Therapeutic Potential of Punica granatum and Isolated Compounds: Evidence-Based Advances to Treat Bacterial Infections

Punica granatum Linn has been known for its nutritional and medicinal value since ancient times and is used in the treatment of various pathologies owing to its antibacterial properties. This review reports the results of the most recent studies on the antibacterial effects of P. granatum and its isolated compounds on bacteria of clinical interest. A search in the PubMed, Scopus, Science Direct, and Science Citation Index Expanded (Web of Science) databases was performed, which included articles that evaluated the antibacterial activity of P. granatum extracts and excluded articles that analyzed other microorganisms or nonpathogenic bacteria, as well as theses, dissertations, duplicate articles, and those not fully available. The literature suggests that P. granatum extracts can act on bacteria, such as methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In addition, fruit peel was the most commonly used pharmacogen and methanol, ethanol, and water were the most common solvents for the extraction of bioactive compounds. The antibacterial potential of the methanolic extract of pomegranate peel could be attributed to the presence of active compounds, such as 5-hydroxymethylfurfural, punicic acid, gallic acid, and punicalagin. Thus, there is evidence that these plant extracts, having high polyphenol content, can disrupt the bacterial plasma membrane and inhibit the action of proteins related to antimicrobial resistance. P. granatum shows antibacterial activity against Gram-positive and Gram-negative bacteria, with great potential against multidrug-resistant strains. Further research is needed to clarify the mechanism of action related to this biological activity and investigate the isolated substances that may be responsible for the antibacterial effects.

Brazilian Amazon Red Propolis: Leishmanicidal Activity and Chemical Composition of a New Variety of Red Propolis

Leishmaniasis is caused by protozoans of the genus Leishmania, and its treatment is highly toxic, leading to treatment discontinuation and the emergence of resistant strains. In this study, we assessed the leishmanicidal activity and chemical composition of red propolis collected from the Amazon-dominated region of northern Tocantins State, Brazil. The MTT assay was employed to determine the samples' activity against Leishmania amazonensis promastigotes and their cytotoxicity against RAW macrophages. Spectrophotometric assays were utilised to measure the concentrations of total phenolics and flavonoids, while high-performance liquid chromatography coupled to a mass spectrometer (LC-MS/MS) was used to determine the chemical composition. An in silico study was conducted to evaluate which compounds from Brazilian Amazon red propolis may correlate with this biological activity. Brazilian Amazon red propolis exhibited a high concentration of phenolic compounds and an inhibitory activity against L. amazonensis, with an IC50 ranging from 23.37 to 36.10 µg/mL. Moreover, fractionation of the propolis yielded a fraction with enhanced bioactivity (16.11 µg/mL). Interestingly, neither the propolis nor its most active fraction showed cytotoxicity towards macrophages at concentrations up to 200 µg/mL. The red colour and the presence of isoflavonoid components (isoflavones, isoflavans, and pterocarpans) confirm that the substance is Brazilian red propolis. However, the absence of polyprenylated benzophenones suggests that this is a new variety of Brazilian red propolis. The in silico study performed with two of the main leishmanicidal drug targets using all compounds identified in Amazon red propolis reported that liquiritigenin was the compound that exhibited the best electronic interaction parameters, which was confirmed in an assay with promastigotes using a standard. The findings indicate that Amazon red propolis possesses leishmanicidal activity, low toxicity, and significant biotechnological potential.

Immunomodulatory Activity of Probiotics in Models of Bacterial Infections

As resistance to conventional antibiotics among bacteria continues to increase, researchers are increasingly focusing on alternative strategies for preventing and treating bacterial infections, one of which is microbiota modulation. The objective of this review is to analyze the scientific literature on the immunomodulatory effects of probiotics in bacterial infections. This is an integrative review of the literature based on systematic steps, with searches performed in the databases Medline, PubMed, Scopus, Embase, and ScienceDirect. The most prevalent bacterial genera used to evaluate infectious processes were Salmonella, Escherichia, Klebsiella, and Streptococcus. Lactobacillus was the most commonly used probiotic genus, with Lactobacillus delbrueckii subsp. bulgaricus is the most frequently used species. In most studies, prophylactic treatment with concentrations of probiotics equal to or greater than 8 log CFU/mL was chosen. However, there was considerable heterogeneity in terms of effective treatment duration, indicating that the results cannot be generalized across all studies. This review found that probiotics interact with the immune system through different mechanisms and have a positive effect on preventing different types of bacterial infections.

