In Vitro and In Vivo Anti-Helicobacter pylori Activity of Natural Products

Since old times plants have been a resource used by human beings an important sources of biologically active products. Recently, efforts have been made in order to identify new antiulcerogenic drugs from natural sources, having as the main target the Helicobacter pylori, a bacterium considered as the most important etiological agent of the human peptic ulcer. It has been shown to be a rich source of bioactive substances, having antifungal, gastroprotective, analgesic, anti-HIV, antibacterial, antitumoral properties and inhibitor of gastric H+,K+-ATPase and angeotensin-converting enzyme. This chapter aims to demonstrate methods anti-Helicobacter pylori in vitro and in vivo for screening of plant extracts. Helicobacter pylori was identified in 1982 by Marshall and Warren (1984) and quickly became the subject of countless microbiological, histological, epidemiological, immunological, ecological and clinical studies (Vaz, 2005). This organism has its nomenclature revised, starting with Campylobacter pyloridis, and a correction of the name was originally Greek to Latin, Campylobacter pylori (Marshall and Goodwin, 1987) and organisms like Campylobacter. Taxonomic studies have led to reclassification, resulting in the name Helicobacter pylori (Goodwin and Armstrong, 1990). H. pylori is a bacillus, Gram negative, microaerobic, spiral and curved (Dunn et al. 1997). It has two to six flagella that provide motility to it to resist the rhythmic contractions of stomach and penetrate the gastric mucosa. It has 2.4 to 4.0 mm in length and 0.5 to 1.0 mm in width (Brown, 2000). The identification and isolation of Helicobacter pylori allowed for a considerable development of knowledge about peptic ulcer (Marshall and Warren, 1984). This pathogen is considered the main etiological agent of human peptic ulcer, with a worldwide prevalence rate of about 40% in developed countries and over 80% in developing countries (Shi et al., 2008). H. pylori produces a number of virulence factors that may have different associations with the disease. The establishment of chronic infection may be influenced by host genetic factors as well as the blood group ABO and Lewis-blood group antigen and differences in susceptibility to particular strains of H. pylori (Brown, 2000). To establish and maintain the infection, H. pylori expresses a variety of different types of maintenance factors that allow bacteria to colonize and remain within the host and virulence factors, which contributes to the pathogenic effects of bacteria, with emphasis on gastric inflammation, mucosal barrier disruption gastric and changes in gastric physiology (Dunn