Bioactive Compounds from P. pertomentellum That Regulate QS, Biofilm Formation and Virulence Factor Production of P. aeruginosa.

Pseudomonas aeruginosa is an opportunistic pathogen responsible for many nosocomial infections. This bacterium uses Quorum Sensing (QS) to generate antimicrobial resistance (AMR) so its disruption is considered a novel approach. The current study describes the antibiofilm and QS inhibitory potential of extract and chemical components from Piper pertomentellum. The methodo- logy included the phytochemical study on the aerial part of the species, the determination of QS inhibition efficacy on Chromobacterium violaceum and the evaluation of the effect on biofilm formation and virulence factors on P. aeruginosa. The phytochemical study led to the isolation and identification of a new piperamide (ethyltembamide 1), together with four known amides (tembamide acetate 2, cepharadione B 3, benzamide 4 and tembamide 5). The results indicated that the ethanolic extract and some fractions reduced violacein production in C. violaceum, however, only the ethanolic extract caused inhibition of biofilm formation of P. aeruginosa on polystyrene microtiter plates. Finally, the investigation determined that molecules (1-5) inhibited the formation of biofilms (50% approximately), while compounds 2-4 can inhibit pyocyanin and elastase production (30-50% approximately). In this way, the study contributes to the determination of the potential of extract and chemical constituents from P pertomentellum to regulate the QS system in P. aeruginosa.

Antiquorum and Antibiofilm Activities of Piper bogotense C. DC. against Pseudomonas aeruginosa and Identification of Bioactive Compounds.

The present study describes the anti-biofilm and quorum sensing (QS) inhibitory potential of extracts and chemical constituents from Piper bogotense. Antibiofilm potential was determined through crystal violet assay against Pseudomonas aeruginosa, while QS inhibition efficacy was determined through violacein inhibition assay using Chromobacterium violaceum as a bacterial model. Additionally, this study reports the effects of the chemical constituents isolated in P. bogotense against various virulent factors associated with QS, such as the percentage decrease in pyocyanin, elastase, and protease production. The chemical study led to the isolation and identification of two prenylated benzoic acids (1 and 2) and a prenylated hydroquinone 3, of which compounds 1 and 2 are reported for the first time for P. bogotense. The ethanolic extract and the DCM fraction from P. bogotense stand out for reducing violacein production in C. violaceum, as well as the biofilm formation in P. aeruginosa. Compounds 2 and 3 stand out for having the lowest violacein production (43.8% and 68.3%), as well as the lowest production of virulence factors such as elastase (60.2% and 51.4%) and pyocyanin (39.7% and 33.2%). These results demonstrate the potential of P. bogotense components to be used as an alternative control against multidrug-resistant P. aeruginosa.

Potencial antimicrobiano de extractos de plantas medicinales y sus mezclas frente a bacterias asociadas con conjuntivitis / Antimicrobial potential of plant extracts and their mixtures against bacteria associated with conjunctivitis

Resumen Introducción. La conjuntivitis bacteriana es una de las infecciones oculares con mayor tasa de consulta oftálmica, siendo el género Staphylococcus el agente etiológico que presenta mayor resistencia a los antibióticos. Objetivo. Determinar el potencial antimicrobiano de extractos de plantas medicinales y sus mezclas frente a bacterias asociadas con conjuntivitis. Métodos. A partir de plantas como Belladona, Caléndula, Albahaca, Achiote y Romerillo se prepararon los extractos etanólicos y se evaluó su potencial antibacteriano frente a S. aureus y S. epidermidis, mediante las técnicas de difusión en disco y dilución en tubo. El efecto de las mezclas se determinó para el extracto con mejor actividad y el antibiótico con mayor halo de inhibición a través de la técnica de tablero. Resultados. Se encontró que el extracto con mayor potencial para S. aureus fue el de achiote (hojas) con un halo de inhibición de 13 mm y CMIs de 15 mg/mL, mientras que para S. epidermidis fueron los de hojas y frutos de achiote con halos de 16,6 y 9,6 mm y CMIs de 15 y 30 mg/mL respectivamente. En relación con las combinaciones, el extracto de achiote y ciprofloxacina mostró un efecto de sinergia parcial para S. aureus con una CFI de 0,83 y un efecto aditivo para S. epidermidis con una CFI de 1,84. Conclusiones. Este trabajo se constituye en la base de futuras investigaciones orientadas hacia el desarrollo de bioproductos de uso ocular que puedan ser considerados como alternativa en el tratamiento de infecciones causadas por Staphylococcus.

