Cholesterol-lowering effect of astringent persimmon fruits (Diospyros kaki Thunb.) extracts

Food Science and Biotechnology - This study aimed to investigate the effects of ethanol extract of astringent persimmon on antioxidant activity, cholesterol, 3-hydroxy-3-methylglutaryl (HMG)-CoA...     

Phenolic compounds and antioxidant activity of tuberous root leaves

The antioxidant potential of five tuberous root leaves was evaluated. High performance liquid chromatography (HPLC/DAD) showed the presence of phenolic compounds in leaves, and the predominant ones were chlorogenic acids in carrot (458.79 mg.L^?1± 0.03): rosmarinic acid in sweet potato (222.05 mg.L^?1± 0.01) and quercetin in sweet potato (292.42 mg.L^?1± 0.01). Radish leaves showed a higher total in vitro antioxidant activity for all methods used in this study. The results indicated that these leaves were natural sources of antioxidants and, therefore, could be included in the health beneficial diet.     

Radical scavenging activity and phenolic compounds in persimmon (Diospyros kaki L. cv. Mopan)

ABSTRACT:  The Mopan persimmon ( Diospyros kaki L. cv. Mopan) is the major cultivar of astringent persimmon in northern China. This study investigates the radical scavenging activity against ABTS and DPPH radical, and the content of total and individual phenolics (catechin, epicatechin, epigallocatechin, chlorogenic acid, caffeic acid, and gallic acid) with apple, grape, and tomato as controls. The radical scavenging activities against ABTS and DPPH radicals of the Mopan persimmon are 23.575 and 22.597 μm trolox eq/g f.w., respectively. These findings suggest that the Mopan persimmon's antioxidant activity is significantly ( P < 0.05) stronger than that of reference materials. The Mopan persimmon showed the highest content of total phenolics among the 4 materials tested. Significant correlations ( R ²= 0.993, P < 0.05, ABTS radical; R ²= 0.980, P < 0.05, DPPH radical) are found between the total phenolics and the radical scavenging activities. The total content of these 6 kinds of phenolics (catechin, epicatechin, epigallocatechin, chlorogenic acid, caffeic acid, and gallic acid) is significantly correlated ( R ²= 0.831, P < 0.05, ABTS radical; R ²= 0.745, P < 0.05, DPPH radical) with the individual radical scavenging activity of the 4 materials, although the total content of the 6 phenolics accounts for no more than 20% of the total phenolics in the Mopan persimmon. Gallic acid exhibits the strongest antioxidant activity in all 6 kinds of phenolics and its content is the largest in the Mopan persimmon, presumably being responsible for its much higher antioxidant activity as compared to apple, grape, and tomato.     

Phenolic composition and antioxidant activity of white mulberry (Morus alba L.) fruits

Eight major mulberry cultivars [Nakhonratchasima 60 (NS 60), Buriram 60 (BR 60), Chumphon (CP), Wavee (WV), Chaingmai (CM), Pikultong (PT), Kamphaengsaen (KS) and Kamnanchul (KJ)] cultivated in Thailand were assessed for their flavonoid and phenolic acid composition using HPLC and tested for antioxidant potential using 2,2‐diphenyl‐1‐picrylhydrazyl hydrate (DPPH) assay. The total phenolic content (TPC) ranged from 104.78 to 213.53 mg GAE/100 g DW, and total flavonoid content (TFC) ranged from 69.58 to 211.01 mg CE/100 g DW. The major flavonoid compounds in mulberry fruit cultivars were (+)‐catechin (309.26–750.01 mg/100 g DW), procyanidin B1 (62.59–224.41 mg/100 g DW), quercetin (5.36–58.42 mg/100 g DW), rutin (18.73–26.90 mg/100 g DW) and (?)‐epicatechin (8.47–29.21 mg/100 g DW). Gallic acid, cinnamic acid and p‐hydroxybenzoic acid were found to be the major phenolic acids in mulberry fruit cultivars. The gallic acid and cinnamic acid contents ranged from 7.33 to 23.90 mg/100 g DW and from 11.64 to 15.05 mg/100 g DW, respectively. p‐Hydroxybenzoic acid content ranged from 1.77 mg/100 g DW (PT) to 7.13 mg/100 g DW (KJ). DPPH‐scavenging ability was excellent for ethanolic extract of NS 60, and EC₅₀ value of NS 60 (241.83 μg mL^?1) was significantly lower than those of the others (P < 0.05). TPC and TFC of the mulberry fruit were positively correlated with the DPPH‐scavenging ability.     

