Antinociceptive and anti-inflammatory activities of standardized extract of polymethoxyflavones from Ageratum conyzoides.

ETHNOPHARMACOLOGICAL RELEVANCE: Ageratum conyzoides L. is a plant widely used in traditional medicine in tropical and subtropical regions of the world due to its anti-inflammatory, antinociceptive and antibacterial properties. AIM OF THE STUDY: To characterize the standardized extract of polymethoxyflavones (SEPAc) from the plant and evaluate its antinociceptive and anti-inflammatory effects. MATERIALS AND METHODS: The SEPAc purified from the ethanol extract of the plant leaves was characterized by high resolution mass spectrometry and the methoxyflavones were quantified by a validated UPLC-PDA method. The antinociceptive and anti-inflammatory activities of the SEPAc were evaluated after oral administration on the acute nocifensive behavior of mice induced by formalin, prostaglandin E2 (PGE2) and proinflammatory cytokines (interleukin-1beta (IL-1ß)) and tumor necrosis factor-alpha (TNF-α) in mice. RESULTS: Qualitative analyses revealed the presence of seven methoxyflavones in the SEPAc, also a simple UPLC-PDA method was developed and validated for the quantification of 5,6,7,3',4',5'-hexametoxyflavone; nobiletin; 5'-methoxynobiletin and eupalestin, major compounds in the extract. The SEPAc exhibited antinociceptive and anti-inflammatory activities in both formalin phases, with significant inhibition of the paw edema formation and significant reduction of the nocifensive response induced by an intraplantar injection of PGE2 and intrathecal injection of interleukin-1ß. CONCLUSIONS: The SEPAc exhibited significant antinociceptive and anti-inflammatory effects. These results provided scientific suggestion of its potential as a source of new medicines to treat inflammatory diseases, such rheumatoid arthritis.

Antinociceptive effect of hydroalcoholic extract and isoflavone isolated from Polygala molluginifolia in mice: evidence for the involvement of opioid receptors and TRPV1 and TRPA1 channels.

PURPOSE: The plants of the genus Polygala (Polygalaceae) have been used for a long time in folk medicine to treat pain and inflammation. The species Polygala molluginifolia is native to southern Brazil and is popularly known as "cânfora". The presented study analyzes the antinociceptive effect of hydroalcoholic extract from Polygala molluginifolia (HEPm) and an isoflavone (ISO) isolated from the extract, in behavioral models of pain in mice, as well as the mechanism underlying this effect. MATERIALS AND METHODS: The phytochemical analysis of HEPm was performed through a capillary electrophoresis analysis and colorimetric test. The antinociceptive effects of HEPm and ISO (10-1000 mg/kg, i.g.) were evaluated by applying the formalin test; mechanical and thermal hyperalgesia to postoperative pain in mice. The possible involvement of opioid receptors, TRPV1 and TRPA1 channels in the antinociceptive effect of HEPm and ISO were also evaluated. Finally, the nonspecific effects of HEPm and ISO were evaluated by measuring locomotor activity (Open-field Test) and corporal temperature. RESULTS: The 5,3',4'-trihydroxy-6″,6″-dimethylpyrano[2″,3″:7,6] isoflavone (ISO) was identified in HEPm by capillary electrophoresis analysis and selected for the experimental tests. The oral administration of HEPm or of ISO significantly inhibited the neurogenic and inflammatory phases of formalin-induced pain, edema formation and local hyperemia, without causing any change to locomotor activity. Acute and repeated treatment of animals with HEPm reduced mechanical and thermal (heat and cold) hyperalgesia in the postoperative pain. In addition, administering HEPm or ISO markedly reduced nociceptive behavior induced by the peripheral and central injection of TRPV1 and TRPA1 channels activators. Finally, the antinociception provided by the administration of HEPm or ISO was reversed by the preadministration of naloxone. CONCLUSIONS: Taken together, these results provide the first experimental evidence of the significant antinociceptive effect of HEPm and ISO in animal models of acute pain without causing sedation or locomotor dysfunction. This effect appears to be mediated, at least in part, by the activation of opioid receptors and/or by the inhibition of TRPV1 and TRPA1 channels. Moreover, this study adds new scientific evidence and highlights the therapeutic potential of the medicinal plant Polygala molluginifolia in the development of phytomedicines with analgesic properties.

Substituted galacturonan from starfruit: Chemical structure and antinociceptive and anti-inflammatory effects.

Starfruit (Averrhoa carambola L.) is an edible tropical fruit, which is usually consumed as a fresh table fruit or as fruit juice. It also exhibits various pharmacological activities. In this study, polysaccharides were extracted with boiling water and purified by freeze-thawing and Fehling treatments. After purification steps, a homogenous fraction was obtained. It was analyzed by sugar composition, gel permeation chromatography, methylation, and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy analyses. It comprised arabinose (Ara), galactose (Gal), and galacturonic acid (GalA) in a molar ratio of 12.3:1.7:86.0. Methylation and NMR spectroscopy analyses showed that it contained a substituted galacturonan composed of (1→4)-linked α-D-Galp A units branched at O-2 by (1→5)-linked α-L-Araf and terminal α-L-Araf and α-D-Galp A units. The effect of PFSCW (10-300mg/kg, i.p.) on nocifensive behavior induced by intraplantar injection of formalin in mice was evaluated. The fraction demonstrated antinociceptive and anti-inflammatory properties, suggesting that it may be useful in therapeutic intervention for the management of inflammatory pain.

Ameliorative potential of standardized fruit extract of Pterodon pubescens Benth on neuropathic pain in mice: Evidence for the mechanisms of action.

