Gastroprotective and anti Helicobacter pylori activities of propolis
Helicobacter pylori (HP) determines the most common human infection overall. Important gastric diseases are associated with HP with percentage of correlation up to 90% (duodenal ulcer and gastric lymphoma). The complexity of the pathogenetic factors of HP has prompted research to identify "phytocomplexes" able to act on different mechanisms of HP pathogenesis . Our group investigated propolis regarding its antibacterial activity and focusing the protection from oxidative stress and massive inflammatory response, key elements of the progression of HP gastric diseases related, scarcely considered in classic antibiotical therapies . We studied propolis marketed in Italy: classic propolis dry extract, hydrodispersible propolis, water-soluble propolis and a new formulation of propolis (75% italian propolis dry extract, 15% green tea catechins, 10% grape seed procyanidins), 50% total polyphenols UV method standardized. The different chemical composition of samples determines different biological activity as evidenced by in vitro and in human cells assays [3,4,5]. Propolis water solutions at different concentrations were tested. Results indicated that propolis has high radical scavenging capacity (IC50 in DPPH test ranging from 8.2 to 65.4 ?g/mL) and protect cell membranes from oxidative stress. Antioxidant activity was directly proportional to the effectiveness against HP: the new propolis formulation MBC and MIC against HPcag+ and HPcag- is 0.250 mg/mL. Tests on human PBMC stimulated with LPS showed that all samples (conc. 200 µg/mL) exhibited anti-inflammatory activity respect to LPS group. This research clearly demonstrated that antioxidant properties of propolis preparations and effectively promote gastric protection acting in different steps of HP pathogenesis.
Keywords: Helicobacter pylori, propolis, anti-inflammatory, antioxidant, gastroprotective
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