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The wild mushroom Leucopaxillus candidus (Bres.) Singer was studied for the first time to obtain information about its chemical composition, nutritional value and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. candidus methanolic extract was tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). L. candidus was shown to be an interesting species in terms of nutritional value, with high content in proteins and carbohydrates, but low fat levels, with the prevalence of polyunsaturated fatty acids. Mannitol was the most abundant free sugar and β-tocopherol was the main tocopherol isoform. Other compounds detected were oxalic and fumaric acids, p-hydroxybenzoic and cinnamic acids. The methanolic extract revealed antioxidant activity and did not show hepatoxicity in porcine liver primary cells. The present study provides new information about L. candidus.

Tocopherols, synthesized by photosynthetic organisms, are micronutrients with antioxidant properties that play important roles in animal and human nutrition. Because of these health benefits, there is considerable interest in identifying the genes involved in tocopherol biosynthesis to allow transgenic alteration of both tocopherol levels and composition in agricultural crops. Tocopherols are generated from the condensation of phytyldiphosphate and homogentisic acid (HGA), followed by cyclization and methylation reactions. Homogentisate phytyltransferase (HPT) performs the first committed step in this pathway, the phytylation of HGA. In this study, bioinformatics techniques were used to identify candidate genes, slr1736 and HPT1, that encode HPT from Synechocystis sp. PCC 6803 and Arabidopsis, respectively. These two genes encode putative membrane-bound proteins, and contain amino acid residues highly conserved with other prenyltransferases of the aromatic type. A Synechocystis sp. PCC 6803 slr1736 null mutant obtained by insertional inactivation did not accumulate tocopherols, and was rescued by the Arabidopsis HPT1 ortholog. The membrane fraction of wild-type Synechocystis sp. PCC 6803 was capable of catalyzing the phytylation of HGA, whereas the membrane fraction from the slr1736 null mutant was not. The microsomal membrane fraction of baculovirus-infected insect cells expressing the Synechocystis sp. PCC 6803 slr1736 were also able to perform the phytylation reaction, verifying HPT activity of the protein encoded by this gene. In addition, evidence that antisense expression of HPT1 in Arabidopsis resulted in reduced seed tocopherol levels, whereas seed-specific sense expression resulted in increased seed tocopherol levels, is presented.

Cyclooxygenase (COX-1/COX-2)-catalyzed eicosanoid formation plays a key role in inflammation-associated diseases. Natural forms of vitamin E are recently shown to be metabolized to long-chain carboxychromanols and their sulfated counterparts. Here we find that vitamin E forms differentially inhibit COX-2-catalyzed prostaglandin E₂ in IL-1β-stimulated A549 cells without affecting COX-2 expression, showing the relative potency of γ-tocotrienol [almost equal to] δ-tocopherol > γ-tocopherol >> α- or β-tocopherol. The cellular inhibition is partially diminished by sesamin, which blocks the metabolism of vitamin E, suggesting that their metabolites may be inhibitory. Consistently, conditioned media enriched with long-chain carboxychromanols, but not their sulfated counterparts or vitamin E, reduce COX-2 activity in COX-preinduced cells with 5 μM arachidonic acid as substrate. Under this condition, 9'- or 13'-carboxychromanol, the vitamin E metabolites that contain a chromanol linked with a 9- or 13-carbon-length carboxylated side chain, inhibits COX-2 with an IC₅₀ of 6 or 4 μM, respectively. But 13'-carboxychromanol inhibits purified COX-1 and COX-2 much more potently than shorter side-chain analogs or vitamin E forms by competitively inhibiting their cyclooxygenase activity with Ki of 3.9 and 10.7 μM, respectively, without affecting the peroxidase activity. Computer simulation consistently indicates that 13'-carboxychromanol binds more strongly than 9'-carboxychromanol to the substrate-binding site of COX-1. Therefore, long-chain carboxychromanols, including 13'-carboxychromanol, are novel cyclooxygenase inhibitors, may serve as anti-inflammation and anticancer agents, and may contribute to the beneficial effects of certain forms of vitamin E.

