Antibacterial activities of almond skins on cagA-positive and-negative clinical isolates of Helicobacter pylori

Abstract

BackgroundHelicobacter pylori is known to be a gastric pathogen of humans. Eradication regimens for H. pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, the need for alternative therapies for H. pylori infections is of special interest. We have previously shown that polyphenols from almond skins are active against a range of food-borne pathogens. The aim of this study was to evaluate the antibacterial effects of natural almond skins before and after simulated human digestion and the pure flavonoid compounds epicatechin, naringenin and protocatechuic acid against H. pylori.ResultsH. pylori strains were isolated from gastric biopsy samples following standard microbiology procedures. Also, cagA and vacA genes were identified using PCR. Susceptibility studies on 34 strains of H. pylori, including two reference strains (ATCC 43504, ATCC 49503), were performed by the standard agar dilution method.Natural almond skin was the most effective compound against H. pylori (MIC range, 64 to 128 μg/ml), followed by natural skin post gastric digestion (MIC range, 128 to 512 μg/ml), and natural almond skin post gastric plus duodenal digestion (MIC range, 256 to 512 μg/ml). Amongst the pure flavonoid compounds, protocatechuic acid showed the greatest activity (MIC range, 128 to 512 μg/ml) against H. pylori strains.ConclusionsPolyphenols from almond skins were effective in vitro against H. pylori, irrespective of genotype status and could therefore be used in combination with antibiotics as a novel strategy for antibiotic resistance.

Medicinal plants in the treatment ofHelicobacter pyloriinfections

“…Webb (Rosaceae), a rich source of nutrients and phytochemicals, are well documented for their biological effects, including anticancer, antiviral, anti-inflammatory, antioxidant, and antimicrobial activities (Amico et al, 2006;Mandalari et al, 2010Mandalari et al, , 2011Takeoka & Dao, 2003). Bisignano et al (2013) prepared polyphenol-rich extracts from natural almond skins and investigated the antimicrobial properties along with pure flavonoid compounds epicatechin, naringenin, and protocatechuic acid against H. pylori strains. Natural almond skin was found to be more effective against H. pylori followed by natural skin DOI: 10.3109/13880209.2014.952837 post gastric digestion and protocatechuic acid, as a pure flavonoid compound.…”

Effectiveness of Citrus Fruits on Helicobacter pylori

“…As a result, several naturally occurring substances have been investigated as potential alternatives for the treatment of H. pylori infection [65–68]. For instance, we have recently demonstrated that polyphenolic fractions from almond skin were active against standard strains and clinical isolates of H. pylori [4]. A recent investigation reported the potential use of several medicinal herbs for the treatment of H. pylori and its complications [69].…”

“…A >3log 10 difference in colony-forming unit (CFU) between BJ 1.25% and BJ 20.0% with H. pylori ATCC 49503 was achieved after 2 h, whereas complete killing was achieved with BJ (10% and 20%) after 8 h and with BJ (5%) after 24 h. BJ gave less killing against H. pylori ATCC 43504, with a complete bacterial killing after 6 h exposure (20% BJ). This outcome could be explained by the increased antibiotic resistance of H. pylori ATCC 43504 compared to H. pylori ATCC 49503 [4]. In the combination assays, the association of BJ with the reference antibiotics determined a reduction of >6log 10 for H. pylori ATCC 49503 after 8 h and for H. pylori ATCC 43504 after 24 h exposure to BJ.…”

“…Therefore, discovering novel bioactive compounds from plant products could help eradicate a number of infectious diseases. We have previously reported the antibacterial activity of polyphenols-rich natural products, including almonds [4, 5], pistachios [6], Citrus plants [7], Vitis vinifera L. [8], Olea europaea L. [9], and Citrus bergamia essential oil [10] and juice [11]. In particular, the identification of novel compounds with bactericidal rather than bacteriostatic effect has attracted a lot of interest in recent years.…”

Amelioration of Helicobacter pylori-Induced PUD by Probiotic Lactic Acid Bacteria

“…Studies revealed that under in vitro conditions irrespective of genotype status, polyphenols extracted from almond skins were effective against H. pylori, and hence can be administered in combination with antibiotics as a novel strategy for antibiotic resistance (Bisignano et al, 2013). Further, Palacios-Espinosa and his coworkers (2014) demonstrated that Cuphea aequipetala possesses some anti-inflammatory, gastroprotective, and antibacterial properties, required for the treatment of bacterial or nonbacterial GU and symbolizes a significant source for the isolation of anti-H. pylori compounds.…”