Essential oils--their antimicrobial activity against Escherichia coli and effect on intestinal cell viability.
Fabian D, Sabol M, Domarack� K, Bujn�kov� D. Institute of Animal Physiology, Slovak Academy of Sciences, Solt�sovej 4-6, 04001 Kosice, Slovakia. [email protected]
Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria. The main objective of this study was to evaluate possible harmful effects of four commonly used essential oils and their major components on intestinal cells. Antimicrobial activity of selected plant extracts against enteroinvasive Escherichia coli was dose dependent. However, doses of essential oils with the ability to completely inhibit bacterial growth (0.05%) showed also relatively high cytotoxicity to intestinal-like cells cultured in vitro. Lower doses of essential oils (0.01%) had only partial antimicrobial activity and their damaging effect on Caco-2 cells was only modest. Cell death assessment based on morphological and viability staining followed by fluorescence microscopy showed that essential oils of cinnamon and clove and their major component eugenol had almost no cytotoxic effect at lower doses. Although essential oil of oregano and its component carvacrol slightly increased the incidence of apoptotic cell death, they showed extensive antimicrobial activity even at lower concentrations. Relatively high cytotoxicity was demonstrated by thyme oil, which increased both apoptotic and necrotic cell death incidence. In contrast, its component thymol showed no cytotoxic effect as well as greatly-reduced ability to inhibit visible growth of the chosen pathogen in the doses used. On the other hand, the addition of all essential oils and their components at lower doses, with the exception of thyme oil, to bacterial suspension significantly reduced the cytotoxic effect of E. coli on Caco-2 cells after 1h culture.
In conclusion, it is possible to find appropriate doses of essential oils showing both antimicrobial activity and very low detrimental effect on intestinal cells.
PMID: 16919909
1: J Environ Biol. 2007 Jan;28(1):145-6.
Antimicrobial activity of methanol extract of Origanum majorana L. (Sweet marjoram).
Leeja L, Thoppil JE. Genetics and Plant Breeding Division, Department of Botany, University of Calicut-673 635, India.
In-vitro microbicidal activity of the methanol extract of Origanum majorana L. was tested against seven fungi (Fusarium solani, Candida albicans, Aspergillus niger, A. parasiticus, Rhizopus oryzae, Rhizoctonia otyzae-sativae and Altemaria brassicicola) and six bacteria (Bacillus subtilis, B. megaterium, Escherichia coil, Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus).
The methanol extract of O. majorana can be used as an effective herbal protectant against different pathogenic bacteria and fungi. High toxicity against the growth of Aspergillus niger was diagnosed.
PMID: 17718003
1: Arch Latinoam Nutr. 2004 Mar;54(1):100-11.
Oregano: properties, composition and biological activity
Arcila-Lozano CC, Loarca-Pi�a G, Lecona-Uribe S, Gonz�lez de Mej�a E.PROPAC, Facultad de Qu�mica, Universidad Aut�noma de Quer�taro.
The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found.
The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods.
Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others.
These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods.
There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer.
PMID: 15332363
-------------------- There is no wealth but life. -John Ruskin
All truth goes through 3 stages: first it is ridiculed: then it is violently opposed: finally it is accepted as self evident. - Schopenhauer Posts: 5639 | From Aptos CA USA | Registered: Apr 2005
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It's true that we need more in vivo studies, but the in vitro ones are promising. It kills yeast, staph, salmonella, E. coli and other things (staph in a test tube as well as traditional antibiotics, according to research out of Georgetown Univ.) It's being studied as a food additive to prevent contamination - only problem is it changes the taste.
There are in vivo animal studies of oregano oil which show its effectiveness against candida/yeast in mice.
There's also a small, uncontrolled human study where it helped clear up intestinal parasitic infections in the majority of patients.
Worked against yeast for me. I didn't use emulsified, I put drops in empty capsules.
Posts: 621 | From US | Registered: Jun 2006
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