Health Beneficial Properties of Grapevine Seed Extract and Its Influence on Selected Biochemical Markers in the Blood, Liver and Kidneys of Rattus norvegicus

Cadmium (Cd) is a heavy metal that occurs in all areas of the environment, including the food chain. In the body, it causes oxidative stress by producing free radicals that are harmful to the cells. Grape seed extract (GSE) contains a wide range of biologically active components that help to neutralize the adverse effects of free radicals. In this study, the effects of GSE prepared form semi-resistant grapevine cultivar Cerason, which is rich in phenolics, on biochemical markers of brown rats exposed to the effects of cadmium were monitored. GSE increased the plasma antioxidant activity and, in the kidneys and the liver, Cd content was significantly lowered by GSE co-administration. Accordingly, the increase in creatinine content and alanine aminotransferase activity and the decrease of catalase and superoxide dismutase activities caused by cadmium were slowed down by GSE co-administration. The results of this work reveal that grape seed extract offers a protective effect against the intake of heavy metals into the organism.

Soybean-Derived Isoflavone Determination in Rumen Fluid and Milk by LC-MS-(TOF)

Soybean-derived isoflavones belong to the family of biologically active phytoestrogens. The purpose of this study was to develop a sensitive method, which permits quantification of the soybean isoflavonoids and equol in bovine rumen fluid and milk using LC-MS-(TOF). The samples of rumen fluid and milk were obtained from 12 lactating dairy cows ingesting 7,500-9,500 mg of total isoflavones daily. The validation of the developed method showed the limits of quantification to be in the range of 0.9-5.0 ng/mL. The precision was determined as relative standard deviation, which was lower than 25% in all cases. The recoveries of the most isoflavonoids were satisfactory. Lower recoveries of daidzin and glycitin can be solved by adding an internal standard. The presented method will be useful for kinetic studies of isoflavone metabolism in ruminants due to simultaneous quantification of free aglycones and glycosides in the rumen fluid.

Effects of Isoflavone-Enriched Feed on the Rumen Microbiota in Dairy Cows

In this study, we compared the effects of two diets containing different isoflavone concentrations on the isoflavone transfer from feed into milk and on the rumen microbiota in lactating dairy cows. The on-farm experiment was conducted on twelve lactating Czech Fleckvieh x Holstein cows divided into two groups, each with similar mean milk yield. Twice daily, cows were individually fed a diet based on maize silage, meadow hay and supplemental mixture. Control group (CTRL) received the basal diet while the experimental group (EXP) received the basal diet supplemented with 40% soybean isoflavone extract. The average daily isoflavone intake in the EXP group (16 g/day) was twice as high as that in the CTRL group (8.4 g/day, P<0.001). Total isoflavone concentrations in milk from the CTRL and EXP groups were 96.89 and 276.07 μg/L, respectively (P<0.001). Equol concentrations in milk increased from 77.78 μg/L in the CTRL group to 186.30 μg/L in the EXP group (P<0.001). The V3-4 region of bacterial 16S rRNA genes was used for metagenomic analysis of the rumen microbiome. The experimental cows exhibited fewer OTUs at a distance level of 0.03 compared to control cows (P<0.05) and reduced microbial richness compared to control cows based on the calculated Inverse Simpson and Shannon indices. Non-metric multidimensional scaling analysis showed that the major contributor to separation between the experimental and control groups were changes in the representation of bacteria belonging to the phyla Bacteroidetes, Proteobacteria, Firmicutes, and Planctomycetes. Surprisingly, a statistically significant positive correlation was found only between isoflavones and the phyla Burkholderiales (r = 0.65, P<0.05) and unclassified Betaproteobacteria (r = 0.58, P<0.05). Previous mouse and human studies of isoflavone effects on the composition of gastrointestinal microbial populations generally report similar findings.

Elucidation of signaling molecules involved in ergosterol perception in tobacco

Ergosterol, a principal compound of the fungal plasma membrane, is regarded as a pathogen-associated molecular pattern. In the present study, the role of salicylic acid (SA), jasmonic acid (JA) and spermine signaling pathways after ergosterol elicitation were evaluated. SA, JA and spermine production, as well as accumulation of transcripts for a lipoxygenase (NaLOX3) gene, the phenylalanine-ammonia lyase gene, selected pathogenesis-related genes (PR1, PR5), and peroxidase tPOXC1 were determined in tobacco (Nicotiana tabacum L. cv. Xanthi) in response to ergosterol elicitation. To understand the sequence of the signaling cascade, several representative steps involved in the synthesis of crucial signaling molecules were targeted using specific inhibitors. SA signaling pathway, together with calmodulin-dependent protein kinases and nitric oxide, was demonstrated to play an important role in the induction of defense-related genes following ergosterol treatment. The results suggested that nitric oxide participates in defense-related gene activation following ergosterol treatment but does not directly participate in activation of reactive oxygen species production. The induction of PR5 and tPOXC1 transcripts was found to be not fully dependent on calmodulin/Ca2+ and SA signaling, contrary to the PR1a transcript. A possible candidate for this SA-independent pathway is the spermine pathway, as elevated spermine levels were detected following ergosterol treatment.

