Helicobacter pylori is considered the main etiological agent of gastritis, ulcers, and gastric carcinoma. It colonizes human gastric mucosa quite efficiently. Fifty % of the world population is actually infected. Since H. pylori discovery in 1982, it is well known the sensitivity of several H. pylori strains to a number of antibiotics when these are assayed in vitro. However, eradication therapies with a single antibacterial agent have failed. Recently, triple, quadruple, sequential, concomitant and hybrid therapies which include antibiotics and a proton pump inhibitor show improved eradication rate and low side effects. However, new problems have emerged. Antimicrobial resistance to the common antibiotics used has become a problem in both developed and developing countries. In particular, H. pylori clarithromycin- and metronidazole-resistant strains are a major problem in countries where H. pylori is highly prevalent. Thus, the widespread use of antibiotics is not economically feasible and might increase difficulties in the treatment of H. pylori. At present, there are no vaccines available in the market. As an alternative, effective non-antibiotic compounds should be highly desirable since their use may be safer and suitable to eradicate H. pylori. The first step in this direction has been to study the effect of medicinal herbs and natural products, such as green tea, ginseng, garlic, propolis, and probiotics, then identify their active components such as polyphenols, antioxidants, purify them, and finally test them using in vitro and in vivo H. pylori growth assays. Some of them have been quite effective. The topics related to alternative therapies for H. pylori infections and current status of their use will be discussed in the present review.
Although antibiotics are usually effective in the treatment of Helicobacter pylori infection their success is limited. H. pylori causes lifelong chronic gastritis, which can lead to peptic ulcers, mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer [
At present there is no large scale production of an effective vaccine against H. pylori available at the market [
Active compounds including antioxidants from plants and other H. pylori natural sources and urease inhibitors [
It has been early reported that tea catechins have antibacterial activity against some food-borne pathogens [
A more recent study on tea polyphenols [
Recently, studies using green tea as therapeutic agent showed that using CSA (comparative screening assay), a score reduction higher than 8 × 10⁴ CFU (colony forming unit) was found in more than 60% of the positive strains by green tea (81.5%), which also possess additional beneficial properties, e.g. antioxidant, anti-inflammatory and antitumor activities. Therefore, these plants may have a beneficial use as prophylactic agents against or adjuvants in the therapy of H. pylori infection [
In a study done by Boyanova et al., (2015) [
Propolis (bee glue) is a resinous product collected by honeybees from plants. The main sources of propolis are the buds of poplars [
Propolis and Zingiber officinalis (ginger root tea) extracts have demonstrated to be specific for H. pylori strains, and also presenting anti-inflammatory, antioxidant and antitumoral activities when employed in traditional medicine [
A recent study [
Early, in 1987, studies on Ginseng consumption have been reported indicating a reduction of the risk of cancer in diverse organs, including the lip, oral cavity, pharynx, larynx, esophagus, lung, liver, pancreas, ovary, colon, rectum, and stomach, as demonstrated in clinical and epidemiological studies [
A study of Bae et al., (2001) [
H. pylori are capable of inducing gastric inflammation, ulceration, and DNA damage, based on which WHO defined this bacterium as a class I carcinogen. Ginseng root (Panax ginseng C.A. Meyer) presented anti-adhesion or antimicrobial activity against H. pylori [
