ABSTRACT
Multidrug-resistant (MDR) Staphylococcus aureus and its biofilm formation have been challenging to control in milk and dairy industries. Biofilms formed by Staph. aureus may result in the failure of antibacterial agents and disinfectants to penetrate the biofilm in an attempt to control contamination. Novel natural antibacterial agents are required to combat MDR bacteria and biofilms. In this study, we evaluated the bactericidal, antibiofilm, and antimotility effects of Rumex japonicus Houtt. (RJH) extract on MDR Staph. aureus isolated from milk. The RJH extract exhibited good antibacterial activity against MDR strains with minimum inhibitory concentrations (MIC) ranging from 0.78 to 6.25 mg/mL and minimum bactericidal concentrations ranging from 3.125 to 12.5 mg/mL. The extract showed strong inhibition of biofilm formation (81.9%) at sub-MIC value and eradication of biofilm at higher concentrations. The motility of Staph. aureus was effectively blocked by the extract. Major compounds emodin, chrysophanol, and physcion were identified in RJH extract using HPLC-linear trap quadrupole (LTQ)/Orbitrap-mass spectrometry. The extract was nontoxic to human epithelial cell lines such as Caco-2 and HT-29 cell lines at concentrations ranging from 0.1 to 0.5 mg/mL, and from 0.1 to 0.75 mg/mL, respectively. These findings suggest that RJH extract could be an alternative to synthetic preservatives in milk and dairy products.
Subject(s)
Methicillin-Resistant Staphylococcus aureus , Rumex , Animals , Anti-Bacterial Agents/pharmacology , Biofilms , Caco-2 Cells , Humans , Microbial Sensitivity Tests/veterinary , Milk , Plant Extracts/pharmacology , Staphylococcus aureusABSTRACT
In this study, we focused on the in vitro anti-metastatic effects of deoxyelephantopin (DOE), a sesquiterpene lactone from Elephantopus scaber on lung cancer A549 cells. DOE significantly decreased the metastatic potential of A549 cells as demonstrated by transwell invasion and migration assay. DOE inhibited the expression of matrix metalloproteinase-2 (MMP-2), MMP-9, urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor at transcript level. Tissue inhibitors of metalloproteinase-2 (TIMP-2) mRNA levels was up-regulated in A549 tumour cells without any change in TIMP-1 expression after DOE treatment. DOE inhibited the protein levels of p-ERK1/2 and p-Akt in A549 cells but it activated p-JNK, p-p38 protein expression. NF-κB and IκBα expressions were down-regulated in DOE-treated cells. All these results demonstrated that DOE has shown anti-metastatic activity against A549 tumour cells.
