Effect of a Klamath algae product ("AFA-B12") on blood levels of vitamin B12 and homocysteine in vegan subjects: a pilot study.

Vitamin B12 is a critical nutrient that is often inadequate in a plant-based (vegan) diet, thus the inclusion of a reliable vitamin B12 source in a vegan diet is recommended as essential. Unfortunately, many natural sources of vitamin B12 have been proven to contain biologically inactive vitamin B12 analogues, inadequate for human supplementation. The aim of this non-randomized open trial was to determine whether supplementation with a natural Klamath algae-based product ("AFA-B12", Aphanizomenon flos-aquae algae plus a proprietary mix of enzymes) could favorably affect the vitamin B12 status of a group of 15 vegan subjects. By assessing blood concentration of vitamin B12, folate, and more importantly homocysteine (Hcy, a reliable marker in vegans of their B12 absorption), the vitamin B12 status of the participants at the end of the 3-month intervention period, while receiving the Klamath-algae supplement (T2), was compared with their vitamin B12 status at the end of the 3-month control period (T1), when they were not receiving any supplement, having stopped taking their usual vitamin B12 supplement at the beginning of the study (T0). Compared to the control period, in the intervention period participants improved their vitamin B12 status, significantly reducing Hcy blood concentration (p=0.003). In conclusion, the Klamath algae product AFA-B12 appears to be, in a preliminary study, an adequate and reliable source of vitamin B12 in humans.

Purification and characterization of phycocyanin from the blue-green alga Aphanizomenon flos-aquae.

Aphanizomenon flos-aquae (AFA) is a blue-green alga and represents a nutrient-dense food source. In this study the presence of phycocyanin (PC), a blue protein belonging to the photosynthetic apparatus, has been demonstrated in AFA. An efficient method for its separation has been set up: PC can be purified by a simple single step chromatographic run using a hydroxyapatite column (ratio A620/A280 of 4.78), allowing its usage for health-enhancing properties while eliminating other aspecific algal components. Proteomic investigation and HPLC analysis of purified AFA phycobilisomes revealed that, contrary to the well-characterized Synechocystis and Spirulina spp., only one type of biliprotein is present in phycobilisomes: phycocyanins with no allo-phycocyanins. Two subunit polypeptides of PC were also separated: the beta subunit containing two bilins as chromophore and the alpha subunit containing only one.

Oxidative stress and antioxidant status in patients undergoing prolonged exposure to hyperbaric oxygen.

OBJECTIVES: To evaluate the condition of oxidative stress in patients undergoing prolonged exposure to hyperbaric oxygen (HBO) and the possible modifications of the antioxidant defense systems in the absence of antioxidant supplementation. DESIGN AND METHODS: Twelve patients exposed to 15 HBO treatments for pathological conditions related to hypoxia were included in the study. Oxidative stress indices as well as plasma and erythrocyte antioxidant levels were measured in blood samples collected both at the 1st and 15th HBO session. RESULTS: The repeated exposures to HBO led to a significant accumulation of plasmatic reactive oxygen metabolites (ROM) and malondialdehyde (MDA). After 15 HBO sessions, no relevant differences were detected for reduced glutathione (GSH), alpha-tocopherol, and retinol plasma levels; however, a significant decrease in erythrocyte superoxide dismutase (SOD) and catalase (CAT) activity was observed when compared to the 1st HBO exposure; glutathione peroxidase (GPx) activity remained almost unchanged. CONCLUSIONS: In the absence of antioxidant supplementation, the prolonged HBO treatment leads to a condition of oxidative stress that seems to affect in particular the response of the enzymatic antioxidant defense system; the possible relationship between the chemical modifications of the enzymes caused by oxygen reactive species and the consequent inactivation of the proteins is under investigation.

Antioxidant properties of a novel phycocyanin extract from the blue-green alga Aphanizomenon flos-aquae.

Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga (cyanophyta) rich in phycocyanin (PC), a photosynthetic pigment with antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate the ability of a novel natural extract from AFA enriched with PC to protect normal human erythrocytes and plasma samples against oxidative damage in vitro. In red blood cells, oxidative hemolysis and lipid peroxidation induced by the aqueous peroxyl radical generator [2,2'-Azobis (2-amidinopropane) dihydrochloride, AAPH] were significantly lowered by the AFA extract in a time- and dose-dependent manner; at the same time, the depletion of cytosolic glutathione was delayed. In plasma samples, the natural extract inhibited the extent of lipid oxidation induced by the pro-oxidant agent cupric chloride (CuCl2); a concomitant increase of plasma resistance to oxidation was observed as evaluated by conjugated diene formation. The involvement of PC in the antioxidant protection of the AFA extract against the oxidative damage was demonstrated by investigating the spectral changes of PC induced by AAPH or CuCl2. The incubation of the extract with the oxidizing agents led to a significant decrease in the absorption of PC at 620 nm accompanied with disappearance of its blue color, thus indicating a rapid oxidation of the protein. In the light of these in vitro results, the potential clinical applications of this natural compound are under investigation.

A comparison between the antioxidant and peroxynitrite-scavenging functions of the vitamin E metabolites alpha- and gamma-carboxyethyl-6-hydroxychromans.

Carboxyethyl-6-hydroxychromans (CEHC) are vitamin E metabolites with proposed in vitro antioxidant function. In this study we compared the antioxidant potency of the two main CEHC metabolites found in biological fluids (i.e.. alpha-CEHC and gamma-CEHC) using two different experimental models of lipid oxidation: 1) plasma diluted 1/50 vol/vol in phosphate buffered saline (PBS) exposed to 50 micro microM Cu2+ ions, and 2) LDL (100 microg of proteins) exposed to different pro-oxidants as 2.5 microM Cu2+, 1 mM of the water soluble peroxyl radical generator 2,2'-Azobis(2-amidinopropane) hydrochloride (AAPH) and human macrophages (4 x 10(5) cells). Moreover, the two CEHC homologues were assessed for the inhibitory effect on the peroxynitrite (ONOO-)-induced nitration of tyrosine (Tyr). The results showed that in the concentration range 0.015-5 microM the CEHC metabolites and the hydrosoluble analogue Trolox exert similar concentration-dependent inhibition of the Cu2+-induced lipid oxidation of plasma. After in vitro exposure to tert-butyl hydroperoxide/Fe2+, CEHC formed chromanoxyl radicals with electron spin resonance spectra matching exactly those of their parent tocopherols. The LDL oxidation induced by AAPH or Cu2+ was significantly and similarly inhibited by 1 microM of both the CEHC homologues and Trolox. gamma-CEHC showed a slight but significantly higher inhibition of the macrophage-induced low-density lipoprotein (LDL) oxidation than alpha-CEHC. Both the CEHC homologues inhibit Tyr nitration induced by ONOO. However, gamma-CEHC produced a slightly greater inhibitory effect than (alpha-CEHC through the formation of the nitrated congener 5-nitro-gamma-CEHC. In all the systems under investigation, low nanomolar concentrations of CEHC (i.e., the concentration range in the blood of subjects with normal dietary intake of vitamin E) produced feeble antioxidant effects. In conclusion, gamma-CEHC and alpha-CEHC show similar concentration-dependent inhibition of plasma and LDL lipid oxidation. gamma-CEHC has a fairly higher potency than alpha-CEHC as ONOO- scavenger through the formation of 5-nitro-gamma-CEHC. CEHC metabolites show the same in vitro antioxidant chemistry of their parent tocopherols, but the characteristic hydrophilicity of these metabolites could result in different biopotency and roles. Further studies are needed to clarify whether CEHC could contribute to the antioxidant network in biological fluids and tissues.

Gas chromatographic--mass spectrometric determination of phenylacetic acid in human blood.

