, a less hydrolysable analogue of ATP, while suramin a P2 blocker abolished migration. In keeping with this idea, we tested whether these receptors are implicated in the migration of eosinophils to an inflammation site in vivo, using a model of rat allergic pleurisy. In fact, migration of eosinophils has increased when ATP or ATPγS were applied in the pleural cavity, and once more suramin blocked this effect. We have demonstrated that rat eosinophils express P2X and P2Y receptors. In addition, the activation of P2 receptors can increase migration of eosinophils in vitro and in vivo, an effect blocked by suramin.

An Improved Method for P2X7R Antagonist Screening.

ATP physiologically activates the P2X7 receptor (P2X7R), a member of the P2X ionotropic receptor family. When activated by high concentrations of ATP (i.e., at inflammation sites), this receptor is capable of forming a pore that allows molecules of up to 900 Da to pass through. This receptor is upregulated in several diseases, particularly leukemia, rheumatoid arthritis and Alzheimer's disease. A selective antagonist of this receptor could be useful in the treatment of P2X7R activation-related diseases. In the present study, we have evaluated several parameters using in vitro protocols to validate a high-throughput screening (HTS) method to identify P2X7R antagonists. We generated dose-response curves to determine the EC50 value of the known agonist ATP and the ICs50 values for the known antagonists Brilliant Blue G (BBG) and oxidized ATP (OATP). The values obtained were consistent with those found in the literature (0.7 ± 0.07 mM, 1.3-2.6 µM and 173-285 µM for ATP, BBG and OATP, respectively) [corrected].The Z-factor, an important statistical tool that can be used to validate the robustness and suitability of an HTS assay, was 0.635 for PI uptake and 0.867 for LY uptake. No inter-operator variation was observed, and the results obtained using our improved method were reproducible. Our data indicate that our assay is suitable for the selective and reliable evaluation of P2X7 activity in multiwell plates using spectrophotometry-based methodology. This method might improve the high-throughput screening of conventional chemical or natural product libraries for possible candidate P2X7R antagonist or agonist.

Chemical profile and antinociceptive efficacy of Rheedia longifolia leaf extract.

Different species of the family Clusiaceae, including Rheedia longifolia, are used in folk medicine to treat inflammatory diseases. This family is largely distributed in tropical and subtropical areas of Brazil, but their chemical and pharmacological properties have been the subject of a few studies. In previous studies, we found that the aqueous extract from R. longifolia leaves presented important anti-inflammatory and analgesic activity. We investigated the chemical profile of R. longifolia and characterized the pharmacological effect of different chemically identified fractions in pharmacological models of neurogenic and inflammatory nociception. The pharmacological tests showed that oral treatment with aqueous crude extract and fractions of methanol extract of R. longifolia leaf induced a significant antinociceptive effect using von Frey filaments. In addition, the most polar fractions presented antinociceptive activity in a neurogenic model of nociception (capsaicin model). The chromatographic analysis indicated the presence of bisflavonoids in the fractions obtained from the methanol extract. These results suggest that bisflavonoids found in methanol-extracted fractions are involved in the inhibition of inflammatory and neurogenic nociception. It is important that the R. longifolia aqueous extract treatment inhibited ulcer formation induced by indomethacin, suggesting an anti-ulcerogenic activity closely associated with its analgesic effect.

Analgesic and anti-inflammatory activity of the aqueous extract of Rheedia longifolia Planch & Triana.

Rheedia longifolia Planch et Triana belongs to the Clusiaceae family. This plant is widely distributed in Brazil, but its chemical and pharmacological properties have not yet been studied. We report here that leaves aqueous extract of R. longifolia (LAE) shows analgesic and anti-inflammatory effects. Oral or intraperitoneal administration of this extract dose-dependently inhibited the abdominal constrictions induced by acetic acid in mice. The analgesic effect and the duration of action were similar to those observed with sodium diclofenac, a classical non-steroidal analgesic. In addition to the effect seen in the abdominal constriction model, LAE was also able to inhibit the hyperalgesia induced by lipopolysaccharide from gram-negative bacteria (LPS) in rats. We also found that R. longifolia LAE inhibited an inflammatory reaction induced by LPS in the pleural cavity of mice. Acute toxicity was evaluated in mice treated with the extract for seven days with 50 mg/kg/day. Neither death, nor alterations in weight, blood leukocyte counts or hematocrit were noted. Our results suggest that aqueous extract from R. longifolia leaves has analgesic and anti-inflammatory activity with minimal toxicity and are therefore endowed with a potential for pharmacological control of pain and inflammation.

Analgesic and anti-inflammatory activity of the aqueous extract of Rheedia longifolia Planch & Triana

Rheedia longifolia Planch et Triana belongs to the Clusiaceae family. This plant is widely distributed in Brazil, but its chemical and pharmacological properties have not yet been studied. We report here that leaves aqueous extract of R. longifolia (LAE) shows analgesic and anti-inflammatory effects. Oral or intraperitoneal administration of this extract dose-dependently inhibited the abdominal constrictions induced by acetic acid in mice. The analgesic effect and the duration of action were similar to those observed with sodium diclofenac, a classical non-steroidal analgesic. In addition to the effect seen in the abdominal constriction model, LAE was also able to inhibit the hyperalgesia induced by lipopolysaccharide from gram-negative bacteria (LPS) in rats. We also found that R. longifolia LAE inhibited an inflammatory reaction induced by LPS in the pleural cavity of mice. Acute toxicity was evaluated in mice treated with the extract for seven days with 50 mg/kg/day. Neither death, nor alterations in weight, blood leukocyte counts or hematocrit were noted. Our results suggest that aqueous extract from R. longifolia leaves has analgesic and anti-inflammatory activity with minimal toxicity and are therefore endowed with a potential for pharmacological control of pain and inflammation.