Safety Assessment of Vitamin D and Its Photo-Isomers in UV-Irradiated Baker’s Yeast

Vitamin D deficiency due to, e.g., nutritional and life style reasons is a health concern that is gaining increasing attention over the last two decades. Vitamin D3, the most common isoform of vitamin D, is only available in food derived from animal sources. However, mushrooms and yeast are rich in ergosterol. This compound can be converted into vitamin D2 by UV-light, and therefore act as a precursor for vitamin D. Vitamin D2 from UV-irradiated mushrooms has become an alternative source of vitamin D, especially for persons pursuing a vegan diet. UV-irradiated baker’s yeast (Saccharomyces cerevisiae) for the production of fortified yeast-leavened bread and baked goods was approved as a Novel Food Ingredient in the European Union, according to Regulation (EC) No. 258/97. The Scientific Opinion provided by the European Food Safety Authority Panel on Dietetic Products, Nutrition, and Allergies has assessed this Novel Food Ingredient as safe under the intended nutritional use. However, recent findings on the formation of side products during UV-irradiation, e.g., the photoproducts tachysterol and lumisterol which are compounds with no adequate risk assessment performed, have only been marginally considered for this EFSA opinion. Furthermore, proceedings in analytics can provide additional insights, which might open up new perspectives, also regarding the bioavailability and potential health benefits of vitamin D-fortified mushrooms and yeast. Therefore, this review is intended to give an overview on the current status of UV irradiation in mushrooms and yeast in general and provide a detailed assessment on the potential health effects of UV-irradiated baker’s yeast

Pyrrolizidine alkaloids in Senecio vulgaris L. depending on development stage and season

Das Gewöhnliche Greiskraut (Senecio vulgaris L.) wird aufgrund seiner toxischen Inhaltsstoffe (Pyrrolizidinalka­loide, PAs) und seines enormen Verbreitungspotentials in landwirtschaftlichen Sonderkulturen als problematisch eingestuft (Robinson et al., 2003; BfR, 2007; Wiedenfeld, 2011; Wiedenfeld und Edgar, 2011). Die vorliegende Untersuchung hatte daher zum Ziel in Parzellenfreilandversuchen die Wachstumsparameter von Senecio vulgaris und den Gehalt von verschiedenen PAs hinsichtlich ontogenetischer Unterschiede zu verschiedenen Jahreszeiten zu untersuchen.Wie bereits für andere Senecio-Arten gezeigt, wird auch in Senecio vulgaris der PA-Gehalt (PA-Gesamtsumme, tertiäre PAs und PA-N-oxide) je nach Jahreszeit durch das Entwicklungsstadium beeinflusst. Allgemein zeigt sich eine Tendenz, dass die PA-Konzentration bis zur Vollblüte ansteigt und nachfolgend zur Frucht- und Samenreife wieder abnimmt. Von den N-oxiden wurden jeweils höhere Gehalte als von den entsprechenden tertiären PAs gefunden. Die Einzelverbindungen werden in ihrer Konzentration unterschiedlich beeinflusst; während einige PAs zu jeder Jahreszeit ontogenetisch verändert wurden (Retrorsin-N-oxid, Senecionin), konnte dieses für Senecivernin-N-oxid nicht nachgewiesen werden.The common groundsel (Senecio vulgaris L.) is a harmful weed because of its toxic compounds (pyrrolizidine alkaloids, PAs) and its enormous distribution potential in agricultural and horticultural crops (Robinson et al., 2003; BfR, 2007; Wiedenfeld, 2011; Wiedenfeld und Edgar, 2011). During different seasons and in plot-field experiments we have examined the growth parameters and the amount of different PAs of Senecio vulgaris L. related to ontogenetic differences.As already shown for other Senecio species, the PA content in Senecio vulgaris (PAs total, tertiary PAs and PA-N-oxides) is influenced by the developmental stage, depending on the season. In general, there is a tendency for the PA concentration to increase until full flowering and subsequently to decrease again for fruit and seed maturity. In each developmental stage the contents of the N-oxides were higher than the corresponding tertiary PAs. The individual compounds are influenced differently in their concentration: while some PAs are always subject to a significant influence by onto­genesis (retrorsine-N-oxide, senecionine), influences for senecivernine-N-oxide could only be detected in one season