不同颜色糙米的酚类物质组成及抗氧化活性分析

以8种不同颜色的糙米为研究对象,分别提取糙米中游离型和结合型酚,并对提取物中的酚类物质(总酚、总黄酮、总花青素、总原花青素、总酚酸)的含量以及ABTS自由基(ABTS+)清除能力与铁离子还原能力进行了研究,比较了不同颜色间糙米的酚类物质和抗氧化活性的差异以及两者与颜色参数间的相关性。研究结果表明:糙米的抗氧化活性与结合型、游离型的酚类物质含量呈正相关(P0.05);结合型酚类物质的含量和抗氧化活性与糙米颜色均无显著相关(P0.05);游离型酚类物质含量、组成以及抗氧化活性与糙米颜色有相关,糙米颜色越深酚含量越高、抗氧化活性越强,且原花青素主要存在于红色糙米或部分黑色糙米中。     

Phenolic compound composition and antioxidant activity of fruits of Rubus and Prunus species from Croatia

Two fraction, one containing flavonols, flavan-3-ols, phenolic acids and the other containing anthocyanins, were isolated from Rubus (red raspberry, blackberry) and Prunus (sweet cherry, sour cherry) fruits to study their phenol content by HPLC and antioxidant activity using the DPPH test. Raspberries and blackberries were characterised by catechins and ellagic acid derivatives; sour and sweet cherries by phenolic acids. All fruits had relatively high anthocyanin content. Anthocyanins contributed more to the antioxidant activity of all fruits (∼90%) than flavonols, flavan-3-ols and phenolic acids (∼10%). A biphasic reaction was observed between DPPH^• radicals and phenols, with 'fast' and 'slow' scavenging rates which might be important in the biological activity of these fruits. Sour cherries and blackberries which stand out with the highest total phenol content (1416 and 1040 mg kg⁻¹) had also the strongest antioxidant activity (EC₅₀ = 807 and 672 g of fruit per gram of DPPH) and can be considered as good source of dietary phenols.     

Phenolic compounds and antioxidant activity of Brazil nut (Bertholletia excelsa)

Brazil nuts were shelled and separated as kernel and brown skin; whole nuts were also used. Soluble phenolics from each portion as well as the whole nut were extracted using 70% acetone under reflux conditions. Insoluble-bound phenolics were subsequently extracted into diethyl ether–ethyl acetate mixture (1:1, v/v) after alkaline hydrolysis. Both soluble and insoluble-bound phenolic extracts were separately examined for their total phenolics content; antioxidant activities were evaluated by trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical scavenging activities using electron paramagnetic resonance (EPR), reducing power, and oxygen radical scavenging capacity (ORAC). Soluble phenolics in brown skin was 1236.07 as compared to 406.83 in kernel and 519.11 mg/100 g in whole nut. Bound phenolics content of brown skin was also 86- and 19-folds higher than kernel and whole nut, respectively. Similarly extracts from the brown skin exhibited the highest antioxidant activity. Free- and bound phenolics were identified and quantified; these included nine phenolic acids and flavonoids and their derivatives (gallic acid, gallocatechin. protocatechuic acid, catechin, vanillic acid, taxifolin, myricetin, ellagic acid, and quercetin). However, some phenolics were present only in the bound form. Furthermore, the phenolics were dominant in the brown skin.     

