Composição química, atividade bacteriana e antioxidante de óleo essencial e diferentes extratos vegetais de Prunus myrtifolia (L.) Urb.

Abstract

The antimicrobial property of the plants can be explained by the production of active compounds generated during secondary metabolism as well as volatile compounds. Currently, the knowledge of this property have been confirmed scientifically, thus revealing the enormous potential of the plants in the control of infectious diseases, while there is an increase in cases of pathogenic microrganisms resistant to known antibiotics. Essential oils and extracts of plants have shown effects on growth of micro -organisms in many situations, suggesting practical use thereof. In the present study focused on the research of plants as alternative and natural source of antimicrobial substances, determined the chemical composition of the essential oil and various plant extracts (aqueous, ethanolic, ethyl acetate and hexane) of Prunus myrtifolia (L.) Urb. by GC/MS and phytochemical screening respectively, and its antimicrobial effect against microorganisms Gram negative Pseudomonas aeruginosa (ATCC 27853), Salmonella typhimurium (ATCC 14028), Proteus mirabilis (ATCC 25933), Klebsiella pneumoniae (ATCC 13883) and Escherichia coli (ATCC 25922) as Gram positive Enterococcus faecalis (ATCC 19433), Staphylococcus epidermidis (ATCC 12228), Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (CCCD - B005) and yeast such as Candida albicans (ATCC 10231) by determining the values of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using the microdilution broth; and finally we sought to evaluate the antioxidant activity of essential oil and plant extracts by the capture of free radicals DPPH (2.2difenil-1-picryl-hydrazyl). The largest class of volatile compounds identified in the oil was Prunus myrtifolia benzaldehyde (97%) followed by 3-hexen-1-ol (0.07 %) and benzyl benzoate (0.09 %). Generally through the phytochemical screening of the extracts was found the presence of secondary metabolites such as, flavonoids, tannins (ethanolic and aqueous), and triterpenoid saponins (ethanolic), which have proven active in different studies in the literature. Compared to hexane extract showed absence of secondary metabolites with antimicrobial activity. The results indicate the aqueous and ethanolic extract as the most effective of the tested pathogens. Regarding oil, showed antimicrobial activity against all pathogens evaluated. In a third stage of the study it was found antioxidant activity of the aqueous extract, ethanolic and ethyl acetate; in relation to essential oil and hexane extract antioxidant activity was not detected. From the results obtained it was established antimicrobial capacity of plant products tested and determined the antioxidant activity of the same . In the second stage of the research took place evaluated the phytochemical profile , antioxidant and antimicrobial activity of ethanolic and aqueous plant extracts from six Brazilian plants obtained from the dried leaves of Maytenus aquifolia Mart., Plinia cauliflora (Mart.) O. Berg, Ocotea spixiana (Nees) Mez., Psidium guajava L., Ricinus communis L. and Schinus molle L. The in vitro antimicrobial activity of plant extracts was tested against 36 serotypes of Salmonella from poultry products by the broth microdilution method to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The antioxidant properties of these was evaluated by DPPH (2.2-diphenyl-1-picryl-hidrazila) method. The phytochemical profile detected components with antimicrobial and antioxidant potential in all extracts , as a percentage capture of DPPH than 65 % , demonstrating the high antioxidant activity of the tested extracts. In microdilution tests, we observed the antimicrobial activity of all tested extracts , and in general the ethanol extracts were more effective when compared to aqueous and ethanol extract of P. cauliflora followed by P. guajava higher end bacteriostatic . The MIC ranged from 1.56 to 100 mg.mL-1 and MBC of 3.13 to 100 mg.mL-1. These results confirmed the antioxidant and antimicrobial potential of these plant extracts