Prenylated flavanone derivatives isolated from Erythrina addisoniae are potent inducers of apoptotic cell death

NoExtracts of Erythrina addisoniae are frequently used in the traditional medicine of Western Africa, but insufficient information about active compounds is available. From the stem bark of E. addisoniae, three (1, 2, 4) and three known (3, 5, 6) flavanones were isolated: addisoniaflavanones I and II, containing either a 2″,3″-epoxyprenyl moiety (1) or a 2″,3″-dihydroxyprenyl moiety (2) were shown to be highly toxic (MTT assay: EC50 values of 5.25 ± 0.7 and 8.5 ± 1.3 μM, respectively) to H4IIE hepatoma cells. The cytotoxic potential of the other isolated flavanones was weaker (range of EC50 values between 15 and >100 μM). Toxic effects of addisoniaflavanone I and II were detectable after 3 h (MTT assay). Both compounds induced an apoptotic cell death (caspase-3/7 activation, nuclear fragmentation) in the hepatoma cells and, at high concentrations, also necrosis (membrane disruption: ethidium bromide staining). Formation of DNA strand breaks was not detectable after incubation with these compounds (comet assay). In conclusion, the prenylated flavanones addisoniaflavanones I and II may be of interest for pharmacological purposes due to their high cytotoxic and pro-apoptotic potential against hepatoma cells

Caenorhabditis elegans as Model System in Pharmacology and Toxicology: Effects of Flavonoids on Redox-Sensitive Signalling Pathways and Ageing

Flavonoids are secondary plant compounds that mediate diverse biological activities, for example, by scavenging free radicals and modulating intracellular signalling pathways. It has been shown in various studies that distinct flavonoid compounds enhance stress resistance and even prolong the life span of organisms. In the last years the model organism C. elegans has gained increasing importance in pharmacological and toxicological sciences due to the availability of various genetically modified nematode strains, the simplicity of modulating genes by RNAi, and the relatively short life span. Several studies have been performed demonstrating that secondary plant compounds influence ageing, stress resistance, and distinct signalling pathways in the nematode. Here we present an overview of the modulating effects of different flavonoids on oxidative stress, redox-sensitive signalling pathways, and life span in C. elegans introducing the usability of this model system for pharmacological and toxicological research

Bioactive pyrrole alkaloids isolated from the Red Sea : marine sponge Stylissa carteri

Fifteen pyrrole alkaloids were isolated from the Red Sea marine sponge Stylissa carteri and investigated for their biological activities. Four of them were dibrominated [(+) dibromophakelline, Z-3-bromohymenialdisine, (±) ageliferin and 3,4-dibromo-1H-pyrrole-2-carbamide], nine compounds were monobrominated [(-) clathramide C, agelongine, (+) manzacidin A, (-) 3-bromomanzacidin D, Z-spongiacidin D, Z-hymenialdisine, 2-debromostevensine, 2-bromoaldisine and 4-bromo-1H-pyrrole-2-carbamide)] and finally, two compounds were non-brominated derivatives viz., E-debromohymenialdisine and aldisine. The structure elucidations of isolated compounds were based on 1D & 2D NMR spectroscopic and MS studies, as well as by comparison with literature. In-vitro, Z-spongiacidin D exhibited a moderate activity on (ARK5, CDK2-CycA, CDK4/CycD1, VEGF-R2, SAK and PDGFR-beta) protein kinases. Moreover, Z-3-bromohymenialdisine showed nearly similar pattern. Furthermore, Z-hymenialdisine displayed a moderate effect on (ARK5 & VEGF-R2) and (-) clathramide C showed a moderate activity on AURORA-A protein kinases. While, agelongine, (+) manzacidin A, E-debromohymenialdisine and 3,4-dibromo-1H-pyrrole-2-carbamide demonstrated only marginal inhibitory activities. The cytotoxicity study was evaluated in two different cell lines. The most effective secondary metabolites were (+) dibromophakelline and Z-3-bromohymenialdisine on L5178Y. Finally, Z-hymenialdisine, Z-3-bromohymenialdisine and (±) ageliferin exhibited the highest cytotoxic activity on HCT116. No report about inhibition of AURORA-A and B by hymenialdisine/hymenialdisine analogs existed and no reported toxicity of ageliferin existed in literature

