Saturation Diving Alters Folate Status and Biomarkers of DNA Damage and Repair

Exposure to oxygen-rich environments can lead to oxidative damage, increased body iron stores, and changes in status of some vitamins, including folate. Assessing the type of oxidative damage in these environments and determining its relationships with changes in folate status are important for defining nutrient requirements and designing countermeasures to mitigate these effects. Responses of humans to oxidative stressors were examined in participants undergoing a saturation dive in an environment with increased partial pressure of oxygen, a NASA Extreme Environment Mission Operations mission. Six participants completed a 13-d saturation dive in a habitat 19 m below the ocean surface near Key Largo, FL. Fasting blood samples were collected before, twice during, and twice after the dive and analyzed for biochemical markers of iron status, oxidative damage, and vitamin status. Body iron stores and ferritin increased during the dive (P<0.001), with a concomitant decrease in RBC folate (P<0.001) and superoxide dismutase activity (P<0.001). Folate status was correlated with serum ferritin (Pearson r = −0.34, P<0.05). Peripheral blood mononuclear cell poly(ADP-ribose) increased during the dive and the increase was significant by the end of the dive (P<0.001); γ-H2AX did not change during the mission. Together, the data provide evidence that when body iron stores were elevated in a hyperoxic environment, a DNA damage repair response occurred in peripheral blood mononuclear cells, but double-stranded DNA damage did not. In addition, folate status decreases quickly in this environment, and this study provides evidence that folate requirements may be greater when body iron stores and DNA damage repair responses are elevated

Assessment of B-group vitamins in oat gluten-free products

Celem badań było oznaczenie zawartości witamin z grupy B: witaminy B₁, B₂, B₆ i PP we wszystkich dostępnych w 2013 roku na polskim rynku owsianych produktach bezglutenowych. Materiał doświadczalny stanowiło 7 owsianych produktów bezglutenowych, takich jak mąki i mieszanki do wypieku chleba i ciastek oraz płatki. Produkty poddano hydrolizie enzymatycznej z użyciem taka-diastazy oraz hydrolizie kwasowej z zastosowaniem kwasu solnego. Zawartość witamin z grupy B oznaczono metodami wysokosprawnej chromatografii cieczowej. Średnia zawartość witamin B₁, B₂, B₆ (jako sumy pirydoksalu, pirydoksaminy, pirydoksyny) oraz PP we wszystkich produktach wynosiła odpowiednio 0,184, 0,050, 0,159, 0,544 mg·100 g⁻¹ produktu. Największą zawartość witaminy B₁ stwierdzono w płatkach owsianych, a pozostałych witamin w musli owsianym z owocami. Owsiane produkty bezglutenowe charakteryzowały się zróżnicowaną zawartością witamin B₁, B₂, B₆ i PP. Najbogatszym źródłem analizowanych witamin były płatki owsiane oraz musli owsiane z owocami.Oat gluten-free products are a new category on the Polish market of foods for particular nutritional use. Oats which was the subject of numerous studies on its safety for use in the diet of patients with coeliac disease, was introduced on Polish market in 2012. Results of clinical trials in patients suffering from coeliac disease, indicate the occurrence of nutritional deficiencies, including deficiencies of B-group vitamins. Due to the fact that nutritional deficiencies refer both to the patients who do not comply with the recommendations, as well as to those on a gluten free diet, quality assessment of gluten-free food plays a significant role in the efficient treatment of coeliac disease. Oat products are an alternative to the commonly consumed cereal gluten-free products. The aim of this study was to determine the content of B-group vitamins: vitamin B₁, B₂, B₆ and PP in all glutenfree oat products available on the Polish market in 2013. Seven oat gluten-free products: flours, bread mixes, cookies mixes and flakes were purchased in the local health food stores. The concentration of B-group vitamins was determined by high performance liquid chromatography (HPLC) after prior enzymatic and acid extraction of sample. The content of thiamine ranged from 0.049 ±0.011 (oat mix for chocolate muffins) to 0.276 ±0.010 mg in 100 g of product (oat flakes) with a mean of 0.184 mg·100 g⁻¹. The most valuable source of vitamin B₂ was oat musli with fruits (0.085 ±0.001 mg·100 g⁻¹), the least valuable was gluten-free flour with oat (0.031 ±0.001 mg·100 g⁻¹). The average content of vitamin B₆ was 0.158 mg·100 g⁻¹ with the lowest content in gluten-free flour with oat (0.039 ±0.008 mg·100 g⁻¹) and the highest in oat musli with fruits (0.569 ±0.019 mg·100 g⁻¹). The niacin content in all selected products ranged from 0.269 ±0.023 (mix for oat cookies) to 1.084 ±0.103 mg·100 g⁻¹ (oat musli with fruits) with an average content of 0.544 mg in 100 g. High content of vitamins in oat muesli is a result of fruits content. Tested gluten-free products significantly differed in vitamin B₁, B₂, B₆ and niacin contents. The richest source of analyzed vitamins were oatmeal and oat muesli with fruits

