Origanum vulgare: peroxidase-, superoxide dismutase- and immunomodulatory activities on macrophages activated with Helicobacter pylori derivatives.

Helicobacter pylori, invades the gastric mucosa and is one of the causative agents of stomach cancer and peptic ulcers. Origanum vulgare, is a flavouring herb used worldwide. But little is known about the effects of extracts prepared by maceration in cold PBS. This study was aimed at determining the superoxide dismutase (SOD)- and peroxidase (Px)-like antioxidant activities as well as the immunomodulatory activity (anti-inflammatory/pro-inflammatory) of an aqueous extract of O. vulgare by evaluating the production of nitric oxide (NO) in macrophages stimulated with H. pylori derivatives. The cold extract presented SOD-like and Px-like activities with effective concentration 50 (EC50) values of Px = 489.7 ± 48 µg/ml and SOD= 384.7 ± 30 µg/ml. The extract was also capable of modulating the production of NO in macrophages stimulated by H. pylori derivatives by exerting a pro-inflammatory activity at high concentrations and an anti-inflammatory activity at low concentrations.

Extra virgin olive oil inhibits Helicobacter pylori growth in vitro and the development of mice gastric mucosa lesions in vivo.

Helicobacter pylori infection is widespread worldwide, with more than a half of the world population infected. H. pylori antibiotic-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. The search for new therapies based on plant extracts is a scientific interest field. The present study was conducted to evaluate the effect in vitro of extra virgin olive oil (EVOO), hydroxytyrosol (HT), and oleuropein (Olp) against two H. pylori strains and the effect in vivo of the oral administration of EVOO on the gastric mucosa of BALB/c mice infected with this microorganism. The broth microdilution method assayed the antibacterial in vitro activity of EVOO, HT, and Olp against H. pylori strains. For in vivo studies, male BALB/c mice were infected orally with an H. pylori suspension every 72 h. Four groups were used: (1) Control, (2) H. pylori-infected (HP), (3) EVOO, and (4) HP + EVOO. Mice were sacrificed at 7, 15, and 30 days. The stomachs were removed and observed under a microscope. Scoring of the degree of erosion was determined. Samples were processed by histological techniques for light microscopy. Macroscopic analysis showed that the presence of small erosions increased, both in number and size, in the infected group. Animals infected and treated with EVOO exhibited the presence of fewer erosions, which decreased in number as the treatment progressed. The mucosa of the control and EVOO groups showed normal histological characteristics at the three times studied. The mucosa of animals infected with H. pylori showed disruptions of the lining epithelium, damage to gastric glands, and vasodilation. The mucosa of animals infected with H. pylori and treated with EVOO showed morphological characteristics similar to those of normal and EVOO mucosa. For the first time, the current study showed the effect in vitro and in vivo of EVOO and combined administration of HT and Olp against H. pylori using an animal model. Future studies are needed to establish the mechanism of EVOO's action at the gastric mucosa level to propose this product as a natural antimicrobial agent for the treatment of gastric H. pylori infections.

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori.

ETHNOPHARMACOLOGICAL RELEVANCE: Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system. AIM OF THE STUDY: To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds. MATERIALS AND METHODS: Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods. RESULTS: The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 µg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay. CONCLUSION: These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections.

Molecular characterization and susceptibility testing of Helicobacter pylori strains isolated in western Argentina.

OBJECTIVE: To characterize Helicobacter pylori isolates from western Argentina using virulence markers and antimicrobial susceptibility patterns in order to assess the association between virulent genotypes, antimicrobial resistance, and disease. DNA fingerprinting was also evaluated for the segregation of virulent or resistant strain clusters. METHODS: Genotyping of 299 H. pylori isolates was performed by PCR using specific primers for the cagA, vacA and iceA genes. Random amplification of polymorphic DNA (RAPD)-PCR and rep-PCR genetic clustering were assessed using five random primers and BOXA1R and ERIC primers, respectively. Resistance to clarithromycin (Cla) and metronidazole (Mtz) was assessed by the agar dilution method. RESULTS: It was observed that 40.8% of the genotypes were cagA-positive; 66.9% were vacA s1m1 genotype and the iceA1 allele was found in 40.8%. A significant correlation (p=0.0000) was observed between cagA positivity and vacA s1m1/iceA1 genotypes. Triple virulent genotypes were statistically associated with peptic ulcer (PU) (p=0.0001) and Cla resistance (p=0.0000). RAPD fingerprints obtained with AO2 primers identified clusters that were strongly associated with PU, virulence markers, and resistance to Cla and Mtz. CONCLUSIONS: The H. pylori isolates that harbored two or three virulence markers were more resistant to Cla and Mtz. Combined analysis of virulent genotypes and resistance patterns may permit identification of high-risk patients to prevent PU later in life or to avoid antimicrobial treatment failure.

