title: The combination of catechin and epicatechin callate from Fructus Crataegi potentiates beta-lactam antibiotics against methicillin-resistant staphylococcus aureus (MRSA) in vitro and in vivo.
abstract: Fructus crataegi (hawthorn) is the common name of all plant species in the genus Crataegus of the Rosaceae family. In the present study, three monomers of  (+)-catechin (C), (-)-epicatechin gallate (ECg) and (-)-epigallocatechin (EGC) were isolated from the hawthorn under the guide of antibacterial sensitization activity. The bioactivity of the composite fraction in enhancing the antibacterial effect of oxacillin against methicillin-resistant Staphylococcus aureus (MRSA) was greater than that of the individual monomer of the hawthorn extract in vitro. Two-fold dilution and checkerboard methods were used to analyze antibacterial activity and screen for the combination and proportion of monomers with the best bioactivity. The result showed that C (128 mg/L) combined with ECg (16 mg/L) had the greatest effect and the combination also reduced the bacterial load in blood of septic mice challenged with a sublethal dose of MRSA, increased daunomycin accumulation within MRSA and down-regulated the mRNA expression of norA, norC and abcA, three important efflux pumps of MRSA. In summary, C and ECg enhanced the antibacterial effect of β-lactam antibiotics against MRSA in vitro and in vivo, which might be related to the increased accumulation of antibiotics within MRSA via suppression of important efflux pumps' gene expression.
authors: Department of Pharmacology, College of Pharmacy, The Third Military Medical University, Chongqing 400038, China. zhengj99219@gmail.com.
authors: Rongxin
authors: R
authors: Qin
authors: Kangkang
authors: K
authors: Xiao
authors: Bin
authors: B
authors: Li
authors: Weiwei
authors: W
authors: Jiang
authors: Wei
authors: W
authors: Peng
authors: Jiang
authors: J
authors: Zheng
authors: Hong
authors: H
authors: Zhou
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D027825:Crataegus / Q000737:chemistry*; D004359:Drug Therapy, Combination; D055624:Methicillin-Resistant Staphylococcus aureus; D051379:Mice; D010068:Oxacillin / Q000494:pharmacology*; D018805:Sepsis / Q000188:drug therapy*; D013203:Staphylococcal Infections / Q000188:drug therapy*
chemical_list: D000900:Anti-Bacterial Agents; D002392:Catechin; C062669:epicatechin gallate; D010068:Oxacillin