In this study, the total phenolic content, the antioxidant activity and toxicity of selected Greek medicinal aromatic namely Melissa officinalis L., Origanum vulgare L., Origanum dictamnus L., Salvia officinalis L. and Hyssopus officinalis L., were investigated under three different extraction processes. Among the plants studied, Melissa officinalis L. showed the highest values in total phenolic content (0.985 ± 0.001 mg caffeic acid/mL) and antioxidant activity (6.61 ± 0.04 mol Trolox/mL) independently of the extraction process. Toxicity evaluation of the infusions prepared in concentrations contained in commercial portions showed that inhibition values of Origanum vulgare L. and Origanum dictamnus L. were greater than 20% thus further research is necessary. Although toxicity of plant extracts examined is not correlated to their total phenolic content and antioxidant activity, it was linked to the interaction of water soluble and volatile organic compounds. Interaction of water soluble and volatile organic compounds was evaluated through the estimation of synergism ratios (SR), where Origanum vulgare L., presented the maximum synergism (SR = 4.2) in toxicity

In response to attack by herbivorous insects, plants produce semiochemicals for intra- and interspecific communication. The perception of these semiochemicals by conspecifics of the herbivore defines their choice for oviposition and feeding. We aimed to investigate the role of herbivore-induced plant volatiles (HIPVs) by Tuta absoluta larvae on the oviposition choice of conspecific females on tomato plants. We performed two- choice and non-choice bioassays with plants damaged by larvae feeding and intact control plants. We also collected headspace volatiles of those plants and tested the response of female antennae on those blends with Gas Chromatography- Electro-Antennographical Detection (GC-EAD). In total 55 compounds were collected from the headspace of T. absoluta larvae-infested plants. Our results show that female moths preferred to oviposit on intact control plants instead of damaged ones. Herbivory induced the emission of hexanal, (Ζ)-3-hexen-1-ol, (E)-β-ocimene, linalool, (Z)-3-hexenyl butanoate, methyl salicylate, indole, nerolidol, guaidiene-6,9, β-pinene, β-myrcene, α-terpinene, hexenyl hexanoate, β-elemene, β-caryophyllene and (Ε-Ε)- 4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), one unidentified sesquiterpene and three unknown compounds. In Electroantennographic (EAG) assays, the antennae of T. absoluta females responded to hexanal, (Ζ)-3-hexen-1-ol, methyl salicylate and indole. The antennae of T. absoluta females exhibited a dose-response in EAG studies with authentic samples. Strong EAG responses were obtained for compounds induced on damaged tomato plants, as well as in nonanal, a compound emitted by both infested and control plants. These compounds could be utilized in integrated pest management of T. absoluta.

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BACKGROUND: Saffron (Crocus sativus L.) is one of the most valuable spices and nowadays its main use is as a foodstuff. Numerous papers have been published on saffron aroma and its volatile content, but nothing has been written about the aroma quality of samples available on the market to consumers. The aim of this study was to analyse and compare 418 commercial samples of saffron belonging to different ISO categories. Ultrasound-assisted extraction (USAE) with an organic solvent and dynamic headspace desorption (DHD) followed by gas chromatography/mass spectrometry were used to screen for saffron volatile composition.