[Microbiological factors that influence the eradication of Helicobacter pylori in adults and children]. / Factores microbiológicos que afectan a la erradicación de Helicobacter pylori en población adulta y pediátrica.

AIM: To study microbiological factors of Helicobacter pylori, such as antimicrobial susceptibility and virulence, which affect the eradication of the microorganism in gastric mucosa of adult and pediatric patients. METHODS: Fifty-five H. Pylori strains were isolated from culture of biopsy specimens from 39 adult and 16 pediatric patients. Antibiotic susceptibility was determined by agar dilution and study of virulence factors (cagA gene and alleles s1 and s2 of the vacA gene) by PCR. Outcome of treatment with amoxicillin (AMX), clarithromycin (CLR) and omeprazole was assessed by the urea breath test. We studied the relation of minimum inhibitory concentration (MIC) of AMX and CLR and presence of virulence factors with eradication of the microorganism.Results. The eradication rate was 69% (38/55), 71.7% in adults and 62.5% in children. Resistance to CLR and AMX was 14.5% and 0%, respectively. Overall eradication rates with respect to the variables studied were: 75% and 53% in strains with AMX MICs of < or = 0.01 6mg/L and > or = 0.032 mg/L (range < or = 0.008-0.5) (p > 0.05), 79% and 12% in strains with clarithromicina MICs of < 1 mg/L and > or = 1mg/L (range # 0.008-64) (p < 0.05), 79% and 54% in cagA+ and cagA strains (p > 0.05) and 82% and 62% in s1 and s2 strains (p > 0.05), respectively. CONCLUSIONS: H. pylori strains with higher amoxicillin and clarithromycin MICs, and cagA and vacA s2 strains were related with lower rates of eradication in both adult and pediatric populations treated with amoxicillin, clarithromycin and omeprazole.

Factores microbiológicos que afectan a la erradicación de Helicobacter pylori en población adulta y pediátrica / Microbiological factors that influence the eradication of Helicobacter pylori in adults and children

OBJETIVOS. Estudiar factores microbiológicos como la sensibilidad a antimicrobianos y factores de virulencia de Helicobacter pylori relacionados con la erradicación del microorganismo de la mucosa gástrica, tanto en población pediátrica como adulta. MÉTODOS. Se obtuvieron 55 cepas aisladas a partir del cultivo de biopsias de 16 pacientes pediátricos y de 39 adultos. La sensibilidad antibiótica se realizó mediante el método de dilución en agar y el estudio de los factores de virulencia, gen cagA y los alelos s1 y s2 del gen vacA mediante reacción en cadena de la polimerasa (PCR). El seguimiento tras el tratamiento que se instauró con amoxicilina, claritromicina y omeprazol se realizó mediante la prueba del aliento con urea marcada. Se estudió la relación entre la concentración inhibitoria mínima (CIM) a amoxicilina y claritromicina y la presencia de estos factores de virulencia con la erradicación del microorganismo. RESULTADOS. La erradicación fue del 69 por ciento (38/55), 71,7 por ciento en adultos y 62,5 por ciento en niños. La resistencia a claritromicina y amoxicilina fue 14,5 y 0 por ciento, respectivamente. Las tasas de erradicación globales en relación con las variables estudiadas fueron del 75 y 53 por ciento en cepas con CIM de amoxicilina 0,016 mg/l y CIM de amoxicilina 0,032 mg/l (intervalo 0,008-0,5) (p > 0,05), 79 y 12 por ciento en cepas con CIM de claritromicina 0,05) y 82 y 62 por ciento en cepas s1 y s2 (p > 0,05), respectivamente. CONCLUSIONES. La infección por cepas con CIM más altas a amoxicilina y claritromicina y por aislamientos cagA- y vacA s2 se relacionaron con tasas más bajas de erradicación de H. pylori, tanto en población adulta como infantil en la terapia con amoxicilina, claritromicina y omeprazol (AU)