Based on literature data it can be concluded essential oils originating from plants have anti- microbial activity and have toxic effects in poultry only when administered at very high doses. Antioxidant activity and hypocholesterolemic effects have been reported in chickens. In various studies, but not all, a growth enhancing effect of essential oils has been found. The characteristic flavor of essential oils might play role in poultry performance, but this needs to be confirmed. Essential oils may stimulate the digestion process. It appears that individual compounds of an essential oil have a wide range of activities and may act in an additive, synergistic and antagonistic fashion. The effect of essential oils in poultry may not only be confined to the microflora, but may extend to animal metabolism. Knowing the activity and effects of individual compounds is useful to formulate mixtures of compounds so as to enhance efficacy. In conclusion, dietary essential oils may be used as alternatives to antibiotics, but whether their effects on growth performance are a consequence of anti-microbial activity needs to be studied further.

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Essential oils in broiler nutrition

Fumigant toxicity of essential oil from Artemisia sieberi Besser against three stored-product insects

In traditional medicine Cinnamon is considered a remedy for respiratory, digestive and gynaecological ailments. In-vitro and in-vivo studies from different parts of the world have demonstrated numerous beneficial medicinal effects of Cinnamomum zeylanicum (CZ). This paper aims to systematically review the scientific literature and provide a comprehensive summary on the potential medicinal benefits of CZ. A comprehensive systematic review was conducted in the following databases; PubMed, Web of Science, SciVerse Scopus for studies published before 31st December 2012. The following keywords were used: “Cinnamomum zeylanicum”, “Ceylon cinnamon”, “True cinnamon” and “Sri Lankan cinnamon”. To obtain additional data a manual search was performed using the reference lists of included articles. The literature search identified the following number of articles in the respective databases; PubMed=54, Web of Science=76 and SciVerse Scopus=591. Thirteen additional articles were identified by searching reference lists. After removing duplicates the total number of articles included in the present review is 70. The beneficial health effects of CZ identified were; a) anti-microbial and anti-parasitic activity, b) lowering of blood glucose, blood pressure and serum cholesterol, c) anti-oxidant and free-radical scavenging properties, d) inhibition of tau aggregation and filament formation (hallmarks of Alzheimer’s disease), e) inhibitory effects on osteoclastogenesis, f) anti-secretagogue and anti-gastric ulcer effects, g) anti-nociceptive and anti-inflammatory activity, h) wound healing properties and i) hepato-protective effects. The studies reported minimal toxic and adverse effects. The available in-vitro and in-vivo evidence suggests that CZ has many beneficial health effects. However, since data on humans are sparse, randomized controlled trials in humans will be necessary to determine whether these effects have public health implications.

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Medicinal properties of ‘true’ cinnamon (Cinnamomum zeylanicum): a systematic review

GC/MS evaluation of thyme (Thymus vulgaris L.) oil composition and variations during the vegetative cycle

Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

Effects of thyme oils extracted from nine Thymus vulgaris chemotypes, cinnamon oil (Cinnamomum zeylanicum), cinnamaldehyde and carvacrol were studied on growth of Malassezia furfur and Candida albicans. The last three substances and the carvacrol chemotype of thyme oil were the most efficient against the two yeasts. Yeast growth was monitored throughout eight days under log-step concentrations (1 μg/mL-1000 μg/mL) of these four substances. MICs (minimum inhibitory concentrations) and MLCs (minimum lethal concentrations) were also determined by two different methods: poisoned food and dilution-neutralization methods. MICs and MLCs values obtained by the former are lower than those determined by the latter. M.fitrfurwas observed to be more sensitive to cinnamon oil and cinnamaldehyde, while C. albicans was more sensitive to thyme oil and carvacrol. It was also found that essential oil activity is mainly due to their respective major components.

Antifungal Activity of Selected Essential Oils, Cinnamaldehyde and Carvacrol against Malassezia furfur and Candida albicans

The effect of oregano (Origanum compactum Benth.), mugwort (Artemisia herba-alba Asso) and eucalyptus (Eucalyptus globulus Labill.) oils on spore germination, mycelial elongation and sporulation were studied in three fungi. All three stages of fungal asexual reproduction were affected, but mycelium growth was the most sensitive, followed by spore germination and then sporulation. Of the three fungi studied, Zygorrhynchus sp. was found to be the most sensitive followed by Aspergillus niger and then Penicillium italicum. Oregano oil was observed to be the most active on the three phenomena studied, followed by mugwort at spore germination and sporulation stages and eucalyptus oil when mycelial elongation was considered. The antifungal activity at all three stages of asexual reproduction was shown to be related to oil composition.

Hicham Ferhout

Papers

Antifungal Activity of Selected Essential Oils, Cinnamaldehyde and Carvacrol against Malassezia furfur and Candida albicans

Inhibition of the fungal asexual reproduction stages by three Moroccan essential oils