Review
Antimicrobial activity of natural products against Helicobacter pylori: a review
Annals of Clinical Microbiology and Antimicrobials 2014, 13:54 doi:10.1186/s12941-014-0054-0
The electronic version of this article is the complete one and can be found online at: http://www.ann-clinmicrob.com/content/13/1/54
| Received: | 20 August 2014 |
| Accepted: | 24 October 2014 |
| Published: | 19 November 2014 |
© 2014 Bonifácio et al.; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Abstract
Throughout the genetic and physiological evolution of microorganisms, the microbiological sciences have been expanding the introduction of new therapeutic trials against microbial diseases. Special attention has been paid to the bacterium Helicobacter pylori, which induces gastric infections capable of causing damage, ranging from acute and chronic gastritis to the development of gastric cancer and death. The use of compounds with natural origins has gained popularity in scientific research focused on drug innovation against H. pylori because of their broad flexibility and low toxicity. The aim of this study was to describe the use of natural products against H. pylori in order to clarify important parameters for related fields. The study demonstrated the vast therapeutic possibilities for compounds originating from natural sources and revealed the need for innovations from future investigations to expand the therapeutic arsenal in the fight against H. pylori infection.
Relevant part of study included below but full study is available at link at the bottom of the page.
Table 2. Anti-Helicobacter pyloriactivity of essential oils
Essential oils or scents are aromatic compounds found in different plant organs. They are also called volatile oils or ethereal oils, as they have a high degree of evaporation when exposed to air at room temperature; it is this feature that confers the significant odor to plants, both for attraction of pollinators and as insect and herbivore repellents [52]-[54]. These compounds have emerged in the medical field by presenting antimicrobial activities of extreme value with regards to drug action against pathogenic or opportunistic microorganisms, including antifungal and antibacterial action. Because the compounds have a complex constitution, the profile exerted against microorganisms is directly related to this feature; for example, the presence of terpenes, which are secondary metabolites of plants with interesting therapeutic properties, have been studied by the scientific community in recent years. The antimicrobial activity demonstrated by terpenes is attributed to their interference with the integrity and functioning of the cell membrane through induction of changes in membrane potential, loss of cytoplasmic material and inhibition of the respiratory chain [54],[55].
Studies with the aim to elucidate the anti-Helicobacter pylori profile presented by essential oils have been developed in recent years because of the need for further drug options in the treatment of disorders arising from this type of infection. This fact is justified by the increased number of strains resistant to the standard drug therapy used in clinical practice, such as clarithromycin, the drug most frequently used as a therapeutic agent, and the lack of an ideal drug regimen with 100% safe applicability [8].
To broaden the knowledge of the anti-H. pylori potential of essential garlic oil, Otha et al. [56] tested compounds isolated from crude oil and obtained MIC values ranging from 10 to 25 μg/mL.
Other antimicrobial profiles of essential oils are reported in the literature. For example, Kalputzakis et al. [57] observed antibacterial action against clinical H. pylori strains extracted from biopsies performed on adults and children from two species of plants from the Nepeta genus, Nepeta camphorata L. and Nepeta argolica ssp. dirphya, belonging to the Lamiaceae family. The profile established by the essential oils of the two species was shown to be relevant, with minimum inhibitory concentrations (MIC) of 128 and 64 μg/mL for N. camphorata and N. argolica ssp. dirphya, respectively. Four compounds of the two species were also isolated and tested, presenting MICs ranging from 16 to 64 μg/mL for the same strains. The results obtained from the isolated substances confirm that flavonoids are mainly responsible for the antimicrobial activity for products derived from plant sources, as these substances were characterized as flavonoid derivatives.
Ohno et al. [58] reported the action of 13 essential oils against strains of H. pylori from clinical and standard origin (ATCC). The study found activity against all strains tested with oils extracted from Cupressus sempervirens, Juniperus communis Melaleuca alternifolia, Lippia citriodora, Ocimum basilicum, Mentha piperita, Origanum majorana, Eucalyptus globulus., Ravensara aromatica, Citrus limonum, Cymbopogon citratus, Rosmarinus officinalis and Lavandula latifolia. The same sensitivity profile was observed by Deriu et al. [59] in 2007, who investigated the activity of the essential oil of Myrtus communis L. against ten clinical isolates of Helicobacter pylori with a resistant profile for triple therapy with metronidazole, clarithromycin and levofloxacin.
The essential oil of Sicilian lemon (Citrus lemon Burm. Rutaceae) is classified as a potentially promising product against gastrointestinal diseases [60]. A study regarding its antimicrobial potential against Helicobacter pylori by Rozza et al. [61] revealed a minimum inhibitory concentration of 125 μg/mL. Furthermore, the authors performed a phytochemical analysis to identify the compounds present in the oil. Approximately 17 compounds were identified, of which 13 were identified by gas chromatography. The authors characterized monoterpene limonene as the major constituent of the essential oil, equivalent to approximately 70.75% of the total product. Moreover, the presence of β -pinene was also detected at a concentration of 13.19%. The antimicrobial profile of the two major isolated compounds resulted in MICs of 75 μg/mL and 500 μg/mL for limonene and β-pinene, respectively. Thus, the results were able to attribute limonene as the main compound responsible for the anti-Helicobacter pyloriactivity.
Conclusion
This review demonstrates the grandiosity of the use of compounds derived from natural products against Helicobacter pylori and denotes the need for scientific and technological expansion regarding these agents. Future work focused on promoting a therapeutic arsenal endowed with significant pharmacological actions and low toxicity and cumulative effects is required.
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