Supercritical carbon dioxide (SC-CO(2)) extraction of flavonoids from pomelo (Citrus grandis (L.) Osbeck) peel and their antioxidant activity were investigated. Box-Behnken design combined with response surface methodology was employed to maximize the extraction yield of flavonoids. Correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be u...

The activity of ascorbate peroxidase (APX) has been studied with H(2)O(2) and various reducing substrates. The activity decreased in the order pyrogallol>ascorbate>guaiacol>2, 2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). The inactivation of APX with H(2)O(2) as the sole substrate was studied. The number of H(2)O(2) molecules required for maximal inactivation of the enzyme was d...

Rhizoid of Laminaria japonica was hydrolyzed with proteases and carbohydrases to obtain antioxidant materials. Oxygen radical absorbance capacity (ORAC) of the enzymatic extracts was evaluated and the Protamex extract (PE) exhibited the highest ORAC value. PE also potently scavenged 2,2-diphenyl-1-picrylhydrazyl radical, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid cation radical, and...

Induction of systemic resistance by neem cake (Azadirachta indica) and endophytic Pseudomonas aeruginosa, a plant growth promoting bacterium, was evaluated in cotton (Gossypium hirsutum L.) under salinity stress and fungal infection. The combination of biocontrol agent and organic matter induced tolerance against fungal infection (Macrophomina phaseolina) and salinity stress (EC= 17.3 dS, m) by...

Two phenolics, 1,2,6-trigalloylglucose (1) and 1,2,3,6-tetragalloylglucose (2), isolated from the stem-bark of Juglans mandshurica were evaluated for their antioxidative activities. The results showed that compounds 1 and 2 exhibited strong scavenging activities against 1,1'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzenthiazoline-6-sulphonic) acid (ABTS(*+)), and superoxide ra...

A sequential injection system based on the ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic-acid) methodology was developed. The proposed method, incorporating a mixing chamber in the side port of the selection valve, was evaluated to measure the total antioxidant activity of several beverages and foods. The ABTS(+) is generated by oxidation of ABTS with potassium persulfate and is redu...

This study describes the synthesis and antioxidant activity of new 1,4-disubstituted 1,2,3-triazoles. These compounds were generated semi-synthetically using Cu(I)-catalysed azide-alkyne cycloaddition (CuAAC) reaction between ethyl 2-azidoacetate terminal acetylenes derived from natural products carvacrol, eugenol, isovanillin, thymol vanillin. The obtained at 50 to 80% yield characterised thro...

Resveratrol (3,5,4'-trihydroxystilbene) is a phytoalexin produced by plants. Resveratrol is known for its anti-cancer, antiviral and antioxidant properties. We prepared imine analogs of resveratrol ((hydroxyphenyliminomethyl)phenols) and tested their antioxidant activity. All prepared resveratrol analogs were able to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR) and 2,...

We investigated the antioxidative activity of LX519290, a derivative of l-allo threonine, in vitro and in vivo. To evaluate the antioxidative activity of LX519290, we performed several in vitro assays (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical-scavenging assays, a ferric reducing antioxidant power assay, cupric-reducing antio...