ascorbic-acid and sinapinic-acid

Due to its advantageous antioxidant phytochemical components,

Topics: Animals; Antioxidants; Ascorbic Acid; Catechin; Flavonoids; Hemolysis; Humans; Oils, Volatile; Phytochemicals; Plant Extracts; Plant Leaves; Psidium

Antioxidant constituents such as carotenoids (capsanthin, phytoene, lutein, β-cryptoxanthin), polyphenols content (p-coumaric, ferulic, p-hydroxybenzoic, caffeic acid, sinapic acid, and quercetin-3-glucoside) and marketable yield were investigated in 11 sweet pepper cultivars grown under controlled temperature plastic tunnel and white shade net. Marketable yield was not affected by either of the environments, while the interaction between cultivar and growing environment significantly affected the accumulation of antioxidant constituents. The principal component analysis illustrated that controlled temperature plastic tunnel improved the accumulation of carotenoid components and ascorbic acid and vitamin C content in most cultivars. On the contrary, white shade nets favoured the accumulation of phenolic compounds and ORAC activity in most cultivars. A strong correlation was noted between phytoene and carotenoid components in this study (capsanthin r = 0.60; P < 0.001; lutein r = 0.75; P < 0.001; β-carotene r = 0.78; P < 0.001) while ORAC correlated with phenolic compounds. Based on this study, it is possible to refine the choice of environment and cultivar to enhance individual antioxidant constituent groups to improve health benefits for consumers.

Topics: Agriculture; Antioxidants; Ascorbic Acid; beta Carotene; Capsicum; Carotenoids; Coumaric Acids; Phenols; Polyphenols; Principal Component Analysis; Quercetin; Temperature; Xanthophylls

Chinese cabbage (Brassica rapa L. ssp. Pekinensis) is a green leafy vegetable used mainly in kimchi, salted and fermented dishes. Consumer preference for the leaf portion differs according to the type of dishes. In this study, Chinese cabbage was divided into three parts, and their antioxidant activities were investigated through in vitro assays. The total phenolic contents (TPC), total flavonoid contents (TFC), and vitamin C contents were also determined as indicators of antioxidant contents. The phenolic acids and flavonoids were separated and identified using high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). The outer leaf had the strongest antioxidant activity with the maximum antioxidant contents, followed by the mid- and inner leaves. Principal component analysis (PCA) revealed that outer leaf is positively related to caffeic acid, p-coumaric acid, ferulic acid, and myricetin contents, whereas the mid- and inner leaves are negatively related to sinapic acid contents.

Topics: Antioxidants; Ascorbic Acid; Brassica; Chromatography, High Pressure Liquid; Coumaric Acids; Flavonoids; Phenols; Plant Leaves; Propionates

Protein S-nitrosation is an important post-translational modification altering protein function. Interaction of nitric oxide with thiols is an active area of research, and is one of the mechanisms by which NO exerts its biological effects. Biotin switch assay is the method, which has been developed to identify S-nitrosated proteins. The major concern with biotin switch assay includes reducing disulfide which may lead to false positives. We report a modification of the biotin switch assay where sinapinic acid is utilized instead of ascorbate to eliminate potential artifacts in the detection of S-nitrosated proteins.. The denitrosation ability of sinapinic acid was assessed by monitoring either the NO or NO(2)(-) released by chemiluminescent NO detection or by the griess assay, respectively. DTNB assay was used to compare disulfide reduction by ascorbate and sinapinic acid. Sinapinic acid and ascorbate were compared in the biotin switch detection of S-nitrosoproteins in RAW 264.7 cells+/-S-nitrosocysteine (CysNO) exposure.. We show that sinapinic acid has the ability to denitrosate S-nitrosothiols at pH 7.0 and denitrate plus denitrosate at pHs 8 and 8.5. Unlike ascorbate, sinapinic acid degrades S-nitrosothiols, but it does not reduce disulfide bridges.. Sinapinic acid denitrosate RSNO and does not reduce disulfides. Thus can readily replace ascorbate in detection of S-nitrosated proteins in biotin switch assay.. The work described is important in view of protein S-nitrosation. In this study we provide an important modification that eliminates artifacts in widely used technique for detecting the S-nitrosoproteome, the biotin switch assay.

Topics: Animals; Ascorbic Acid; Biotin; Blotting, Western; Cell Line; Coumaric Acids; Disulfides; Dithionitrobenzoic Acid; Hydrogen-Ion Concentration; Luminescent Measurements; Macrophages; Molecular Structure; Nitric Oxide; Nitrites; Nitrosation; Protein Processing, Post-Translational; Proteins; Proteomics; Reproducibility of Results; S-Nitrosothiols; Sulfhydryl Compounds

As a powerful natural antioxidant, lipoic acid exerts significant antioxidant activities in vivo and in vitro by deactivation of reactive oxygen and nitrogen species. In this study we present a novel synergistic interaction of lipoic acid with other endogenous or exogenous antioxidants. Antioxidants vitamins C and E analogue (Trolox C) and hydroxycinnamic acid derivatives were found to recycle lipoic acid by donating electrons to lipoic acid radical cations, thereby increasing the antioxidant capacity of lipoic acid in vivo and in vitro. The rate constant of the electron transfer is in the order 10(9)dm(3)mol(-1)s(-1), close to the diffusion-controlled limit, and transfer quantum yield is above 95%.

Topics: Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Coumaric Acids; Free Radicals; Kinetics; Molecular Structure; Particle Accelerators; Structure-Activity Relationship; Thioctic Acid; Vitamin E