title: Antimicrobial activity of coronarin D and its synergistic potential with antibiotics.
abstract: Coronarin D is a labdane-type diterpene from the rhizomes of Hedychium coronarium. In the view of our ongoing effort to explore its novel biological activity, antimicrobial activity study of coronarin D was performed. The results showed that coronarin D was active against tested Gram-positive bacteria, inactive for tested Gram-negative bacteria, and weakly active against tested fungi. The antibacterial effect of the combination of coronarin D with nine classical antibiotics against four Gram-positive bacteria was also evaluated. The fractional inhibitory concentration indices (FICI) of coronarin D-antibiotics combinations, calculated from the checkerboard assay, were used as synergism indicator. Out of 36 combinations, 47% showed total synergism, 33% had partial synergistic interaction, 17% showed no effect, and 3% showed antagonism. By combination with coronarin D at concentration of 0.25 minimal inhibitory concentration (MIC), the activities of antibiotics were boosted to 4- to 128-fold. These finding suggested an attractive approach to combat the infectious diseases by using coronarin D-antibiotic drug combination.
authors.affiliation: Laboratory of Organic Synthesis, Chulabhorn Research Institute, Vibhavadi-Rangsit Highway, Laksi, Bangkok 10210, Thailand.
authors.forename: Nanthawan
authors.initials: N
authors.lastname: Reuk-ngam
authors.affiliation: Laboratory of Natural Products, Chulabhorn Research Institute, Vibhavadi-Rangsit Highway, Laksi, Bangkok 10210, Thailand.
authors.forename: Nitirat
authors.initials: N
authors.lastname: Chimnoi
authors.affiliation: Laboratory of Organic Synthesis, Chulabhorn Research Institute, Vibhavadi-Rangsit Highway, Laksi, Bangkok 10210, Thailand.
authors.forename: Nisachon
authors.identifier: 0000-0002-0032-3075
authors.initials: N
authors.lastname: Khunnawutmanotham
authors.affiliation: Laboratory of Organic Synthesis, Chulabhorn Research Institute, Vibhavadi-Rangsit Highway, Laksi, Bangkok 10210, Thailand ; Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
authors.forename: Supanna
authors.initials: S
authors.lastname: Techasakul
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000890:Anti-Infective Agents / Q000008:administration & dosage; D004224:Diterpenes / Q000008:administration & dosage*; D004357:Drug Synergism; D005658:Fungi / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D004224:Diterpenes; C532843:coronarin D