ETHNOPHARMACOLOGICAL RELEVANCE: The medicinal plant Pterodon pubescens Benth has been traditionally used for a long time to treat rheumatic diseases due to its anti-inflammatory and analgesic activities. The present study aims to evaluate the antinociceptive effect of ethanolic extract from P. pubescens fruits (EEPp) in a model of neuropathic pain in mice. MATERIALS AND METHODS: The phytochemical analysis of EEPp was performed through GC-MS, HPLC and colorimetric analysis. The antinociceptive effects of EEPp (30-300 mg/kg, i.g.) were evaluated on mechanical and thermal (cold or heat) hyperalgesia in neuropathic pain induced by partial sciatic nerve ligation (PSNL) in mice. We also investigated the effects of EEPp on the nociceptive response induced by intrathecal injection (i.t.) of ionotropic (AMPA, NMDA and kainate) and metabotropic (trans-ACPD) glutamate receptor agonists, proinflammatory cytokines such as IL-1ß and TNF-α, as well as TRPV1 and TRPA1 agonists. In addition, we also investigated the safety profile of prolonged treatment with EEPp in mice. RESULTS: The phytochemical analysis showed a higher amount terpenes, being nine sesquiterpenes and seven diterpenes with vouacapan skeletons, as well as a small amount of phenols and flavonoids. The exact mechanism by which EEPp promotes its antinociceptive effect is not yet fully understood, but its oral administration causes significant inhibition of glutamate-, kainate-, NMDA-, trans-ACPD-induced biting responses, as well as of proinflammatory cytokines (TNF-α and IL-1ß) and TRPV1 and TRPA1 channels activators (capsaicin and cinnamaldehyde, respectively). These results may indicate, at least in part, some of the mechanisms that are involved in this effect. In particular, EEPp decreases neuropathic pain and clearly shows, for the first time, a thermal and mechanical hyperalgesia reduction in the model of partial sciatic nerve ligation (PSNL), without inducing tolerance. Furthermore, the prolonged treatment with EEPp (300 mg/kg, i.g.) showed a cumulative effect over 24h, in the 15th day, after last treatment. In addition, the open-field test showed that doses up to 300 mg/kg in both treatments, acute and/or prolonged, did not affect the motor activity of mice. Also, EEPp showed no toxicity according to the serum levels of the renal and hepatic injury indicators or observed macroscopic organs, after PSNL. CONCLUSIONS: Taken together, these results provide the first experimental evidence of the significant antinociceptive effect of EEPp on neuropathic pain without causing side effects, such as sedation or locomotor dysfunction. Moreover, these results appear to be mediated, at least in part, by the inhibition of glutamatergic receptors, TRPV1 and TRPA1 channels and proinflammatory cytokines. Thus, this study adds new scientific evidence and highlights the therapeutic potential of the medicinal plant P. pubescens in the development of phytomedicines for the management of neuropathic pain.

N-(1'-naphthyl)-3,4,5-trimethoxybenzohydrazide as microtubule destabilizer: Synthesis, cytotoxicity, inhibition of cell migration and in vivo activity against acute lymphoblastic leukemia.

Tubulin-interacting agents, like vinca alkaloid and taxanes, play a fundamental role in cancer chemotherapy, making cellular microtubules (MT), one of the few validated anticancer targets. Cancer resistance to classical MT inhibitors has motivated the development of novel molecules with increased efficacy and lower toxicity. Aiming at designing structurally-simple inhibitors of MT assembly, we synthesized a series of thirty-one 3,4,5-trimethoxy-hydrazones and twenty-five derivatives or analogs. Docking simulations suggested that a representative N-acylhydrazone could adopt an appropriate stereochemistry inside the colchicine-binding domain of tubulin. Several of these compounds showed anti-leukemia effects in the nanomolar concentration range. Interference with MT polymerization was validated by the compounds' ability to inhibit MT assembly at the biochemical and cellular level. Selective toxicity investigations done with the most potent compound, a 3,4,5-trimethoxy-hydrazone with a 1-naphthyl group, showed remarkably selective toxicity against leukemia cells in comparison with stimulated normal lymphocytes, and no acute toxicity in vivo. Finally, this molecule was as active as vincristine in a murine model of human acute lymphoblastic leukemia at a weekly dose of 1 mg/kg.

Chemical constituents from three medicinal plants: Piper renitens, Siparuna guianensis and Alternanthera brasiliana

Chemical study of three medicinal plants: from leaves of Piper renitens (Miq.) Yunck, Piperaceae, and Siparuna guianensis Aubl., Siparunaceae, and from flowers of Alternanthera brasiliana (L.) Kuntze, Amaranthaceae, resulted in isolation of nine compounds: three steroids, β-sitosterol, stigmasterol from P. renitens and sitosterol-3-O-β-D-glucopyranoside from A. brasiliana, the diterpene kaurane ent-kauran-16α,17-diol from P. renitens, two derivatives kaempferol-methylether, kumatakenine (kaempferol-3,7-dimethylether) and kaempferol-3,7,3'-trimethylether from S. guianensis and three flavones, crysoeriol (5,7,4'-trihydroxy-3'-methoxyflavone), tricin (5,7,4'-trihydroxy-3',5'-dimethoxyflavone) and 7-O-β-D-glucopyranoside-5,4'-dihydroxy-3'-methoxyflavone from A. brasiliana. Compounds structures were determinate using 1D and 2D ¹H NMR and 13C spectral data, mass and IR spectra, comparing with literature data.