Kazuki Harada

Antioxidative activity of the buckwheat polyphenol rutin in combination with ovalbumin

Buckwheat flour is well known for its highly antioxidative ingredient, rutin. We have undertaken to examine alterations in the characteristics of rutin treated with various proteins. In this study, the radical scavenging activities of a rutin-ovalbumin complex were examined. Dissolved rutin hydrate and ovalbumin were combined and boiled in water for 10 min. In the resulting rutin-ovalbumin complex, a new high molecular weight peak was detected using gel permeation chromatography analysis, and an existing high molecular weight area of ovalbumin was observed to be increased by the addition of rutin. This suggested that ovalbumin molecules produce a complex through their interaction with rutin. Alkaline luminol chemiluminescence and electron spin resonance analysis revealed the formation of a rutin-ovalbumin complex that markedly enhanced the peroxyl, but not the hydroxyl, radical scavenging activity of rutin. Rutin also demonstrated antioxidative activity against hydroxyl radicals in a DNA protection assay. We therefore conclude that, compared with ovalbumin or rutin alone, the rutin-ovalbumin complex has improved antioxidative activities in the form of enhanced peroxyl radical scavenging activity and DNA protection from apurinic/apyrimidinic site formation caused by hydroxyl radicals.

Mutations of a shuttle vector plasmid, pZ189, in Escherichia coli induced by boron neutron captured beam (BNCB) containing α-particles

A shuttle vector, pZ189, carrying a bacterial suppressor tRNA marker gene (supF) was dissolved in Tris-EDTA buffer containing 0.3 M 10B-enriched boric acid and then irradiated with boron neutron captured beam (BNCB) produced by the nuclear reaction 10B (n,alpha) 7Li with thermal neutrons. A DNA repair-deficient mutant, KS46 (uvrA-), of Escherichia coli was transformed with the plasmid DNA, and the transformants carrying mutations on the supF gene were selected as nalidixic acid-resistant colonies. The mutation frequency (2.4 x 10(-4)) of pZ189 at the D10 dose was about 70 times greater than the spontaneous rate (3.5 x 10(-6)). The plasmid mutations were analyzed using DNA sequencers; 88% of them were base substitutions. A few minus-one frameshifts (7%) and deletions (5%) were detected. Among these base substitutions, transversions of G:C to T:A (42%) and G:C to C:G (29%) predominated. Twenty-seven percent of the base substitutions were G:C to A:T transitions; no A:T to G:C transitions were detected.

Biochemical analyses of the antioxidative activity and chemical ingredients in eight different Allium alien monosomic addition lines.

We measured the antioxidant contents and antioxidative activities in eight Allium fistulosum–shallot monosomic addition lines (MAL; FF+1A–FF+8A). The high antioxidative activity lines (FF+2A and FF+6A) showed high polyphenol accumulation. These additional chromosomes (2A and 6A) would therefore have anonymous genes related to the upregulation of polyphenol production, the antioxidative activities consequently being increased in these MALs.