Fatores de risco e distribuição espacial dos óbitos por COVID-19: revisão integrativa

Justificativa e objetivos: a compreensão sobre os fatores clínico–epidemiológicos e ambientais relacionados aos óbitos por COVID-19 e sua distribuição no espaço podem servir de subsídios para direcionar e implementar ações de saúde mais eficazes às populações vulneráveis. Desse modo, objetivou-se sintetizar as evidências científicas relacionadas aos fatores de risco e distribuição espacial dos óbitos por COVID-19 no mundo. Conteúdo: trata-se de uma revisão integrativa da literatura, formulando-se a seguinte questão norteadora: quais as evidências científicas relacionadas aos fatores de risco e distribuição espacial dos óbitos por COVID-19 no mundo? Realizaram-se buscas na biblioteca Scientific Eletronic Library Online (SciELO) e nas bases de dados Scopus, Web of Science e National Library of Medicine (PubMed) em junho de 2021. Foram considerados estudos originais, nos idiomas português, inglês ou espanhol, sem recorte temporal, sendo excluídos estudos com grupo específico de idade ou com público com comorbidade específica. Foram incluídos 25 estudos, com achados em distintos cenários pelo mundo. Fatores, como idade, sexo e doenças pré-existentes, estiveram associados aos óbitos por COVID-19, que apresentaram distribuição espacial heterogênea e ocorreram em condições ambientais, socioeconômicas e geográficas peculiares desses territórios. Conclusão: idade igual ou maior que 60 anos, sexo masculino, doenças cardiovasculares, diabetes mellitus e áreas geográficas com maior poluição ambiental, maior densidade populacional e precárias condições sanitárias influenciaram na mortalidade da COVID-19.

Phenolic acids, hydrolyzable tannins, and antioxidant activity of geopropolis from the stingless bee Melipona fasciculata Smith

Geopropolis is a mixture of plant resins, waxes, and soil produced by the stingless bee Melipona fasciculata Smith. This paper describes the antioxidant activity and chemical composition of geopropolis produced by M. fasciculata. The total phenolic content determined with the Folin-Ciocalteu reagent was highest in the ethyl acetate fraction and hydroalcoholic extract. Antioxidant activity was assayed by the in vitro DPPH, ABTS, and FRAP assays. The hydroalcoholic extract and fractions of geopropolis, except for the hexane fraction, exhibited antioxidant activity against DPPH, ABTS, and FRAP. The phenolic compounds were identified by HPLC-DAD-MS on the basis of the evaluation of their UV-vis absorption maxima (λmax) and mass spectral analysis. Eleven compounds belonging to the classes of phenolic acids and hydrolyzable tannins (gallotannins and ellagitannins) were tentatively identified. These compounds are responsible for the antioxidant activity and high phenolic content of geopropolis produced by M. fasciculata.

Pharmacognostic and acute toxicological evaluation of Scaptotrigona aff. postica propolis extract in pre-clinical assays

The propolis of Scaptotrigona aff. postica is popularly used in Maranhão State, Brazil, for treating wounds and respiratory illnesses. Nevertheless, little is known about the chemical composition of this propolis and the adverse effects of its use. Hence, this study is a pharmacognostic characterisation of the propolis hydroalcoholic extract (PHE) from S. aff. postica. The methodology consisted of an evaluation of the sensory and chemical parameters. Chemical analysis of PHE indicated high concentrations of phenolic and triterpens substances, and the absence of steroids. Additionally, we evaluated the acute toxicity of propolis using 48 Swiss male and female mice. The animals received single doses of PHE (1000, 2000 or 4000 mg kg⁻¹) orally and were observed for 14 days. After this period, the mice were sacrificed and the blood was used for biochemical and haematological evaluation. PHE did not induce any death, and the acute treatment significantly reduced serum concentrations of alanine aminotransferase and alkaline phosphatase. The resultant data indicate that PHE from S. aff. postica has low toxicity when used orally, even in high doses.