Antimicrobial effect of quercetin against Streptococcus pneumoniae

Streptococcus pneumoniae is a bacterium that causes serious infections, including pneumonia. The limited range of available vaccines and the rise of antibiotic-resistant bacteria mean that new treatments are needed. This study looked at the potential of quercetin as an antimicrobial agent against S. pneumoniae in both isolation and in biofilms. The researchers used microdilution tests, checkerboard assays, and death curve assays, as well as in silico and in vitro cytotoxicity evaluations. They found that quercetin at a concentration of 125.0 μg/mL had both inhibitory and bactericidal effects against S. pneumoniae, and these effects were increased when quercetin was combined with ampicillin. Quercetin also reduced the growth of pneumococcal biofilms. In addition, quercetin (absence or in combination with ampicillin) reduced the death time of Tenebrio molitor larvae compared to the infection control. The study also demonstrated that quercetin had low toxicity in both in silico and in vivo assays, suggesting that it could be a promising treatment for infections caused by S. pneumoniae.

Characterization, antimicrobial and cytotoxic activity of polymer blends based on chitosan and fish collagen

This study aims to produce, characterize, and assess the antimicrobial activity and cytotoxicity of polymer blends based on chitosan (CT) and fish collagen (COL) produced by different precipitation methods. Polymer blends were obtained in alkaline (NaOH), saline (NaCl), and alkaline/saline (NaOH/NaCl) solutions with different CT:COL concentration ratios (20:80, 50:50, and 80:20). The polymer blends were characterized by various physicochemical methods and subsequently evaluated in terms of their in vitro antimicrobial and cytotoxicity activity. In this study, the degree of chitosan deacetylation was 82%. The total hydroxyproline and collagen content in the fish matrix was 47.56 mg. g⁻¹ and 394.75 mg. g⁻¹, respectively. The highest yield was 44% and was obtained for a CT:COL (80:20) blend prepared by precipitation in NaOH. High concentrations of hydroxyproline and collagen in the blends were observed when NaOH precipitation was used. Microbiological analysis revealed that the strains used in this work were sensitive to the biomaterial; this sensitivity was dose-dependent and increased with increasing chitosan concentration in the products. The biocompatibility test showed that the blends did not reduce the viability of fibroblast cells after 48 h of culture. An analysis of the microbiological activity of the all-polymer blends showed a decrease in the values of minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) for S. aureus and P. aeruginosa. The blends showed biocompatibility with NIH-3T3 murine fibroblast cells and demonstrated their potential for use in biomedical applications such as wound healing, implants, and scaffolds.

Different precipitation methods do not change the biological properties of polymer blends.

Gram-positive bacterias and Pseudomonas aeruginosa were sensitive to polymer blends.

The blends produced showed biocompatibility in NIH-3T3 murine fibroblast cells.

Galloyl-Hexahydroxydiphenoyl (HHDP)-Glucose Isolated From Punica granatum L. Leaves Protects Against Lipopolysaccharide (LPS)-Induced Acute Lung Injury in BALB/c Mice

The hydroalcoholic extract and ethyl acetate fraction of Punica granatum leaves have been known to exhibit anti-inflammatory activities. In this study, we investigated the therapeutic effects of galloyl-hexahydroxydiphenoyl (HHDP)-glucose isolated from pomegranate leaves on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Male BALB/c mice were treated with different doses of galloyl-HHDP-glucose (5, 50, and 100 mg/Kg) or dexamethasone at 5 mg/Kg (per os) 6 h after intra-tracheal instillation of LPS. Vehicle-treated mice were used as controls. Twenty-four hours after LPS challenge, bronchoalveolar lavage fluid (BALF), and lung samples were collected for analyses. They were evaluated by monitoring the expression of NF-κB, JNK, and cytokine genes and proteins, as well as cell migration and lung function. All doses of galloyl-HHDP-glucose inhibited LPS-induced JNK and NF-κB activation. Likewise, the galloyl-HHDP-glucose-treated animals presented reduced expression of the TNF-α, IL-6, and IL-1β genes in the lungs and reduced TNF-α, IL-6, IL-1β, and IL-8 protein levels when compared with the vehicle-treated LPS-challenged mice. In addition, the ALI mice treated with galloyl-HHDP-glucose also presented reduced lung inflammatory cell accumulation, especially that of neutrophils, in their BALF and lungs. In addition, galloyl-HHDP-glucose treatment markedly ameliorated the LPS-induced pulmonary mechanism complications and attenuated weight loss. Overall, we showed for the first time that galloyl-HHDP-glucose protects against ALI, and may be useful for treating ALI and other inflammatory disorders.

Efeito Antiproliferativo do Zoledronato em Linhagens Celulares Tumorais

Introdução: Bisfosfonatos são fármacos utilizados para o tratamento de enfermidades ósseas, como a osteoporose e metástases ósseas, em razão do seu mecanismo de ação, que consiste na diminuição do processo de reabsorção do osso. Outros estudos verificaram que bisfosfonatos de alta potência, como o zoledronato, poderiam auxiliar no tratamento de outras enfermidades malignas por causa da promoção de um efeito antiproliferativo. Objetivo: Este estudo in vitro objetivou avaliar a atividade antiproliferativa de zoledronato em diferentes linhagens de células tumorais. Método: Nove linhagens humanas (U251; MCF7; NCI/ADR-RES; 786-0; NCI-H460; PC-3; OVCAR-3; HT29; K-562 e HaCaT) foram submetidas ao tratamento com as concentrações de 0,12; 1,2; 12 e 120 μM de zoledronato e tiveram sua atividade proliferativa avaliada após 48 horas, utilizando-se o corante sulforrodamina B. Resultados: Verificou-se que as concentrações de 12 μM e 120 μM de zoledronato foram eficazes para a redução em 50% e 100%, respectivamente, da proliferação das células 786-0 (carcinoma renal). A maior concentração de zoledronato (120 μM) promoveu um efeito citostático (redução da proliferação celular em 50%) para as células HaCaT (queratinócito humano não tumoral), HT-29 (carcinoma de cólon), NCI-ADR/ RES (adenocarcinoma de ovário com fenótipo de multirresistência) e NCI-H460 (carcinoma pulmonar). Conclusão: Esses resultados sugerem um promissor efeito auxiliar do zoledronato para o tratamento de alguns tipos de tumores; estudos complementares in vitro e in vivo são necessários para a validação dessa hipótese.