The first 100s of reaction between gallic acid (GA) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical follows the second order reaction. The addition of zinc (Zn) significantly enhanced the rate of reaction, such that the rate constant when GA:Zn is 1:1 was significantly higher, (P<0.05), 120 ± 12 Ms as compared to 92 ± 6 Ms when zinc was absent. However, the addition of excess zinc, GA:Zn 1:2,...

The effect of allyl isothiocyanate (AITC) on radical scavenging capacity, and fruit decay of blueberries var. Duke (Vaccinium corymbosum L.) was evaluated. Results from this study showed that AITC was effective in retarding blueberry decay during storage at 10 C. However, AITC-treated fruit decreased the contents of total phenolics and anthocyanins. Compared to control, AITC-treated berries had...

The present study was carried out to evaluate the antimicrobial and antioxidant activities of methanol extract of Careya arborea (MECA) stem barks (Myrtaceae) in various in-vitro systems. Antimicrobial activities of MECA were carried out using disc diffusion methods with Gram positive and Gram negative bacteria and some fungal species. MECA showed broad-spectrum antimicrobial activity against a...

This study compares the radical scavenging capacity of high-molar-mass hyaluronan (HA) using standardized methods applying 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and 2,2'-azinobis[3-ethylbenzthiazoline sulfonate] (ABTS) radical cations as oxidants. Additionally, spin-trapping technique combined with electron paramagnetic resonance (EPR) was used to evaluate the ability of HA to scavenge ...

A response surface approach was used to investigate the effects of temperature, concentration, and time on the antioxidant properties (total flavonoid (TF), total phenol (TP), peroxide scavenging activity (PS), iron chelating activity (IC), DPPH radical-scavenging ability (DPPH), ABTS assay (ABTS)) of aqueous extract of tea-ginger (2:1) powder. Color indices, pH, and redox potential of the tea-...

The aim of the study was to perform a quantitative analysis of fluid extracts of maidenhair tree (Ginkgo biloba L.), motherwort (Leonurus cardiaca L.) and hawthorn (Crataegus monogyna Jacq.), to evaluate their antioxidant activity and to compare their ability to inactivate free radicals. The antioxidant activity was measured using the DPPH*and the ABTS*+ radical scavenging reaction systems. The...

The enhanced antioxidant activity of surface-functionalized gold nanoparticles (AuNPs) synthesized by self-assembly has attracted great attention, but little is known about the mechanism behind the enhanced activity. To address this challenge, the antioxidant activity of Au@PEG3SA (i.e., surface-functionalization of spherical AuNPs with the antioxidant salvianic acid A) was used as an example t...

The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this p...

Chick embryo egg hydrolysates (CEEH) were obtained by enzymatic hydrolysis of chick embryo egg in vitro-simulated gastrointestinal digestion. The antioxidant activities of CEEH were investigated by employing three in vitro assays, including the 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate)/1,1-diphenyl-2-picrylhydrazyl (ABTS/DPPH)/hydroxyl radical-scavenging assays. The radical-scavenging e...

The present study was carried out to evaluate the antioxidant and free radical scavenging activity of methanolic extract of Ervatamia coronaria leaves (Apocynaceae) in various systems. DPPH radical, superoxide anion radical, nitric oxide radical and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of methanolic ex...