Miloslav Šulc

Major factors influencing antioxidant contents and antioxidant activity in grapes and wines

Phenolic compounds in wines, especially in red wines, possess strong antioxidant activity, have the largest effect in decreasing atherosclerosis by both hypolipemic and antioxidant mechanisms. The long-term uptake of red wine has a positive impact on antioxidant activity (AA) of blood plasma in rats in vivo and increases AA by 15%–20% compared to a control group. In the article the effect of total phenolics (TP), total anthocyanins (TA), individual anthocyanins, procyanidins and phenolics contained in red grapes, musts, grape seeds and skins and wines on the AA is discussed. Significant impact of varieties, viticultural regions and locations, climate conditions and vintage has been shown. Likewise, the ways and individual stages of the vinification technology process, and storage conditions affect color, TP, TA, and AA and health aspects of produced wines. Resveratrol, another free radical scavenger mainly contained in the skins of grapes, inhibits the risk of cardiovascular diseases. Higher amounts of trans-resveratrol (RES) have been found in wines from cool and wet climate regions and lesser amounts are typical for warm and dry regions. Changes in the TP content and AA affected by grape variety, vineyard location and winemaking process in white and blue varieties from different vineyards of the Czech Republic were studied. Significant differences in TP among varieties were found. Analysis of variance showed statistically high differences among red and white wines and growing locations. Wines differed significantly in TP content and AA increased significantly during the winemaking process. Statistically significant differences in AA values were found among growing areas, wines and varieties. Significant positive correlations between TP and AA were determined. Total antioxidant status (TAS) of white and red wines (white and blue vine varieties) determined by DPPH and ABTS assays revealed significant differences in AA between white and red wines. Moreover, differences were ascertained between individual varieties of red wine. The results obtained supported the assumption that variety plays a considerable role in TAS; the blue vine varieties showed a much higher TAS. Analysis of variance in AA showed statistically high significance between red and white wines. AA increased during the winemaking process, the highest increase was determined during fermentation and maturation stages of red wine.

Bisphenol S negatively affects the meotic maturation of pig oocytes

Bisphenol A (BPA), a chemical component of plastics, is a widely distributed environmental pollutant and contaminant of water, air, and food that negatively impacts human health. Concerns regarding BPA have led to the use of BPA-free alternatives, one of which is bisphenol S (BPS). However, the effects of BPS are not well characterized, and its specific effects on reproduction and fertility remain unknown. It is therefore necessary to evaluate any effects of BPS on mammalian oocytes. The present study is the first to demonstrate the markedly negative effects of BPS on pig oocyte maturation in vitro, even at doses lower than those humans are exposed to in the environment. Our results demonstrate (1) an effect of BPS on the course of the meiotic cell cycle; (2) the failure of tubulin fibre formation, which controls proper chromosome movement; (3) changes in the supply of maternal mRNA; (4) changes in the protein amounts and distribution of oestrogen receptors α and β and of aromatase; and (5) disrupted cumulus cell expansion. Thus, these results confirm that BPS is an example of regrettable substitution because this substance exerts similar or even worse negative effects than those of the material it replaced.

Carotenoid profile and retention in yellow-, purple- and red-fleshed potatoes after thermal processing.

This research aimed to investigate the effect of thermal processing on carotenoid profile, quantity and stability in 22 colour-fleshed potato cultivars grown in the Czech Republic. The total of nine carotenoids was analysed by HPLC using a C30 column and PDA detection. The total carotenoid content for all cultivars ranged from 1.44 to 40.13 μg/g DM. Yellow cultivars showed a much higher average total carotenoid content (26.22 μg/g DM) when compared to red/purple-fleshed potatoes (5.69 μg/g DM). Yellow cultivars were dominated by antheraxanthin, whereas neoxanthin was the main carotenoid in red/purple cultivars. Thermal processing significantly impacted all potato cultivars. Boiling decreased the total carotenoids by 92% compared to baking (88%). Lutein was the most stable carotenoid against thermal processing (decreased by 24-43%) followed by β-carotene (decreased by 78-83%); other carotenoids were degraded nearly completely. Increased formation of (Z)-isomers by thermal processing has not been confirmed.

