Amyloid fibril formation is associated with various amyloidoses, including neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Despite the numerous studies on the inhibition of amyloid formation, the prevention and treatment of a majority of amyloid-related disorders are still challenging. In this study, we investigated the effects of various plant extracts on amyloid formation of alpha-synuclein. We found that the extracts from Eucalyptus gunnii are able to inhibit amyloid formation, and to disaggregate preformed fibrils, in vitro. The extract itself did not lead to cell damage. In the extract, miquelianin, which is a glycosylated form of quercetin and has been detected in the plasma and the brain, was identified and assessed to have a moderate inhibitory activity, compared to the effects of ellagic acid and quercetin, which are strong inhibitors for amyloid formation. The properties of miquelianin provide insights into the mechanisms controlling the assembly of alpha-synuclein in the brain. Graphical Abstract Inhibitory effect of Eucalyptus gunnii extract on alpha-synuclein amyloid fibrils.

Aims: Although physiological effects of hydrophilic- (H-) and lipophilic- (L-) antioxidant capacities (AOCs) are suggested to differ, the association of an antioxidant-rich diet and chronic kidney disease (CKD) incidence has not been examined. We therefore explored the association between the H- or L-AOC of a whole Japanese diet and CKD risk in a general population. Methods: A total of 922 individuals without CKD (69.2% women; mean age, 59.5 years old) from Ohasama Town, Japan, were examined. CKD incidence was defined as the presence of proteinuria and/or an estimated glomerular filtration rate (eGFR) of ＜60 ml/min/1.73 m2. Consumption of H-/L-AOC was determined based on the oxygen radical absorbance capacity in a specially developed Japanese food AOC database. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for new-onset CKD using a Cox proportional hazards model. Results: During the median follow-up of 9.7 years, 137 CKD incidents were recorded. After adjusting for potential confounding variables, the highest quartile of L-AOC was significantly associated with a 51% reduced CKD risk among only women. An increased L-AOC intake was more effective in preventing eGFR reduction than in preventing proteinuria in women. These associations were not seen for H-AOC intake in both sexes and L-AOC intake in men. Conclusions: A high intake of lipophilic antioxidants may be associated with a reduced CKD risk. The balance between dietary antioxidant intake and pro-oxidants induced by unhealthy lifestyles may be crucial for preventing future kidney deterioration.

BACKGROUND:Previous Japanese studies have led to the erroneous conclusion of antioxidant capacity (AOC) intakes of the overall Japanese diet due to limitations in the number and types of food measured, especially in rice and seafood intake. The aims of the study were to construct an AOC database of foods representative of the typical Japanese diet and to clarify the high contributors to AOC intake from the overall diet of the Japanese population.METHODS:Commonly consumed foods were estimated using 3-day dietary records (DRs) over the four seasons among 55 men and 58 women in Japan. To generate an AOC database suitable for the typical Japanese diet, hydrophilic (H-)/lipophilic (L-) oxygen radical absorbance capacity (ORAC) values of foods in each food group were measured via validated methods using the food intake rankings. Subsequently, we estimated the AOC intake and the AOC characteristics of a typical Japanese diet.RESULTS:Of 989 food items consumed by the participants, 189 food items were measured, which covered 78.8% of the total food intake. The most commonly consumed types of antioxidant-containing food were tea, soybean products, coffee, and rice according to H-ORAC, and soybean products, fish and shellfish, vegetables, and algae according to L-ORAC.CONCLUSIONS:The characteristics of high AOC intake in rice and seafood more appropriately reflected the Japanese-style diet. Further studies are expected to clarify the association between food-derived AOC and its role in preventing or ameliorating lifestyle-related diseases.

