Antimicrobial and sanitizer activity of Baccharis dracunculifolia DC. (Asteraceae) extract

Abstract

Baccharis dracunculifolia (Asteraceae) is a woody shrub, native from the southeast of Brazil, widely used in folk medicine for the treatment of inflammatory and gastrointestinal diseases. To obtain the B. dracunculifolia extract (BDE) the plant was collected, dried, grounded and macerated using ethanol:water 96:4 (v/v). The extract was lyophilized and used to evaluate the antimicrobial and sanitizer activities. Therefore, the antimicrobial activity was performed by the minimum inhibitory concentration (MIC) assay, against microorganisms Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella choleraesuis. Penicillin and streptomycin were used as positive controls. The other assay (sanitizer activity) was analyzed using a 40% alcohol solution containing 0.2% BDE. Thus, it was performed against the bacteria listed above using carriers cylinders contaminated with cultures of the same microorganisms. These cylinders were exposed to the test solution for 15 minutes and transferred to tubes containing nutrient medium. Results were positive when was not observed bacterial growth in the subculture tubes. Assays showed that the extract presented antimicrobial activity only against S. aureus (MIC ≤200µg/mL). However, the 40% alcohol solution containing 0,2% BDE demonstrated the ability to eliminate all microorganisms tested and controls were carried out using only 40% alcohol solution. It was also observed that the antibacterial activity of BDE was pronounced when associated with 40% alcohol, which should be allowed the entry of BDE active constituents into bacterial cells, improving the antimicrobial activity. Assays using isolated substances from the BDE are being conducted to determine (s) which active (s) constituent (s) is responsible for the antimicrobial activity.