Antinociceptive Effects of Aza-Bicyclic Isoxazoline-Acylhydrazone Derivatives in Different Models of Nociception in Mice.

BACKGROUND: In a study recently published by our research group, the isoxazoline-acylhydrazone derivatives R-99 and R-123 presented promising antinociceptive activity. However, the mechanism of action of this compound is still unknown. OBJECTIVE: This study aimed to assess the mechanisms involved in the antinociceptive activity of these compounds in chemical models of pain. METHODS: Animals were orally pretreated and evaluated in the acetic acid-, formalin-, capsaicin-, carrageenan- and Complete Freund's Adjuvant (CFA)-induced pain models in mice. The effects of the compounds after pretreatment with naloxone, prazosin, yohimbine, atropine, L-arginine, or glibenclamide were studied, using the acetic acid-induced writhing test to verify the possible involvement of opioid, α1-adrenergic, α2-adrenergic or cholinergic receptors, and nitric oxide or potassium channels pathways, respectively. RESULTS: R-99 and R-123 compounds showed significant antinociceptive activity on pain models induced by acetic acid, formalin, and capsaicin. Both compounds decreased the mechanical hyperalgesia induced by carrageenan or CFA in mice. The antinociceptive effects of R-99 and R-123 on the acetic acid-induced writhing test were significantly attenuated by pretreatment with naloxone, yohimbine or atropine. R-99 also showed an attenuated response after pretreatment with atropine and glibenclamide. However, on the pretreatment with prazosin, there was no change in the animals' response to both compounds. CONCLUSION: R-99 and R-123 showed antinociceptive effects related to mechanisms that involve, at least in part, interaction with the opioid and adrenergic systems and TRPV1 pathways. The compound R-99 also interacts with the cholinergic pathways and potassium channels.

Evaluation of anti-inflammatory activity and molecular docking study of new aza-bicyclic isoxazoline acylhydrazone derivatives.

The aim of this study was to investigate the anti-inflammatory effects of two new isoxazoline-acylhydrazone derivatives: N'-(4-methoxybenzylidene)-6-(4-nitro-benzoyl)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,2-d]isoxazole-3-carbohydrazide (R-123) and N'-(4-chlorobenzylidene)-6-(4-chlorobenzoyl)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,2-d]isoxazole-3-carbohydrazide (R-99). An air pouch induced by carrageenan was used for screening the best dose of R-99 and R-123. Using this mouse model, leukocyte migration and cytokine levels (TNF-α and IL-1ß) were determined. Paw edema induced by several phlogistic agents and vascular permeability induced by acetic acid were employed to investigate the mechanism of action of the isoxazoline-acylhydrazone derivatives. A docking study was performed with the human histamine H1 receptor to investigate potential antihistaminic activity. Treatment with the compounds reduced leukocyte migration in the air pouch at all doses tested. TNF-α and IL-1ß levels were similarly reduced by the two compounds. Vasoactive amines were inhibited in models of paw edema induced by several agents and vascular permeability induced by acetic acid. The docking study suggests that R-99 and R-123 may be inhibitors of the histamine H1 receptor. In conclusion, the results indicate that R-99 and R-123 exhibit promising anti-inflammatory activity related to their ability to inhibit TNF-α, IL-1ß, and vasoactive amine production, as well as reduce leukocyte migration and inhibit mast cell degranulation.

Anti-inflammatory and antinociceptive activities of the leaf methanol extract of Miconia minutiflora (Bonpl.) DC. and characterization of compounds by UPLC-DAD-QTOF-MS/MS.

Some species of the genus Miconia are used in Brazilian folk medicine as analgesic and anti-inflammatory; however, several species of this genus are still poorly studied. Therefore, the aims of this study were to investigate the phytochemistry characterization by UPLC-DAD-QTOF-MS/MS, acute toxicity, anti-inflammatory and antinociceptive properties of Miconia minutiflora (Bonpl.) DC. The methanol extract of M. minutiflora (Mm-MeOH) was subjected to ultra-high-performance liquid chromatography (UPLC-DAD-QTOF-MS/MS) for the identification of the main phytocompounds. The anti-inflammatory properties of the extracts were studied using several inflammation models induced by carrageenan and acetic acid-induced vascular permeability. Antinociceptive effects of Mm-MeOH were assessed in nociception induced by intraperitoneal acetic acid or subplantar formalin injection. The role of α-adrenergic, cholinergic, and opioid receptors in modulating the extract's antinociceptive activity was determined. Analyses by UPLC-DAD-QTOF-MS/MS revealed the presence of ellagic acid, gallotannin, and terpenes in the methanol extract. Mm-MeOH (100 mg/kg) reduced carrageenan-induced paw edema and vascular permeability and inhibited leukocyte migration toward the air pouch and pleural cavity. Furthermore, Mm-MeOH decreased tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) levels. Administration of Mm-MeOH reduced the number of writhes by 58.9% and increased the pain threshold in the formalin test. The anti-inflammatory action mechanism of Mm-MeOH is associated with inhibition of proinflammatory cytokines TNF-α and IL-1ß, whereas the antinociceptive actions involve peripheral and central mechanisms with participation of α2-adrenergic receptors. These effects may be attributed to the presence of polyphenolics in the extract.

