Antimicrobial effects of antioxidants with and without clarithromycin on Helicobacter pylori

Garcinia kola: a critical review on chemistry and pharmacology of an important West African medicinal plant

Garcinia kola Heckel (Clusiaceae) is a tree indigenous to West and Central Africa. All plant parts, but especially the seeds, are of value in local folklore medicine. Garcinia kola is used in treatment of numerous diseases, including gastric disorders, bronchial diseases, fever, malaria and is used to induce a stimulating and aphrodisiac effect. The plant is now attracting considerable interest as a possible source of pharmaceutically important drugs. Several different classes of compounds such as biflavonoids, benzophenones, benzofurans, benzopyran, vitamin E derivatives, xanthones, and phytosterols, have been isolated from G. kola, of which many appears to be found only in this species, such as garcinianin (found in seeds and roots), kolanone (fruit pulp, seeds, roots), gakolanone (stem bark), garcinoic acid, garcinal (both in seeds), garcifuran A and B, and garcipyran (all in roots). They showed a wide range of pharmacological activities (e.g. analgesic, anticancer, antidiabetic, anti-inflammatory, antimalarial, antimicrobial, hepatoprotective and neuroprotective effects), though this has only been confirmed in animal models. Kolaviron is the most studied compound and is perceived by many studies as the active principle of G. kola. However, its research is associated with significant flaws (e.g. too high doses tested, inappropriate positive control). Garcinol has been tested under better conditions and is perhaps showing more promising results and should attract deeper research interest (especially in the area of anticancer, antimicrobial, and neuroprotective activity). Human clinical trials and mechanism-of-action studies must be carried out to verify whether any of the compounds present in G. kola may be used as a lead in the drug development.

Antidepressant and anxiolytic effects of Garcinia indica fruit rind via monoaminergic pathway

Depression and anxiety are the most crippling neuropsychiatric disorders of this modern era. These mostly occur as anxiety followed by depression or in mixed state. Therefore, there is an urgent need of a safe and effective treatment, which proves its worth in this ailment. What else than a conventional food would be a better choice for a convenient therapy. Therefore, Garcinia indica, commonly known as Kokam, fruit rind has been used in the present study to investigate its antidepressant and anti-anxiety potential using forced swim test, tail suspension test, and reserpine-induced hypothermia; and elevated plus maze, hole-board test, and light dark model, respectively. Garcinia indica fruit rind given to mice with food for consecutive 14 days at 0.5, 1, and 2% w/w significantly (p < 0.05) reduced despair behavior in forced swim test, immobility duration in tail suspension test, and also switched the hypothermia (reserpine induced) to normal temperature significantly (p < 0.05). Garcinia indica significantly (p < 0.05) raised the time elapsed and count of entries in open arms of elevated plus maze, enhanced incidence of head dipping in holes of hole board along with duration of expending time in lit compartment of light dark model, exhibiting its anti-anxiety effect. Garcinia indica significantly reduced monoamine oxidase and malondialdehyde levels providing support to neuroprotective potential of fruit rind. The mechanistic study showed the participation of G. indica at α1-adrenoceptor and D2-dopamine receptor, by attenuating prazosin and sulpiride-induced increase in immobility duration. Garcinia indica fruit rind showed a significant antidepressant and anxiolytic effect while no effect on locomotor activity, i.e., no psycho-stimulation.

Effect of grape pomace on fermentation quality and aerobic stability of sweet sorghum silage

The objective of this study was to evaluate the effect of grape pomace (GP) with different adding levels (0%, 5%, 10% and 15%, fresh matter basis), alone (GP-LAB) or in combine with an inoculant LAB (GP+LAB), on the fermentation quality and aerobic stability of sweet sorghum silage. After 90 days of ensiling in vacuumized mini-silos, silages were subject to a 7-day aerobic stability test, in which chemical, microbial and polyphenol composition were measured. In the GP-LAB group, adding GP decreased (P < 0.05) concentrations of water-soluble carbohydrate (WSC) and butyric acid in silage. In the GP+LAB group, adding GP increased (P < 0.05) concentrations of lactic acid, WSC and crude protein, decreased (P < 0.05) final pH value, NH₃ -N ratio and butyric acid concentration in silage. Polyphenol level was reduced (P < 0.05) after silage fermentation. During aerobic exposure, the fungi count, pH value and silage temperature increased (P < 0.05), the levels of lactic acid, acetic acid and polyphenols (quercetin 3-O-glucoside and quercetin 3-O-glucuronid) decreased (P < 0.05) in silage. GP+LAB treated silage had a lag phase for aerobic spoilage. When the fermentation products, microbial counts, chemical and polyphenol composition were considered, the use of 10% GP+LAB at ensiling could provide a valuable source for improved fermentation quality and aerobic stability of sweet sorghum silage.

