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The fungotoxicity against Botrytis cinerea of a flavonoid isolated from Pseudognaphalium robustum was analyzed. Two absorption column chromatographies and one semipreparative thin layer chromatography were used to purify the active flavonoid. It was determined, by 1H-NMR spectroscopy and co-elution with standards in HPLC, that this compound was 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A). To determine the fungitoxicity of the purified compound, the effect on in vitro mycelial growth and conidial germination was studied. The compound concentration that reduced mycelial growth by 50% was 45.5 μg/mL. This compound also partially affected conidial germination of B. cinerea, reduced oxygen consumption by germinating conidia and affected the integrity of plasma membrane. Finally, using cyclic voltammetry, it was shown that the purified flavone had a pro-oxidant effect.

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This paper reports the use of a new LC method with a fused-core analytical column coupled to ESI-MS to determine residues of the biopesticide spinosad in bee pollen and beeswax. The method analyzes the active ingredients, spinosyns A and D, with a simple and efficient sample treatment (recovery between 90 and 105%) consisting of a solid-liquid extraction with acetone (bee pollen) or acetonitrile (beeswax). The method was validated in terms of selectivity, LOD, LOQ, linearity, and precision. The LOD and LOQ values ranged between 0.1-0.2 and 0.4-0.7 μg/kg, respectively. Moreover, the precision obtained within the linear concentration range (LOQ 500 μg/kg) was satisfactory (RSD lower than 5%). Finally, the proposed method was applied to analyze bee pollen and beeswax samples collected from apiaries located close to fruit orchards in two Spanish regions.