Browsing by Author "Alencar, Severino Matias"

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    Novel apocynin regulates TRPV1 activity in the trigeminal system and controls pain in a temporomandibular joint neurogenic model
    (2024) Machado, Taisa Maria Mendes Matuiama; Aquino, Iara Goncalves; Franchin, Marcelo; Zarraga, Miguel O.; Bustos, Daniel; Spada, Fernanda Papa; Napimoga, Marcelo Henrique; Clemente-Napimoga, Juliana Trindade; Alencar, Severino Matias; Benso, Bruna; Abdalla, Henrique Ballassini
    Objective: Herein, we investigate the potential analgesic effect of a newly synthesized chalcone-derived apocynin in a neurogenic pain model. Methods: Molecular docking was used to foretell the apocynin binding features and dynamics with the TRPV1 channel, and the activity was tested in vitro, using transfected HEK 293T cells with the rat TRPV1 receptor. The analgesic effect of apocynin was investigated using a capsaicin-induced pain model. The expression of TRPV1, TRPA1, TRPM8, and MAPKs was assessed by electrophoresis, and immunosorbent assays were performed to quantify the neurotransmitters Substance P, Glutamate, and CGRP. A survival assay using Galleria mellonella was carried out to determine the toxicity. Results: We observed that apocynin exhibits greater thermodynamic stability. Upon apocynin ligand binding, it changes the electrostatic potential for a predominantly electronegative state in the interior and neutral in its external vanilloid pocket. Treatment of apocynin induces antinociceptive effects against the noxious challenge of capsaicin. Histologically, apocynin decreased the number of TRPV1+ immunopositive cells. Electrophoresis showed reduced phosphorylation of p44/42 (ERK1/2) and decreased protein levels of substance P, and CGRP. In the survival assay, apocynin showed low toxicity. Conclusions: In conclusion, we provide proof-of-principles that the newly synthesized apocynin compound effectively prevented nociception in a neurogenic model of orofacial pain.
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    Should we ban total phenolics and antioxidant screening methods? The link between antioxidant potential and activation of NF-κB using phenolic compounds from grape by-products
    (2019) de Camargo, Adriano Costa; Telles Biasoto, Aline Camarao; Schwember, Andres R.; Granato, Daniel; Rasera, Gabriela Boscariol; Franchin, Marcelo; Rosalen, Pedro L.; Alencar, Severino Matias; Shahidi, Fereidoon
    Free radical imbalance is associated with several chronic diseases. However, recent controversies have put in check the validity of colorimetric methods to screen the functionality of polyphenols. Therefore, in this study two antioxidant methods, based on chemical reactions, were tested for their ability in anticipating the reduction of the activation of NF-kappa 3 using LPS-activated RAW 264.7 macrophages, selected as a biological model. Grape processing by-products from winemaking showed higher total phenolic content (TPC), antioxidant capacity towards peroxyl radical (31.1%) as well as reducing power (39.5%) than those of grape juice by-products. The same trend was observed when these samples were tested against LPS-activated RAW 264.7 macrophages by reducing the activation NF-kappa B. Feedstocks containing higher TPC and corresponding ORAC and FRAP results translated to higher reduction in the activation of NF-kappa 3 (36.5%). Therefore, this contribution demonstrates that colorimetric methods are still important screening tools owing their simplicity and widespread application.