The influence of 60Co gamma radiation on the action of phenolic compounds of Anadenanthera colubrina (Vell.) Brenan in the microbiological control of crude extracts

Abstract

This study investigates the influence of gamma radiation on the total phenols, tannins and antimicrobial activity of ethanolic plant extracts of the bark and leaves of Anadenanthera colubrina (Vell.) Brenan (angico). The extracts were separated into four groups (0, 5, 7.5 and 10 kGy) to quantify total phenols (Folin-Ciocalteu method), tannins (precipitation of casein), and antimicrobial activity (disk diffusion of Gram-positive, Gram-negative, acid-alcohol-resistant bacteria and yeasts; Minimal Inhibitory Concentration (MIC) of Gram positive and alcohol-acid resistant bacteria). Tannin levels were 52% to 57% of total phenols in bark, and 58% to 60% in leaves, and there was no statistically significant difference between groups. There was antimicrobial activity against Gram-positive and alcohol-acid-resistant bacteria (bark and leaves) and Gram-negative bacteria and yeasts (leaves). However, the gamma radiation had no influence on the levels of total phenols and tannins or the antimicrobial activity of extracts of bark and leaves of A. colubrina.