Phenyl acetic acid, a metabolite of 2-phenyl ethylamine, acts as a neuromodulator in the nigrostriatal dopaminergic pathway stimulating the release of dopamine. The evaluation of phenyl acetic acid concentration in the biological fluid reflects phenyl ethylamine levels thus allowing the assessment of the modulatory role of this endogenous substance. Changes in biological fluids levels of 2-phenylethylamine and/or in its metabolite have been reported in affective disorders, such as depression and schizophrenia. Recently, the occurrence of the "attention deficit hyperactivity syndrome" has been frequently reported in childhood population and involvement of dopaminergic dysfunction in this disease has been suspected. A fast, reliable and reproducible method for the determination of phenyl acetic acid in human blood, is therefore needed in order to have a screening tool for monitoring both healthy childhood population and suspected "attention deficit hyperactivity syndrome" patients. The gas chromatographic-mass spectrometric method here described makes use of a deuterated internal standard in order to overcome problems related to the lack of reproducibility often encountered when a derivatization step is performed.

The 8-epimer of prostaglandin F(2alpha), a marker of lipid peroxidation and oxidative stress, is decreased in the nipple aspirate fluid of women with breast cancer.

Breast cancer (BC), a worldwide disease with increasing incidence, develops from ductal/lobular epithelium. Nipple aspirate fluid (NAF), secreted from the breast ducts and lobules, can be analyzed to assess breast metabolic activity. Whether lipid peroxidation in the mammary gland promotes or prevents tumorigenesis is unclear. Malondialdehyde (MDA) and the 8-epimer of Prostaglandin F(2alpha) (8-iso-PGF(2alpha)), two lipid peroxidation markers, were studied in milk (n = 10), NAF (n = 140) and plasma (n = 35) samples. MDA was detected in all plasma, in 80% of milk samples and in 95% of NAF samples. MDA levels in NAF and plasma were significantly higher than in milk (p = 0.016 and p = 0.029, respectively). We found no significant difference between levels of MDA in NAF samples from BC patients compared to healthy controls. 8-iso-PGF(2alpha) was detectable in all samples. 8-iso-PGF(2alpha) median levels in NAF were significantly higher than in both milk and plasma (p < 0.0001). The highest 8-iso-PGF(2alpha) levels were found in NAF from healthy women, significantly higher than in women with BC (p < 0.0001). No significant differences were found in both markers after the age-adjustment. High levels of lipid peroxidation products in NAF suggest their in situ production in the nonlactating breast. Active lipid peroxidation may have a physiologic role in the normal mammary gland. Lower levels of 8-iso-PGF(2alpha) in NAF from BC patients suggest altered production of arachidonic acid metabolites during breast carcinogenesis.

Vitamin E affects cell death in adult rat dentate gyrus.

We have previously reported the presence of dying cells in the granule cell layer (GCL) of adult rat dentate gyrus (DG), where neurogenesis occurs. In particular, we found that cell death in the GCL increased in vitamin E deficiency and decreased in vitamin E supplementation. These findings were regarded as related to changes in neurogenesis rate, which in turn was influenced by vitamin E availability; a neuroprotective effect of vitamin E on cell death was also proposed. In order to verify this latter hypothesis, we have studied cell death in all layers of DG in vitamin E-deficient and vitamin E-supplemented rats and in control rats at different ages, using TUNEL and nick translation techniques. The phenotype of TUNEL-positive cells was characterized and the existence of dying BrdU-positive cells was investigated. Dying cells with neuronal phenotype were observed throughout the DG in all experimental groups. The number of TUNEL-positive cells decreased from juvenile to adult age. A higher number of TUNEL-positive cells in vitamin E-deficient rats and a lower number in vitamin E-supplemented rats, with respect to age-matched controls, were found; moreover, in these groups, TUNEL-positive cells had a different percentage distribution in the different layers of the DG. Our results confirm the occurrence of cell death in DG, demonstrate that cell death affects neuronal cells and support the hypothesis that the effect of vitamin E on cell death is not related to neurogenesis.