Evaluation of the antimicrobial and anti-Varroa destructor L. activity of the essential oil of clove (Syzygium aromaticum L. Myrtaceae)

Antimicrobial and anti-Varroa destructor L. activity of the essential oil (EO) of clove (Syzygium aromaticum L. Myrtaceae) was evaluated in this study. Antimicrobial activity concerned 9 bacterial strains (Bacillus cereus, Escherichia coli ATCC 25911, Staphylococcus aureus 29213 ATCC, Proteus mirabilis, Serratia marcescens, Enterobacter sakazakii, Pseudomonas aeruginosa ATCC, Escherichia coli and Acinetobacter sp.), a fungal strain (Penicillium sp.) and a yeast species (Candida albicans). The extraction of the EO was carried out by the method of hydrodistillation. Results showed that EO has no toxicity on bees Apis mellifera. EO demonstrated effective and stable anti-V. destructor activity, indicating the absence of possible resistance, in contrast to what was observed for Amitraz. The inhibitory activity of EO revealed an inhibition zone of diameter varying between 20 mm and 42 mm for bacteria. However, no inhibition zones were observed for Pseudomonas aeruginosa ATCC. The inhibitory activity of EO on Penicillium sp and Candida albicans revealed an inhibition zone of 39 mm in diameter. This study shows that the EO of cloves constitutes a simple and natural treatment, without inconveniences, with a high activity antimicrobial and anti-Varroa destructor which merits it to be proposed as a means to fight against varroosis and the tested pathogens.