Up-regulations of inflammatory mediators such as IL-1β, IL-8, and iNOS have been previously shown in gastric mucosa of H. pylori-infected patients with gastric inflammation (gastritis, gastric ulcer). Korean red ginseng is one of the most popular traditional medicines in Korea due to its stimulating effect on the immune system and inhibition on inflammation. The study of Bae et al., (2011) [
However, evidence-based medicine, consisting of large-scale or well designed clinical studies, is still warranted whether Korean red ginseng is to be recognized as an essential therapeutic strategy as an “H. pylori-associated gastric cancer preventive”. Specifically, comprehensive clinical trials of Korean red ginseng are needed to demonstrate that mucosa regeneration in patients with atrophic gastritis is feasible using Korean red ginseng supplements after the eradication of H. pylori infection. Ginseng is a good example of a natural herb and its ubiquitous properties may include the reduction or delay of inflammation carcinogenesis. Korean red ginseng contains ample amounts of active ginsenosides and it has been demonstrated their effects by in vitro and in vivo studies with positive outcomes [
In another study described by Cho et al., (2013) [
H. pylori is a major cause of gastric inflammation and gastric carcinoma in humans and Mongolian gerbils which have been used as animal model for gastric cancer. Recently, Bae et al., (2014) [
A recent meta-analysis [
Garlic (Allium sativum) may provide a suitable source to obtain new drugs with anti-H. pylori activities since it have been known for a long time that it has antimicrobial properties [
Garlic has been frequently used as a traditional treatment for several gastrointestinal infections. Several groups have reported the effect of garlic on H. pylori [
A study of O’Gara et al., (2000) [
The common use of dietary garlic to fight infections and the medicinal use of GO to treat various diseases [
In the search for the target of these garlic compounds Chung et al., (1998) [
Recently, Tang et al., (2014) [
As a result of the use of diverse antibiotic treatments and better hygienic conditions, particularly in developed countries, this resulted in significant decline in the prevalence of H. pylori infection. However, persistent high H. pylori infection in developing countries, decreased patience compliance and emerging antibiotic resistance forced researchers to quest for novel candidates to fight H. pylori. Herbal medicines have always served as a leading source in drug discovery [
Ethanol and methylene chloride (MC) extracts of cinnamon were studied to compare their in vitro effect on H. pylori growth and urease activity [
Chatterjee et al., (2004) [
The combined use of silver nanoparticles (AgNps) and methanol extract of Solanum xanthocarpum, commonly known as yellow-berried nightshade effectively inhibited the growth of H. pylori, indicating a stronger anti-H. pylori activity than that of AgNO3 or metronidazole, being almost equally potent to tetracycline but less potent than amoxicillin and clarithromycin. Yellow-berried nightshade is a prickly plant, which grows wild in different regions of the Indo-Pakistan subcontinent has been tested and compare with typical antibiotics. AgNps (silver nanoparticles) sample and S1-extract with AgNps were found equally efficient when tested against the antibiotic-resistant or antibiotic-susceptible H. pylori strains. The anti-H. pylori activity was measured by the agar dilution method. The MIC90 was determined as standard procedure. The s1 extract contained typical Ag nanoparticles (20 ml 1mM AgNO3 mixed with 10 ml of S. xanthocarpum methanolic extract. Other S. xanthocarpum extracts were prepared to vary the amount of extract. In addition, after the H. pylori urease inhibitory assay, S1 exhibited a significant inhibition [
There are several studies done on different medicinal plants searching for anti-H. pylori activity described in differents countries and regions around the globe, such as Mali, Nigeria, South Africa (in Africa), Iran, Pakistan China Taiwan, Korea (in Asia), Southern Chios (Greek Island, Europe), Ecuador, Peru, Brazil, The Amazon (in South America).