Interactions between components of dietary supplements: a case of quercetin and vitamin C

W pracy przedstawiono wyniki badań nad wpływem pH środowiska na aktywność przeciwrodnikową kwercetyny w obecności witaminy C (kwasu askorbinowego). Stwierdzono, że aktywność przeciwrodnikowa kwercetyny, zmierzona w teście TEAC (Trolox Equivalent Antioxidant Capacity), ulega znacznemu obniżeniu w pH 4,5-9,0 w wyniku interakcji z kwasem askorbinowym. Wykonano odpowiednie obliczenia kwantowo-chemiczne w celu wyjaśnienia obserwowanego antagonistycznego oddziaływania pomiędzy tymi przeciwutleniaczami.In the present study, the effect of pH of the surrounding medium on the radical-scavenging activity of quercetin in the presence of vitamin C (ascorbic acid) was investigated. It was found that at pH 4.5-9.0 radical-scavenging activity of quercetin in the TEAC (Trolox Equivalent Antioxidant Capacity) assay is strongly reduced by ascorbic acid as a result of their interactions. Some relevant quantum-chemical calculations were performed to get some insight into the mechanism of observed antagonistic interaction between these two popular antioxidants

pH-dependent radical scavenging capacity of green tea catechins

The effect of pH on the radical scavenging capacity of green tea catechins was investigated using experimental as well as theoretical methods. It was shown that the radical scavenging capacity of the catechins, quantified by the TEAC value, increases with increasing pH of the medium. Comparison of the pKa values to theoretically calculated parameters for the neutral and deprotonated forms indicates that the pH-dependent increase in radical scavenging activity of the catechins is due to an increase of electron-donating ability upon deprotonation. The data also reveal that the radical scavenging activity of the catechins containing the pyrogallol (or catechol) and the galloyl moiety over the whole pH range is due to an additive effect of these two independent radical scavenging structural elements. Altogether, the results obtained provide better insight into the factors determining the radical scavenging activity of the catechins and reveal that the biological activity of green tea catechins will be influenced by the pH of the surrounding medium or tissues

Biphasic modulation of cell proliferation by quercetin at concentrations physiologically relevant in humans

Optimal in vitro conditions regarding quercetin solubility and stability were defined. Using these conditions, the effect of quercetin on proliferation of the colon carcinoma cell lines HCT-116 and HT29 and the mammary adenocarcinoma cell line MCF-7 was investigated. For the colon carcinoma cell lines, at relatively high concentrations, a significant decrease in cell proliferation was observed, providing a basis for claims on the anti-carcinogenic activity of quercetin. However, at lower concentrations, a subtle but significant stimulation of cell proliferation was observed for all cell lines tested. These results point at a dualistic influence of quercetin on cell proliferation that may affect present views on its supposed beneficial anti-proliferative effect. (C) 2003 Elsevier Ireland Ltd. All rights reserved