New thiazolidinedione LPSF/GQ-2 inhibits NFκB and MAPK activation in LPS-induced acute lung inflammation.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are responsible for high mortality rates in critical patients. Despite >50 years of intensive research, there is no pharmacologically effective treatment to treat ALI. PPARs agonists, chemically named thiazolidinediones (TZDs) have emerged as potential drugs for the treatment of ALI and ARDS due to their anti-inflammatory efficacy. The present study aims to evaluate the potential anti-inflammatory effects of new TZDs derivatives, LPSF/GQ-2 and LPSF/RA-4, on ALI induced by LPS. BALB/c mice were divided into five groups: 1) Control; 2) LPS intranasal 25 µg; 3) LPSF/GQ-2 30 mg/kg + LPS; 4) LPSF/RA-4 20 mg/kg + LPS; and 5) DEXA 1 mg/Kg + LPS. BALF analyses revealed that LPSF/GQ-2 and LPSF/RA-4 reduced NO levels in BALF and inflammatory cell infiltration induced by LPS. MPO levels were also reduced by the LPSF/GQ-2 and LPSF/RA-4 pre-treatments. In contrast, histopathological analyses showed better tissue protection with LPSF/GQ-2 than DEXA and LPSF/RA-4 groups. Similarly, LPSF/GQ-2 reduced inflammatory markers (IL-1, iNOS, TNFα, IL-1ß, IL-6) better than LPSF/RA-4. The LPSF/GQ-2 anti-inflammatory action could be attributed to the inhibition of NFκB, ERK, p38, and PARP pathways. In contrast, LPSF/RA-4 had no effect on the expression of p38, JNK, NFκB. The present study indicates that LPSF/GQ-2 presents a potential therapeutic role as an anti-inflammatory drug for ALI.

Evaluation of cytotoxic and anti-inflammatory activities of extracts and lectins from Moringa oleifera seeds.

BACKGROUND: The extract from Moringa oleifera seeds is used worldwide, especially in rural areas of developing countries, to treat drinking water. M. oleifera seeds contain the lectins cmol and WSMoL, which are carbohydrate-binding proteins that are able to reduce water turbidity because of their coagulant activity. Studies investigating the ability of natural products to damage normal cells are essential for the safe use of these substances. This study evaluated the cytotoxic and anti-inflammatory properties of the aqueous seed extract, the extract used by population to treat water (named diluted seed extract in this work), and the isolated lectins cmol and WSMoL. METHODOLOGY/PRINCIPAL FINDINGS: The data showed that the aqueous seed extract and cmol were potentially cytotoxic to human peripheral blood mononuclear cells, while WSMoL and diluted seed extract were not cytotoxic. The M. oleifera aqueous seed extract and the lectins cmol and WSMoL were weakly/moderately cytotoxic to the NCI-H292, HT-29 and HEp-2 cancer cell lines and were not hemolytic to murine erythrocytes. Evaluation of acute toxicity in mice revealed that the aqueous seed extract (2.000 mg/kg) did not cause systemic toxicity. The aqueous seed extract, cmol and WSMoL (6.25 µg/mL) and diluted seed extract at 50 µg/mL exhibited anti-inflammatory activity on lipopolyssaccharide-stimulated murine macrophages by regulating the production of nitric oxide, TNF-α and IL-1ß. The aqueous seed extract reduced leukocyte migration in a mouse model of carrageenan-induced pleurisy; the myeloperoxidase activity and nitric oxide, TNF-α and IL-1ß levels were similarly reduced. Histological analysis of the lungs showed that the extract reduced the number of leukocytes. CONCLUSION/SIGNIFICANCE: This study shows that the extract prepared according to folk use and WSMoL may be non-toxic to mammalian cells; however, the aqueous seed extract and cmol may be cytotoxic to immune cells which may explain the immunosuppressive potential of the extract.