Psychotria malayana Jack belongs to the Rubiacea and is widespread in Southeast Asian countries. It is traditionally used to treat diabetes. Despite its potential medicinal use, scientific proof of this pharmacological action and the toxic effect of this plant are still lacking. Hence, this study aimed to investigate the in vitro antidiabetic and antioxidant activities, toxicity, and preliminary phytochemical screening of P. malayana leaf extracts by gas chromatography-mass spectrometry (GC-MS) after derivatization. The antidiabetic activities of different extracts of this plant were investigated through alpha-glucosidase inhibitory (AGI) and 2-NBDG glucose uptake using 3T3-L1 cell line assays, while the antioxidant activity was evaluated using DPPH and FRAP assays. Its toxicological effect was investigated using the zebrafish embryo/larvae (Danio rerio) model. The mortality, hatchability, tail-detachment, yolk size, eye size, beat per minute (BPM), and body length were taken into account to observe the teratogenicity in all zebrafish embryos exposed to methanol extract. The LC50 was determined using probit analysis. The methanol extract showed the AGI activity (IC50 = 2.71 ± 0.11 μg/mL), insulin-sensitizing activity (at a concentration of 5 µg/mL), and potent antioxidant activities (IC50 = 10.85 μg/mL and 72.53 mg AAE/g for DPPH and FRAP activity, respectively). Similarly, the water extract exhibited AGI activity (IC50 = 6.75 μg/mL), insulin-sensitizing activity at the concentration of 10 μg/mL, and antioxidant activities (IC50 = 27.12 and 33.71 μg/mL for DPPH and FRAP activity, respectively). The methanol and water extracts exhibited the LC50 value higher than their therapeutic concentration, i.e., 37.50 and 252.45 µg/mL, respectively. These results indicate that both water and methanol extracts are safe and potentially an antidiabetic agent, but the former is preferable since its therapeutic index (LC50/therapeutic concentration) is much higher than for methanol extracts. Analysis using GC-MS on derivatized methanol and water extracts of P. malayana leaves detected partial information on some constituents including palmitic acid, 1,3,5-benzenetriol, 1-monopalmitin, beta-tocopherol, 24-epicampesterol, alpha-tocopherol, and stigmast-5-ene, that could be a potential target to further investigate the antidiabetic properties of the plant. Nevertheless, isolation and identification of the bioactive compounds are required to confirm their antidiabetic activity and toxicity.

Within Europe there are differences in cardiovascular disease (CVD) risk between countries and this might be related to dietary habits. Oxidative modification of LDL is suggested to increase the risk of CVD and both the fatty acid and antioxidant content of LDL can affect its oxidation. In the present study, concentration of LDL fatty acid and antioxidant micronutrients (tocopherols and carotenoids) and ex vivo oxidative resistance of LDL (lag phase) was compared in volunteers from five countries with different fruit and vegetable intakes and reported rates of CVD. Eighty volunteers (forty males, forty females per centre), age range 25–45 years, were recruited from France, Northern Ireland, UK, Republic of Ireland, The Netherlands, and Spain, and their LDL composition and lag phase were measured. There were some differences in LDL carotenoid and α-tocopherol concentrations between countries. α-Tocopherol was low and β- + γ-tocopherol were high (P<0·001) in the Dutch subjects. β-Carotene concentrations were significantly different between the French and Spanish volunteers, with French showing the highest and Spanish the lowest concentration. LDL lycopene was not different between centres in contrast to lutein, which was highest in French (twofold that in the Dutch and Spanish and threefold that in Northern Ireland and the Republic of Ireland, P<0·001). However absolute LDL saturated, monounsaturated, polyunsaturated and total unsaturated fatty acid concentrations were different between countries (P<0·001, total unsaturated highest in Northern Ireland) there was little difference in unsaturated:saturated fatty acid concentration ratios and no difference in polyunsaturated:saturated fatty acid concentration ratios. LDL from the Republic of Ireland (a region with a high rate of CVD) had greater resistance to Cu-stimulated oxidation than samples obtained from volunteers in other countries. In conclusion, LDL composition did not predict resistance to Cu-stimulated oxidation, nor is there evidence that LDL from volunteers in countries with lower rates of CVD have greater resistance to oxidation.

Duplicate meals of those eaten by 14 healthy young males (25-35 years of age), usual hospital diets for breakfast, lunch, and dinner, were collected for 5 consecutive days and freeze-dried. Fat-soluble vitamin (alpha-, beta-, gamma-, and delta-tocopherols, retinol, alpha- and beta-carotenes) and vitamin C contents were analyzed. Duplicate meals presented a wide range in vitamin levels. Large individual day-to-day variations were observed. The median daily intakes (n = 70) of retinol equivalent (0.31 mg/day) and tocopherol equivalent (3.48 mg/day) were low. Only one third of the meals could provide sufficient amounts of fat-soluble vitamins, whereas vitamin C intakes were adequate (87.4 mg/day). So, fat-soluble recommended intakes were not supplied for most of the subjects in this study.