When attacked by herbivorous insects, plants emit volatile compounds that attract natural enemies of the insects. It has been proposed that these volatile signals can be manipulated to improve crop protection. Here, we demonstrate the full potential of this strategy by restoring the emission of a specific belowground signal emitted by insect-damaged maize roots. The western corn rootworm induce...

Plants release a blend of volatile defense compounds in response to herbivore feeding. Whereas some of these volatiles act as direct deterrents, others serve as indirect defense signals that attract natural enemies of the foraging herbivores (reviewed in Dicke et al., 2003). For instance, the signal emitted from maize leaves damaged by lepidopteran larvae attracts parasitic wasps that deposit t...

A comparative study of the chemical composition of essential oils of two very similar species of the Verbenaceae family (Lantana camara and L. radula) revealed that the main components of essential oil of L. camara were germacrene-D (19.8%) and E-caryophyllene (19.7%), while those of L. radula were E-caryophyllene (25.3%), phytol (29.2%) and E-nerolidol (19.0%). We have hypothesized that the ob...

The essential oils of leaves and twigs from the Euphorbiaceous Croton draconoides, C. urucurana and Julocroton triqueter were obtained and analyzed by GC and GC-MS. In total, 101 volatile constituents were identified, comprising an average of 90% of the oil, mostly made up of mono- and sesquiterpenes. The monoterpene hydrocarbons varied from 1.2 to 40.2%, the sesquiterpene hydrocarbons from 34....

Caryophyllene-6,7-epoxide and caryophyllene-6,7-episulfi de can be easily synthesized from -caryophyllene by autoxidation or episulfi dation. The bioactivities of -caryophyllene and its derivatives were investigated against the subterranean termite Reticulitermes speratus Kolbe. The antifeedant, feeding, and termiticidal activities of each compound were tested using no-choice, dual-choice, and ...

The present study reports a bioassay-guided isolation of β-caryophyllene from the essential oil of Aquilaria crassna. The structure of β-caryophyllene was confirmed using FT-IR, NMR and MS. The antimicrobial effect of β-caryophyllene was examined using human pathogenic bacterial and fungal strains. Its anti-oxidant properties were evaluated by DPPH and FRAP scavenging assays. The cytotoxicity o...

Polymers with their myriad functions are indispensable to any modern technology. Today, their production is largely based on fossil fuels. In view of their limited range, other sources are desirable on the long term. Beyond such considerations, renewable resources are also attractive as they can contain unique chemical structures. Thus, carbohydrates, fatty acids or terpenes contain a wealth of...

The essential oils of the aerial part of two Asteraceae species, namely Euryops arabicus Steud. and Laggera decurrens (Vahl.) Hepper and Wood, were studied by GC and GC/MS. In parallel the antimicrobial and antioxidant activities were evaluated. The investigation led to the identification of 48 and 44 compounds for both plants, respectively. The essential oil of E. arabicus was rich in oxygenat...

The chemical composition of the essential oil of Etlingera yunnanensis rhizomes and its contact and repellent activities against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel) were investigated. The essential oil obtained from E. yunnanensis rhizomes with hydrodistillation was performed by gas chromatography-flame ionization detection and gas chromatography-mass spectrome...