E de Souza Araújo1, A S Pimenta1, F M C Feijó2, R V O Castro3, M Fasciotti4, T V C Monteiro4, K M G de Lima5. 1. Agricultural Sciences Academic Unit, Forest Sciences Graduate Program - PPGCFL, Forest, Bioenergy and Environment Research Group, Federal University of Rio Grande do Norte - UFRN, Natal, Brazil. 2. Department of Veterinary Sciences, Veterinary Microbiology Laboratory, Federal University of Semiarid - UFERSA, Natal, Brazil. 3. Department of Agricultural Sciences, Sete Lagoas Campus, Federal University of São João del Rei - UFSJ, Sete Lagoas, Brazil. 4. Division of Chemical Metrology, National Institute of Metrology, Quality and Technology, Rio de Janeiro, Brazil. 5. Institute of Chemistry, Chemistry Graduate Program, Biological Chemistry and Chemometrics Research Group, Federal University of Rio Grande do Norte - UFRN, Rio Grande do Norte, Brazil.
Abstract
AIMS: This work aimed to evaluate the antibacterial and antifungal activities of two types of pyroligneous acid (PA) obtained from slow pyrolysis of wood of Mimosa tenuiflora and of a hybrid of Eucalyptus urophylla × Eucalyptus grandis. METHODS AND RESULTS: Wood wedges were carbonized on a heating rate of 1·25°C min-1 until 450°C. Pyrolysis smoke was trapped and condensed to yield liquid products. Crude pyrolysis liquids were bidistilled under 5 mmHg vacuum yielding purified PA. Multi-antibiotic-resistant strains of Escherichia coli, Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) had their sensitivity to PA evaluated using agar diffusion test. Two yeasts were evaluated as well, Candida albicans (ATCC 10231) and Cryptococcus neoformans. GC-MS analysis of both PAs was carried out to obtain their chemical composition. Regression analysis was performed, and models were adjusted, with diameter of inhibition halos and PA concentration (100, 50 and 20%) as parameters. Identity of regression models and equality of parameters in polynomial orthogonal equations were verified. Inhibition halos were observed in the range 15-25 mm of diameter. CONCLUSIONS: All micro-organisms were inhibited by both types of PA even in the lowest concentration of 20%. SIGNIFICANCE AND IMPACT OF THE STUDY: The feasibility of the usage of PAs produced with wood species planted in large scale in Brazil was evident and the real potential as a basis to produce natural antibacterial and antifungal agents, with real possibility to be used in veterinary and zootechnical applications.
AIMS: This work aimed to evaluate the antibacterial and antifungal activities of two types of pyroligneous acid (PA) obtained from slow pyrolysis of wood of Mimosa tenuiflora and of a hybrid of Eucalyptus urophylla × Eucalyptus grandis. METHODS AND RESULTS: Wood wedges were carbonized on a heating rate of 1·25°C min-1 until 450°C. Pyrolysis smoke was trapped and condensed to yield liquid products. Crude pyrolysis liquids were bidistilled under 5 mmHg vacuum yielding purified PA. Multi-antibiotic-resistant strains of Escherichia coli, Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) had their sensitivity to PA evaluated using agar diffusion test. Two yeasts were evaluated as well, Candida albicans (ATCC 10231) and Cryptococcus neoformans. GC-MS analysis of both PAs was carried out to obtain their chemical composition. Regression analysis was performed, and models were adjusted, with diameter of inhibition halos and PA concentration (100, 50 and 20%) as parameters. Identity of regression models and equality of parameters in polynomial orthogonal equations were verified. Inhibition halos were observed in the range 15-25 mm of diameter. CONCLUSIONS: All micro-organisms were inhibited by both types of PA even in the lowest concentration of 20%. SIGNIFICANCE AND IMPACT OF THE STUDY: The feasibility of the usage of PAs produced with wood species planted in large scale in Brazil was evident and the real potential as a basis to produce natural antibacterial and antifungal agents, with real possibility to be used in veterinary and zootechnical applications.