Wound healing can be delayed following colonization and infection with the common bacterium Pseudomonas aeruginosa. While multiple therapies are used for their treatment, these are ineffective, expensive, and labour-intensive. Thus, there is an enormous unmet need for the treatment of infected wounds. Cinnamaldehyde, the major component of cinnamon oil, is well known for its antimicrobial properties. Herein, we investigated the effects of sub-inhibitory concentrations of cinnamaldehyde in the virulence of P. aeruginosa. We also assessed its healing potential in P. aeruginosa-infected mouse skin wounds and the mechanisms involved in this response. Sub-inhibitory concentrations of cinnamaldehyde reduced P. aeruginosa metabolic rate and its ability to form biofilm and to cause haemolysis. Daily topical application of cinnamaldehyde on P. aeruginosa-infected skin wounds reduced tissue bacterial load and promoted faster healing. Lower interleukin-17 (IL-17), vascular endothelial growth factor (VEGF) and nitric oxide levels were detected in cinnamaldehyde-treated wound samples. Blockage of transient receptor potential ankyrin 1, the pharmacological target of cinnamaldehyde, abrogated its healing activity and partially reversed the inhibitory actions of this compound on VEGF and IL-17 generation. We suggest that topical application of sub-inhibitory concentrations of cinnamaldehyde may represent an interesting approach to improve the healing of P. aeruginosa-infected skin wounds.

In the face of increasing bacterial resistance to antibiotics currently in use, the search for new antimicrobial agents has received a boost in recent years, with natural products playing an important role in this field. In fact, several methods have been proposed to investigate the antibacterial activities of natural products. However, given that the ultimate aim is future therapeutic use as novel drugs, it is extremely necessary to elucidate their modes of action, stating the molecular effects in detail, and identifying their targets in the bacterial cell. This review analyzes the application of “omics technologies” to understand the antibacterial mechanisms of bioactive natural products, to stimulate research interest in this area and promote scientific collaborations. Some studies have been specifically highlighted herein by examining their procedures and results (targeted proteins and metabolic pathways). These approaches have the potential to provide new insights into our comprehension of antimicrobial resistance/susceptibility, creating new perspectives for the struggle against bacteria, and leading to the development of novel products in the future.

Eugenol is a phenolic compound and the main constituent of the essential oil of clove India. Although there are reports of some pharmacological effects of eugenol, this study is the first that proposes to evaluate the antifungal effects of this phenol against both Cryptococcus gattii and C. neoformans cells. The effect of eugenol against yeast cells was analyzed for drug susceptibility, alterations in cell diameter, capsule properties, amounts of ergosterol, oxidative burst, and thermodynamics data. Data demonstrated that there is no interaction between eugenol and fluconazole and amphotericin B. Eugenol reduced the cell diameter and the capsule size, increased cell surface/volume, changed positively the cell surface charge of cryptococcal cells. We also verified increased levels of reactive oxygen species without activation of antioxidant enzymes, leading to increased lipid peroxidation, mitochondrial membrane depolarization and reduction of lysosomal integrity in cryptococcal cells. Additionally, the results showed that there is no significant molecular interaction between eugenol and C. neoformans. Morphological alterations, changes of cellular superficial charges and oxidative stress play an important role in antifungal activity of eugenol against C. gattii and C. neoformans that could be used as an auxiliary treatment to cutaneous cryptococcosis.

Rheumatoid arthritis (RA) is characterized by inflammation of one or more joints, and affects ~1% of the adult population worldwide. Sulforaphane (SFN) is a natural compound that has been suggested as an antioxidant. Here, SFN’s effects were evaluated in a murine mono-arthritis model. Mono-arthritis was induced in mice by a single intra-articular injection of Complete Freund’s Adjuvant (CFA-10 µg/joint, in 10 µL) into the ipsilateral joint. The contralateral joint received an equal volume of PBS. On the 4th day post-joint inflammation induction, animals received either SFN (10 mg/kg) or vehicle (3% DMSO in saline), intraperitoneally (i.p.), twice a day for 3 days. Joint swelling and secondary mechanical allodynia and hyperalgesia were evaluated over 7 days post-CFA. After this period, animals were culled and their blood and synovial fluid samples were collected for analysis of cell populations, cytokine release and thioredoxin reductase (TrxR) activity. Knee joint samples were also collected for histology. SFN reduced joint swelling and damage whilst increasing the recruitment of Ly6C+ and Ly6G+ cells to CFA-injected joints. SFN-treated animals presented down-regulation of CD11b and CD62L on synovial fluid Ly6G+ cells. Synovial fluid samples obtained from CFA-injected joints and plasma samples of SFN-treated mice presented higher levels of IL-6 and increased activity of TrxR, in comparison with controls. These results indicate that SFN reduces knee joint damage by modulating cell activation/migration to the joints, cytokine production and increasing the activity of TrxR, and therefore, may represent an alternative treatment to joint inflammation.

