Publications by authors named "Pedro T R Figueiredo"

2 Publications

  • Page 1 of 1

MHTP, a synthetic alkaloid, attenuates combined allergic rhinitis and asthma syndrome through downregulation of the p38/ERK1/2 MAPK signaling pathway in mice.

Int Immunopharmacol 2021 Apr 13;96:107590. Epub 2021 Apr 13.

Laboratory of Immunopharmacology, Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraíba, João Pessoa, PB, Brazil; Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, PB, Brazil. Electronic address:

The combined allergic rhinitis and asthma syndrome (CARAS) is a chronic airway inflammation of allergic individuals, with a type 2 immune response. Pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study was to evaluate the synthetic alkaloid, MHTP in the experimental model of CARAS. Therefore, BALB/c mice were ovalbumin (OVA) -sensitized and -challenged and treated with MHTP by intranasal or oral routes. Treated animals showed a decrease (p < 0.05) of sneezing, nasal rubbings, and histamine nasal hyperactivity. Besides, MHTP presented binding energy and favorable interaction for adequate anchoring in the histamine H1 receptor. MHTP treatment inhibited the eosinophil migration into the nasal (NALF) and the bronchoalveolar (BALF) fluids. Histological analysis showed that the alkaloid decreased the inflammatory cells in the subepithelial and perivascular regions of nasal tissue and in the peribronchiolar and perivascular regions of lung tissue. The MHTP treatment also reduced the pulmonary hyperactivity by decreasing the smooth muscle layer hypertrophy and the collagen fiber deposition in the extracellular matrix. The immunomodulatory effect of the alkaloid was due to the decrease of cytokines like IL-5 and IL-17A (type 2 and 3), TSLP (epithelial), and the immunoregulatory cytokine, TGF-β. These MHTP effects on granulocytes were dependent on the p38/ERK1/2 MAP kinase signaling pathway axis. Indeed, the synthetic alkaloid reduced the frequency of activation of both kinases independent of the NF-κB (p65) pathway indicating that the molecule shut down the intracellular transduction signals underlie the cytokine gene transcription.
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http://dx.doi.org/10.1016/j.intimp.2021.107590DOI Listing
April 2021

Modulation of the antibiotic activity against multidrug resistant strains of coumarins isolated from Rutaceae species.

Microb Pathog 2017 Mar 19;104:151-154. Epub 2017 Jan 19.

Departamento de Ciências Farmacêuticas, Universidade Federal da Paraíba, João Pessoa, Brazil. Electronic address:

The first occurrences and dissemination of resistant microorganisms led to the inefficacy of many antibiotics, available in the market nowadays, therefore, the search for new substances with antimicrobial activity from natural sources has gained a great importance. The purpose of this work is to evaluate the antibacterial activity and modulation of drug resistance in Staphylococcus aureus by coumarins such as bergapten, xantotoxin, isopimpinellin and imperatorin obtained from two Rutaceae species (Metrodorea mollis and Pilocarpus spicatus). The antimicrobial activity was assessed based on the minimum inhibitory concentration (MIC), using the microdilution method. The MIC was >256 g/mL for all coumarins tested. Regarding the modulation of drug resistance assay, the isopimpinellin reducted the MIC of erytromicin by 4 times, whereas imperatorin exhibited the best result, reducing the MIC of tetracycline (2 times), erytomicin (4 times) and norfloxacin (4 times). By reducing the MIC of ethidium bromide, the imperatorin is consider in fact, as a putative efflux pump inhibitor of bacteria.
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http://dx.doi.org/10.1016/j.micpath.2017.01.028DOI Listing
March 2017