Biological and Molecular Docking Evaluation of a Benzylisothiocyanate Semisynthetic Derivative From Moringa oleifera in a Pre-clinical Study of Temporomandibular Joint Pain.

Objective: Moringa oleifera possesses multiple biological effects and the 4-[(4'-O-acetyl-α-L- rhamnosyloxy) benzyl] isothiocyanate accounts for them. Based on the original isothiocyanate molecule we obtained a semisynthetic derivative, named 4-[(2',3',4'-O-triacetyl-α-L-rhamnosyloxy) N-benzyl] hydrazine carbothioamide (MC-H) which was safe and effective in a temporomandibular joint (TMJ) inflammatory hypernociception in rats. Therefore, considering that there is still a gap in the knowledge concerning the mechanisms of action through which the MC-H effects are mediated, this study aimed to investigate the involvement of the adhesion molecules (ICAM-1, CD55), the pathways heme oxygenase-1 (HO-1) and NO/cGMP/PKG/K+ ATP, and the central opioid receptors in the efficacy of the MC-H in a pre-clinical study of TMJ pain. Methods: Molecular docking studies were performed to test the binding performance of MC-H against the ten targets of interest (ICAM-1, CD55, HO-1, iNOS, soluble cGMP, cGMP-dependent protein kinase (PKG), K+ ATP channel, mu (µ), kappa (κ), and delta (δ) opioid receptors). In in vivo studies, male Wistar rats were treated with MC-H 1 µg/kg before TMJ formalin injection and nociception was evaluated. Periarticular tissues were removed to assess ICAM-1 and CD55 protein levels by Western blotting. To investigate the role of HO-1 and NO/cGMP/PKG/K+ ATP pathways, the inhibitors ZnPP-IX, aminoguanidine, ODQ, KT5823, or glibenclamide were used. To study the involvement of opioid receptors, rats were pre-treated (15 min) with an intrathecal injection of non-selective inhibitor naloxone or with CTOP, naltrindole, or norbinaltorphimine. Results: All interactions presented acceptable binding energy values (below -6.0 kcal/mol) which suggest MC-H might strongly bind to its molecular targets. MC-H reduced the protein levels of ICAM-1 and CD55 in periarticular tissues. ZnPP-IX, naloxone, CTOP, and naltrindole reversed the antinociceptive effect of MC-H. Conclusion: MC-H demonstrated antinociceptive and anti-inflammatory effects peripherally by the activation of the HO-1 pathway, as well as through inhibition of the protein levels of adhesion molecules, and centrally by µ and δ opioid receptors.

A Systematic Review of the Potential Effects of Lippia sidoides on Dental Plaque and Periodontal Diseases.

Lippia sidoides is a typical shrub from Brazil that has been used in traditional medicine. This is a systematic review on the effect of L. sidoides for controlling dental plaque, gingivitis, and periodontitis. A database search through May 2021 in Medline/PubMed, SCOPUS, BVS, and Web of Science identified 711 reports of which 17 met our inclusion criteria. Five randomized controlled trials and three animal studies were included that compared L. sidoides-based products (toothpaste, mouthrinse, and gel) to cetylpyridinium chloride, chlorhexidine, and placebo products. Among the human studies, a significant antiplaque effect after treatment with L. sidoides-based products was observed in three studies and an antigingivitis effect in two studies, similar to chlorhexidine-based products. One study found superior dental plaque reduction compared to cetylpyridinium chloride mouthrinse. Only one study testing a L. sidoides gel found no antiplaque effect. Among the animal studies, an L. sidoides mouthrinse significantly reduced calculus in two studies, inflammatory infiltrate in one study, and plaque bacteria and gingivitis in one study. An L. sidoides gel significantly reduced alveolar bone loss and inflammatory response in one study in which mice were submitted to ligature-induced periodontal disease. In general, L. sidoides-based products were effective in reducing dental plaque and calculus formation, as well as clinical signs of gingivitis. As most studies present methodological limitations, these results should be interpreted carefully. Further clinical trials with greater methodological accuracy and control of biases are necessary for the use of L. sidoides-based products in humans to be viable in clinical practice.

Sulfated polysaccharide from the green marine algae Caulerpa racemosa reduces experimental pain in the rat temporomandibular joint.

Temporomandibular disorder is a clinical painful condition in the temporomandibular joint (TMJ) region. The purified sulfated polysaccharide from the green marine algae Caulerpa racemosa (Cr) has provided anti-inflammatory and antinociceptive activity. This study evaluated these effects on a TMJ hypernociception model. Wistar rats (180 - 250 g) were pre-treated (i.v.) with Cr at 0.01, 0.1, or 1 mg/kg or vehicle 30 min before formalin (1.5%/50 µL, i.art.), capsaicin (1.5%/20 µL, i.art.), or serotonin (225 µg/50 µL, i.art.) in the TMJ, and nociceptive behaviors were measured for 45 or 30 min upon inflammatory stimuli. Inflammatory parameters vascular permeability assay, TNF-α, and IL-1ß by ELISA, protein expression of adhesion molecules ICAM-1 and CD55 by Western blot were assessed. The involvement of heme oxygenase-1 (HO-1) and nitric oxide (NO) pathways were assessed by pharmacological inhibition. Cr (1 mg/kg) reduced nociceptive behavior, plasmatic extravasation, TNF-α, and IL-1ß levels, as well as ICAM-1 and CD55 expression in periarticular tissues. Cr antinociceptive effect was not prevented by aminoguanidine, but ZnPP-IX did reduce its antinociceptive effect. Therefore, Cr antinociceptive and anti-inflammatory effects in this experimental model of hypernociception depended on the HO-1 pathway integrity, as well as reducing peripheral inflammatory events, e.g., TNF-α and IL-1ß cytokines levels, ICAM-1 and CD55 expression.