To provide reliable data for high quality epidemiological studies examining the relationship between health and antioxidant intake from daily foods, 107 plant-derived food items (12 rice, bread and noodles, 5 potatoes and starches, 9 pulses, 6 nuts/seeds, 29 vegetables, 22 fruits, 5 mushrooms, 7 algae, and 12 beverages) were selected as commonly consumed foods in Japan based on dietary records, and their antioxidant capacities were evaluated by validated hydrophilic- and lipophilic-oxygen radical absorbance capacity (H-ORAC and L-ORAC) methods. The food items covered more than 60% of total food intake for each category on a weight basis. The H-ORAC and L-ORAC values were widely distributed at 0-210 and 0-30 μmol-Trolox equivalent/g, respectively. The foods possessing potent antioxidant capacities were found in vegetables and fruits as well as other plant-derived foods. In most foods measured, the H-ORAC values were much larger than the L-ORAC values, except for certain kinds of pulses, nuts/seeds, mushrooms, and algae. The ORAC data shown here is sufficient to accurately estimate the antioxidant intake from plant-derived foods in Japan, and should be useful in future epidemiological studies aiming to clarify the biological significance of ORAC values.

This study examined changes in hydrophilic oxygen radical absorbance capacity (H-ORAC) of fruits from one line and four cultivars of strawberry (Fragaria x ananassa Duch.) harvested thorough January to April. The H-ORAC of strawberry fruits changed significantly (p< 0.01) over the course of harvest time, showing a tendency to increase from winter to spring. Total anthocyanin content and total polyphenol content in strawberry fruits were both highly correlated to H-ORAC (r=0.83 and 0.97, respectively). Total soluble solids and titratable acidity were not significantly correlated with H-ORAC (p < 0.01). Compared to the other four cultivars, strawberry line "Kurume 66" exhibited potent H-ORAC with higher anthocyanin and polyphenol contents.

The aim of this study was to investigate the composition and contents of anthocyanins and proanthocyanidins, and the antioxidant capacity of black and red cowpeas grown in Japan, with comparison to grain legumes (black kidney beans, black soybeans, and azuki beans) commonly consumed in Japan. This study revealed that black cowpeas contained seven anthocyanins, the 3-O-galactosides and 3-O-glucosides of cyanidin and delphinidin, and the 3-O-glucosides of malvidin, peonidin, and petunidin, at higher levels than other grain legumes. In addition, black and red cowpeas were rich in proanthocyanidin oligomers (monomers to hexamers) when compared with other grain legumes. Among these, black and red cowpeas showed potent hydrophilic oxygen radical absorbance capacity (H-ORAC), reaching 540.6 and 367.5 mu mol-Trolox equivalents/g dry matter, respectively. The contributions of anthocyanins and proanthocyanidin oligomers to H ORAC values were 45.8 % and 17.5 % in black and red cowpeas, respectively.

This chapter introduces the main categories, individual phenolic composition, physiological functions, processing stability, and utilization of polyphenols from sweet potato roots and tops. It starts by presenting the definition and chemical composition of anthocyanins and caffeoylquinic acids (CQAs) from sweet potato roots and tops. Then the physiological functions of polyphenols from sweet potato, including antioxidant activity, antimutagenic effect, and anticancer activity, are introduced, followed by a detailed introduction into the effect of different cooking and processing conditions, including different pH values, heating temperature, and light treatment on the stability of anthocyanins and CQA s from sweet potato roots and tops. At the end of this chapter, the research and development trend of sweet potato polyphenols are presented.

Cowpea (Vigna unguiculata) is one of the traditional ingredients of Japan. The objective of this study was to investigate the nutritional and chemical composition, and the biological activities of cowpea grown in Okinawa region, a subtropical area located in south west Japan. This study demonstrated that the protein and dietary fiber content of cowpea grown in the Okinawa region was similar to that of cowpeas grown in other countries. In addition, it was found that the sodium content and anthocyanin composition of cowpeas grown in the Okinawa region was different from that grown in other regions of Japan; however, no significant differences were observed in proanthocyanidin composition and content among the cowpeas grown in different cultivation areas in Japan.