Prevalence of Helicobacter pylori infection among preschool children in Latvia: no significant decrease in prevalence during a ten year period

Aims: Published data show a trend of decreasing prevalence of Helicobacter pylori in Eastern European countries due to socioeconomic changes. The aim of this study was to determine the prevalence of H. pylori infection among children in Latvia and to compare these results with previous studies in the same population. The risk factors associated with infection were also analysed. Methods: Preschool children in kindergartens and primary health care centres were investigated using a stool antigen test. Their parents were asked to fill out a questionnaire about possible risk factors. Statistical analysis included Pearson’s χ2 test and linear regression analysis. Results: The prevalence of H. pylori infection determined by the monoclonal stool antigen test in children aged 1–6 years (median 5 years) was 15.5% (15/101) (95% confidence interval 8.67–23.48%). In the regression analysis, H. pylori positivity was significantly negatively associated with the consumption of imported fruit at least once per week ( p=0.02). Conclusions: The prevalence of H. pylori in the studied population has not decreased significantly during the last decade and is still associated with socioeconomic factors. The role of some dietary factors (e.g. the consumption of fruit) in the spread of infection should be studied further.

Combination of anti-tuberculosis drugs with vitamin C or NAC against different Staphylococcus aureus and Mycobacterium tuberculosis strains

BACKGROUNDS

Hepatotoxicity due to anti tuberculosis drugs, rifampin and isoniazid, is a major problem in tuberculosis patients. Vitamin C, an antioxidant, and N-acetyl cysteine (NAC), a scavenger of active metabolites, reduce the hepatotoxicity. The aim of present study was to investigate the effect of vitamin C and NAC individually on the antibacterial activity of anti tuberculosis drugs against Mycobacterium tuberculosis and Staphylococcus aureus strains.

METHODS

The MICs of each compound against all strains were determined in 96 wells plate. Rifampin was tested at serial two fold concentrations alone or in combination with NAC or vitamin C.

RESULTS

The MIC of rifampin against different strains of S. aureus was 0.008-0.032 μg/ml. The MIC of rifampin and isoniazid against M. tuberculosis strains were 40 and 0.2 μg/ml, respectively. Vitamin C and NAC had no antibacterial activity against all strains. MIC of rifampin was reduced two fold by combination with vitamin C for all S. aureus strains, while NAC did not affect the antibacterial activity of rifampin. Vitamin C and NAC had remarkable effects on the antibacterial activity of anti-tuberculosis drugs against M. tuberculosis.

CONCLUSIONS

Synergistic effects were observed between rifampin or isoniazid and vitamin C against all tested strains. However, combination therapy of rifampin and isoniazid with NAC was not being effective. This study highlighted the advantages of combination of anti-tuberculosis drugs and vitamin C to eradicate the microbial infections.

Antimicrobial activity and composition profile of grape (Vitis vinifera) pomace extracts obtained by supercritical fluids

The possibility of increasing the aggregated value of the huge amount of residues generated by wineries around the world foment studies using the grape pomace - the residue from the wine production, composed by seed, skin and stems - to obtain functional ingredients. Nowadays, consumers in general prefer natural and safe products mainly for food and cosmetic fields, where the supercritical fluid extraction is of great importance due to the purity of the extracts provided. Therefore, the objective of this work is to evaluate the global extraction yield, the antimicrobial activity and the composition profile of Merlot and Syrah grape pomace extracts obtained by supercritical CO2 (SC-CO2) and CO2 added with co-solvent at pressures up to 300 bar and temperatures of 50 and 60 °C. The results were compared with the ones obtained by Soxhlet and by ultrasound-assisted leaching extraction methods. The main components from the extracts, identified by HPLC, were gallic acid, p-OH-benzoic acid, vanillic acid and epicatechin. The antibacterial and antifungal activities of the extracts were evaluated using four strains of bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa) and three fungi strains (Candida albicans, Candida parapsilosis, Candida krusei). Despite lower extraction yield results, the supercritical fluid extracts presented the highest antimicrobial effectiveness compared to the other grape pomace extracts due to the presence of antimicrobial active compounds. Syrah extracts were less efficient against the microorganisms tested and Merlot extracts were more active against Gram-positive bacteria.

