Bioactivity of Rosmarinus officinalis essential oils against Apis mellifera, Varroa destructor and Paenibacillus larvae related to the drying treatment of the plant material

MAGGI M.; GENDE L.; RUSSO K.; FRITZ R.; EGUARAS M.

NATURAL PRODUCT RESEARCH

TAYLOR & FRANCIS LTD

Año: 2011 vol. 25 p. 397 - 406

1478-6419

In this study, chemical composition, physicochemical properties andbioactivity of two essential oils of Rosmarinus officinalis extracted fromplant material with different drying treatments against Apis mellifera,Varroa destructor and Paenibacillus larvae were assessed. The lethalconcentration 50 (LC50) for mites and bees was estimated using acomplete exposure method test. The broth microdilution method wasfollowed in order to determine the minimum inhibitory concentrations(MICs) of the essential oils against P. larvae. Physicochemical propertieswere similar in both the essential oils, but the percentage of componentsshowed certain differences according to their drying treatment. -Myrceneand 1,8-cineole were the main constituents in the oils. The LC50 forcomplete exposure method at 24, 48 and 72 h was minor for mitesexposed to R. officinalis essential oil dried in oven conditions. MIC valueswere 700–800 mgmL1 and 1200 mgmL1 for R. officinalis dried in air andoven conditions, respectively. The results reported in this research showthat oil toxicity against V. destructor and P. larvae differed dependingon the drying treatment of the plant material before the distillation ofessential oil.