Bioactive compounds and antioxidant activity of fresh exotic fruits from northeastern Brazil

Foods rich in antioxidants play an essential role in the prevention of diseases. The present study compared contents of phenolics, vitamin C, anthocyanin and antioxidant activity of 11 fresh exotic fruits, cultivated in the northeastern part of Brazil. The antioxidant activities were evaluated using two antioxidant systems 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), expressed as TEAC (Trolox Equivalent Antioxidant Capacity) and VCEAC (Vitamin C Equivalent Antioxidant Capacity) values. The results indicated that the above fruits, such as murici and mangaba, were good sources of antioxidants. The phenolic contents showed positive correlations with total antioxidant by ABTS (R = 0.94, P ≤ 0.001) and DPPH (R = 0.88, P ≤ 0.001) assays. However, this correlation was not noticed when examining vitamin C and anthocyanins contents. The 11 fruits studied had comparable antioxidant activity in both, ABTS and DPPH assays. These methods are recommended as useful tools for the evaluation of the total activity antioxidant in fruits. Our results indicated promising perspectives for the development and usage of fruits species studied with considerable levels of antioxidant activity.     

Phenolic composition in different genotypes of Guabiju fruits (Myrcianthes pungens) and their potential as antioxidant and antichemotactic agents

Fruits of Myrcianthes pungens Berg. Legr. (Myrtaceae), known as guabiju, are widely consumed fresh as well as dried, processed into jam, marmalade, and juices. In this study, chemical composition and antichemotactic and antioxidant activities of fruits from a wild type (GB) and 2 genotypes, PL2 and PL1, of guabiju were investigated. Total anthocyanins for the genotypes ranged from 334 to 531 mg/100 g dry weight (dwt). Total flavonoids and polyphenols ranged from 79.8 to 154 mg/100 g and 2438 to 4613 mg/100 g (dwt), respectively. A reversed phase liquid chromatography method with photodiode array detection was used to determine chemical profiles of the main anthocyanins found in the extracts. An HPLC method for the quantification of flavonoids is proposed, providing a simple procedure with rapid sample preparation. All samples contained 5 identical anthocyanidins, distributed differently, with cyanidin as the main compound. Identified flavonoids were quercitrin, hyperoside, and isoquercitrin; their relative amounts varied among the extracts. The antioxidant activity of guabiju methanolic extract was comparable to that of Trolox, and at a test concentration of 0.25 mg/mL, GB and PL2 activities were higher than those exhibited by Trolox. Total dry extracts of guabiju exhibited greater inhibition of chemotaxis at a concentration of 4 μg/mL, except for GBH (wild-type hydrolyzed extract) which already presented high values at a concentration of 2 μg/mL. These results suggest that the consumption of this fruit, rich in polyphenols, may be beneficial to human health. Practical Application: The paper is the first attempt on the improvement of this native fruit, since it is widely consumed regularly as part of the South American diet. The content of phenolic compounds demonstrates that consumption of guabiju would be beneficial to human health. Differences among samples, originating from open pollination of plants growing on the same site, lead to the conclusion that improvements can be made in the chemical composition and beneficial activity of guabiju fruits by simply selecting genotypes for these characteristics among open-pollinated seedlings.     

Phenolic compounds in fruits – an overview

Phenolic compounds are secondary metabolites widely found in fruits, mostly represented by flavonoids and phenolic acids. The growing interest in these substances is mainly because of their antioxidant potential and the association between their consumption and the prevention of some diseases. The health benefits of these phytochemicals are directly linked to a regular intake and their bioavailability. Studies have shown the importance of the regular consumption of fruits, especially for preventing diseases associated with oxidative stress. In the present review, the most recent articles dealing with polyphenols in fruits are reviewed, focusing on their occurrence, main methods of extraction, quantification and antioxidant assays. In addition, the health benefits and bioaccessibility/bioavailability of phenolic compounds in fruits are addressed.     