Scientific name or vernacular name | Type of extracta | MIC or MIC90 (µg/ml)b | Country of origin | Reference |
---|---|---|---|---|
Cominus ciminus | ET | 75 | [ | |
Plrleopsis tuberosa | ME | 31.25 - 250 | Mali (Africa) | [ |
Allium ascalonicum | E | 6.25 - 12.5 | [ | |
Terminalia chebula Retz | AQ | 100 - 2500 | Iran Iran | [ |
Xantium. brasilicum | 31.25 - 250 | Iran | [ | |
Trachispermum copticum | NA | Iran | [ | |
Arbus cantoniensis, Fabaceae | ET | 40 | China | [ |
Saussu realappa, Asteraceae | 40 | China | [ | |
Eugeniacaryo fillata, Myrtaceae | 40 | China | [ | |
Plumbazo ceylanica | EA | 320 - 1280 | Taiwan | [ |
Germinaricum khatamsciz | NA | Iran | [ | |
Terminalia macroptera | ET-ACE (80-20) | 100 | Africa | [ |
Terminalia catappa L | AQ-ET, HEX, EA, AQ | 125 (AQ) | Brazil | [ |
Phyllanthus niruri L/ Chancapiedra | AQ | NA | Ecuador-Peru | [ |
Calophylum brasiliense Camb | NA | Brazil | [ | |
Pistascia lenticus var chia | NA | Brazil | [ | |
Eucalyptus torreliana | 100 | [ | ||
Cambricum mella | 1250 - 5000 | [ | ||
Rhus verniciflua/Urishiol | 64 - 256 | Korea | [ | |
Acacianilotica | ME & AQ | 8 - 64 | Pakistan | [ |
Calotropis procera | ACE | NA | [ | |
Geranium wilfordii | ME®CHL®EAc | 4 - 8 (AQ) | Brazil (Amazon) | [ |
Piper umbellatum | AQ/ET | NA | Brazil (Amazon) | [ |
aAQ = aqueous, ET = ethanol, ME = methanol, CHL = chloroform, ACE = acetone, HEX = hexane, EA = ethylacetate; bMIC = Minimal Inhibitory Concentration (values are not fully comparative); NA = Not available; c“®” means that these were sequential extractions.
In some cases extracts obtained with different organic solvent have been tested. In some others the chemical nature of the compound having this inhibitory has been identified. In few cases the target for these antimicrobials has been established. Some examples are cited below.
A group of 17 plants as ethanolic or aqueous extracts was studied as containing active agents for the treatment of H. pylori infections [
At Mali, Western Africa, traditional medicine uses the plant Pteleopsis suberosa for the treatment of gastric and duodenal ulcers. Germano et al., (1998) [
A methanolic extract from Allium ascalonicum Linn (Liliaceae) leaves has been tried in vitro on five strains of H. pylori by the agar diffusion method [
Among several other plants studied, thyme, a low grower herb, with tiny white flowers lasting for several weeks each summer, was used as aqueous extract and resulted effective against H. pylori [
A study of Wang et al., (1998) [
Another work was done by Malekzadeh et al., (2001) [
Bae et al. (1998) [
Grapefruit (Aristotochia pucinervis) methanolic and hexane extract fractions obtained from rhizome and leaves were effective as H. pylori growth inhibitors [
A study was done by Nariman et al., (2004) [
Li et al., (2005) [
Wang and Huang (2005) [
Methanol extracts from roots of an endemic plant that grows in Iran (Geumiranicum Khatamsaz) which belongs to the Rosacea family have shown significant anti-H. pylori activity against a metronidazole resistant strain [
The root of Terminalia macroptera Guill & Perr, (Combretaceae) has been widely used in African traditional medicine to treat different infectious diseases, including stomach-associated diseases. The study of Silva et al., (2012) [
Fractionated extracts of persimmon (Diospyros kaki) peels were studied for cytotoxic activity, multidrug resistance (MDR) reversal activity, anti-human immunodeficiency virus (HIV) activity and anti-H. pylori activity. The potent cytotoxic activity against human oral squamous cell carcinoma cells (HSC-2) and human submandibular gland tumor (HSG) cells was found in the acetone fractions (A4 and A5 fractions) with IC50 ranging from 21 to 59 µg/ml. However, the cytotoxic activity was not correlated with the radical intensity of the fractions. Three 70% MeOH extract fractions (70M2-4) produced radical and efficiently scavenged the
Ranilla et al (2012) [