Abstract Introduction. Bacterial conjunctivitis is one of the ocular infections with the highest rate of ophthalmic consultation, being the Staphylococcus genus the etiological agent that presents the greatest resistance to antibiotics. Objective. To determine the antimicrobial potential of medicinal plant extracts and their mixtures against bacteria associated with conjunctivitis. Methods. From plants such as Belladonna, Calendula, Basil, Achiote and Romerillo, ethanolic extracts were prepared and their antibacterial potential against S. aureus and S. epidermidis was evaluated by means of disk diffusion and tube dilution techniques. The effect of the mixtures was determined for the extract with the best activity and the antibiotic with the highest inhibition halo through the board technique. Results. It was found that the extract with the highest potential for S. aureus was that of annatto (leaves) with an inhibition halo of 13 mm and MICs of 15 mg / mL, while for S. epidermidis it was those of annatto leaves and fruits with halos of 16.6 and 9.6 mm and MICs of 15 and 30 mg / mL respectively. In relation to the combinations, the annatto extract and ciprofloxacin showed a partial synergistic effect for S. aureus with a CFI of 0.83 and an additive effect for S. epidermidis with a CFI of 1.84. Conclusions. This work constitutes the basis for future research aimed at the development of bioproducts for ocular use that can be considered as an alternative in the treatment of infections caused by Staphylococcus.

Actividad antioxidante y antibacteriana de extractos de hojas de cuatro especies agroforestales de la Orinoquía colombiana / Antioxidant and antibacterial activity of leaf extracts from four agroforestry species located in Colombian Orinoquia

Introducción: las especies agroforestales son fuente importante de metabolitos secundarios de utilidad en la industria farmacéutica, cosmética y veterinaria. En los países con alta diversidad biológica como Colombia se busca ampliar el conocimiento biológico, químico y económico de especies vegetales con uso potencial. Objetivo: establecer la actividad antimicrobiana y antioxidante de los extractos de hojas de Jatropha curcas L. y de 3 variedades de Hibiscus cannabinus L. (Tainung, Everglades y Whitten). Métodos: las hojas se recolectaron en Restrepo (Meta) y se sometieron a extracción por soxhlet, y microondas con solventes de diferente polaridad como éter de petróleo, diclorometano y etanol (EP, CH2Cl2 y EtOH). La actividad antibacteriana se estableció por difusión en agar frente a cepas de Escherichia coli y Staphylococcus aureus, y la actividad antioxidante por el método autobiográfico utilizando como agentes reveladores 2,2-difenil-1-picrilhidrazilo y ß-caroteno. Resultados: de acuerdo con los porcentajes de extracción hallados, se determinó que la mayoría de los compuestos presentes en estas especies tienen alta polaridad. Los extractos que presentaron la mayor actividad antioxidante fueron los correspondientes a las variedades de Hibiscus cannabinus y, en especial, los extractos de baja y alta polaridad obtenidos por el método de soxhlet. El 20 % del total de los extractos presentaron una respuesta favorable frente a las 2 cepas; los extractos obtenidos por el método de microondas resultaron más selectivos para Escherichia coli. Conclusión: este trabajo se presenta como una contribución al avance de investigaciones biodirigidas, que identifiquen principios activos para el desarrollo de antibióticos y antioxidantes naturales a partir de residuos agroforestales.

Introduction: the agroforestry species are important sources of useful secondary metabolites for pharmaceutical, cosmetic and veterinary medicine. Those countries with high biodiversity like Colombia are looking to expand the biological, chemical and economic knowledge about plant species with potential uses. Objective: to determine the antimicrobial and antioxidant activity of leaf extracts of Jatropha curcas L. and three varieties of Hibiscus cannabinus L. (Tainung, Everglades and Whitten). Methods: the leaves were collected in Restrepo (Meta) and subjected to Soxhlet and microwave extraction processes with different polarity solvents such as petroleum ether, dichloromethane and ethanol (EP, CH2Cl2 and EtOH). The antibacterial activity was established by agar diffusion method against Escherichia coli and Staphylococcus aureus strains, whereas antioxidant activity was determined by the autobiographical method using developing agents 2,2-diphenyl-1-picrylhydrazyl and ß-carotene. Results: in accordance with the extraction percentages found, most of the compounds present in these species had high polarity. The extracts with the highest antioxidant activity were those of Hibiscus cannabinus varieties, particularly low and high polarity extracts obtained by the Soxhlet method. The 20 % of total extracts showed a positive response against the two strains, being the extracts obtained by the microwave method more selective for Escherichia coli strains. Conclusion: this paper is a contribution to the development of bio-directed research to identify the active principles for the development of antibiotics and natural antioxidants from agroforestry wastes.