Daniela Erba

Lycopene and vitamin C concentrations increase in plasma and lymphocytes after tomato intake. Effects on cellular antioxidant protection

Objective: This study seeks to verify whether the regular consumption of small amounts of tomato products can protect lymphocyte DNA and lipids from oxidative damage.Design: Standardized dietary intervention.Subjects: Twelve healthy female subjects (mean age 25.2 y).Intervention: Subjects were instructed to follow a standardized diet for 1 week, followed by 3 weeks consumption of the same diet enriched with small amounts of different tomato products providing as a mean 8 mg lycopene, 0.5 mg β-carotene and 11 mg vitamin C per day. Plasma and lymphocyte concentrations of carotenoids, vitamin C and vitamin E were analysed. Ex vivo protection of lymphocyte DNA from oxidative injury produced by iron ions was evaluated by means of the Comet assay, and lipid peroxidation by HPLC analysis of malondialdehyde (MDA).Results: Dietary intervention with tomato products increased lycopene concentration both in plasma (P<0.001) and lymphocytes (P<0.01). Vitamin C concentrations increased by ∼35% in plasma (P<0.05) and by ∼230% in lymphocytes (P<0.005). Vitamin E decreased significantly in plasma (P<0.0001) but not in lymphocytes. Finally, there was an improved protection from DNA oxidative damage (P<0.05) with no significant effect on MDA levels.Conclusions: Our results suggest that tomato products are not only good sources of lycopene but also sources of bioavailable vitamin C. A Regular intake of small amounts of tomato products can increase cell protection from DNA damage induced by oxidant species. This effect may originate from the synergism of different antioxidants present in tomatoes.Sponsorship: Supported by the Ministry of University and Scientific Research (MURST).

Effect of the ratio of casein phosphopeptides to calcium (w/w) on passive calcium transport in the distal small intestine of rats ☆

OBJECTIVE We investigated the influence of different ratios between casein phosphopeptides and calcium (CPP/Ca) in intestinal lumen on passive Ca transport across the distal small intestine of rats in vitro. METHODS We measured the amounts of passive Ca absorbed across the everted distal small intestine of rats with the use of radioactive 45Ca as tracer. Four CPP/Ca ratios (5, 10, 15, and 20 w/w) and three mineral concentrations (4, 8, and 12 mmol/L) were tested on groups of six rats. RESULTS We found a significant effect of the CPP/Ca ratio on mineral absorption (P < 0.001). The amounts of Ca absorbed increased from a ratio of 5 to a ratio of 15 and decreased with a ratio of 20, with a similar trend for every concentration tested. The more evident effect was found with the concentration of 12 mmol/L of Ca (P < 0.001 to 0.05). CONCLUSION The positive effect of CPPs on passive Ca absorption seems to depend on the relative amounts of both species in intestinal lumen. In this study, the ratio 15 was identified as the most efficient at increasing mineral transport. This evidence might be considered before suggesting CPP as a Ca dietary integrator, although more studies in vitro and in vivo are needed.

Oxidative stress signalling in the apoptosis of Jurkat T lymphocytes

The pathways of transduction of oxidative stress signals have been studied using the Jurkat T cell model. The oxidative stress was induced by exposure of the cells to 100 μM H2O2. DNA damage was detected within 15 min after commencement of treatment. DNA damage repair occurred within about 1 h in cells exposed to oxidative stress for 15 min. In continuous exposure to stress, DNA repair was slower and control levels of DNA integrity were not reached. DNA repair did not involve gene transcription. H2O2 at 100 μM caused cell death by necrosis as well as by apoptosis. Both these processes were induced by 15 min exposure to the stress stimulus. However, some important differences were found between necrosis and apoptosis. Necrosis was more rapid, began within an hour of treatment and continued to increase during the full duration of the experiment. But apoptosis was seen after 4 h from treatment and was conspicuous between 6 and 20 h after the start of treatment. The necrotic phase preceded apoptosis, although these did show an overlap. In the necrotic phase, Bcl‐2, Caspase 8 genes were down regulated. The 6–20 h phase characterised by a marked increase in apoptosis is accompanied by the up regulation of both Bcl‐2 and Caspase genes. Expression of the Fas and p53 genes was not altered in either phase. We also analysed the levels of expression of the scavenging genes whose gene products are involved in detoxification. No modulation of the antioxidant enzymes, catalase, Cu/Zn superoxide dismutase and glutatione peroxidase was detectable. J. Cell. Biochem. 82:437–444, 2001.

