Hypericum sp.: essential oil composition and biological activities

Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging EO improvement of some species of the genus.Fundação para a Ciência e a Tecnologia (FCT) - project PTDC/AGR AAM/70418/2006, SFRH/BD/ 13283/2003

Tanacetum vulgare essential oil as grain protectant against adults and larvae of four major stored-product insect pests

In this study the adulticidal and larvicidal effect of tansy, Tanacetum vulgare L. (Asteraceae) essential oil (EO) was estimated against four noxious stored-product insect species; Tribolium castaneum (Herbst) (Coleoptera: Tene-brionidae), Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). The EO chemical composition, as determined by GC-MS, was dominated by oxygenated monoterpenes (68.2%), with borneol (13.6%), umbellu-lone (11.7%), artemisia ketone (9.3%), cis-chrysanthenol (6.9%), camphor (5.9%), and terpinen-4-ol (5.5%) as the major constituents. This profile was quite different from those previously reported from other T. vulgare European accessions which are characterized by high content of the toxic trans-thujone. The T. vulgare EO was applied as wheat protectant at two concentrations of 500 and 1000 ppm. Adult and larval mortality levels were estimated after 4, 8 and 16 h and 1, 2, 3, 4, 5, 6 and 7 days. Tanacetum vulgare EO caused complete mortality (100%) to T. castaneum larvae, but only 25.6% to adults at 1000 ppm 6 and 7 days post-exposure, respectively. The mortality rates of T. confusum larvae and adults were 56.7 and 8.9% on wheat treated with 1000 ppm EO, respectively after 7 days of exposure. The ЕΟ caused moderate mortality to T. molitor adults (52.2%), and low mortality to larvae (8.9%), at 1000 ppm at the end of the experimental period. High mortality of O. surinamensis larvae (93.3%) was noticed at 1000 ppm after 7 days of exposure, while only 13.3% of the exposed adults were dead at the same concentration and exposure interval. Overall, the T. vulgare EO could be considered as a po-tential wheat protectant for the management of important stored-product insects. However, its efficacy depends on the species and the life stage of the target pest

Exploring essential oils of Slovak medicinal plants for insecticidal activity: the case of Thymus alternans and Teucrium montanum subsp. jailae

Thymus alternansandTeucrium montanumsubsp. jailaeare medicinal and aromatic plants, typical of Slovakianflora, producing bioactive essential oils. In the present study, we evaluated the insecticidal potential of theessential oils, obtained by hydrodistillation from the plant aerial parts and analysed by GC-MS, as insecticidalagents. For the purpose, they were assayed against three insect species acting as agricultural pests or vectors ofmedical relevance, such as the common housefly,Musca domesticaL., the lymphaticfilariasis vector,Culexquinquefasciatusand the Egyptian cotton leafwormSpodoptera littoralis;α-cypermethrin was tested as positivecontrol. The two essential oils exhibited a different chemical profile, with monoterpenes and sesquiterpenesbeing the main fractions in the essential oils fromTh. alternansandT. montanumsubsp. jailae, respectively.Insecticidal tests showed that theT. montanumessential oil was effective againstS. littoralis(LD50(90)= 56.7(170.0)μg larva−1) andCx. quinquefasciatuslarvae (LC50(90)= 180.5 (268.7) mg L−1), whereasT. alternansessential oil displayed good toxicity againstM. domesticaadults (LD50(90)= 103.7 (223.9)μg adult−1). Overall,our results add useful knowledge about the potential of Slovakianflora as a source of botanicals for the eco-friendly management of insect pests and vectors

Intra-population chemical polymorphism in Thymus pannonicus All. growing in Slovakia

Solid-phase microextraction technique coupled with gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry was used to investigate the inter- and intra-population chemical polymorphism in volatile constituents of three populations of Thymus pannonicus growing in Slovakia. To have an idea on what really the plant emits under different environmental and physiological conditions, a total of 86 individuals were separately analysed using low extraction temperatures (30°C). Data were analysed using a chemometric approach such as the principal component analysis which revealed a significant intra-population variability with the existence of up to four chemotypes: the most abundant is the p-cymene/γ-terpinene chemotype, followed by the geraniol and linalool chemotypes, and, only in one population, by the γ-muurolene/(E)-caryophyllene chemotype. This differentiation of individual plants inside the populations allows better adaptation to ecological conditions of localities and is probably connected with intrinsic genetic diversity of the species