In order to investigate the properties of frozen concentrated orange juice from 5 countries imported into Japan, we evaluated colorimetric value, glucose, fructose, sucrose, citric acid, L-malic acid, D-isocitric acid, L-ascorbic acid, flavonoids, and headspace volatile flavor components by principal component analysis. The products from Brazil contained a large amount of glucose and fructose, while the products from Belize had much more sucrose content. In addition, products from Israel contained high amounts of organic acids. The content of flavonoids depended on the country of origin and were not detected in products from Israel. The flavor component contained the largest amount of d-limonene in all the samples. Principal component analysis using 59 data items showed that the flavor components strongly contribute to the first principal component, and that sugars and flavonoids contribute to the second principal component. In a scatter plot using the principal component scores, products from Brazil and America were divided into two groups, but generally products were gathered and distributed by country of origin. The data analyzed in this study demonstrated that concentrated orange juice products from the same country contained similar components, suggesting that each country of origin has unique differences in components.

This study aimed to evaluate both the lipophilic and hydrophilic oxygen radical absorbance capacities (ORAC) in pressed oils made from sesame (Sesamum indicum L.) cultivar "Maruhime" and rapeseed (Brassica napus L.) cultivar "Nanaharuka." For this reason, we slightly modified the extraction method for antioxidant compounds using an accelerated solvent extractor system, and the multi-laboratory validated lipophilic ORAC method previously reported. Acceptable recovery was observed when four matrices of oils and fats fortified with a-tocopherol and gallic acid were subjected to the modified extraction method. Moreover, it was confirmed that the lipophilic ORAC value of a-tocopherol, as determined by the modified method, was within the range of the mean reproducibility standard deviation in the multi-laboratory comparison study. In the pressed oil from sesame cultivar "Maruhime," L-ORAC value was 12.6 to 33.8 times higher than H-ORAC, and the mean L-ORAC and H-ORAC values were 2 926 and 130 mu mol-Trolox equivalent/100 g, respectively. Also, L-ORAC value in the pressed oil from rapeseed cultivar "Nanaharuka" was 2.2 to 13.1 times higher than H-ORAC, and the mean L-ORAC and H-ORAC values were 552 and 87 mu mol-Trolox equivalent/100 g, respectively. The contribution of tocopherols to L-ORAC value of the pressed oil from rapeseed cultivar "Nanaharuka" ranged from 24 to 55 %; however, the contribution was smaller, ranging from 7 to 22 %, in the pressed oil from sesame cultivar "Maruhime."

In addition to the nutritionally important components such as starches, vitamins and minerals, storage roots and leaves of sweetpotato (Ipomoea batatas) contains several components with health-promoting functions. Of these, the functionalities of carotenoids, anthocyanins and caffeoylquinic acids have been well established by in vitro and in vivo experiments. Several sweetpotato cultivars containing high levels of these components have been developed in Japan; e.g., 'Ayamurasaki', which has high amounts of anthocyanin in its storage roots. To further improve the content and also to change the composition of these functional components, the identification of the genes involved in their biosynthesis and genetic modification of the biosynthetic pathway has been attempted. In this review, we summarize the present status of the research and breeding for these functional components, and we discuss the future prospects for improving sweetpotato functionality.

