Search

The antioxidant activities of ethanolic extract from edible mushroom Agaricus bisporus (A. bisporus) were evaluated by various methods in vitro and in vivo. In antioxidant assays in vitro, ethanolic extract of A. bisporus was found to have strong reducing power, superoxide radical, hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, and moderate hydrogen peroxide scavenging activity. In antioxidant assays in vivo, mice were administered with ethanolic extract of A. bisporus via gavage for 30 consecutive days. As a result, administration of ethanolic extract significantly enhanced the activities of antioxidant enzymes in serums, livers and hearts of mice. In addition, the total phenolic content in the extract determined by Folin-Ciocalteu method was 6.18mg of gallic acid equivalents per gram of dry weight. The main phenolic compounds in ethanolic extract analyzed by ultra-high performance liquid chromatography tandem mass spectrometry were determined as gallic acid, protocatechuic acid, catechin, caffeic acid, ferulic acid and myricetin. These results suggested that ethanolic extract of A. bisporus had potent antioxidant activity and could be explored as a novel natural antioxidant., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Several analytical approaches are available for investigating the antioxidant power for antioxidants, and they are based on a variety of chemical principles, such as oxygen radical absorbance capacity (ORAC), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing/antioxidant power (FRAP). This paper reports a new rapid method for investigating antioxidant power on the basis of the electron-donating ability. This method is called chemiluminescence analysis of antioxidant power (CAAP). The electrons donated from antioxidants are capable of inducing chemiluminescence in the presence of lucigenin and a base. Thus, the intensity of chemiluminescence induced by antioxidants is proportional to their electron-donating ability (antioxidant power). It was found that the correlation between CAAP and FRAP was positive (r = 0.959) and statistically significant (p < 0.05). In addition to the FRAP assay, the rapid CAAP assay is convenient for investigating the antioxidant power of herbal extracts.

This study aimed to compare the extraction efficiency of dynamic high pressure microfluidization-assisted extraction (DHPMAE) and other commonly used extraction methods on the antioxidant activities (AAs) of sweet potato leaves ( Ipomoea batatas L., SPL), and to identify the antioxidant compounds by HPLC-QTOF-MS 2 . Two highly consumed commercial varieties, orange-fleshed and cream-fleshed sweet potato leaves (OFL and CFL), were taken as materials. OFL was evidenced to be a better antioxidants resource than CFL due to higher polyphenols and AAs. DHPMAE had the best extraction efficiency on total phenolics and total flavonoids, with the values in OFL extract at 16.35 mg GAE/g DM and 16.51 mg RE/g DM, respectively. DHPMAE extract also exhibited the strongest DPPH· and ABTS· + scavenging ability, chelating ability and reducing power. Multiple regression analysis revealed that polyphenols played an important contribution to the AAs of SPL extracts. After successive fractionation of DHPMAE extract by chloroform, ethyl acetate, and n -butanol, the ethyl acetate fraction showed the highest total phenolic (569.38 mg GAE/g Extract) and total flavonoid (43.15 mg RE/g Extract) content, as well as the highest AAs. HPLC-QTOF-MS 2 analysis of the ethyl acetate fraction resulted in identifying 37 compounds including 20 phenolic acids, 12 flavonoids, 3 organic acids, 1 nucleoside and 1 ester, and 20 of them were firstly detected in SPL. Caffeoylquinic acid derivatives and flavonoids were the most abundant antioxidant compounds. The presented results suggested that DHPM might be a promising assisted technology in extracting polyphenols from plants, and SPL could be utilized for the development of functional food. [ABSTRACT FROM AUTHOR]

Abstract: Hemodialysis can remove uremic solutes but this treatment induces oxidative stress in uremic patients because of hemo-incompatibility. Therefore, we hypothesised that an antioxidant dialysate (a dialysate containing antioxidant(s)) would provide antioxidant defence in uremic patients during hemodialysis. Several herbal extracts were studied and measurements of antioxidant power and stability assays indicated that epigallocatechin gallate (EGCG) was the best of those tested for use as an antioxidant dialysate (EGCG dialysate). We observed that EGCG dialysate could provide the highest level of antioxidant defence at a dialysate flow rate of 500ml/min and a blood flow rate of 200ml/min. In addition, some important parameters for hemodialysis were calculated for supporting the protective role of EGCG dialysate. This is the first description of the preparation of an antioxidant dialysate. We suggest that EGCG dialysate will reduce the level of oxidative stress in hemodialysis patients, leading to a decrease of complications associated with oxidative damage. [Copyright &y& Elsevier]

AbstractUremic patients with diabetes suffer from high levels of oxidative stress due to regular hemodialysis therapy (neutrophil activation induced by hemo-incompatibility between the hemodialyser and blood) and complications associated with diabetes. Several plasma biomarkers were screened in 13 uremic diabetic patients after receiving the mixture of (–)-epigallocatechin gallate (EGCG), a major component of green tea extract, and Amla extract (AE), from Emblica officinalis, the Indian gooseberry, for 3 months. We found that oral administration of a 1:1 mixture of EGCG and AE for 3 months significantly improved antioxidant defense as well as diabetic and atherogenic indices in uremic patients with diabetes. Furthermore, no significant changes in hepatic function, renal function, or inflammatory responses were observed. These results suggest that a 1:1 combination of EGCG and AE is a safe and effective treatment for uremic patients with diabetes. [ABSTRACT FROM AUTHOR]