RESUMO
Background: The resistance to antibiotics shown by some dermatological pathogenic microorganisms has increased the interest of pharmaceutical and cosmetic industries in developing natural products that possess different biological activities, including antimicrobial effects. Methods: In the present investigation, the antibacterial activity of ethanolic extracts of Dodonaea viscosa aerial part and Mammea americana leaves and seed was evaluated against resistant strains of Staphylococcus isolated from skin lesions and against S. aureus ATCC 25923 (reference strain). Column chromatography (CC) and preparative thin-layer chromatography (PTLC) were used to obtain separate fractions of the seed extract of M. americana. We also determined the antimicrobial resistance of the strains against antibiotics using the agar disc diffusion assay. In addition, phytochemical screening was performed by colorimetric standard techniques. Results: M. americana seed extract showed the highest antibacterial activity with MBC from 2.3 µg/mL to 19.5 µg/mL without differences with gentamicin (p = 0.998). The isolated strain S. epidermidis I showed the highest antimicrobial resistance against the tested antibiotics. PTLC-fractions of M. americana seed extract showed MBC from 3.2 µg/mL to 40.7 µg/mL against S. epidermidis I and S. aureus 25923 (reference), respectively, which suggests a synergistic effect of the secondary metabolites present in the crude ethanolic extract compared to its active PTLC-fractions, where only coumarins and compounds with lactone groups were detected in the phytochemical screening. Conclusion: M. americana seed extract has promising effects that should be considered in further studies as an alternative or adjuvant in treating skin infections caused by staphylococci.
Assuntos
Mammea , Dermatopatias , Staphylococcus , Staphylococcus aureus , Antibacterianos/farmacologia , Staphylococcus epidermidis , Etanol , Extratos Vegetais/farmacologiaRESUMO
Abstract Introduction: Pathogenic protozoans, like Entamoeba histolytica and Trichomonas vaginalis, represent a major health problem in tropical countries; and polymeric nanoparticles could be used to apply plant extracts against those parasites. Objective: To test Curcuma longa ethanolic extract and Berberis vulgaris methanolic extracts, and their main constituents, against two species of protozoans. Methods: We tested the extracts, as well as their main constituents, curcumin (Cur) and berberine (Ber), both non-encapsulated and encapsulated in polymeric nanoparticles (NPs), in vitro. We also determined nanoparticle characteristics by photon correlation spectroscopy and scanning electron microscopy, and hemolytic capacity by hemolysis in healthy erythrocytes. Results: C. longa consisted mainly of tannins, phenols, and flavonoids; and B. vulgaris in alkaloids. Encapsulated particles were more effective (P < 0.001); however, curcumin and berberine nanoparticles were the most effective treatments. CurNPs had IC50 values (µg/mL) of 9.48 and 4.25, against E. histolytica and T. vaginalis, respectively, and BerNPs 0.24 and 0.71. The particle size and encapsulation percentage for CurNPs and BerNPs were 66.5 and 73.4 nm, and 83.59 and 76.48 %, respectively. The NPs were spherical and significantly reduced hemolysis when compared to non-encapsulated extracts. Conclusions: NPs represent a useful and novel bioactive compound delivery system for therapy in diseases caused by protozoans.
Resumen Introducción: Los protozoos patógenos, como Entamoeba histolytica y Trichomonas vaginalis, representan un importante problema de salud en los países tropicales; y se podrían usar nanopartículas poliméricas para aplicar extractos de plantas contra esos parásitos. Objetivo: Probar los extractos etanólicos de Curcuma longa y Berberis vulgaris, y sus principales constituyentes, contra dos especies de protozoos. Métodos: Probamos los extractos, así como sus principales constituyentes, curcumina (Cur) y berberina (Ber), tanto no encapsulados como encapsulados en nanopartículas poliméricas (NPs), in vitro. También determinamos las características de las nanopartículas por espectroscopía de correlación de fotones y microscopía electrónica de barrido, y la capacidad hemolítica por hemólisis en eritrocitos sanos. Resultados: C. longa tenía principalmente: taninos, fenoles y flavonoides; y B. vulgaris, alcaloides. Las partículas encapsuladas fueron más efectivas (P < 0.001); sin embargo, las nanopartículas de curcumina y berberina fueron los tratamientos más efectivos. CurNPs tenía valores IC50 (µg/mL) de 9.48 y 4.25, contra E. histolytica y T. vaginalis, respectivamente, y BerNPs 0.24 y 0.71. El tamaño de partícula y el porcentaje de encapsulación para CurNPs y BerNPs fueron: 66.5 y 73.4 nm, y 83.59 y 76.48 %, respectivamente. Los NP son esféricos y redujeron significativamente la hemólisis en comparación con los extractos no encapsulados. Conclusiones: Las NP representan un sistema de administración de compuestos bioactivos útil y novedoso para la terapia enfermedades causadas por protozoos.