Effect of caseinphosphopeptides on inhibition of calcium intestinal absorption due to phosphate

Abstract Caseinphosphopeptides (CPPs) are peptides resulting from enzyme digestion of whole casein, characterized by the presence of an aminoacid cluster, negatively charged at physiological intestinal pH, that binds cations. The aim of the present study was to compare Ca absorption through the everted small intestine of rats from CaCl 2 or Ca-CPPs solutions, in absence of inorganic phosphate (Pi) or when two ratios between Ca and Pi occur. Secondly, it was evaluated whether the ion absorption could be affected by the fatty acid pattern of enterocyte membrane. Results showed that in the absence of Pi, Ca transport from CaCl 2 was higher than from Ca-CPPs solutions. However, when Pi was added to the CaCl 2 solution, Ca absorption decreased by 90% (Ca:Pi = 1:1) and 97% (Ca:Pi = 1:2). On the contrary, when Pi was added to the Ca-CPPs solution, Ca transport decreased only by 40% (Ca:Pi = 1:1) and 60% (Ca:Pi = 1:2). The enrichment of enterocyte membrane with n-3 fatty acids (fish oil diet) compared to control diet did not modify the effect of CPPs on Ca transport in ileum of rats. These findings demonstrate that CPPs can limit the inhibitory effect of phosphate on Ca availability and increase Ca transport across the distal small intestine. This action could be of nutritional relevance especially when the dietary intake of this mineral is lower than the recommended level or there is an unbalanced ratio Ca/Pi in diet.

Effect of green tea extract on DNA repair and oxidative damage due to H2O2 in Jurkat T cells

Abstract Green tea is considered as an aid to good health since it should increase the antioxidants defence system of the body against radical damage. The aim of this study was to investigate, in Jurkat cells, the protective effect of green tea extract (GTE) supplementation (10 mg/L, corresponding to 15 μmol/L EGCg, 24 h) against oxidative DNA damage induced by different concentrations of hydrogen peroxide (from 10 to 200 μmol/L H 2 O 2 for 15 min). The DNA damage, evaluated by the Comet assay, was dose dependent, however it reached a plateau at 75 μmol/L of H 2 O 2 without any protective effect exerted by GTE. The DNA repair process, completed within 2 hours, was unaffected by supplementation. These results seem to suggest that GTE supplementation, is not able to protect Jurkat cells against H 2 O 2 induced DNA damage, at least under the conditions used in this study.

Malondialdehyde production in Jurkat T cells subjected to oxidative stress

OBJECTIVE We investigated the relation between membrane lipid peroxidation, as evaluated by malondialdehyde (MDA), and oxidative stimuli in the Jurkat T-cell line and designed a cellular model to assess the antioxidant potential of compounds. METHODS Jurkat T cells were subjected to different concentrations of Fe(2+) ions (from 25 to 150 micromol/L) or H(2)O(2) (from 0.1 to 5 mmol/L), and MDA was determined after separation in high-performance liquid chromatography of the adduct with thiobarbituric acid. MDA production also was investigated in cells supplemented with epigallocatechin gallate and genistein and subjected to Fe(2+) oxidative treatment. RESULTS MDA production increased with the concentration of Fe(2+), whereas H(2)O(2) had no effect at any concentration. Oxidative stress for 15 min or 2 h produced similar MDA levels. The supplementation of epigallocatechin gallate partly prevented MDA production (about 40%, P < 0.05), whereas genistein exerted no preventive effect on lipid peroxidation. CONCLUSION We propose this cellular model, consisting of Jurkat T cells subjected to 100 micromol/L of Fe(2+) for 15 min, to study the protective effect of antioxidant supplementation against membrane lipid peroxidation.