Guanandi (Calophyllum brasiliense Camb), is a large tree belonging to Clusiaceae family widely distributed in Latin America that grows in tropical and swampy areas in Brazil. From its stem bark produces an exudate similar to latex, which has been used in folk medicine for treatment of gastric ulcer among other disease and symptoms [
A resin known as mastic, was obtained from Pistacia lentiscus (L.) var. chia (Duham), an evergreen shrub belonging to the family Anacardiaceae and uniquely cultivated in Southern Chios, a Greek island [
In Nigeria, Eucalyptus torelliana F. Muell leaf extracts have been used in traditional medicine to treat Peptic Ulcer Disease (PUD) and other gastrointestinal disorders. These extracts present additive and synergistic effects when given in combination with clarithromycin, Studies done by Lawal et al., (2012) [
Ferreira et al., (2012) [
Njume et al., (2011) [
Another example of plant product with antimicrobial activity against H. pylori is Urushiol [
There are a number of plants in Pakistan such as Acacia nilotica (L.), Delile, Calotropis procera (Aiton), T.T (Aiton), Adhato davasica Nees, Fagonia arabica and Casuarina equisetifolia L, which have been traditionally used in folk medicine. A recent study carried out by Amin et al., (2013) [
Another plant, Geranium wilfordii Maxim, widely used in Chinese Herbal Medicine to treat gastrointestinal disorders has been studied by Zhang et al., (2013) [
A recent study has been done to evaluate the anti-H. pylori activity of Alchemilla glabra Neygenf (Alchemilla), A. monticola Opiz (Plicatae S.E. Fröhner), A. fissa Günther and Schummel (Calycinae Buser) and A. viridiflora Rothm (Calycinae), and identified ellagic acid and quercetin-3-O-β-glucoside. Anti-H. pylori activity was tested against ten clinical isolates and one reference strain (ATCC 43504). The methanol extracts were more active than the dichloromethane and cyclohexane extracts. The ranges of concentrations were between 4 μg/ml for methanol extracts of A. viridiflora, A. glabra and A. monticola, and 256 μg/ml for cyclohexane extracts of A. viridiflora, A. glabra and A. fissa. The best inhibitory activity was obtained with A. monticola extracts. No significant difference was found in the ellagic acid contents of the methanol extracts of the Alchemilla species (0.2 - 0.3 mg/ml), and anti-H. pylori activity was similar (4 - 32 μg/ml). Ellagic acid exhibited strong activity at very low concentrations (0.125-0.5 μg/ml), while the second identified compound, quercetin-3-O-β-D-glucoside, was also very active but at the concentration of 2 - 16 μg/ml [
A recent study [
Pomegranate tree (Pome granatum) is originally from Occidental Asia and Mediterranean Europe with an extent history of use in traditional medicine. Leaves, flowers, fruits and seeds of this plant have been used to ameliorate diseases. There are several reports indicating that various extracts and their purified fractions have antibacterial activity against Gram positive and Gram negative [
The only human trials examining the antibacterial properties of pomegranate extracts have focused on oral bacteria [
During recent years, a problem due to antibiotic resistance by bacteria has emerged and requires the search for novel compounds to be used as therapy agents. Recently, Hajimahmoodi et al., (2011) [
Based on these results, peel extracts from nine different cultivars of Punica granatum were further tested. It was found that all but excepting one pomegranate cultivar had significant high in vitro activity against H. pylori with inhibition zone diameter mean ranged from 16 to 40 mm at 50 mg per disc.
One of the most recent reports regarding pomegranate extracts was published by Haghayeghi et al., (2013) [
N-acetyltransferase enzyme (NAT) is a ubiquitous enzyme found in bacteria, fungi and protozoa, mammals and even common fruits and vegetables. This NAT activity has been demonstrated to be present in some human gastrointestinal flora [
In this context, the effect of vitamin E on the arylamine N-acetyltransferase activity in H. pylori strains isolated from patients with peptic ulcers has been studied. Chung (1999) [
Another study reported by Chatterjee et al., (2003) [