The anti-cancer agent guttiferone-A permeabilizes mitochondrial membrane: ensuing energetic and oxidative stress implications

Guttiferone-A (GA) is a natural occurring polyisoprenylated benzophenone with cytotoxic action in vitro and anti-tumor action in rodent models. We addressed a potential involvement of mitochondria in GA toxicity (1-25 μM) toward cancer cells by employing both hepatic carcinoma (HepG2) cells and succinate-energized mitochondria, isolated from rat liver. In HepG2 cells GA decreased viability, dissipated mitochondrial membrane potential, depleted ATP and increased reactive oxygen species (ROS) levels. In isolated rat-liver mitochondria GA promoted membrane fluidity increase, cyclosporine A/EGTA-insensitive membrane permeabilization, uncoupling (membrane potential dissipation/state 4 respiration rate increase), Ca²⁺ efflux, ATP depletion, NAD(P)H depletion/oxidation and ROS levels increase. All effects in cells, except mitochondrial membrane potential dissipation, as well as NADPH depletion/oxidation and permeabilization in isolated mitochondria, were partly prevented by the a NAD(P)H regenerating substrate isocitrate. The results suggest the following sequence of events: 1) GA interaction with mitochondrial membrane promoting its permeabilization; 2) mitochondrial membrane potential dissipation; 3) NAD(P)H oxidation/depletion due to inability of membrane potential-sensitive NADP+ transhydrogenase of sustaining its reduced state; 4) ROS accumulation inside mitochondria and cells; 5) additional mitochondrial membrane permeabilization due to ROS; and 6) ATP depletion. These GA actions are potentially implicated in the well-documented anti-cancer property of GA/structure related compounds.

Essential role of vitamin C and zinc in child immunity and health

With the progressive elimination of dietary protein-energy deficits, deficiencies of micronutrients are emerging as the limiting factors in ensuring children's optimal health. Data from several countries in Asia and Latin America indicate that deficiencies of vitamin C and zinc continue to be at alarming levels. This article reviews the roles of vitamin C and zinc in supporting children's growth and development, with a particular focus on the complementary roles they play in supporting immune functions and combating infections. The contemporary relevance of vitamin C and zinc deficiency in the Asian and Latin American regions, both undergoing a rapid nutritional transition, are also discussed. Overall, there is increasing evidence that deficiency of vitamin C and zinc adversely affects the physical and mental growth of children and can impair their immune defences. Nutrition should be the main vehicle for providing these essential nutrients; however, supplementation can represent a valid support method, especially in developing regions.

Emerging role of Garcinol, the antioxidant chalcone from Garcinia indica Choisy and its synthetic analogs

Garcinol, harvested from Garcinia indica, has traditionally been used in tropical regions and appreciated for centuries; however its biological properties are only beginning to be elucidated. There is ample data to suggest potent antioxidant properties of this compound which have been used to explain most of its observed biological activities. However, emerging evidence suggests that garcinol could be useful as an anti-cancer agent, and it is increasingly being realized that garcinol is a pleiotropic agent capable of modulating key regulatory cell signaling pathways. Here we have summarized the progress of our current research knowledge on garcinol and its observed biological activities. We have also provided an explanation of observed properties based on its chemical structure and provided an insight into the structure and properties of chalcones, the precursors of garcinol. The available data is promising but more detailed investigations into the various properties of this compound, particularly its anti-cancer activity are urgently needed, and it is our hope that this review will stimulate further research for elucidating and appreciating the value of this nature's wonder agent.

A marine sulfate-reducing bacterium producing multiple antibiotics: biological and chemical investigation

A marine sulfate-reducing bacterium SRB-22 was isolated by means of the agar shake dilution method and identified as Desulfovibrio desulfuricans by morphological, physiological and biochemical characteristics and 16S rDNA analysis. In the bioassay, its extract showed broad-spectrum antimicrobial activity using the paper disc agar diffusion method. This isolate showed a different antimicrobial profile than either ampicillin or nystatin and was found to produce at least eight antimicrobial components by bioautography. Suitable fermentation conditions for production of the active constituents were determined to be 28 day cultivation at 25 °C to 30 °C with a 10% inoculation ratio. Under these conditions, the SRB-22 was fermented, extracted and chemically investigated. So far an antimicrobial compound, mono-n-butyl phthalate, and an inactive compound, thymine, have been isolated and characterized.