Black tea extract supplementation decreases oxidative damage in Jurkat T cells

The purpose of this study was to investigate the protective effect of black tea (BT) extract against induced oxidative damage in Jurkat T-cell line. Cells supplemented with 10 or 25 mg/L BT were subjected to oxidation with ferrous ions. Malondialdehyde (MDA) production as marker of lipid peroxidation, DNA single strand breaks as marker of DNA damage, and modification of the antioxidant enzyme activity, glutathione peroxidase (GPX) were measured. Results show the efficacy of BT polyphenols to decrease DNA oxidative damage and to affect GPX activity (P<0.05), while no effect was shown on MDA production. The succeeding investigation of the activity of caffeine and epigallocatechin gallate demonstrated their antioxidant potential with respect to the cellular markers evaluated. In conclusion, this study supports the protective effect of BT against ferrous ions induced oxidative damage to DNA and the ability of BT to affect the enzyme antioxidant system of Jurkat cells.

Nutritive Evaluation of the Bambara Groundnut Ci12 Landrace [Vigna subterranea (L.) Verdc. (Fabaceae)] Produced in Cote d'Ivoire.

The nutritional evaluation of the Bambara groundnut Ci12 landrace (Vigna subterranea (L.) Verdc.) seeds produced in Côte d’Ivoire shows a 19% content of protein, containing all the essential amino acids with tryptophan as the limiting amino acid, a total dietary fiber level of 10%, with a low soluble fraction content, and a fat content of 1.4%, with a high proportion of total unsaturated fatty acids (61%) of which 36% were n-6 fatty acids. This legume contains phosphorus, as the major mineral, followed by magnesium and calcium, and trace elements (iron, copper and zinc). It is characterized by the same amount of α-tocopherol and antioxidant capacity as common legumes. The high concentration of essential amino acids, n-6 fatty acids and minerals, mainly Fe, in the Ci12 landrace of Bambara groundnut indicates that this local legume has the potentiality to improve the nutritional status in Côte d’Ivoire and it could be regarded as a nutrient dense food.

Quality and nutritional properties of pasta products enriched with immature wheat grain

In this study, nutritional and sensory properties of pasta enriched with 30% immature wheat grain (IWG), a natural source of fructo-oligosaccharides (FOS), are evaluated. Colour and cooking quality, nutritional value and glycaemic index (GI) of pasta were assessed in comparison with commercially enriched inulin and 100% wholewheat pastas. IWG integration induced deep changes in colour, without negatively affecting the cooking quality of pasta, and promoted nutritional quality by increasing the fibre content; IWG pasta presented a remarkable leaching of FOS in cooking water, thus providing only 1 g of FOS per serving. IWG pastas showed a GI of 67 (dried) and 79 (fresh), not significantly different from commercial pasta products. IWG can be considered an interesting ingredient to obtain functional products ‘naturally enriched’ in FOS and fibre. Results about FOS leaching suggest that, in dealing with functional effects, the actual prebiotic content should be carefully considered on food ‘as eaten’.

Isoflavone supplementation reduces DNA oxidative damage and increases O-β-N-acetyl-d-glucosaminidase activity in healthy women

Phenolic compounds are believed to boost the human antioxidant defense system and health; therefore, the aim of this research was to investigate the hypothesis that soy isoflavones (IFs) provide antioxidant protection in healthy women by evaluating DNA resistance to oxidative damage and O-β-N-acetyl-D-glucosaminidase (OGA) activity. An IF supplement (80 mg/d) was given to 9 postmenopausal women and 13 young women for 6 months and then stopped up to the 14th month. The women were allowed to consume their normal diet. Blood samples were collected at the beginning of the study after 2, 4, and 6 months and then at the 8th and 14th months. Plasma concentrations of genistein and daidzein, total antioxidant capacity, plasma vitamin status, markers of oxidative stress (red blood cell membrane fluidity, activity of the red blood cell cytosolic enzyme OGA and lymphocyte DNA susceptibility to oxidative stress), and serum lipid profile were analyzed. Analysis of variance for repeated measures was used for statistical analysis. Plasma concentrations of IFs rose significantly during the supplementation period, and plasma total antioxidant capacity increased in young women; membrane fluidity and OGA activity increased, and DNA oxidative damage decreased (P < .05) at 4 months, then returned to the basal level. There was a significant inverse correlation between DNA damage and plasma IF concentrations (P < .01). The results indicated a positive effect of IF supplementation on oxidative stress in women, thus suggesting that the healthful action ascribed to soy consumption may be partially related to the antioxidant potential of IFs.