Volatiles profiling and bioactivities of <i>Cupressus</i> spp. leaf and cone essential oils as analyzed via chemometrics tools

<p><i>Cupressus</i> is a genus of considerable medicinal value worldwide. The present work aims at assessing essential oil compositional differences within <i>Cupressus</i> in the context of its different genotypes and organs. Volatiles profiling was determined via gas chromatography-mass spectrometry coupled to chemometrics. A total of 75 volatile components were identified. Monoterpene hydrocarbons amounted for the major volatile class, with α-pinene and 3-carene most abundant in <i>Cupressus sempervirens</i> versus sabinene and terpinen-4-ol in <i>Cupressus macrocarpa</i>. Multivariate data analyses revealed that α-pinene, sabinene, terpinen-4-ol and 3-carene are the most significant for species classification. The five examined essential oils exhibited potential insecticidal and anticholinesterase effects, with C. <i>sempervirens</i> var. pyramidalis cone oil being the most potent for acetylcholinesterase inhibitory effect. The oil also exhibited potential fumigant toxicity toward <i>Sitophilus oryzae</i> and <i>Tribolium castaneum</i>.  The results of the orthogonal partial least-square discriminant analysis revealed that α-pinene is the key bioactive component in <i>Cupressus oil</i>.</p

Chemical composition, antimicrobial and insecticidal activities of the essential oils of <i>Conyza linifolia</i> and <i>Chenopodium ambrosioides</i>

<div><p>Two essential oil-containing plants growing wildly in Egypt: <i>Conyza linifolia</i> (Willd.) Täckh. (Asteraceae) and <i>Chenopodium ambrosioides</i> L. (Chenopodiaceae) were subjected to essential oil analysis and biological investigation. The essential oils from both plants were prepared by hydrodistillation, and GC/MS was employed for volatiles profiling. This study is the first to perform GC/MS analysis of <i>C. linifolia</i> essential oil growing in Egypt. <i>C. linifolia</i> essential oil contained mainly sesquiterpenes, while that of <i>C. ambrosioides</i> was rich in monoterpenes. Ascaridole, previously identified as the major component of the latter, was found at much lower levels. In addition, the oils were investigated for their antimicrobial activity against two Gram positive and two Gram negative bacteria, and one fungus. The insecticidal activities of both oils, including mosquitocidal and pesticidal potentials, were also evaluated. The results of biological activities encourage further investigation of the two oils as antimicrobial and insecticidal agents of natural origin.</p></div