Strains of Helicobacter pylori (H. pylori) resistant to various antibiotics have increased in recent years. In this context, the search for new therapeutic approaches is crucial. The aim of the present study was to demonstrate the antibacterial activity of a procyanidin-rich extract obtained from food-grade winery grape seeds against 14 H. pylori strains and elucidate its phenolic composition. Ten strains (71.4%) showed resistance to at least some of the tested antibiotics, while four isolates (28.6%) were susceptible to all antibiotics. Resistance to more than one class of antibiotics was observed in six strains (42.9%). The extract was able to inhibit the growth of all H. pylori strains in a range of a minimum inhibitory concentration (MIC) from 0.015 mg/mL to 0.125 mg/mL, confirming also the existence of a strain-dependent effect. The phenolic composition determined by reverse phase high pressure liquid chromatography, photodiode array, and mass spectrometry detection (RP-HPLC-PAD-MS) analysis revealed the presence of 43 individual compounds and allowed the quantification of 41 of them, including seven procyanidin tetramers, seven procyanidin pentamers, and six galloylated procyanidin dimers, trimers, and tetramers. The extract was composed mainly by catechin and procyanidin oligomers with a total amount of 5801 mg/100 g, which represent 92% of the total individual phenolic content. Among them, the most abundant were catechins (2047 mg/100 g), followed by procyanidin dimers (1550 mg/100 g), trimers (1176 mg/100 g), tetramers (436 mg/100 g), and pentamers (296 mg/100 g) that represent 35, 27, 20, 8, and 5%, respectively of the total flavanol constituents. The composition profile information may help to improve the production process of useful antibacterial extracts against H. pylori.

Helicobacter pylori (H. pylori) is one of the major human pathogens and the main cause of pathological damages that can progress from chronic gastritis to gastric cancer. During the colonization of gastric mucosa, this bacterium provokes a strong inflammatory response and subsequent oxidative process, which are associated with tissue damage. Therefore, the objective of this research was to evaluate the ability of two olive-leaf extracts (E1 and E2) to modulate the inflammatory response and oxidative stress in H. pylori-infected human gastric AGS cells. The obtained results showed that both extracts significantly decreased interleukin-8 (IL-8) secretion and reactive oxygen species (ROS) production in human gastric AGS cells. Both extracts also showed antibacterial activity against different H. pylori strains. HPLC-PAD-MS characterization demonstrated that extract E1 was mainly composed of highly hydrophilic compounds, such as hydroxytyrosol (HT) and its glucosides, and it was the most effective extract as an antibacterial agent. In contrast, extract E2 was composed mostly of moderately hydrophilic compounds, such as oleuropein (OLE), and it was more effective than extract E1 as an anti-inflammatory agent. Both extracts exhibited similar potential to decrease ROS production. These results show the importance of standardizing the extract composition according to the bioactive properties that should be potentiated.

Helicobacter pylori (H. pylori) is a pathogenic bacteria identified as a potential risk factor for gastritis, gastric ulcers and gastric cancer. During the stomach colonization, H. pylori triggers a strong inflammatory response and subsequent oxidative stress, which are associated with tissue damage. For this reason, it is of particular interest to develop alternative natural tools that enable modulation of the associated damaging immune response. With this purpose, we obtained grape seed extract (GSE) from sweet (not fermented) food grade seeds. The aim of our study was to investigate the effect of GSE and its two enriched procyanidins fractions (OPC and PPC) on the inflammatory process and oxidative stress produced by different H. pylori strains in human gastric epithelial cells (AGS). Anti-inflammatory activity was evaluated by measuring the level of interleukin-8 (IL-8) secretion. IL-8 production was significantly reduced in H. pylori-infected human gastric epithelial cells pre-treated with GSE or its enriched fractions when compared with non-pre-treated infected cells (from 21.6% to 87.8%). Pre-treatment with GSE or its fractions significantly decreased intracellular reactive oxygen species (ROS) production in AGS cells after infection, depending on the H. pylori strain. Our results also showed that GSE and its fractions demonstrate antibacterial activity against all strains of H. pylori used in the study. This work demonstrates the effectiveness of GSE enriched in procyanidins against the main events associated with H. pylori infection.

Campylobacter spp. are the main cause of bacterial gastroenteritis worldwide, and broiler chicks are the main vector of transmission to humans. The high prevalence of Campylobacter in poultry meat and the increase of antibiotic resistant strains have raised the need to identify new antimicrobial agents. For this reason, the aim of the current study was to evaluate the antibacterial activity of two extracts of olive leaf against antibiotic-resistant Campylobacter strains (C. jejuni and C. coli) isolated from poultry food chain. The extracts of olive leaf (E1 and E2) were markedly different in their chemical compositions. While E1 was composed predominantly of highly hydrophilic compounds such as hydroxytyrosol and hydroxytyrosol glucosides (14,708 mg/100 g), E2 mainly contained moderately hydrophilic compounds, with oleuropein (20,471 mg/100 g) being prevalent. All Campylobacter strains exhibited similar antibiotic profiles, being resistant to ciprofloxacin and tetracycline. E1 showed strong antibacterial activity and reduced bacterial growth from 4.12 to 8.14 log CFU/mL, depending on the strain. Hydroxytyrosol was the main compound responsible, causing the inhibition of growth of Campylobacter strains at low concentrations (0.1–0.25 mg/mL). E2 demonstrated a lower antibacterial effect than E1, reducing growth from 0.52 to 2.49 log CFU/mL. The results of this study suggest that the optimization of the composition of olive-leaf extracts can provide improved treatment results against Campylobacter strains.