Avaliação do potencial antimicrobiano e antioxidantedos taninos das cascas de espécies arbóreas

Abstract

This work aimed to carry out a bibliometric review on the use of tannic extracts as antimicrobial agents and to evaluate the antioxidant and antibacterial potential of tannic substances from the stem barks of woody species with a view to aiding the treatment of bovine mastitis and foodborne toxin infection. Scopus was the database used for the bibliometric and state-of-the-art analyses. The barks of the species Mimosa tenuiflora Willd.; Mimosa caesalpiniifolia Benth.; Anacardium occidentale L.; Stryphnodendron adstringens (Mart.) Coville.and the commercial tannin of Acacia mearnsii De Willd. were used for chemical characterization and determination of the antimicrobial and antioxidant potential of the tannins. The total solid content (TST), Stiasny Index (IS), condensed tannin content (TCT), total phenols and flavonoids ; the chemical constitution of the tannin by Fourier Transform Infrared Spectroscopy (FTIR) and chemical composition of the extracts by liquid chromatography (HPCL) were determinated. Antioxidant activity was estimated by DPPH method. The antimicrobial potential was determined by disc diffusion technique, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), respectively, with clinical and subclinical isolated strains of bovine mastitis and bacteria associated with food toxinfection. The bibliometric analysis accounted for 320 studies, also becoming evident the lack of interaction between the most influential authors and institutions. M. tenuiflora showed the highest percentage of TCT in the bark (37.27%), while for HS, A. occidentale and M. caesalpiniifolia stood out in relation to the others, with values above 90%. The presence of the OH groups was common to all the tannins evaluated. Catechin concentration was higher for A. mearnsii and gallic acid for A. occidentale, with values of 1634.48 and 115.2 mg/100g, respectively. All tannins showed better antioxidant potential than BHT and proved to be excellent antimicrobial agents. However, E. coli bacteria showed higher resistance when compared to the other bacteria analyzed. Therefore, tannins have the potential to be used as antioxidants and antimicrobial agents for the treatment of bovine mastitis and bacterial foodborne infections.