his paper described a modified HPLC method for the determination of eight acylated anthocyanins in purple-fleshed sweet potato tuber samples, including lyophilized powder and concentrated juice. Recoveries determined for two materials spiked with anthocyanin levels of 71 mu g g(-1) to 8.8 mg g(-1) ranges 91.8 - 105.0%. For repeatability, the relative standard deviation and intermediate precision ranged from 0.8% to 5.0% and 1.9% to 8.2%, respectively. HorRat values ranged from 0.3 to 1.0, except for YGM-1a and YGM-1b in two samples, which were well within the limits of performance acceptability. The proposed method showed good intralaboratory reproducibility in the range from 0.10 +/- 0.0027 (mean +/- expanded measurement uncertainty, k = 2) to 0.51 +/- 0.016, 0.10 +/- 0.0084 to 0.21 +/- 0.011, 0.40 +/- 0.017 to 4.5 +/- 0.12, 0.21 +/- 0.0066 to 0.96 +/- 0.021, 0.23 +/- 0.014 to 0.57 +/- 0.026, 0.15 +/- 0.0087 to 1.3 +/- 0.040, 0.94 +/- 0.021 to 6.5 +/- 0.19, and 0.63 +/- 0.016 to 2.4 +/- 0.061 mg g(-1) for YGM-1a, YGM-1b, YGM-2, YGM-3, YGM-4b, YGM-5a, YGM-5b, and YGM-6, respectively.

In addition to the nutritionally important components such as starches, vitamins and minerals, storage roots and leaves of sweetpotato (Ipomoea batatas) contains several components with health-promoting functions. Of these, the functionalities of carotenoids, anthocyanins and caffeoylquinic acids have been well established by in vitro and in vivo experiments. Several sweetpotato cultivars containing high levels of these components have been developed in Japan; e.g., 'Ayamurasaki', which has high amounts of anthocyanin in its storage roots. To further improve the content and also to change the composition of these functional components, the identification of the genes involved in their biosynthesis and genetic modification of the biosynthetic pathway has been attempted. In this review, we summarize the present status of the research and breeding for these functional components, and we discuss the future prospects for improving sweetpotato functionality.

A lipophilic oxygen radical absorbance capacity (L-ORAC) assay is an evaluation of the antioxidant capacity of solutions of lipophilic compounds. The concentrations of fluorescein k]radical generator k]and Trolox standard solutions were optimized to improve the precision of the assay. An interlaboratory study using two antioxidant solutions and three food extracts as test samples conducted in accordance with harmonized protocol demonstrated satisfactory L-ORAC measurements; the intermediate precision relative standard deviations (RSRDint) ranged from 7.0 to 16.7% k]the reproducibility relative standard deviations (RSDR) ranged from 14.8 to 19.4% k]and the HorRat values ranged from 1.35 to 1.78.

Two cultivars of Japanese parsley were harvested in different seasons; their antioxidant capacities were evaluated by oxygen radical absorbance capacity (ORAC) methods, and the contents of hydrophilic and lipophilic antioxidants were compared. Japanese parsley possessed potent antioxidant capacities both in hydrophilic and lipophilic extracts when evaluated by ORAC methods. LC/MS/MS analyses revealed that chlorogenic acid and four kinds of quercetin glycosides were major antioxidants in the hydrophilic extract. Lutein was the main contributor to the antioxidant capacity of the lipophilic extract. Antioxidant capacities of the hydrophilic extracts of both cultivars tended to be higher in winter because of the increase in the contents of chlorogenic acid and quercetin glycosides. An obvious trend in the lipophilic antioxidant capacities or lutein contents was not observed irrespective of the cultivar.

An open-label study with one treatment arm was conducted to investigate changes in health-related biomarkers (blood pressure and liver enzyme activity) and the safety of 4 weeks of consuming a purple-fleshed sweet potato beverage in Caucasian subjects. Twenty healthy adults, 18–70 years of age, with a body mass index >25 kg/m2, elevated blood pressure and elevated levels of liver function biomarkers consumed two cartons of purple-fleshed sweet potato beverage (125 ml, including 117 mg anthocyanin per carton) daily for 4 weeks. Hematology, serum clinical profile, dipstick urinalysis and blood pressure were determined before consumption, at 2 and 4 weeks of consumption and after a 2-week washout period. A trend was found toward lowering systolic blood pressure during the treatment period (p=0.0590). No significant changes were found in diastolic blood pressure throughout the study period. Systolic blood pressure was significantly lower after 4 weeks of consumption compared with before consumption (p=0.0125) and was significantly higher after the 2-week washout period compared with after consumption (p=0.0496). The serum alanine aminotransferase level significantly increased over time, but aspartate aminotransferase and γ-glutamyltransferase levels stayed within the normal range of reference values. Safety parameters of the blood and urine showed no clinically relevant changes. The consumption of a purple-fleshed sweet potato beverage for 4 weeks resulted in no clinically relevant changes in safety parameters of the blood and urine and showed a trend toward lowering systolic blood pressure.

