A Review on the Effect of Medicinal Plant Essences on the Performance of Probiotic Bacteria

Background and Essential oils are volatile components of plants. Some essential oils with phenolic compounds have a strong antimicrobial properties. Probiotics are live microbial food supplements which beneficially affect host by improving its intestinal microbial balance, and they are well recognized as antimicrobial agents that compete with pathogenic bacteria and inhibit their growth. Various types of probiotic bacteria have different sensitivities to essential oils. Some essential oils increase the growth of probiotics and some others decrease the growth or inhibit that. Simultaneous use of herbal essential oils and probiotics is a new approach in preventing growth of pathogenic bacteria in food, therefore, this study aimed at evaluating researches conducted in Iran about the effect of medicinal plant essential oils on the performance of probiotic microorganisms.
A literature search was conducted in electronic databases including Pubmed, Science Direct, Elsevier, SID, Magiran, and Google Scholar and articles published from 2006 until 2016 (the last decade) were selected. The search keywords included medicinal plants, probiotics, and growth inhibition.
The studies showed that compounds found in essential oils have different functions on probiotic bacteria. In other words, in some cases they acted as amplifiers and in some they showed inhibitory effects.
Essential oils of oregano, olive leaf, malt, cinnamon, garlic, dill, cumin, soy, and peppermint have positive effects on the growth of probiotic bacteria, while Kelussia, thyme, Teucrium polium and simultaneous use of oregano and Ziziphora have negative effect on probiotic growth.