| Abstract text: |
Phytoncides and phytoalexins are antibiotic substances that have been isolated from a large number of plants. Tropical plants in particular possess many antibacterial compounds, such as sophoraflavanone G (Sophora), calozeylaxanthone (Calophyllum), α-mangostin, and the stilbene olygomers of gnemonal B and gnetin E. Other plants like garlic (Allium sativum) and onion (Allium cepa), mustard (Sinapis alba), horseradish (Armoracia rusticana), radish (Raphanus sativus) and lichens (like Centraria islandica and Usnea barbata) also manifest antibiotic properties. The antibacterial activities of sophoraflavanone G, calozeylaxanthine, α-mangostine are observed as strong against methicillin-resistant Staphylococcus aureus (MRSA) and against vancomicyn-resistant enterococci (VRE). This was evaluated by measuring minimum inhibitory concentration (MIC) values determined by the agar dilution method of the Japanese Society of Chemotherapy. Allicine in garlic and dihydroallinine in onion are found to kill species of pathogens like methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Esterechia coli and Bacillus subtilis. Interaction between Phytoncides and phytoalexins and commercially available antibiotics, such as ampicilin, gentamicin, minocyclin, fosfomycin, and vancomycin hydrochloride, evaluated by using fraction inhibitory concentrations (FIC) indices measured by the MIC values of the compounds, alone or in combination with the antibiotic, have shown that there is a level of synergism between them. Because of the strong anti-VRE and anti-MRSA activities and because some of them show synergistic interactions, these compounds could be used in the medical field to decrease infectious bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomicyn-resistant enterococci (VRE). |