In this study, a newly developed heating system, which consisted of superheated steam and hot water spray (Aqua-gas) treatment, was applied to sweet potato leaves. Upon initiation of Aqua-gas treatment, the internal temperature of sweet potato leaves was immediately increased, and reached 95 degrees C in 30 seconds. Notably, polyphenol oxidase (PPO) activity was not deactivated by short-term Aqua-gas treatment, while 5-minute treatment almost completely inactivated PPO activity. Moreover, the amounts of caffeic acid and 7 species of caffeoylquinic acids (CQAs) in sweet potato leaves after Aqua-gas treatment were significantly higher compared to leaves subjected to boiling treatment. Therefore, we propose that Aqua-gas treatment is a useful heating system to maintain the nutritional components such as CQAs.

The objective is to evaluate the efficacy of anthocyanin-rich purple-fleshed sweet potato (PSP) beverage on the serum levels of gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in healthy Caucasians with borderline hepatitis. Forty healthy Caucasians (41–69 years) consumed three bottles of the PSP beverage (177 mg anthocyanins per 125-ml bottle) or placebo (1.3 mg) per day for 8 weeks. Thirty-nine subjects completed the study and two subjects were excluded from statistical analysis. GGT levels in the PSP group on days 15 and 43 were lower ( P =0.077 and 0.038, respectively), AST levels in the PSP group on days 29 and 43 were lower ( P =0.010 and 0.045, respectively) and ALT level in the PSP group on day 43 was lower ( P =0.037) than in the placebo group. The PSP beverage did not induce clinically relevant changes in other blood and clinical chemistry parameters.

During boiling treatment of sweet potato cultivar, "Suioh" leaves, the contents of caffeic acid (CA), 3-caffeoylquinic acid, 5-caffeoylquinic acid, 3,5-dicaffeoylquinic acid and 3,4,5-tricaffeoylquinic acid (3,4,5-triCQA) were significantly decreased. However, no significant changes of 4-caffeoylquinic acid and 3,4-dicaffeoylquinic acid were observed, and the content of 4,5-dicaffeoylquinic acid was significantly increased. When each standard solution of CA and caffeoylquinic acids (CQAs) were heated to 100 degrees C, structural isomers were generated from mono-CQAs and di-CQAs, although no significant changes were observed in CA and 3,4,5-triCQA. Therefore, differences in the contents of CA and CQAs during boiling treatment of "Suioh" leaves might be attributed to the formation of structural isomers of mono-CQAs or di-CQAs, in addition to the broth outflow of CA and CQAs in the leaves.

The purpose of this study was to investigate the effect of repeated harvesting on the content of caffeic acid (CA) and seven species of caffeoylquinic acids (CQAs) in sweet potato leaves using a newly developed high-performance liquid chromatography method. Six cultivars and two breeding lines were used in this study. Leaves were collected at monthly intervals from 1st harvest (May) to 4th harvest (August) in 2011 and 2012. ANOVA analysis revealed that the contents of CQAs were significantly different among all cultivars and breeding lines, but no significant differences were found for CA. No annual variation was confirmed in CA and CQAs. Repeated harvest of sweet potato leaves affected the content of only 4-CQA and 5-CQA. Post-hoc comparisons using Tukey's method indicated that the contents of 4-CQA and 5-CQA in sweet potato leaves harvested at first time were significantly higher compared to those at the other harvest times.