Assessment of the reducing capacity of processed fruit juices with the copper(I)/4,4'-dicarboxy-2,2'-biquinoline complexes.

An alternative method for quantification of the total reducing capacity (TRC) of processed ready-to-drink fruit juices (orange, grape, peach, mango, cashew, strawberry, apple and guava) is suggested. The spectrophotometric procedure is based on the reduction of Cu(II) to Cu(I) by antioxidants (present in the samples) in aqueous buffered solution (pH 7.0), containing 4,4'-dicarboxy-2,2'-biquinoline acid (HBCA), yielding the [Formula: see text] complexes.

Study of DNA damage caused by dipyrone in presence of some transition metal ions.

The DNA damage in the presence of dipyrone (used as its sodium salt, NaDip) and some transition metal ions in an air saturated ([O] ≈ 0.25 mM) non-buffered solution at T = (25.0 ± 0.

Antioxidant Activity and Polyphenol Content of Some Brazilian Medicinal Plants Exploiting the Formation of the Fe(II)/2,2'-bipyridine Complexes.

Aqueous plant extracts contain polyphenols that reduce Fe3+ to Fe2+, which in the presence of excess 2,2'-bipyridine (bipy) yield the Fe(bipy)3(2+) complex (λmax = 521 nm). This reaction was used to quantify the total polyphenol content (TPC) of nineteen Brazilian medicinal species using pyrogallic acid (PA) as a standard. A calibration curve of absorbance values at 521 nm values vs.

A Comprehensive Study of the Use of Cu(I)/4,4'-Dicarboxy-2,2'-biquinoline Complexes to Measure the Total Reducing Capacity: Application in Herbal Extracts.

A method for the determination of total reducing capacity (TRC) based on the reduction of Cu(II) to Cu(I) by antioxidants in a buffered solution (pH 7.0) containing 4,4'-dicarboxy-2,2'-biquinoline acid (BCA) was developed. Absorbance values at 558 nm characteristic of the Cu(I)/BCA complexes formed were used to determine the TRC of aqueous extracts of twelve Brazilian plants.

The evaluation of reduction of Fe(III) in 3-hydroxy-4-nitroso-2,7-naphthalene disulphonic medium as an alternative ferric reducing activity power assay.

Introduction: The growing interest in determination of anti-oxidant capacity through non-labour, effective and less costly methods encouraged the development of the spectrophotometric procedure presented in this study.

Objective: To investigate the reduction reaction of Fe(III) in 3-hydroxy-4-nitroso-2,7-naphthalenedisulphonic anion (NRS) medium as an alternative ferric reducing activity power (FRAP) assay for determining the total reduction capacity (RC).

Materials And Methods: The absorbance values at 730 nm were used to determine the RC of aqueous extracts of nine Brazilian plants.

A critical study of use of the Fe(II)/3-hydroxy-4-nitroso-2,7-naphthalenedisulfonic acid complexes in the quantification of polyphenols in medicinal plants.

A critical study of the use of the Fe(III)/3-hydroxy-4-nitroso-2,7-naphthalenedisulfonic acid (NRS) complexes on the quantification of the polyphenols content in aqueous extracts of plants, expressed as pyrogallic acid, [PA], is presented. The reaction used is based on the reduction of Fe(III) to Fe(II) by [PA] in the presence of NRS in a buffered medium (Tris; pH 8.0) with formation of Fe(II)/NRS complexes.

Analysis of the polyphenols content in medicinal plants based on the reduction of Cu(II)/bicinchoninic complexes.

A spectrophotometric method is proposed for the determination of the polyphenols content in aqueous extracts of plants. The method is based on the reduction of Cu(II) to Cu(I) by polyphenols, in the presence of bicinchoninic acid in a buffered medium (ammonium acetate, pH 7.0) with the formation of Cu(I)/BCA complexes.