Essential oils as antibacterial agents against food-borne pathogens: are they really as useful as they are claimed to be ?

Original articleMost studies evaluating the use of essential oils (EO) as antibacterial agents focus mainly on minimal inhibitory concentrations (MIC) rather than minimal bactericidal concentrations (MBC). In this work, we compared MICs and MBCs of EO from condiment plants commonly used in Mediterranean Europe, namely Origanum vulgare, Salvia lavandulaefolia, Salvia officinalis, Salvia sclarea and Rosmarinus officinalis, aiming to evaluate their application as disinfecting agents in minimally processed produce. Outbreaks-related pathogens such as Listeria monocytogenes, Pseudomonas aeruginosa and Yarrowia lipolytica were used. Results showed that all EO were able to reduce bacterial growth in all bacterial strains tested, particularly O. vulgare. However, fewer EO exhibited bactericidal activities, and were only effective against one or two bacterial strains, hence eliminating the possibility to use them as broad range disinfectants. Furthermore, the necessary concentrations were too high for food application. Hence, our work suggests the need to evaluate MBC rather than MIC and questions EO usefulness in controlling undesired microorganisms. Overall, and despite the large volume of data published on EO, results obtained were not very encouraging for a realistic application on produce and question the viability of EOs as disinfecting agents in foodinfo:eu-repo/semantics/publishedVersio

Anti- Sporothrix spp. activity of medicinal plants

ABSTRACT Cases of sporotrichosis in humans and animals without satisfactory clinical response have increased, a warning sign of strains resistant to conventional antifungal agents. The urgent search for alternative therapies was an incentive for research on medicinal plants with anti-Sporothrix spp. properties. A bibliographic survey was performed based on scientific papers about in vitro and in vivo antifungal activity of essential oils and extracts of plants in differents solvents against the fungal of the Sporothrix schenckii complex. The study methodology consisted of a literature review in Google Scholar, Science Direct, Pubmed, Bireme and Springer link with papers from 1986 to 2015. We found 141 species of plants that were investigated, of which 100 species were concentrated in 39 botanical families that had confirmed anti-Sporothrix activity. Combretaceae, Asteraceae and Lamiaceae represented the botanical families with the greatest number of plants species with antifungal potential, using different methodologies. However, there are few studies with medicinal plants in experimental infection in animals that prove their activity in the treatment of sporotrichosis. It reinforces the need for further research related to standardization of in vitro methodologies and in vivo studies related to safety and to toxicity potential of these plants with anti-Sporothrix spp. activity