Determination of capsidiol in tobacco cells culture by HPLC

Capsidiol is a bicyclic sesquiterpene, which accumulates extracellularly in plants, and has been isolated from many types of Solanaceae. It acts as a phytoalexin produced by Nicotiana tabacum in response to pathogens. Capsidiol has antifungal activity and is formed first in tobacco and pepper plants after infestation. The amount of capsidiol in tobacco cell suspension culture has been previously determined by solid-phase extraction and organic solvent extraction with thin-layer chromatography or gas chromatography analysis. A high-performance liquid chromatography method with UV detection at 210 nm on a C(8) column utilizing both extraction methods was developed to analyze capsidiol in suspension cell culture. The HPLC method was linear in the concentration range of 0.1-2.0 mg/L. The lower limit of quantitation was 0.1 mg/L. Organic solvent extraction and solid-phase extraction methods were compared. Both methods are generally similar in their overall efficiency (82% and 75%, respectively), but eliminations of interfering compounds are different. The relative standard deviation across five extractions of known amounts of capsidiol from plant sample was less than 5.1%. The relative standard deviation across five elicitations of cell cultures was less than 5.9%. Gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analysis of capsidiol was performed, and corresponding mass spectra are presented.

Construction of cryptogein mutants, a proteinaceous elicitor from Phytophthora, with altered abilities to induce a defense reaction in tobacco cells

We prepared a series of cryptogein mutants, an elicitor from Phytophthora cryptogea, with altered abilities to bind sterols and fatty acids. The induction of the early events, i.e., synthesis of active oxygen species and pH changes, in suspension tobacco cells by these mutated proteins was proportional to their ability to bind sterols but not fatty acids. Although the cryptogein-sterol complex was suggested to be a form triggering a defense reaction in tobacco, some proteins unable to bind sterols induced the synthesis of active oxygen species and pH changes. The modeling experiments showed that conformational changes after the introduction of bulky residues into the omega loop of cryptogein resemble those induced by sterol binding. These changes may be necessary for the ability to trigger the early events by elicitins. However, the ability to stimulate necrosis in suspension tobacco cells and the expression of defense proteins in tobacco plants were linked neither to the lipid binding capacity nor to the capacity to provoke the early events. On the basis of these experiments and previous results, we propose that elicitins could stimulate two signal pathways. The first one induces necroses and the expression of pathogen-related proteins, includes tyrosine protein kinases and mitogen-activated protein kinases, and depends on the overall structure and charge distribution. The second type of interaction is mediated by phospholipase C and protein kinase C. It triggers the synthesis of active oxygen species and pH changes. This interaction depends on the ability of elicitins to bind sterols.

Ergosterol elicits oxidative burst in tobacco cells via phospholipase A2 and protein kinase C signal pathway

Ergosterol, a typical fungal sterol, induced in tobacco (Nicotiana tabacum L. cv. Xanthi) suspension cells the synthesis of reactive oxygen species and alkalization of the external medium that are dependent on the mobilization of calcium from internal stores. We used specific inhibitors to elucidate the signal pathway triggered by ergosterol compared with cryptogein, a proteinaceous elicitor of Phytophthora cryptogea. Herbimycin A and genistein, inhibitors of tyrosine protein kinases, had no effect on the oxidative burst and pH changes induced by both elicitors. Similarly, H-89, an inhibitor of protein kinase A, had no effect on the induction of these defense reactions. However, the response to both elicitors was completely blocked by NPC-15437, a specific inhibitor of animal protein kinase C (PKC). The responses induced by cryptogein but not those induced by ergosterol were inhibited by U73122 and neomycin, inhibitors of phospholipase C (PLC). On the other hand, the activity of phospholipase A2 (PLA2) measured using a fluorogenic substrate was stimulated by ergosterol and not by cholesterol and cryptogein. A specific inhibitor of PLA2, arachidonic acid trifluoromethyl ketone (AACOCF3), inhibited the pathway stimulated by ergosterol but not that induced by cryptogein. These results suggest that the cryptogein-induced signal pathway leading to the oxidative burst and DeltapH changes includes PLC and PKC, whereas this response induced by ergosterol includes PLA2 and PKC.