There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

CA : A Cancer Journal for Clinicians

Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: the oxygen radical absorbance capacity (ORAC) assay, the Folin-Ciocalteu method, and possibly the Trolox equivalent antioxidant capacity (TEAC) assay. ORAC represent a hydrogen atom transfer (HAT) reaction mechanism, which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity, which has normally been expressed as phenolic contents. The TEAC assay represents a second ET-based method. Other assays may need to be considered in the future as more is learned about some of the other radical sources and their importance to human biology.

https://faculty.missouri.edu/~glaserr/3700s14/Antioxidant-Capacity_jf0502698.pdf

Standardized Methods for the Determination of Antioxidant Capacity and Phenolics in Foods and Dietary Supplements

中枢神経系疾患の治療は正常細胞（ニューロン）の機能維持を目的とするが，脳血管障害のように機能障害の原因が細胞の死滅に基づくことは多い．一方，脳腫瘍の治療においては薬物療法や放射線療法といった腫瘍細胞の死滅を目標とするものが大きな位置を占める．いずれの場合にも，細胞死の機序を理解することは各種病態や治療法の理解のうえで重要である．現在のところ最も研究の進んでいる細胞死の型はアポトーシスである．そのなかで重要な位置を占めるミトコンドリアにおける反応および抗アポトーシス因子について概要を紹介する．

Neuroscience 細胞死：最近の知見

■ Abstract Apoptosis is a genetically programmed, morphologically distinct form of cell death that can be triggered by a variety of physiological and pathological stimuli. Studies performed over the past 10 years have demonstrated that proteases play critical roles in initiation and execution of this process. The caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases. Caspases are synthesized as relatively inactive zymogens that become activated by scaffold-mediated transactivation or by cleavage via upstream proteases in an intracellular cascade. Regulation of caspase activation and activity occurs at several different levels: ( a) Zymogen gene transcription is regulated; ( b) antiapoptotic members of the Bcl-2 family and other cellular polypeptides block proximity-induced activation of certain procaspases; and ( c) certain cellular inhibitor of apoptosis proteins (cIAPs) can bind to and inhibit active caspases. Once activated, caspases cleave a variety of intracellular polypeptides, including major structural elements of the cytoplasm and nucleus, components of the DNA repair machinery, and a number of protein kinases. Collectively, these scissions disrupt survival pathways and disassemble important architectural components of the cell, contributing to the stereotypic morphological and biochemical changes that characterize apoptotic cell death.

Mammalian caspases: structure ,a ctivation ,s ubstrates, and functions during apoptosis

Ten phenolic compounds were isolated from a butanol fraction of sage extracts. Their structures were determined by spectral methods (NMR, MS, IR). Among them, a novel compound, 4-hydroxyacetophenone-4-O-β-d-apiofuranosyl-(1→6)-O-β-d-glucopyranoside, was identified. Two test systems, DPPH free radical scavenging activity and radical cation ABTS•+ scavenging activity, were used to evaluate their antioxidant activity. The most active compounds were found to be rosmarinic acid and luteolin-7-O-β-glucopyranoside. Keywords: Sage; Salvia officinalis; phenolic compounds; antioxidant activity

/pdf/antioxidative-phenolic-compounds-from-sage-salvia-295ccbrkd2.pdf

Antioxidative Phenolic Compounds from Sage (Salvia officinalis)

Artichoke leaf is an herbal medicine known for a long time. A systematic antioxidant activity-directed fractionation procedure was used to purify antioxidative components from the aqueous methanol extractions of artichoke heads and leaves in this study. Seven active polyphenolic compounds were purified from artichoke, and structural elucidation of each was achieved using MS and NMR. Two of these compounds, apigenin-7-rutinoside and narirutin, were found to be unique to artichoke heads, this represents the first report of these compounds in the edible portion of this plant. The contents of these antioxidants and total phenols in dried artichoke samples from leaves and immature and mature heads of three varieties, Imperial Star, Green Globe, and Violet, were then analyzed and compared by colorimetric and validated HPLC methods. Significant differences by variety and plant organ were observed.