A lectin fraction from green seaweed Caulerpa cupressoides inhibits inflammatory nociception in the temporomandibular joint of rats dependent from peripheral mechanisms.

Temporomandibular disorders are the second most common cause of orofacial pain mediated by inflammatory compounds, which in many cases leads to chronic orofacial pain. This study assessed the antinociceptive and anti-inflammatory effects of a lectin from the green seaweed Caulerpa cupressoides (CcL) on hypernociception inflammatory in TMJ of rats and investigated the involvement of different mechanisms. Rats received i.v. CcL 30 min prior to injection of flogistic agentes or 0.9% saline into the left TMJ. Pretreatment with CcL (0. 1; 1 or 10 mg/kg) promoted a reduction (p < 0.05) of inflammatory hypernociception induced by 1.5% Formalin along with inhibition of inflammatory plasma extravasation, cytokines levels, ciclooxigenase-2, and intercellular adhesion molecule (ICAM-1). CcL was able to inhibit the nociceptive response induced by 1.5% Capsaicin, suggesting that CcL has an antinociceptive effect, acting directly on the primary nociceptive neurons. CcL also inhibited the nociceptive response induced by Carrageenan (100 µg/TMJ) or Serotonin (5-HT) (225 µg/TMJ). In conclusion, the results demonstrate that administration of CcL has a potential antinociceptive and anti-inflammatory effect, with a mechanism that is partially dependent on TNF-α, IL-1ß, COX-2 and ICAM-1 inhibition and independently from the cannabinoide and opioid system and NO/cGMP/PKG/K+ATP channel pathway.

Antinociceptive, anti-inflammatory and toxicological evaluation of semi-synthetic molecules obtained from a benzyl-isothiocyanate isolated from Moringa oleifera Lam. in a temporomandibular joint inflammatory hypernociception model in rats.

Inflammation is a key component of many clinical conditions that affect the temporomandibular joint (TMJ) and Moringa oleifera Lam. has been used to treat inflammatory diseases. Here, we evaluated the toxicological effects on mice of a naturally-occurring isothiocyanate from M. oleifera and its seven analogue molecules. Further, the anti-nociceptive and anti-inflammatory effects on a rat model of TMJ inflammatory hypernociception were assessed. The systemic toxicological profile was determined in mice over a 14-day period: MC-1 1 µg/kg; MC-D1 1 µg/kg, MC-D3 100 µg/kg, MC-D6 1 µg/kg, MC-D7 1 µg/kg, MC-D8 1 µg/kg, MC-D9 10 µg/kg, and MC-H 1 µg/kg. The safest molecules were assayed for anti-nociceptive efficacy in the formalin (1.5%, 50 µL) and serotonin (255 mg) induced TMJ inflammatory hypernociception tests. The anti-inflammatory effect was evaluated through the vascular permeability assay using Evans blue. Further, the rota-rod test evaluated any motor impairment. Among the tested molecules, MC-D7, MC-D9, and MC-H were not toxic at the survival rate test, biochemical, and hystological analysis. They reduced the formalin-induced TMJ inflammatory hypernociception, but only MC-H decreased the serotonin-induced TMJ inflammation, suggesting an adrenergic receptor-dependent effect. They diminished the plasmatic extravasation, showing anti-inflammatory activity. At the rota-rod test, no difference was observed in comparison with control groups, reinforcing the hypothesis of anti-nociceptive effetc without motor impairment in animals. The analogues MC-D7, MC-D9, and MC-H were safe at the tested doses and efficient in reducing the formalin-induced TMJ hypernociception in rats. Our next steps include determining their mechanisms of anti-nociceptive action.

Mechanisms involved in antinociception induced by a polysulfated fraction from seaweed Gracilaria cornea in the temporomandibular joint of rats.

Temporomandibular disorder is a common clinical condition involving pain in the temporomandibular joint (TMJ) region. This study assessed the antinociceptive effects of a polysulfated fraction from the red seaweed Gracilaria cornea (Gc-FI) on the formalin-induced TMJ hypernociception in rats and investigated the involvement of different mechanisms. Male Wistar rats were pretreated with injection (sc) of saline or Gc-FI 1h before intra- TMJ injection of formalin to evaluate the nociception. The results showed that pretreatment with Gc-FI significantly reduced formalin-induced nociceptive behavior. Moreover, the antinociceptive effect of the Gc-FI was blocked by naloxone (a non-selective opioid antagonist), suggesting the involvement of opioids selective receptors. Thus, the pretreatment with selective opioids receptors antagonists, reversed the antinociceptive effect of the Gc-FI in the TMJ. The Gc-FI antinociceptive effect depends on the nitric oxide/cyclic GMP/protein kinase G/ATP-sensitive potassium channel (NO/cGMP/PKG/K+ATP) pathway because it was prevented by pretreatment with inhibitors of nitric oxide synthase, guanylate cyclase enzyme, PKG and a K+ATP blocker. In addition, after inhibition with a specific heme oxygenase-1 (HO-1) inhibitor, the antinociceptive effect of the Gc-FI was not observed. Collectively, these data suggest that the antinociceptive effect induced by Gc-FI is mediated by µ/δ/κ-opioid receptors and by activation NO/cGMP/PKG/K+ATP channel pathway, besides of HO-1.