Introdução: Cinamaldeído (CND) é o principal componente ativo do óleo essencial da canela (Cinnamomum sp) e tem sido amplamente utilizado em atividades biológicas e farmacológicas, tendo sido relatado atividade antimicrobiana, antioxidante, antidiabética, dentre outras. Objetivo: Devido os diversos relatos das propriedades farmacológicas do composto, esse foi escolhido para revisão de literatura. A seleção da bibliografia foi obtida a partir de bases de dados (google scholar, NCBI - National Center for Biotechnology Information, PubMed e Scielo - Scientific Electronic Library Online). Discussão: A composição química do CND tem compostos terpenóides que têm poderosa atividade antimicrobiana contra fungos, bactérias Gram-positivas e Gram-negativas tais como Aeromonas hydrophila, Enterococcus faecalis, Clostridium botulinum, Staphylococcus aureus, Escherichia coli O157: H7 e Salmonella enterica serovar Typhimurium. A atividade anti-inflamatória induz a apoptose e inibi a proliferação celular, nas respostas imunes mediadas por monócitos/macrófagos, além de diminuir a produção de óxido nítrico induzido por lipopolissacáridos de um modo dependente da dose. CND ao ser administrado por via oral em ratos diabéticos demonstrou melhora no conteúdo de glicogênio muscular e hepático aumentando a liberação de insulina. Além disso CND estimulou a angiogênese in vivo e in vitro, regulando positivamente o fator de crescimento endotelial vascular. Conclusão: A partir do que foi relatado constatou-se que o CND possui muitas atividades com potencial farmacológico, mas percebe-se que se faz necessário estudos sobre o(s) mecanismos(s) de ação dessas atividades a fim de se proporcionar o uso seguro e eficaz do cinamaldeído.

No abstract

Plant-derived products have played a fundamental role in the development of new therapeutic agents. This study aimed to analyze antimicrobial, antibiofilm, cytotoxicity and antiproliferative potentials of the extract and fractions from leaves of Himatanthus drasticus, a plant from the Apocynaceae family. After harvesting, H. drasticus leaves were macerated and a hydroalcoholic extract (HDHE) and fractions were prepared. Antimicrobial tests, such as agar-diffusion, Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were carried out against several bacterial species. Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes and Klebsiella pneumoniae were inhibited by at least one extract or fraction in the agar-diffusion assay (inhibition halos from 12 mm to 30 mm). However, the lowest MIC value was found for HDHE against K. pneumoniae. In addition, HDHE and its fractions were able to inhibit biofilm formation at sub-inhibitory concentrations (780 µg/mL and 1.56 µg/mL). As the best activities were found for HDHE, we selected it for further assays. HDHE was able to increase ciprofloxacin (CIP) activity against K. pneumoniae, displaying synergistic (initial concentration CIP + HDHE: 2 µg/mL + 600 µg/mL and 2.5 µg/mL + 500 µg/mL) and additive effects (CIP + HDHE: 3 µg/mL + 400 µg/mL). This action seems to be associated with the alteration in bacterial membrane permeability induced by HDHE (as seen by propidium iodide labeling). This extract was non-toxic for red blood cell or human peripheral blood mononuclear cells (PBMCs). Additionally, it inhibited the lipopolysaccharide-induced proliferation of PBMCs. The following compounds were detected in HDHE using HPLC-ESI-MS analysis: plumieride, plumericin or isoplumericin, rutin, quercetin and derivatives, and chlorogenic acid. Based on these results we suggest that compounds from H. drasticus have antimicrobial and antibiofilm activities against K. pneumoniae and display low cytotoxicity and anti-proliferative action in PBMC stimulated with lipopolysaccharide.

A Punica granatum L. (Romã), família Punicaceae, é uma planta largamente utilizada na medicina popular para o tratamento de estomatites, faringites e laringites e é popularmente usada para rouquidão e inflamação da garganta. Sua utilização popular tem sido respaldada por estudos científicos de suas propriedades terapêuticas, principalmente antimicrobiana e anti-inflamatória. Estas propriedades têm sido estudadas em diferentes preparações desta planta, incluindo extratos e frações do fruto, flores e folhas; e parecem estar relacionadas ao alto teor de compostos fenólicos em suas composições. Este trabalho apresentará as diversas evidências das propriedades farmacológicas da P. granatum, compostos relacionados e aplicações atuais e futuras da utilização desta planta no tratamento de doenças de cunho inflamatório e/ou infeccioso.  PALAVRAS-CHAVE: P. granatum; antimicrobiana; anti-inflamatória; antioxidante; compostos fenólicos.