title: Positive antibacterial co-action between hop (Humulus lupulus) constituents and selected antibiotics.
abstract: The research reported here deals with co-action of the hop (Humulus lupulus)-derived anti-bacterial compounds, lupulone and xanthohumol, with several antibiotics. Among the antibiotics investigated for their co-action, polymyxin B sulfate, tobramycin and ciprofloxacin had a positive co-action in inhibiting selected test bacteria. The disc/well-diffusion assay and the minimum inhibitory concentration test (MIC) were employed to determine co-action. Both Gram-positive and Gram-negative bacteria were used in the evaluation. There was some co-action against all Gram-positive bacteria tested. Surprisingly, there was some positive co-action even against certain Gram-negative bacteria but not against others. Particularly, there was no co-action against E.coli. An antibacterial cream with lupulone, neomycin and polymyxin B sulfate was prepared and showed co-action. Ideas for other practical applications of this effect are put forth. The mechanism of the synergistic effect is briefly discussed but no attempt was made to prove it experimentally.
authors.affiliation: School of Natural Sciences, Fairleigh Dickinson University, Teaneck, NJ, USA.
authors.forename: P
authors.initials: P
authors.lastname: Natarajan
authors.forename: S
authors.initials: S
authors.lastname: Katta
authors.forename: I
authors.initials: I
authors.lastname: Andrei
authors.forename: V
authors.initials: V
authors.lastname: Babu Rao Ambati
authors.forename: M
authors.initials: M
authors.lastname: Leonida
authors.forename: G J
authors.initials: GJ
authors.lastname: Haas
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002939:Ciprofloxacin / Q000494:pharmacology; D053138:Cyclohexenes / Q000494:pharmacology*; D004338:Drug Combinations; D004357:Drug Synergism; D005419:Flavonoids; D027582:Humulus / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011112:Polymyxin B / Q000494:pharmacology; D011427:Propiophenones / Q000494:pharmacology*; D013729:Terpenes / Q000494:pharmacology*; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D053138:Cyclohexenes; D004338:Drug Combinations; D005419:Flavonoids; D010936:Plant Extracts; D011427:Propiophenones; D013729:Terpenes; D002939:Ciprofloxacin; C008299:lupulon; D011112:Polymyxin B; C007966:humulon; C104536:xanthohumol; D014031:Tobramycin