Influence of parasitism on the use of small terrestrial rodents in environmental pollution monitoring.

Bioaccumulation of cadmium, chromium, copper, manganese, nickel, lead and zinc in small terrestrial rodents - voles and their cestode parasite Paranoplocephala dentata was studied. Contents of Pb, Mn, Ni and Zn in the parasite were found to be higher than in the kidney and liver of the parasitized animals. Lead level in the cestode was 37 fold higher than in the liver of the infected rodents. Bioaccumulation factors of zinc, nickel and manganese in the cestode are mostly in the range from 2 to 4.5. Considering the different contents of manganese and zinc in livers of non-parasitized and parasitized rodents, kidney tissue was found to be more reliable than liver as an indicator of environmental pollution by manganese and zinc; the kidneys of parasitized animals showed no significant change in the concentrations of those elements that are accumulated in the cestode.

Endogenously produced hydrogen sulfide is involved in porcine oocyte maturation in vitro.

Hydrogen sulfide, one of three known gasotransmitters, is involved in physiological processes, including reproductive functions. Oocyte maturation and surrounding cumulus cell expansion play an essential role in female reproduction and subsequent embryonic development. Although the positive effects of exogenous hydrogen sulfide on maturing oocytes are well known, the role of endogenous hydrogen sulfide, which is physiologically released by enzymes, has not yet been described in oocytes. In this study, we observed the presence of Cystathionine β-Synthase (CBS), Cystathionine γ-Lyase (CTH) and 3-Mercaptopyruvate Sulfurtransferase (3-MPST), hydrogen sulfide-releasing enzymes, in porcine oocytes. Endogenous hydrogen sulfide production was detected in immature and matured oocytes as well as its requirement for meiotic maturation. Individual hydrogen sulfide-releasing enzymes seem to be capable of substituting for each other in hydrogen sulfide production. However, meiosis suppression by inhibition of all hydrogen sulfide-releasing enzymes is not irreversible and this effect is a result of M-Phase/Maturation Promoting Factor (MPF) and Mitogen-Activated Protein Kinase (MAPK) activity inhibition. Futhermore, cumulus expansion expressed by hyaluronic acid (HA) production is affected by the inhibition of hydrogen sulfide production. Moreover, quality changes of the expanded cumuli are indicated. These results demonstrate hydrogen sulfide involvement in oocyte maturation as well as cumulus expansion. As such, hydrogen sulfide appears to be an important cell messenger during mammalian oocyte meiosis and adequate cumulus expansion.

Impact of Phenolic Content on Antioxidant Activity in Yellow and Purple-fleshed Potatoes Grown in the Czech Republic

ABSTRACT Purple-fleshed potatoes cultivars are new on the Czech market. Intensive trials about growing purple-fleshed potato cultivars in the Czech Republic are currently being carried out. Recently many articles deal with phenolic antioxidants and their contribution to the human health; thus the aim of this study was to determine the differences in total phenolic (TP) content and antioxidant activity (AA) between yellow (cvs. Impala, Karin, Dita, Saturna) and purple-fleshed (cvs. Valfi, Violette) potatoes grown in the Czech Republic in 2004 in four locations in field trials. TP content was determined by Folin-Ciocalteau assay and AA by DPPH assay both in freeze-dried tuber matter. Results showed a statistical significant difference in TP content and AA between yellow- and purple-fleshed potatoes. Purple-fleshed cultivars showed 60% higher TP content than yellow-fleshed cultivars and AA content was double in purple-fleshed cultivars. A significant linear correlation between TP and AA was found (r2 = 0.747). Average TP content in yellow-fleshed cultivars was 2.96 GAE (gallic acid mg g−l DM) and in purple-fleshed cultivars 4.68 GAE was found. Average AA in yellow-fleshed cultivars was 11.26 AAE (ascorbic acid equivalent mg 100 g−1 DM) and in purple-fleshed cvs. 24.79 AAE. Purple-fleshed potatoes showed a lower variation among localities (6 % only). The results showed that AA of freeze-dried tuber matter is very low when compared to other plants or sources (wine, tea, chocolate and blueberries) although a high potato intake in humans by Czechs (72 kg capita−1 year−1) is considered.

