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Origanum
About: Origanum is a research topic. Over the lifetime, 1565 publications have been published within this topic receiving 51822 citations.
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TL;DR: The volatile oils of black pepper, clove, and thyme exhibited considerable inhibitory effects against all the organisms under test while their major components demonstrated various degrees of growth inhibition.
Abstract: The volatile oils of black pepper [Piper nigrum L. (Piperaceae)], clove [Syzygium aromaticum (L.) Merr. & Perry (Myrtaceae)], geranium [Pelargonium graveolens L'Herit (Geraniaceae)], nutmeg [Myristica fragrans Houtt. (Myristicaceae), oregano [Origanum vulgare ssp. hirtum (Link) Letsw. (Lamiaceae)] and thyme [Thymus vulgaris L. (Lamiaceae)] were assessed for antibacterial activity against 25 different genera of bacteria. These included animal and plant pathogens, food poisoning and spoilage bacteria. The volatile oils exhibited considerable inhibitory effects against all the organisms under test while their major components demonstrated various degrees of growth inhibition.
4,014 citations
TL;DR: The essential oils obtained from the aerial parts of Origanum scabrum and Origaum microphyllum exhibited a very interesting antimicrobial profile after they were tested against six Gram-negative and -positive bacteria and three pathogenic fungi.
Abstract: The essential oils obtained from the aerial parts of Origanum scabrum and Origaum microphyllum, both endemic species in Greece, were analyzed by means of GC and GC-MS. Forty-eight constituents were...
810 citations
TL;DR: To quantify the antibacterial properties of five essential oils on a non‐toxigenic strain of Escherichia coli O157:H7 in the presence and absence of a stabilizer and an emulsifier and at three different temperatures.
Abstract: Aims: To quantify the antibacterial properties of five essential oils (EO) on a non-toxigenic strain of Escherichia coli O157:H7 in the presence and absence of a stabilizer and an emulsifier and at three different temperatures.
Methods and Results: Five EOs known to exhibit antibacterial properties were screened by disc diffusion assay and the most active were selected for further study in microdilution colorimetric assays. Oregano (Origanum vulgare) and thyme (Thymus vulgaris; light and red varieties) EO had the strongest bacteriostatic and bactericidal properties, followed by bay (Pimenta racemosa) and clove bud (Eugenia caryophyllata synonym: Syzygium aromaticum) EO. Oregano oil was colicidal at 625 μl l−1 at 10, 20 and 37°C. The addition of 0·05% (w/v) agar as stabilizer reinforced the antibacterial properties, particularly at 10°C, whereas 0·25% (w/v) lecithin reduced antibacterial activity. Scanning electron micrographs showed extensive morphological changes to treated cells.
Conclusions: Oregano and thyme EO possess significant in vitro colicidal and colistatic properties, which are exhibited in a broad temperature range and substantially improved by the addition of agar as stabilizer. Bay and clove bud EO are less active. Lecithin diminished antibacterial properties. The bactericidal concentration of oregano EO irreversibly damaged E. coli O157:H7 cells within 1 min.
Significance and Impact of the Study: Oregano and light thyme EO, particularly when enhanced by agar stabilizer, may be effective in reducing the number or preventing the growth of E. coli O157:H7 in foods.
787 citations
TL;DR: The most effective antibacterial activity was expressed by the essential oil of oregano, even on multiresistant strains of Pseudomonas aeruginosa and Escherichia coli, and a significant rate of antifungal activity of all of the examined essential oils was also exhibited.
Abstract: The essential oils of Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. were analyzed by means of gas chromatography−mass spectrometry and assayed for their antioxidant and antimicrobial activities. The antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with effects on lipid peroxidation (LP). RSC was assessed measuring the scavenging activity of the essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH•) and OH• radicals. Effects on LP were evaluated following the activities of essential oils in Fe2+/ascorbate and Fe2+/H2O2 systems of induction. Essential oils exhibited very strong RSCs, reducing the DPPH radical formation (IC50) in the range from 0.17 (oregano) to 0.39 μg/mL (basil). The essential oil of T. vulgaris exhibited the highest OH radical scavenging activity, although none of the examined essential oils reached 50% of neutralization (IC50). All of the tested essential oils strongly inhibited LP, induced either by Fe2+/ascorbate or by Fe2+/H2...
734 citations
TL;DR: The essential oil of O. vulgare ssp.
Abstract: Three Origanum essential oils, Origanum vulgare ssp. hirtum, Origanum dictamnus, and a commercially available Origanum oil, were analyzed by gas chromatography-mass spectrometry (GC-MS) and showed a high content of carvacrol, thymol, A-terpinene, and p-cymene representing 73.7%, 92.8%, and 87.78% of the total oil, respectively. The three essential oils exhibited high levels of antimicrobial activity against eight strains of Gram-positive and Gram-negative bacteria. Among the major components of the three oils, carvacrol and thymol exhibited the highest levels of antimicrobial activity, while their biosynthetic precursors A-terpinene and p-cymene were inactive. The essential oil of O. vulgare ssp. hirtum was extremely bactericidal at 1/4000 dilution and even at dilutions as high as 1/50000 caused considerable decrease in bacterial growth rates. The same essential oil also exhibited high levels of cytotoxicity against four permanent animal cell lines including two derived from human cancers.
728 citations