The levels of total soluble phenols and the activity of the oxidative enzymes polyphenol oxidases and peroxidases were studied in healthy leaf tissue of cocoa (Theobroma cacao) clones SCA 6, TSH 1188, TSH 565, TSH 516, EET 397, EET 62, TSA 641, SIAL 505, RIM 106, RIM 52, SIC 24 and UF 613, for the purpose of detecting the possible resistance mechanism(s) to Crinipellis perniciosa. The total soluble phenol content of T. cacao clones with resistance to C. perniciosa was generally higher than in the susceptible clones, which may contribute to defense against the pathogen. The activity of polyphenol oxidases was lower in the resistant clones compared to the susceptible ones. The activity of peroxidases in mature leaves was lower in resistant clones, but when considering young leaves it was not possible to establish a clear relation between the activity of this enzyme with resistance. The levels of soluble phenols and the activity of oxidative enzymes studied were inversely correlated in the majority of the studied clones, suggesting a possible inhibition of the oxidative enzymes by phenols.
