scispace - formally typeset
Search or ask a question
Author

Chia-Chi Chang

Bio: Chia-Chi Chang is an academic researcher. The author has contributed to research in topics: Propolis. The author has an hindex of 1, co-authored 1 publications receiving 3197 citations.
Topics: Propolis

Papers
More filters
Journal ArticleDOI
TL;DR: In this article, two complementary colorimetric methods, aluminum chloride method and 2,4-dini trophenylhydrazine method, were used to determine the real content of total flavonoids in propolis.

3,899 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this paper, several honey samples (27) from Burkina Faso were analyzed to determine their total phenolic, flavonoid and proline contents as well as their radical scavenging activity.

1,850 citations

Journal ArticleDOI
TL;DR: In this article, the relative antioxidant activity in selected Iranian medicinal plant species' extracts was determined spectrophotometrically, and the highest radical scavenging effect was observed in Mellilotus officinalis with IC50 = 0.018 mg ml −1.
Abstract: In present study, we carried out a systematic record of the relative antioxidant activity in selected Iranian medicinal plant species' extracts. The total phenol varied from 24.1 ± 1 to 289.5 ± 5 mg g -1 in the extracts. Flavonoid contents were between 25.15 ± 0.8 and 78.3 ± 4.5 mg g-1. 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect of the extracts was determined spectrophotometrically. The highest radical scavenging effect was observed in Mellilotus officinalis with IC50 = 0.018 mg ml –1. The potency of radical scavenging effect of M. officinalis extract was about 4 times greater than synthetic antioxidant butylated hydroxy toluene (BHT). The greater amount of phenolic compounds leads to morepotent radical scavenging effect as shown by M. officinalis extract

1,029 citations

Journal ArticleDOI
TL;DR: This review intends to offer a critical evaluation of existing antioxidant assays applied to phenolics, and reports the development of a simple and low-cost antioxidant capacity assay for dietary polyphenols, vitamins C and E, and human serum antioxidants, which is named the CUPRAC (cupric ion reducing antioxidant capacity) method.
Abstract: It would be desirable to establish and standardize methods that can measure the total antioxidant capacity level directly from vegetable extracts containing phenolics. Antioxidant capacity assays may be broadly classified as electron transfer (ET)- and hydrogen atom transfer (HAT)-based assays. The majority of HAT assays are kinetics-based, and involve a competitive reaction scheme in which antioxidant and substrate compete for peroxyl radicals thermally generated through the decomposition of azo compounds. ET-based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes colour when reduced. ET assays include the ABTS/TEAC, CUPRAC, DPPH, Folin-Ciocalteu and FRAP methods, each using different chromogenic redox reagents with different standard potentials. This review intends to offer a critical evaluation of existing antioxidant assays applied to phenolics, and reports the development by our research group of a simple and low-cost antioxidant capacity assay for dietary polyphenols, vitamins C and E, and human serum antioxidants, utilizing the copper(II)-neocuproine reagent as the chromogenic oxidizing agent, which we haved named the CUPRAC (cupric ion reducing antioxidant capacity) method. This method offers distinct advantages over other ET-based assays, namely the selection of working pH at physiological pH (as opposed to the Folin and FRAP methods, which work at alkaline and acidic pHs, respectively), applicability to both hydrophilic and lipophilic antioxidants (unlike Folin and DPPH), completion of the redox reactions for most common flavonoids (unlike FRAP), selective oxidation of antioxidant compounds without affecting sugars and citric acid commonly contained in foodstuffs and the capability to assay -SH bearing antioxidants (unlike FRAP). Other similar ET-based antioxidant assays that we have developed or modified for phenolics are the Fe(III)- and Ce(IV)-reducing capacity methods.

921 citations

Journal ArticleDOI
TL;DR: The highest total phenolic content was observed in mulberry (1515.9 ± 5.7 mg gallic acid equivalents (GAE)/100 g fresh matter (FM) among four selected fruit species as discussed by the authors.

773 citations