tannins and Helicobacter-Infections

This review of the current literature aims to study correlations between the chemical structure and gastric anti-ulcer activity of tannins. Tannins are used in medicine primarily because of their astringent properties. These properties are due to the fact that tannins react with the tissue proteins with which they come into contact. In gastric ulcers, this tannin-protein complex layer protects the stomach by promoting greater resistance to chemical and mechanical injury or irritation. Moreover, in several experimental models of gastric ulcer, tannins have been shown to present antioxidant activity, promote tissue repair, exhibit anti Helicobacter pylori effects, and they are involved in gastrointestinal tract anti-inflammatory processes. The presence of tannins explains the anti-ulcer effects of many natural products.

Topics: Anti-Bacterial Agents; Anti-Ulcer Agents; Helicobacter Infections; Helicobacter pylori; Humans; Peptic Ulcer; Phytochemicals; Plant Extracts; Structure-Activity Relationship; Tannins

The inhibitory effects of a standarized apple peel polyphenol-rich extract (APPE) against Helicobacter pylori infection and vacuolating bacterial toxin (VacA) induced vacuolation were investigated. Apple peel polyphenols significantly prevented vacuolation in HeLa cells with an IC(50) value of 390 microg of gallic acid equivalents (GAE)/mL. APPE also displayed an in vitro antiadhesive effect against H. pylori. A significant inhibition was observed with a 20-60% reduction of H. pylori attachment at concentrations between 0.250 and 5 mg of GAE/mL. In a short-term infection model (C57BL6/J mice), two levels of APPE doses (150 and 300 mg/kg/day) showed an inhibitory effect on H. pylori attachment. Orally administered apple peel polyphenols also showed an anti-inflammatory effect on H. pylori-associated gastritis, lowering malondialdehyde levels and gastritis scores.

Topics: Administration, Oral; Animals; Chlorogenic Acid; Flavonoids; Gastritis; HeLa Cells; Helicobacter Infections; Helicobacter pylori; Humans; Malus; Mice; Mice, Inbred C57BL; Tannins

Mouriri elliptica Martius (Melastomataceae) is species reputed in folk medicine to heal gastric ulcer and gastritis.. Methanolic extract (ME) and ethyl acetate fraction (EAF) from leaves of Mouriri elliptica were evaluated for their gastroprotective, healing, immunological, toxicological and anti-Helicobacter pylori activities.. The gastroprotective action of ME and EAF was evaluated in rodent experimental models and to elucidate mechanisms of action, the antisecretory action, involvements of NO, SH, PGE(2), anti-Helicobacter pylori action of ME was evaluated. We also used immunohistochemical (PCNA and COX-2) and immunomodulatory (murine peritoneal macrophages) assays to evaluate Mouriri elliptica effects.. ME present gastroprotective action without antisecretory effect. Otherwise, ME showed anti-Helicobacter pylori action (MIC=0.025mug/mL) and was able to inhibit NO production by macrophages. This species also accelerate the healing of ulcerated gastric mucosa by stimulating proliferation factors (PCNA), COX-2 and maintained basal PGE(2) level independent action of NSAID in gastric mucosa. The phytochemical investigation showed that this species possesses phenolic acid derivatives, acylglycoflavonoids and condensed tannins which probably influenced their pharmacological action.. All these results suggest the efficacy and safety of Mouriri elliptica in combating and healing gastric ulcer.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Anti-Ulcer Agents; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Ethanol; Female; Flavonoids; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Macrophages; Male; Melastomataceae; Mice; Nitric Oxide; Phenols; Phytotherapy; Plant Extracts; Plant Leaves; Proliferating Cell Nuclear Antigen; Rats; Stomach Ulcer; Tannins

Helicobacter pylori colonizes the human gastric mucosa, causing inflammation that leads to atrophic gastritis, and it can cause peptic ulcer and gastric cancer. We show that polyphenol administration to mice experimentally infected by H. pylori or treated with VacA toxin can limit gastric epithelium damage, an effect that may be linked to VacA inhibition.

Topics: Animals; Bacterial Proteins; Colony Count, Microbial; Flavonoids; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Mice; Mice, Inbred BALB C; Phenols; Polyphenols; Specific Pathogen-Free Organisms; Tannins