FTIR analysis of pyrogallol and phytotoxicity-reductive effect against mercury chloride.

Human activities, especially in industry, have contributed to soil contamination with heavy or toxic metals. The objective of this study was to determine the chelating effect and antioxidant activity of pyrogallol, as well as to evaluate its cytoprotective activity in prokaryotic and eukaryotic models, animal and plant, respectively, against toxic mercury chloride action. Antioxidant activity was determined by DPPH where pyrogallol showed considerable action, chelating even iron ions. For the microbiologic activity assays, microdilution was performed to obtain the minimal inhibitory concentration, minimum bactericidal and minimum fungicide concentration, from which the sub-inhibitory concentrations were determined. The product did not conferred cytoprotection to the tested bacteria and fungi. To evaluate plant cytoprotection, Lactuta sativa seeds were used together with the product at a sub-allelopathic concentration with different HgCl2 concentrations. In this case, the tannin conferred cytoprotection to the plant model, allowing the best growth and development of caulicles and radicles, thus preserving tissues necessary for plant survival. From the results, it is observable that pyrogallol possesses cytoprotective action in the eukaryotic plant model, this action being useful as an alternative which favors the growth of plants in contaminated areas, as the recovering of crop fields or reforestation projects.

Modulation of the antibiotic activity by extracts from Amburana cearensis A. C. Smith and Anadenanthera macrocarpa (Benth.) Brenan.

The aim of this study was to verify the possible interactions between ethanol extracts of Amburana cearensis A. C. Smith and Anadenanthera macrocarpa (Benth.) Brenan, combined with six antimicrobial drugs against multiresistant strains of Staphylococcus aureus and Escherichia coli isolated from humans. The antibacterial activity of the extracts was determined using the minimum inhibitory concentration (MIC). The microdilution assay was performed to verify the interactions between the natural products and the antibiotics using a subinhibitory concentration. The activity of amikacin associated with the extract of Anadenanthera macrocarpa against EC 27 was enhanced, demonstrating an MIC reduction from 128 to 4 µg/mL. Among the ß-lactams, no potentiation on its activity was observed, with exception to the antagonism of the natural products with ampicillin against S. aureus 358.

Synergistic antibiotic activity of volatile compounds from the essential oil of Lippia sidoides and thymol.

Lippia sidoides Cham. (Verbenaceae) is used in the folk medicine as topical antiseptic in skin and mucous membranes and its therapeutic effect is attributed to the thymol presence. The objective of this work was to verify the chemical composition and antibiotic modifying activity of the essential oil extracted from the leaves of L. sidoides and its major component thymol. The essential oil was obtained by hydrodistillation and analyzed by GC/MS. The synergistic activity was evaluated using gaseous contact method. The essential oil was obtained (yield of 1.06%) and the GC/MS analysis identified the main constituents: thymol (84.9%) and p-cymene (5.33%). The antibiotic modifying activity was verified using the minimal inhibitory dose method and gaseous contact. It verified the interference of essential oil and thymol against all tested aminoglycosides. There were no statistical differences between the activity of the essential oil and thymol against Pseudomonas aeruginosa, indicating this to be the responsible composition for such activity. However, the oil was shown more effective when compared to the thymol against Staphylococcus aureus. The essential oil of L. sidoides and its major component thymol influence the activity of aminoglycosides and may be used as adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.