Safety Assessment of Vitamin D and Its Photo-Isomers in UV-Irradiated Baker’s Yeast

Vitamin D deficiency due to, e.g., nutritional and life style reasons is a health concern that is gaining increasing attention over the last two decades. Vitamin D3, the most common isoform of vitamin D, is only available in food derived from animal sources. However, mushrooms and yeast are rich in ergosterol. This compound can be converted into vitamin D2 by UV-light, and therefore act as a precursor for vitamin D. Vitamin D2 from UV-irradiated mushrooms has become an alternative source of vitamin D, especially for persons pursuing a vegan diet. UV-irradiated baker’s yeast (Saccharomyces cerevisiae) for the production of fortified yeast-leavened bread and baked goods was approved as a Novel Food Ingredient in the European Union, according to Regulation (EC) No. 258/97. The Scientific Opinion provided by the European Food Safety Authority Panel on Dietetic Products, Nutrition, and Allergies has assessed this Novel Food Ingredient as safe under the intended nutritional use. However, recent findings on the formation of side products during UV-irradiation, e.g., the photoproducts tachysterol and lumisterol which are compounds with no adequate risk assessment performed, have only been marginally considered for this EFSA opinion. Furthermore, proceedings in analytics can provide additional insights, which might open up new perspectives, also regarding the bioavailability and potential health benefits of vitamin D-fortified mushrooms and yeast. Therefore, this review is intended to give an overview on the current status of UV irradiation in mushrooms and yeast in general and provide a detailed assessment on the potential health effects of UV-irradiated baker’s yeast

Safety Assessment of Vitamin D and Its Photo-Isomers in UV-Irradiated Baker’s Yeast

Vitamin D deficiency due to, e.g., nutritional and life style reasons is a health concern that is gaining increasing attention over the last two decades. Vitamin D3, the most common isoform of vitamin D, is only available in food derived from animal sources. However, mushrooms and yeast are rich in ergosterol. This compound can be converted into vitamin D2 by UV-light, and therefore act as a precursor for vitamin D. Vitamin D2 from UV-irradiated mushrooms has become an alternative source of vitamin D, especially for persons pursuing a vegan diet. UV-irradiated baker’s yeast (Saccharomyces cerevisiae) for the production of fortified yeast-leavened bread and baked goods was approved as a Novel Food Ingredient in the European Union, according to Regulation (EC) No. 258/97. The Scientific Opinion provided by the European Food Safety Authority Panel on Dietetic Products, Nutrition, and Allergies has assessed this Novel Food Ingredient as safe under the intended nutritional use. However, recent findings on the formation of side products during UV-irradiation, e.g., the photoproducts tachysterol and lumisterol which are compounds with no adequate risk assessment performed, have only been marginally considered for this EFSA opinion. Furthermore, proceedings in analytics can provide additional insights, which might open up new perspectives, also regarding the bioavailability and potential health benefits of vitamin D-fortified mushrooms and yeast. Therefore, this review is intended to give an overview on the current status of UV irradiation in mushrooms and yeast in general and provide a detailed assessment on the potential health effects of UV-irradiated baker’s yeast