Analysis of antioxidative phenolic compounds in artichoke (Cynara scolymus L.)

An activity-directed fractionation and purification process was used to identify the antioxidative components of Polygonum multiflorum Thunb. (PM). Dried root of PM was extracted with 95% ethanol and then separated into water, ethyl acetate, and hexane fractions. Among these only the ethyl acetate phase showed strong antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test when compared with water and hexane phases. The ethyl acetate fraction was then subjected to separation and purification using silica gel column chromatography and Sephadex LH-20 chromatography. Three compounds showing strong antioxidant activity were identified by spectral methods ((1)H NMR, (13)C NMR, and MS) and by comparison with authentic samples to be gallic acid, catechin, and 2,3,5, 4'-tetrahydroxystilbene 2-O-beta-D-glucopyranoside.

2,2-Diphenyl-1-picrylhydrazyl radical-scavenging active components from Polygonum multiflorum thunb.

Cinnamon bark has been reported to be effective in the alleviation of diabetes through its antioxidant and insulin-potentiating activities. In this study, the inhibitory effect of cinnamon bark on the formation of advanced glycation endproducts (AGEs) was investigated in a bovine serum albumin (BSA)-glucose model. Several phenolic compounds, such as catechin, epicatechin, and procyanidin B2, and phenol polymers were identified from the subfractions of aqueous cinnamon extract. These compounds showed significant inhibitory effects on the formation of AGEs. Their antiglycation activities were not only brought about by their antioxidant activities but also related to their trapping abilities of reactive carbonyl species such as methylglyoxal (MGO), an intermediate reactive carbonyl of AGE formation. Preliminary study on the reaction between MGO and procyanidin B2 revealed that MGO-procyanidin B2 adducts are primary products which are supposed to be stereoisomers. This is the first report that proanthocyanidins can effectively scavenge reactive carbonyl species and thus inhibit the formation of AGEs. As proanthocyanidins behave in a similar fashion as aminoguanidine (AG), the first AGE inhibitor explored in clinical trials, they show great potential to be developed as agents to alleviate diabetic complications.

Cinnamon bark proanthocyanidins as reactive carbonyl scavengers to prevent the formation of advanced glycation endproducts

Advanced glycation end-products (AGEs) are the final products of the non-enzymatic reaction between reducing sugars and amino groups in proteins, lipids and nucleic acids. Recently, the accumulation of AGEs in vivo has been implicated as a major pathogenic process in diabetic complications, atherosclerosis, Alzheimer's disease and normal aging. The early recognition of AGEs can ascend to the late 1960s when a non-enzymatic glycation process was found in human body which is similar to the Maillard reaction. To some extent, AGEs can be regarded as products of the Maillard reaction. This review firstly introduces the Maillard reaction, the formation process of AGEs and harmful effects of AGEs to human health. As AGEs can cause undesirable diseases or disorders, it is necessary to investigate AGE inhibitors to offer a potential therapeutic approach for the prevention of diabetic or other pathogenic complications induced by AGEs. Typical effective AGE inhibitors with different inhibition mechanisms are also reviewed in this paper. Both synthetic compounds and natural products have been evaluated as inhibitors against the formation of AGEs. However, considering toxic or side effects of synthetic molecules present in clinical trials, natural products are more promising to be developed as potent AGE inhibitors.

Mingfu Wang

Papers

Antioxidative Phenolic Compounds from Sage (Salvia officinalis)

Analysis of antioxidative phenolic compounds in artichoke (Cynara scolymus L.)

2,2-Diphenyl-1-picrylhydrazyl radical-scavenging active components from Polygonum multiflorum thunb.

Cinnamon bark proanthocyanidins as reactive carbonyl scavengers to prevent the formation of advanced glycation endproducts

Naturally occurring inhibitors against the formation of advanced glycation end-products