title: Baicalin synergy with beta-lactam antibiotics against methicillin-resistant Staphylococcus aureus and other beta-lactam-resistant strains of S. aureus.
abstract: Bacterial resistance to antibiotics is a serious global problem and includes strains of beta-lactam-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Novel antimicrobials and/or new approaches to combat the problem are urgently needed. The Chinese herb Xi-nan Huangqin (Scutellaria amoena C.H. Wright) has been used in traditional Chinese medicine to treat a wide range of infectious diseases. In this study we have examined the antibacterial action of baicalin, a flavone isolated from the herb. When combined with 16 microg mL(-1) baicalin, minimum inhibitory concentrations (MICs) of benzylpenicillin against MRSA and penicillin-resistant S. aureus were reduced from 125 and 250 microg mL(-1) to 4 and 16 microg mL(-1), respectively. This activity of baicalin was dose-dependent. Viable counts showed that the killing of MRSA and beta-lactam-resistant S. aureus cells by 10 to 50 microg mL(-1) ampicillin, amoxycillin, benzylpenicillin, methicillin and cefotaxime was potentiated by 25 microg mL(-1) baicalin. From the study it was concluded that baicalin has the potential to restore the effectiveness of beta-lactam antibiotics against MRSA and other strains of beta-lactam-resistant S. aureus. In view of its limited toxicity baicalin offers potential for the development of a valuable adjunct to beta-lactam treatments against otherwise resistant strains of microorganisms.
authors.affiliation: The School of Pharmacy, Faculty of Health and Social Care, The Robert Gordon University, Schoolhill, Aberdeen, UK.
authors.forename: I X
authors.initials: IX
authors.lastname: Liu
authors.forename: D G
authors.initials: DG
authors.lastname: Durham
authors.forename: R M
authors.initials: RM
authors.lastname: Richards
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002439:Cefotaxime / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D004359:Drug Therapy, Combination / Q000494:pharmacology; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D008712:Methicillin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects*; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal; D005419:Flavonoids; C038044:baicalin; D000667:Ampicillin; D002439:Cefotaxime; D010400:Penicillin G; D008712:Methicillin