Ethanol extract of plants from biome 'cerrado' active against bacteria related to respiratory disease in pets

Abstract

Disorders of the respiratory tract occur in pets and signs of illness may include sniffling, difficulty breathing and discharge from the nose. Infections may be caused by bacteria, viruses, or sometimes by different microorganisms. Bacteria obtained from several pets as cats and dogs, presenting clinical signs were collected, cultured and then tested by in vitro assays (Kirby Bauer method) using ethanol extract from leaves of Anacardium humile, Byrsonima crassiflora, Eugenia dysenterica and Annona crassiflora, which were harvested in the Brazilian federal district. Brazilian savannah (cerrado) comprises high diversity of species well adapted to fire and to the seasonal contrast between the dry and the rainy seasons. The material was dried at 37 °C, transformed to powder by a grinder and used in maceration with ethanol for five days, under constant shaking, at room temperature. After, the extracts were filtered using a filter paper and concentrated using an evaporator at 50 °C. Here, bacteria obtained from different clinical cases in pets were tested by in vitro assay of agar diffusion method (Kirby Bauer modified). 30 µl of concentrated ethanol extract from all plants mentioned above were used in all tests. After 24h all extracts were able to inhibit the growth of all bacteria tested (Staphylococcus aureus, Pseudomonas aeruginosa, Bordetella bronchiseptica and Rhodococcus equi). A. humile and B. crassiflora extracts presented greater efficiency against B. bronchiseptica (halo of 20 mm and 14 mm, respectively). E. dysenterica extract was more effective against S. aureus (halo of 10 mm) and A. crassiflora extract inhibited more effectively R. equi (halo of 17 mm). Antibiotics are designed to kill bacteria that cause infection. However, in this process we can observe that some strains are highly resistant to most antibiotics available. Thus, this work contributes to the search for new agents effective against bacteria causing respiratory disease in pets.