Toxicity evaluation in a series of natural phenolic compounds with pesticidal activity

Plant diseases caused by fungi are of considerable economic concern due to crop production losses. The fungicides currently used to control fungal infections may be toxic, and harmful to the environment and human health. Many naturally-occurring phytochemicals in plants have been reported to exhibit antifungal activity, showing in addition beneficial activities for human health, instead of toxicity of synthetic fungicides. The present study attempts to evaluate the aquatic toxicity of some natural phenolic compounds with already demonstrated antifungal activity, using a modern computational structural-toxicity method, respectively Hyper Chem Professional by CSTR system, semi-empirical optimization, algorithm Polak-Ribiere. Computational measured toxicity values were considered as dependent variables and were related to structural features obtained by molecular and quantum mechanics calculations by MLR approaches. The obtained model was validated. The results showed that toxicity of studied natural phenols was strongly influenced by log Kow, HOMO orbital and dipole moment.