Several compounds present in food extracts have been used to reduce the risk of damage due to H. pylori infections. Epigallocatechin-3-gallate present in green tea inhibited the urease enzyme of these bacteria in vitro and also in vivo, after infection of Mongolian gerbils [
The inhibitory effect of flavonoids and phenolic acids, which could be transformed from flavonoids by human intestinal microflora, on H. pylori growth has been studied [
Other flavonoids have been obtained from the licorice (Glycyrrhiza uralensis) root extract [
A recent work of Isobe et al., (2006) [
Product name | Scientific/vernacular name | Antimicrobial or HP enzyme inhibitor | MIC (µg/ml) | MIC90 (µg/ml) | MBC (µg/ml) | Reference |
---|---|---|---|---|---|---|
PHENOLICS AND LACTONES | ||||||
Epigallocatechin 3-gallate | Green tea | Urease inhibitor | 32 | [ | ||
Sulforaphane (SFN) | Broccoli | Antimicrobial Bactericidal, Antiurease, bactericidal | 2 - 4 | 2.8 - 5.6 | [ | |
Dehydrocostus lactone | Magnolia sieboldii | Antimicrobial | 4 | [ | ||
FLAVONOIDS | ||||||
Glucoraphamin | Broccoli | [ | ||||
Ponciretin | Antimicrobial | 10 - 20 | [ | |||
Licorice | Glycirrhiza uralensis | Antimicrobial | [ | |||
Vestitol,licoricone, 1MeOPhaseolidine, gancaonol C | Glycirrhiza uralensis | Antimicrobial against Clarithromycin and amoxicillin resistant | 3.2 | [ | ||
Cirsimaritin | G. uralensis | Antimicrobial | 6.3 | [ | ||
ISOFLAVONES | ||||||
Cirsilineol | Hyptis fasciculata | Antimicrobial | 3.2 | [ | ||
Cirsimaritin | Hyptis fasciculata | Antimicrobial | 6.3 | [ | ||
Irisolidone | Pueraria thunbergiana | Antimicrobial | 12.5 - 25 | [ | ||
Luteolin (phytoestrogen) | Terminalia arjuna | Inhibe NAT & human cancer cells Inhibes N. gonorrhoeae | 12.5/disk* | [ | ||
Quercetin, Naringenin | Inhibes VacA 0.046 - 0.36 mM | --- | [ | |||
Glabridin (GutGardÒ) | Glicyrriza glabra | Inhibes: Protein synthesis, DNA gyrase &DHF reductase | --- | [ | ||
COUMARINS | ||||||
Auraptene | Grapefruit | Inhibes adhesion to gastric gastric cells, interferes CD74 | --- | [ | ||
CAFFEATES | ||||||
Caffeic acid phenethyl ester (CAPE) | Propolis | Inhibes deformylase | [ | |||
Caffeic esters (Heptycaffeate) | Inhibes ROS species | 250 | [ | |||
ESSENTIAL OILS | ||||||
Lemon grass oil | Cymbopogon citrates | Reduce HP colonization | 0.01% | [ | ||
Fish oil | Antibacterial activity | [ | ||||
Garlic oil (98% allyl/methyl sulfides) | Allium sativum | Antibacterial activity Antibacterial activity | 32.4 | 32.4 | [ | |
Carvacrol, terpinene | S. bachtiarica | Antibacterial activity | ----- | [ | ||
aTerpineol | Pistacia lentiscus | Antibacterial activity | 1 - 16 | [ | ||
MISCELANEOUS | ||||||
Protopanaxotriol | Arialiaceae /Ginseng | Inhibits HP growth | 50 | [ |
characterized the active constituents which resulted in the isolation of 5 known compounds: cirsilineol, cirsimaritin, aurantiamide acetate, aurantiamide benzoate and methoxy-nepetaefolin and 2 new diterpenoids. The extraction of the mashed aerial part of the plant was done with chloroform and then methanol. The chloroform extract was separated with an MPLC (Medium Pressure Liquid Chromatography) system and eluted with different solvents. The methanol extract was partitioned in water and ethyl acetate. The ethyl acetate fraction was further separated in a solvent system. The water soluble fraction was separated by MLPC method. The characterization was mainly done by NMR and mass spectrometry. These authors found that cirsilineol exhibited potent anti-H. pylori activity (IC90 = 3.2 µg/ml) but weak activity against Escherichia coli and Salmonella enteritidis. Cirsimaritin was also active against H. pylori (6.3 µg/ml) but having activity on other microorganisms as well. Considering structural features of these compounds they propose that flavonoids with potent activities had mainly adjacent dimethoxy-groups, especially at positions 6 and 7, and simultaneously some hydroxyl groups in the molecule as cirsilineol and cirsimaritin. The targets for these compounds have not been yet identified.
