Conversion of procyanidin B-type (catechin dimer) to A-type: evidence for abstraction of C-2 hydrogen in catechin during radical oxidation

Kondo, Kazunari; Kurihara, Masaaki; Fukuhara, Kiyoshi; Tanaka, Takashi; Suzuki, Takashi; Miyata, Naoki; Toyoda, Masatake

doi:10.1016/s0040-4039(99)02097-3

Cited by 120 publications

(93 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Antioxidant, antimicrobial, anti-allergy and anticancer effects of catechin have been reported in a number of earlier studies (Kondo et al, 2000;Shimamura et al, 2007). Catechin was found in R. delica with 5.33 mg/g by Yaltirak et al (2009).…”

Section: Phenolic Compounds Of a Caesareamentioning

confidence: 80%

Biological activity and fatty acid composition of Caesar's mushroom

Doğan

Akbaş

2013

Pharmaceutical Biology

View full text Add to dashboard Cite

Context: Due to its pleasant aroma and flavor, Amanita caesarea (Scop.) Pers. (Amanitaceae) has been a famous macrofungus since ancient times. This species is also well known in Turkey where people consume it extensively. Objective: Evaluation of the medicinal importance of A. caesarea for human health. Materials and methods: Antioxidant capacity of A. caesarea was studied using the methods of a scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radicals, b-carotene-linoleic acid assay, reducing power and estimation of phenolics. Chloroform, acetone and methanol extracts of A. caesarea were tested for their antimicrobial activity against four Gram-positive bacteria, five Gram-negative bacteria and one yeast by applying a micro dilution method. The fatty acids were estimated via the method of gas chromatography analysis. Results: The scavenging effect of A. caesarea on DPPH radicals was measured as 40.91% at 0.5 mg/mL concentration, and its reducing power was 0.451 mg/mL at 1.2 mg/mL concentration. The phenolics found were catechin (32.5 mg/g), ferulic acid (7 mg/g), p-coumaric acid (6 mg/g) and cinnamic acid (6.2 mg/g). The highest minimum inhibitory concentration observed against the test microorganisms were with the acetone extract (4.8 mg/mL concentration) against Candida albicans. Thirty-seven different fatty acids were determined from A. caesarea, and oleic acid (58%) was the dominant component. Discussion and conclusion: Amanita caesarea had a high-antioxidant and -antimicrobial activity, and it also had important essential fatty acids required for human health. According to the results, this mushroom can be recommended as a major source of natural food.

show abstract

Section: Phenolic Compounds Of a Caesareamentioning

confidence: 80%

Biological activity and fatty acid composition of Caesar's mushroom

Doğan

Akbaş

2013

Pharmaceutical Biology

View full text Add to dashboard Cite

show abstract

“…Therefore, to the best of our knowledge, this is the first study where the extensive profile of phenolic compounds in extracts of different parts of V. cauliflora plant is reported. Gallic acid, (À)-epicatechin, and quercetin were positively identified, based on comparisons with UV-Vis and MS spectrum characteristics of authentic standards and by co- (trimer) and both showed fragments at m/z 289, corresponding to the characteristic loss of 152 u due to retro-Diels-Alder fission, and of a molecule of catechin or epicatechin, respectively (Cuyckens & Claeys, 2004;Kondo et al, 2000). Peaks 8, 9, and 12-16 were assigned as quercetin glycosides due to the similar UV-Vis spectra and the presence of intense MS/MS fragment at m/z 301 (quercetin), after respective losses of 162 u (hexose, peaks 8 and 9), 132 u (pentose, peaks 12, 13, and 14), and 146 u (deoxyhexose, peaks 15 and 16).…”

Section: Resultsmentioning

confidence: 99%

Bioactive compounds and scavenging capacity of extracts from different parts ofVismia caulifloraagainst reactive oxygen and nitrogen species

Ribeiro¹,

Berto

Chisté

et al. 2015

Pharmaceutical Biology

View full text Add to dashboard Cite

Context: Vismia cauliflora A.C.Sm. [Hypericaceae (Clusiaceae)] is a plant from Amazonian forest. It is used by Amerindians to treat dermatosis and inflammatory processes in the skin and has been considered an interesting source of bioactive compounds. Objective: We evaluated the scavenging capacity of extracts from V. cauliflora (leaf, branch, stem bark, flower, and whole fruit) against reactive oxygen (ROS) and nitrogen species (RNS), namely, superoxide radical (O . The identification and the quantification of phenolic compounds and carotenoids were carried out by HPLC-DAD-ESI-MS/MS and HPLC-DAD, respectively. Results: (À)-Epicatechin and proanthocyanidin dimers and trimer were the major phenolic compounds tentatively identified in leaf, branch, stem bark, and flower extracts, while dihydroxybenzoic acids were the major compounds in whole fruit extracts. All-trans-zeinoxanthin and all-trans-b-carotene were the major carotenoids tentatively identified in leaf extracts. All extracts of V. cauliflora showed high efficiency against all tested ROS and RNS, although flower and stem bark extracts exhibited the most remarkable scavenging capacity, especially for NO and ONOO À . Discussion and conclusion: Vismia cauliflora has great potential to be used in the development of phytopharmaceutical products due to its characteristic of being a promising source of bioactive compounds with high antioxidant properties.

show abstract

“…Recently, the identi"cation of the reaction products of cyanidin 3-O--D-glucoside with the free radical initiator 2,2-azobis OXIDATIVE DEGRADATION OF QUERCETIN AND MORIN (2,4-dimethylvaleronitrile) to some extent elucidated the antioxidant mechanism of anthocyanins (Tsuda et al, 1996). Also, a mechanism involving C-2 hydrogen abstraction by 2,2-azobis (2-aminopropane) hydrochloride (AAPH) has been proposed as a critical step during radical oxidation of catechin (Kondo et al, 1999(Kondo et al, , 2000.…”

Section: Discussionmentioning

confidence: 99%