Free and esterified carotenoids in pigmented wheat, tritordeum and barley grains

Carotenoids are important phytonutrients responsible for the yellow endosperm color in cereal grains. Five carotenoids, namely lutein, zeaxanthin, antheraxanthin, α- and β-carotene, were quantified by HPLC-DAD-MS in fourteen genotypes of wheat, barley and tritordeum harvested in Czechia in 2014 and 2015. The highest carotenoid contents were found in yellow-grained tritordeum HT 439 (12.16μg/gDW), followed by blue-grained wheat V1-131-15 (7.46μg/gDW), and yellow-grained wheat TA 4024 (7.04μg/gDW). Comparing carotenoid contents, blue varieties had lower whereas purple ones had the same or higher levels than conventional bread wheat. Lutein was the main carotenoid found in wheat and tritordeum while zeaxanthin dominated in barley. The majority of cereals contained considerable levels of esterified forms (up to 61%) of which lutein esters prevailed. It was assessed that cereal genotype determines the proportion of free and esterified forms. High temperatures and drought during the growing season promoted carotenoid biosynthesis.

A simple method for assessing hyaluronic acid production by cumulus-oocyte complexes

The cumulus expansion of cumulus-oocyte complex (COC) is an essential regulating process of oocyte maturation and as such it is a possible biomarker of the in vitro maturing oocytes quality. Cumulus expansion is usually assessed by non-invasive methods based on visual evaluation with many inaccuracies. On the other hand, analytical measurement of the quantity of hyaluronic acid (HA), the most abundant compound of expanded cumuli, is one of possible methods to evaluate cumulus expansion precisely. Therefore, this study aimed to verify the applicability of HA analysis for evaluating the cumulus expansion and testing oocyte maturation. The COCs were cultured in modified M199 medium for 8–48 h. The samples for the HA analysis were prepared on an 8-hour time scale, and HA retained in COCs was measured using a spectrophotometric method adapted for this purpose. We observed an increasing quantity of HA during the in vitro cultivation. A comparison with expanded COCs’ classification or expansion area proved the proposed method of HA analysis suitable for the evaluation of cumulus expansion in vitro. Our findings consider the quantity of HA-expressed cumulus expansion to be a valuable marker of COC quality enabling an adequate oocyte meiotic stage estimation.

Resveratrol and piceid isomers concentrations in grapevine shoots, leaves, and tendrils

Lachman J., Kotikova Z., Hejtmankova A., Pivec V., Psenicnaja O., Sulc M., Střalkova R., Dědina M.

Changes in anthocyanidin levels during the maturation of color-fleshed potato (Solanum tuberosum L.) tubers

Certain potato cultivars are capable of producing anthocyanin pigments in the potato skin and flesh and those pigments have been shown, together with other phytochemicals, to promote good health. Six common anthocyanidins (cyanidin, delphinidin, petunidin, pelargonidin, malvidin and peonidin) were analyzed weekly for 15weeks in red- and purple-fleshed potato cultivars (Red Emma, Königspurpur, Valfi and Blaue de la Mancha) grown in field conditions using a validated LC-(+ESI)MS/MS method. Pelargonidin was the major type detected in red-fleshed cultivars whereas petunidin was the major type detected in the purple ones. Neither cyanidin nor delphinidin were found in any of the cultivars. The anthocyanidin levels observed were as high as 78mg/100g FW during tuber growth; however, fully matured tubers contained only 10-39mg anthocyanidins/100gFW. Anthocyanidin levels were moderately correlated with global solar irradiation (r<0.6252) but not with rainfall or daily temperature.