Synergistic and Antibiofilm Effects of the Essential Oil from Croton conduplicatus (Euphorbiaceae) against Methicillin-Resistant Staphylococcus aureus.

Bacterial resistance refers to the ability of bacteria to resist the action of some antibiotics due to the development of adaptation and resistance mechanisms. It is a serious public health problem, especially for diseases caused by opportunistic bacteria. In this context, the search for new drugs, used alone or in combination, appears as an alternative for the treatment of microbial infections, and natural products, such as essential oils, are important in this process due to their structural diversity, which increases the probability for antimicrobial action. The objective of this study was to extract and identify the chemical components of the essential oil from Croton conduplicatus (EOCC), to evaluate the antimicrobial activity, to investigate the effect of the interaction between the EOCC and different antibiotics and to evaluate its antibiofilm potential. The EOCC was obtained by hydrodistillation. Based on chemical characterisation, 70 compounds were identified, with 1.8 cineole (13.15%), p-cymene (10.68%), caryophyllene (9.73%) and spathulenol (6.36%) being the major constituents. The minimum inhibitory concentration (MIC) values of EOCC were 256 and 512 µg mL-1 for methicillin-sensitive and -resistant Staphylococcus aureus strains (MSSA and MRSA), respectively. The combinations of EOCC with the antibiotics oxacillin and ampicillin were synergistic (OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and AMP MIC to 0.5 and 0.25 for MSSA, respectively, and OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and the AMP MIC to 1 and 0.5 for MRSA, respectively) and could modify the resistance profile of MSSA and MRSA strains. The results indicated that EOCC was also able to partially inhibit biofilm formation. Our study presents important information about the chemical composition of EOCC and its antimicrobial potential and provides a reference to determine the mechanisms of action of EOCC and its use in pharmaceutical formulations.

Phytochemical study of Harrisia adscendens

ABSTRACT Harrisia adscendens (Gürke) Britton & Rose is a species of the family Cactaceae found in the northeastern semi-arid and popularly known as foxtail. In folk medicine, the roots of this species are used for the treatment of toothache and heartburn. The objective of this study was to perform the isolation and identification of the secondary metabolites obtained from the vegetal drug by chromatographic and spectroscopic techniques and to evaluate the antimicrobial activity of the extract. The qualitative phytochemical analysis of the extract showed suggestive results for the presence of alkaloids. Two compounds were isolated and identified: 2-methyl-9H-β-carboline-2-ion, a β-carboline alkaloid obtained for the first time as a natural product and 2',6'-dihydroxy-4'-methoxyacetophenone-2'-O-β-glucoside. In the antimicrobial tests, it was possible to observe activity against Pseudomonas aeruginosa. The results obtained by spectroscopic techniques allowed to characterize the phytochemical properties of the vegetal drug and may be useful in future studies for production of herbal medicines.

Isolation of Monoterpene Dihydrochalcones from Piper montealegreanum Yuncker (Piperaceae).

Four new compounds were isolated from the branches of Piper montealegreanum Yuncker, a shrub found in the Amazon rainforest, including two new dihydrochalcones named claricine (1) and maisine (2), a cinnamic acid derivative 3 and a phenylalkanoid 4, along with a porphyrin identified as the known compound phaeophytin a (5). The structures were established using spectroscopic experiments, including 1D and 2D NMR and HRESIMS experiments, performed on the two monoterpene dihydrochalcones and their monoacetyl derivatives. The structural diversity of these substances is very important for the Piper genus chemotaxonomy.

Atividade antibacteriana e efeito interativo in vitro de um produto a base de cranberry sobre Escherichia coli / Antibacterial activity and interactive effect in vitro of a cranberry product on Escherichia coli

Produtos derivados de plantas estão sendo bastante estudados devido à possibilidade de apresentarem substâncias com atividades antimicrobianas, principalmente, em decorrência do aumento da resistência bacteriana aos antimicrobianos, Vaccinium macrocarpon Aiton, conhecido como cranberry, é uma planta nativa, bastante difundida na América do Norte por suas propriedades terapêuticas, particularmente, na prevenção e tratamento de infecções urinárias, Este estudo objetivou avaliar in vitro a atividade antibacteriana, a concentração inibitória mínima (CIM) de um produto comercial a base de cranberry bem como as possíveis interações deste produto quando em associação com antimicrobianos, frente a cepas de Escherichia coli, As avaliações da atividade antibacteriana e da CIM foram realizadas utilizando-se discos de papel filtro estéreis (Cefar®), embebidos em 30µL da solução contendo frutos de cranberry em diferentes concentrações, O estudo da interferência do produto sobre a efetividade dos antimicrobianos foi realizado embebendo-se os discos de antibióticos, com 30µL da solução de cranberry [20mg/mL] equivalente a ½ CIM, Os resultados mostraram que a solução de cranberry apresentou atividade para todas as cepas de E, coli testadas independentemente do perfil de resistência e foi capaz de provocar diferentes efeitos interativos quando associado aos antimicrobianos, Estes dados comprovam o potencial antibacteriano deste fruto, promissor, para estudos de desenvolvimento de novos fármacos, entretanto, também mostram que em algumas situações, pode interferir sobre a efetividade de antimicrobianos de uso clínico...

Products derived from plants are being studied because often have substances with antimicrobial activity, mainly due to the increase in bacterial resistance to antimicrobial compounds. Vaccinium macrocarpon Aiton, known as cranberry, is a plant native to, quite widespread in North America for its therapeutic properties, particularly in the prevention and treatment of urinary infections. This study aimed to evaluate the antibacterial activity, the minimum inhibitory concentration (MIC) and the possible interactions between a cranberry product when in association with antimicrobial agents against strains of Escherichia coli. The sensitivity profile was performed by disk diffusion using discs (Multifar ®), and the assessments of antibacterial activity and the MIC were performed using sterile filter paper discs (Cefar ®), soaked in 30 µl of the solution of cranberry, tested in different concentrations. The study of interference of cranberry solution about the effectiveness of antimicrobials was accomplished by soaking the antibiotic discs in their respective concentrations, with cranberry solution 30µL [20 mg/mL] equivalent to 0.5 MIC. The results showed that cranberry solution presented activity for all strains regardless of resistance profile of these lineages and was able to provoke different interactive effects when associated to antimicrobials. These results prove the antibacterial potential of this fruit promising possible, for studies of development of new products, however, also show that in some situations, it may interfere on the effectiveness of antimicrobials for clinical use...