Evaluation of Propiophenone, 4-Methylacetophenone and 2',4'-Dimethylacetophenone as Phytotoxic Compounds of Labdanum Oil from Cistus ladanifer L.

This is the first study to evaluate the phytotoxic activity of three phenolic compounds present in the essential oil of the labdanum of Cistus ladanifer, an allelopathic species of the Mediterranean ecosystem. Propiophenone, 4'-methylacetophenone, and 2',4'-dimethylacetophenone slightly inhibit total germination and radicle growth of Lactuca sativa, and they strongly delay germination and reduce hypocotyl size. On the other hand, the inhibition effect of these compounds on Allium cepa was stronger on total germination than on germination rate, and radicle length compared to hypocotyl size. The position and number of methyl groups will affect the efficacy of the derivative. 2',4'-dimethylacetophenone was the most phytotoxic compound. The activity of the compounds depended on their concentration and presented hormetic effects. In L. sativa, on paper, propiophenone presented greater inhibition of hypocotyl size at greater concentrations, with IC50 = 0.1 mM, whereas 4'-methylacetophenone obtained IC50 = 0.4 mM for germination rate. When the mixture of the three compounds was applied, in L. sativa, on paper, the inhibition effect on total germination and the germination rate was significantly greater compared to the effect of the compounds when they were applied separately; moreover, the mixture inhibited radicle growth, whereas propiophenone and 4'-methylacetophenone did not exert such effect when applied separately. The activity of the pure compounds and that of the mixture also changed based on the substrate used. When the trial was conducted in soil, the separate compounds delayed the germination of the A. cepa to a greater extent compared to the trial on paper, although they stimulated seedling growth. In soil, L. sativa against 4'-methylacetophenone also showed the opposite effect at low concentrations (0.1 mM), with stimulation of germination rate, whereas propiophenone and 4'-methylacetophenone presented a slightly increased effect.

Metal and metalloid concentrations in wild mammals from SW Europe: European hedgehog (Erinaceus europaeus) and badger (Meles meles).

In recent years, there have been increasing ecological and global concerns associated to Potentially Toxic Elements (PTEs). Thus, the relevance of wild mammals as biomonitors has been globally recognised. In the present study, Cd, Pb, Hg, Zn and As concentrations were quantified in European hedgehog and badger inhabiting SW Europe, and cumulative trends in relation to age and sex were evaluated. Liver and kidney samples were collected, mineralised and PTE content was determined by ICP-MS. Zn was the most abundant element quantified in both organs (239 and 89.8 mg kg-1 for hedgehogs and 179 and 164 mg kg-1 dw for badgers). In hedgehogs, very high Hg concentration were quantified (4.35 and 15.5 mg kg-1 dw in liver and kidney), and Cd was the most abundant for badgers (4.70 and 7.61 mg kg-1 dw in liver and kidney). Positive correlations were observed for the concentrations of PTE in the organs of both species. Age-dependence increased only Cd concentration, with levels in adult kidneys being significantly higher. In this study, European hedgehog and badger were used as biomonitors for the determination of PTEs to provide current reference values in relatively non-polluted areas of SW Europe, and to enhance the use of these species for future ecotoxicological studies.