Isoflavones isolated from the flowers and rhizomes of Pueraria thunbergiana (Leguminosae) were tested on the growth of H. pylori [
Another studied flavonoid is luteolin (2-[3,4dihydroxy-phenyl]-5,7-dihydroxy-4H-1-benzopyran-4one) defined as a type of phytoestrogen which is present in many plants (family Combretaceae). In particular, the red bell pepper has been demonstrated to contain an abundance of luteolin [
Since in most cases the target for antimicrobial activity of flavonoids and polyphenols has not been described, recent works of Shin (2005) [
Traditional medicine in India has employed Glycyrrhiza glabra Linn, a plant belonging to a legume family (Fabaceae) that grow as small bushes in Asia, Australia, Europe and the Americas, in the treatment of peptic ulcer caused by H. pylori. Recently, Asha et al., (2013) [
Recently, Sekiguchi et al., (2012) [
A recent study of Paracatu et al., (2014) [
Njume et al. (2011) [
Essential oils, which are extracted from plants (e.g., leaves, peels), showed the growth inhibition of H. pylori in vitro [
Considerable work on naturally occurring H. pylori therapeutics has focused upon the truly lipoidal oils, which include short-, medium-, and long-chain fatty acids as well as monoglycerides; and polyunsaturated fatty acids (commonly referred as PUFAs). Fish oil [
Numerous investigators have reported in vitro positive effects of specific polyunsaturated fatty acids against H. pylori [
Satureja bachtiarica Bunge is traditionally used as the antimicrobial agent. In a recent study, Falsafi et al., (2015) [
Probiotics in the Treatment of h. Pylori Infections
Probiotics, according to Fueller (1989) [
It has been proposed that probiotics may control H. pylori infection considering that some of the Lactobacilli strains may survive in the acidic environment of the human stomach, remaining for some time in that niche. Some strains may produce antimicrobial products such as bacteriocins [
In vitro studies of Chatterjee et al., (2003) [
As a consequence of therapy failure, an increase in the prevalence of antibiotic-resistant bacteria has arisen, which has led to the search for alternative therapies. Vitor and Vale (2011) [
Over the past 8 years, 11 meta-analyses have been published assessing the efficacy of probiotics as adjuvants to cooperate with antibiotics for the eradication of H. pylori (
Probiotic tested | Antibiotic therapya | Trials (N) | Patientb (ITT, N) | Study designc | Pooled eradication (treated) | Pooled eradication (control) | Odds Rate | P valued | Reference |
---|---|---|---|---|---|---|---|---|---|
Any probiotic (also Inactive) | Tor Q | 14 | 1671 | RCT | 83.6% | 74.8% | 1.84 | 0.0002 | [ |
Lactobacilli | Triple | 8 | 1372 | RCT | 82.3% | 77.0% | 1.78 | 0.003 | [ |
Bovine lactoferrin Yogurt Fermented milk | T, Q or N | 10 | 963 | RCT | 67.7% | 58.1% | 1.91 | <0.0001 | [ |
Streptococcus. boulardii | T | 4 | 915 | RCT | 80.4% | 71.2% | 1.13 | 0.001 | [ |
Lactobacillus. spp. ± Bifidobacterium spp. | D, T or Q | 10 | 1469 | Controlled | 82.6% | 71.7% | 2.07 | NR | [ |
Lactobacillus spp. | T or Sq | 9 | 1163 | RCT | 78.2% | 68.5% | 1.14 | 0.0002 | [ |
Any | T | 7 | 505 | RCT | 78.1% | 66.7% | 1.96 | NR | [ |
Any | T orQ or Sq | 33 | 4459 | RCT | 80.4% | 70.0% | 1.12 | NR | [ |
Any | Triple | 14 | 2259 | RCT | NR | NR | 1.67 | NR | [ |
Any | T, Q or Sq | 45a | 6997 | RCT | 82.3% | 72.1% | 1.13 | <0.001 | [ |
Any | T | 23 | 3900 | RCT | 80.8% | 72.3% | 1.72 | <0.001 | [ |
aType of therapy: T = triple; Q = quadruple; Sq = sequential; D = dual; N = none; bITT = intention to treat; N = not treated; cRCT = randomized controlled trial; dNR = not reported; eIncludes Chinese literature.
