Sir, The increasing resistance of head lice to established insecticides means that patients and parents are seeking alternative effective treatments (1). Essential oils, including tea tree oil and Biz Niz, are promoted as treatments for head lice by alternative medicine therapists. Tea tree oil is the essential oil steam distilled from the leaves and terminal branches of tea trees, in particula...

The compositions of essential oils (EOs) from Spanish marjoram (Thymus mastichina L.) grown in several bioclimatic zones of Murcia (SE Spain) were studied to determine their absolute and relative concentrations using gas chromatography-mass spectrometry. 1,8-Cineole and linalool were the main components, followed by α-pinene, β-pinene and α-terpineol. (-)-Linalool, (+)-α-terpineol and (+)-α-pin...

The inhibitory effects of nutmeg essential oil and three components of this oil at different concentrations were tested by GABA-induced chloride current (I GABA) stimulation through gamma-aminobutyric acid type A (GABAA) receptors comprising of α1β2γ2s subtype using the two-microelectrode voltage clamp technique on Xenopus laevis oocytes. The essential oil of the kernels of Myristica fragrans w...

Many secondary compounds are typically present in unpalatable shrubs on arid and semi-arid rangelands. However, the relationship between intake by livestock and concentration of individual chemicals has been examined for very few of these compounds. Four experiments were conducted to examine effects of individual volatile compounds on intake of alfalfa pellets by lambs. Forty-five lambs (9 lamb...

The relative proportions of chemical classes (hydrocarbons, oxides, alcohols, ketones, esters) in the essential oil of rosemary (Rosmarinus officinalis L., Lamicaeae) and in the volatile fraction of the infusion extracts were examined and showed remarkable differences.The volatile compounds of the infusion were isolated by two different methods, hydrodistillation and solid phase extraction (SPE...

Terpene synthases are responsible for the biosynthesis of the complex chemical defense arsenal of plants and microorganisms. How do these enzymes, which all appear to share a common terpene synthase fold, specify the many different products made almost entirely from one of only three substrates? Elucidation of the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined with ...

Chronic obstructive pulmonary disease (COPD) is a chronic obstructive lung disease and is frequently found in well-developed countries due to the issue of aging populations. Not all forms of medical treatment are unable to return a patient's limited pulmonary function back to normal and eventually they could require a lung transplant. At this time, COPD is the leading cause of death in the worl...

The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by 'shield budding'. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely or partially, leading to bad union of the buds with the rootstocks. Budding strips are used ver...

Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be descri...

Acute toxicities of 34 naturally occurring monoterpenoids were evaluated against 3 important arthropod pest species; the larva of the western corn rootworm, Diabrotica virgifera virgifera LeConte; the adult of the twospotted spider mite. Tetranychus urticae Koch; and the adult house fly. Musca domestica L. Potential larvicidal or acaricidal activities of each monoterpenoid were determined by to...