beta-carotene and ferric-chloride

To determine the effect of oxidative stress and exogenous beta-carotene on sclerotial differentiation and carotenoid yield of Penicillium sp. PT95.. In this experiment, high oxidative stress was applied by inclusion of FeCl(3) (10 micromol l(-1)) in the growth medium and by light exposure. Low oxidative stress was applied by omitting iron from the growth medium and by incubation in the dark. Supplementation of exogenous beta-carotene (as antioxidant) to the basal medium caused a concentration-dependent delay of sclerotial differentiation (up to 72 h), decrease of sclerotial biomass (up to 43%) and reduction of carotenoid yield (up to 92%). On the contrary, the exogenous beta-carotene also caused a concentration-dependent decrease of lipid peroxidation in colonies of this fungus.. Under high oxidative stress growth condition, the sclerotial biomass and carotenoid yield of PT95 strain in each plate culture reached 141 mg and 30.03 microg, which were 1.53 and 3.51 times higher respectively, than that at low oxidative stress growth condition.. These data prompted us to consider that in order to attain higher sclerotial biomass and pigment yield, the strain PT95 should be grown under high oxidative stress and in the absence of antioxidants.

Topics: Antioxidants; beta Carotene; Biomass; Carotenoids; Chlorides; Ferric Compounds; Light; Lipid Peroxidation; Oxidative Stress; Penicillium

Potential antioxidant properties of therapeutically achievable concentrations of the protonated, active form of omeprazole (OM) were investigated in vitro at specific acidic pH values to mimic intragastric conditions in the clinical setting. We found that OM is a powerful scavenger of hypochlorous acid (HOCl) even at a drug concentration of 10 microM at pH 5.3 or 3.5. This effect is also evident in the presence of the physiological HOCl scavenger ascorbate. Moreover, 10 and 50 microM OM inhibit significantly both iron- and copper-driven oxidant damage at pH 5.3 and 3.5, respectively. Since oxidative stress is involved the gastric injury of peptic ulcer and gastritis, it may be hypothesized that some therapeutical effects of OM could also be related to its antioxidant properties.

Topics: Anti-Ulcer Agents; Antioxidants; Ascorbic Acid; beta Carotene; Carotenoids; Chlorides; Copper; Deoxyribose; Ferric Compounds; Hydrogen-Ion Concentration; Hypochlorous Acid; Omeprazole; Oxidation-Reduction

To clarify the mechanism of fluorescence formation between DNA and lipid degradation products in the presence of ferric chloride and ascorbic acid, a number of carbonyl compounds and decomposition products of pure methyl linolenate hydroperoxides were examined. Keto derivatives of methyl ricinoleate, linoleate, and oleate, alkanals and 2-alkenals produced little or no fluorescence with DNA in the presence of ferric chloride-ascorbic acid. 2,4-Alkadienals were more active and 2,4,7-decatrienal was the most active. Mixtures of volatile aldehydes prepared from linolenate hydroperoxide decomposed either thermally or with iron and ascorbate had the same activity as 2,4,7-decatrienal. Higher molecular-weight products from the decomposition of methyl linolenate hydroperoxides showed relatively low activity. beta-Carotene, alpha-tocopherol and other antioxidants effectively reduced the amount of fluorescence formed by linolenate hydroperoxides. The results suggest that, in addition to hydroperoxide decomposition products, singlet oxygen and/or free radical species contribute significantly to the fluorescence formed from the interaction of methyl linolenate hydroperoxides with DNA in the presence of ferric chloride and ascorbic acid.

Topics: Aldehydes; Antioxidants; Ascorbic Acid; beta Carotene; Carotenoids; Chemical Phenomena; Chemistry; Chlorides; DNA; Ferric Compounds; Free Radicals; Gases; Lipid Peroxides; Oxygen; Spectrometry, Fluorescence; Vitamin E