Boltin et al., 2016 [
Nowadays, the prevalence and the emergence of bacterial antibiotic resistances are a very serious problem. Concordantly, the antimicrobial eradication success rate of H. pylori has been declining globally in recent years. For example, clarithromycin resistance, in particular, has been rapidly increased in many countries over the past decade, with rates as high as 30% in both Japan and Italy, 50% in China and 40% in Turkey; whereas resistance rates are much lower in Sweden and Taiwan, with a rate of approximately 15% (Thung et al., 2016). Moreover, to date, there is no large scale production of an effective vaccine against H. pylori available in the market (Talebi, 2016) for different reasons as previously and extensively been reviewed by Hongying et al., (2014) [
Ancestral folk medicine passed from mouth to mouth for many years and has been wisely applied by “Chamanes” and “Curanderos” in some cases. It has been globally proven by diverse aborigine populations that some natural products obtained from nature can be helpful to alleviate and fight gastrointestinal diseases caused by microorganisms. This knowledge traditionally transferred within these families has been useful to identify the source to isolate and purify new and effective compounds to control many diseases. With the technology available today we can elucidate how folk medicine actually works and understand how it has helped our ancestors for many decades to counteract or reduce disease symptoms since many years ago.
There is a conundrum of components detected in plant extracts that should be studied as potential substitutes or additives in the antibiotic therapy. There are plants and marine algae living in extreme habitats that are able to synthesize bizarre but useful antibacterial compounds to fight the increased number of antibiotic resistant strains. However, the isolation and identification of such compounds responsible for the positive effect on eradication of diverse diseases must be accomplished to test the safety of them and understand their mechanisms of action.
Considering the present situation of a large variety of natural sources with antimicrobial activities further studies will be required to identify the most powerful and useful compounds and test them for toxicity and genotoxic effects on humans before use them to successfully eradicate H. pylori from the human stomach.
A comparative study of the antimicrobial activity of different products will be a must in order to use mixtures displaying synergism. Also, the synergism already described between some plant organic compounds and antibiotics could be a very effective alliance. It is also desirable that most of these new products should work in a specific way against pathogenic bacteria without affecting our normal microbiome.
At present, it is very difficult to compare efficacy among all these products pursuing the same objective against H. pylori. In the case of plant derivatives, when using a particular vegetal extract, the amount of active compound extracted will depend on the source, section or organ used as starting material for the isolation, as well as other parameters such as time taking for the extraction, appropriate solvent for the procedure and so on. Moreover, the existence of different H. pylori strains does make difficult to compare which extract is better than other. The use of a combination of agents or purified compounds with or without antibiotics could be a faster way to find out a rapid answer to improving the treatment against H. pylori. This combined strategy will make more difficult to allow emergence of resistant strains after a treatment with mixed compounds, due to the large chemical differences among these compounds and their biological and physical characteristics.
The intention of this revision was to describe potential alternatives for the treatment of H. pylori but due to the great diversity of compounds we cannot provide a clear and define comparative analysis of the different products with antimicrobial activity. In addition, a diet rich in foods having different natural activities anti-H. pylori may be an inexpensive but effective collaborator against the rise of antibiotic resistant strains. On the other hand, pharmaceutical companies would be more supportive of development of new drugs based on natural products.
Finally, it is required even more research studies to elucidate the mechanisms of action of these molecules, their synergisms, antagonisms and other pharmacological aspects.
This study was financially supported by the Semilla Funds from the Dirección de Postgrado e Investigación, Universidad Diego Portales, Chile (Project No: 201521).
The present study was funded by research funds of the authors. No pharmaceutical grants were used for this study.
Venegas, A., Touma, J.H., Bravo, J. and Perez-Perez, G. (2016) Progress in Use of Natural Products and Their Active Components against Heli- cobacter pylori. Advances in Microbiology, 6, 1091-1129. http://dx.doi.org/10.4236/aim.2016.614101