Essential oils (EOs) have been long recognized for their antibacterial, antifungal, antiviral, insecticidal and antioxidant properties. They are widely used in medicine and the food industry for these purposes. The increased interest in alternative natural substances is driving the research community to find new uses and applications of these substances. EOs and their components show promising activities against many food-borne pathogens and spoilage microorganisms when tested in vitro. In food systems, higher concentrations of EOs are needed to exert similar antibacterial effects as those obtained in in vitro assays. The use of combinations of EOs and their isolated components are thus new approaches to increase the efficacy of EOs in foods, taking advantage of their synergistic and additive effects. The purpose of this review is to provide an overview on the antimicrobial efficacy of these combinations. A survey of the methods used for the determination of the interactions and mechanisms involved in the antimicrobial activities of these combinations are also reported.

Essential oils in combination and their antimicrobial properties.

Gas chromatographic retention indices were evaluated for 505 frequently reported plant essential oil components using a large retention index database. Retention data are presented for three types of commonly used stationary phases: dimethyl silicone (nonpolar), dimethyl silicone with 5% phenyl groups (slightly polar), and polyethylene glycol (polar) stationary phases. The evaluations are based on the treatment of multiple measurements with the number of data records ranging from about 5 to 800 per compound. Data analysis was limited to temperature programmed conditions. The data reported include the average and median values of retention index with standard deviations and confidence intervals.

Retention Indices for Frequently Reported Compounds of Plant Essential Oils

Acute and chronic toxicological studies of Ajuga iva in experimental animals

Screening of selected indigenous plants of Lebanon for antimicrobial activity.

Plants based pest control agents have long been touted as alternatives to synthetic chemicals for integrated pest management. Such phytochemicals reputedly pose little threat to the environment or to human health. Bioactivity of plant-based compounds is well documented in literature and is a subject of increasing importance. An antifeedant approach for insect control has been extensively studied, at least at laboratory level, though only a handful of plant-based compounds are currently used in agriculture. The known active plant-based antifeedants belong to groups like chromenes, polyacetylenes, saponins, quassinoids, cucurbitacins, cyclopropanoid acids, phenolics, alkaloids, various types of terpenes and their derivatives etc., and each insect species may process these allomones in a thoroughly idiosyncratic way, so that the same compound may have very different fates and consequences in different species of insects, thus pointing to different mechanisms involved in antifeedant action. It can also be vis...

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Phytochemicals and Insect Control: An Antifeedant Approach

Responses of Spodoptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves.

A flavanone and a flavanone glycoside, together with vomifoliol, have been isolated for the first time from the aerial parts of the plant Echiochilon fruticosum and identified. Their structures were established on the basis of spectroscopic measurements, mainly 2D NMR using COSY, HMQC and HMBC experiments.

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Isolation and Structure Elucidation of a Flavanone, a Flavanone Glycoside and Vomifoliol from Echiochilon Fruticosum Growing in Tunisia

Chemical composition and antimicrobial activity of essential oils of Cupressus arizonica Greene

Antifeedant activity of plant extracts and of new natural diglyceride compounds isolated from Ajuga pseudoiva leaves against Spodoptera littoralis larvae.

H. Ben Jannet

Papers

Responses of Spodoptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves.

Isolation and Structure Elucidation of a Flavanone, a Flavanone Glycoside and Vomifoliol from Echiochilon Fruticosum Growing in Tunisia

Chemical composition and antimicrobial activity of essential oils of Cupressus arizonica Greene

Antifeedant activity of plant extracts and of new natural diglyceride compounds isolated from Ajuga pseudoiva leaves against Spodoptera littoralis larvae.

Neo-clerodane diterpenoids from Ajuga pseudoiva leaves