Salvia cadmica extracts rich in polyphenols neutralize a deleterious effects of oxidative stress driven by Helicobacter pylori lipopolysaccharide in cell cultures of gastric epithelial cells or fibroblasts

Abstract

IntroductionPlant ingredients are candidates for new therapeutic formulations against bacterial pathogens with high rate of antibiotic resistance and deleterious inflammation. Helicobacter pylori Gram-negative rods causing gastritis, gastric/duodenal ulcers and gastric cancer, which show high antibiotic resistance require new effective drugs. AimTo examine antibacterial activity of Salvia cadmica Boiss. extracts (roots and aerial parts) towards H. pylori strains resistant to clarithromycin and/or metronidazole. To determine whether extracts neutralize deleterious effects driven by H. pylori lipopolysaccharide (LPS) such as elevated oxidative stress and apoptosis, and promote cell regeneration of gastric epithelial cells or fibroblasts in vitro. Material and methodsHydromethanolic extracts (20:80 v/v) from roots and aerial parts of seed-derived plants of S. cadmica were used for biological study. Biocompatibility was tested according to the ISO norm 10993–5 in the MTT (3-(4,5-dimethylthiazol-2-yl)− 2,5-diphenyltetrazolium bromide) reduction assay. Antibacterial activity against H. pylori (two reference strains and five clinical isolates clarithromycin and/or metronidazole resistant) was tested in the broth microdilution assay as recommended by The European Committee on Antimicrobial Susceptibility (EUCAST). Cell cultures of guinea pig gastric epithelial cells or fibroblasts exposed to H. pylori LPS, and/or S. cadmica extracts, were tested for the rate of oxidative stress (3-nitrotyrosine-3NT), apoptosis (immunostaining of pro- or anti-apoptotic proteins, DNA degradation), phosphorylated extracellular signal-regulated kinase - pErk (immunostaining), cell migration (scratch assay), collagen I and interleukin (IL)− 33 (enzyme linked immunosorbent assay – ELISA). ResultsThe minimal inhibitory concentration (MIC) of root extract for H. pylori reference strains ranged from 39 to 78 µg/mL whereas minimal bactericidal concentration (MBC) was in the range of 78–310 µg/mL. The MIC for clinical H. pylori isolates ranged from 195 to 1560 µg/mL while MBC from 390 to 1560 µg/mL. Aerial part extract showed a weaker inhibitory and bactericidal effects towards H. pylori reference strains (MIC/MBC range 78 −156 µg/mL), and to clinical isolates (MIC/MBC range 390 −1560 µg/mL). S. cadmica extracts effectively diminished oxidative stress, cell apoptosis rate and phosphorylated extracellular signal-regulated kinase (pErk) level, which were driven by H. pylori lipopolysaccharide (LPS). ConclusionsThe hydromethanolic extracts from S. cadmica (root and aerial part) show anti-H. pylori activity, in conjunction with anti-oxidative/anti-apoptotic effects in cell cultures of gastric epithelial cells and fibroblasts. These effects are promising for the development of potentially therapeutic formulations.