Growth inhibition of colon cancer cells by polyisoprenylated benzophenones is associated with induction of the endoplasmic reticulum response

Polyisoprenylated benzophenones derived from Garcinia xanthochymus have cytotoxic activity in vitro and antitumor activity in rodent models, but the mechanism is unknown. The purpose of our study was to examine in parallel molecular pathways that are targeted by 3 Garcinia-derived benzophenones-xanthochymol (X), guttiferone E (GE) and guttiferone H (GH), in 3 human colon cancer cell lines, HCT116, HT29 and SW480. The IC50 concentrations were determined and the cells were then treated with X, GE or GH at their respective IC50 or IC50x2 concentrations. Effects on the cell cycle, mitochondrial membrane potential and apoptosis were assessed by flow cytometry and caspase activation. Changes in gene expression were assessed with Illumina 24 K gene arrays. We found that X, GE and GH induced loss of mitochondrial membrane potential and G1 arrest at their IC50 concentrations and induced caspase activation at IC50 x 2 concentrations. An analysis of the changes in gene expression revealed that with all 3 compounds and all 3 cell lines there was a marked increase in expression of several genes, including XBP1, ATF4 and DDIT3/CHOP, which are components of the endoplasmic reticulum stress response. The DDIT4/REDD1 gene, an inhibitor of the mTOR survival pathway, was also up-regulated. Therefore, X, GE and GH appear to inhibit the growth of human colon cancer cells, at least in part, by activating the endoplasmic reticulum stress response and inhibiting the mTOR cell survival pathway. These combined effects may contribute to the anticancer activity of these novel compounds.

Cytokine expression due to Helicobacter pylori in a tissue culture model

Helicobacter pylori, in recent years, has been recognized as the major causative agent in chronic gastritis and peptic ulcer disease in humans. H. pylori is a ubiquitous organism, with at least half of the world's population infected. Of those individuals with peptic ulcer disease, it is estimated that 90% of cases are caused by H. pylori. Currently, the efficacy of therapies is starting to decline due to increasing resistance rates, especially towards clarithromycin. Due to this, new therapies are needed to combat this bacterium. It is hypothesized that cytokine release (especially interleukin-1beta, -6, -8, and TNF-alpha) due to H. pylori infection and the subsequent influx of inflammatory cells causes a massive release of reactive oxygen species (ROS) during the inflammatory reaction. The ROS then cause the pathologic changes seen in the infected tissues. In this study, human gastric adenocarcinoma cell line ATCC 1739 (a cell line not previously evaluated) was examined for its production of interleukin-1beta, -6, -8, and TNF-alpha when cocultured in a ratio of 10:1 H. pylori to adenocarcinoma cells, to determine its value as a model to demonstrate the inflammatory response. Results from this study indicated that ATCC 1739 cells only reliably produced IL-8 when cocultured with H. pylori and stimulated with TNF-alpha. The production of IL-1beta, IL-6, and TNF-alpha by the ATCC 1739 cells was no different in H. pylori-exposed cells than non-exposed cells. It was concluded that the ATCC 1739 cell line is not suitable to study the effects of coculture with H. pylori on cytokine production.

Influence of vitamin E on gastric mucosal injury induced by Helicobacter pylori infection

We investigated the effect of vitamin E on gastric mucosal injury induced by Helicobacter pylori (H. pylori) infection. Male Mongolian gerbils were divided into 4 groups (normal group without H. pylori infection, vitamin E-deficient, -sufficient and -supplemented groups with H. pylori infection). Following oral inoculation with H. pylori (ATCC43504 2 x 10(8) CFU), animals were fed diets alpha-tocopherol 2 mg/100 g diet in the normal and vitamin E-sufficient groups and alpha-tocopherol 0.1 mg/100 g and 50 mg/100 g in the vitamin E-deficient and -supplemented groups, respectively, for 24 weeks. Chronic gastritis was detected in all gerbils inoculated H. pylori. Gastric ulcer was detected in 2 of 7 gerbils only in the vitamin E-deficient group. In the vitamin E-deficient group, myeloperoxidase activity and mouse keratinocyte derived chemokine (KC) in gastric mucosa was significantly higher than in the vitamin E supplemented group. Subsequently, in an in vitro study expression of CD11b/CD18 on neutrophils was enhanced by H. pylori water extract. This effect was suppressed in a dose dependent manner by the addition of alpha-tocopherol. These results suggest that vitamin E has a protective effect on gastric mucosal injury induced by H. pylori infection in gerbils, through the inhibition of accumulation of activated neutrophils.