Phenolic compounds from Canna edulis Ker residue and their antioxidant activity

Using the bleaching of the free radical scavenger 1,1-diphenyl-2-picrylhydrazyl (DPPH) as the guiding assay, a novel compound, 4-(3-(3,4-dihydroxyphenyl)acryloyl)-6-hydroxy-1-methoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid, was isolated from water-soluble extract of Canna edulis Ker with ten known compounds: rosmarinic acid, salvianolic acid B, ferulic acid, caffeic acid, 1-caffeoylquinic acid, 3-caffeoylquinic acid, 4-caffeoylquinic acid, 5-caffeoylquinic acid, salicylic acid and gallic acid. The structures were characterized by spectroscopic methods including extensive 2D-NMR techniques. Moreover, antioxidant activities of total extract and the new compound were determined through six different kinds of modes. In view of antioxidant activity confirmed, C. edulis extract and the new compound can be developed as natural food additives. In addition, the correlations between concentration and antioxidant activity and among the modes were analyzed. The results of DPPH and ABTS radical scavenging and FRAP assay exhibited high consistency. However, those for other modes showed difference to a certain extent.     

五粮液大曲中的酚类成分及其抗氧化活性

大曲是白酒中活性成分的重要来源。采用正相硅胶、反相硅胶、葡聚糖凝胶Sephadex LH-20等色谱分离材料和柱层析分离技术,联合核磁共振(NMR)、质谱(MS)等波谱技术分离鉴定了6个化合物,分别为5-正十九烷基雷锁辛(1)、5-正二十一烷基雷锁辛(2)和5-正二十三烷基雷锁辛(3)、(1E,22Z)-1,22-diferuloyloxydocosane (4)、(1E,24Z)-1,24-diferuloyloxyteracosane (5)和(1E,26Z)-1,26-diferuloyloxyhexacosane(6),以上6种化合物均为首次从酿酒大曲中发现的酚类化合物,且均具有显著的抗氧化活性。     

Phenolic compounds from winemaking waste and its antioxidant activity towards oxidation of rapeseed oil

The effects of extraction parameters on bioactive compound contents of winemaking waste extracts (WWE) and its effect on rapeseed oil oxidative stability were evaluated. Research showed that the total phenols and anthocyanin contents and antioxidant activity (AA) of WWE significantly depended on the extraction parameters. Increasing the temperature (60 °C) and time (5 h) of extraction and an addition of water to ethanol statistically improved the rate of active component extraction. HPLC analysis showed that procyanidin B_2, catechin, gallic acid, γ‐resorcylic acid and p‐coumaric acid were the major phenolic compounds of WWE. Important correlations between total phenolic compounds quantified by HPLC and both DPPH and (ferric reducing antioxidant power) (FRAP) values were found. WWE added to the oil at three different levels clearly slowed down the process of fatty acid oxidation, inhibiting hydroperoxide formation by about 86%, comparable with BHT, while it was more effective than that of α‐tocopherol. When using volatile compound formation as a marker of lipid oxidation, WWE at the level of 2000 ppm were the most effective inhibitors of the decomposition of hydroperoxides. The research showed that the WWE are a rich source of phenolic compounds with powerful antioxidant activities and are suitable for preventing rapeseed oil oxidation.     

Phenolic compounds and total antioxidant potential of commercial wines

Growing evidence of the role of free radicals and antioxidants in health and ageing has focussed great interest on these compounds. The relationship between the total antioxidant potential and the phenolic content of commercial wines was evaluated. A close relationship between total phenolic content and total antioxidant potential for all wines was observed. Capillary zone electrophoresis showed that, in red wines, gallic acid was the highest of the phenolic acids and (+)-catechin and (−)-epicatechin were the next most abundant phenolics. Also, these compounds were strictly correlated with the total antioxidant potential of wines. Total antioxidant potential, by bleaching of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations, using gallic acid as standard, could be a practical and simple measurement to evaluate the characteristics of different wines. Furthermore, capillary electrophoresis is a powerful and high-performing tool for evaluating principal antioxidant wine components.     

Solvent effects on antioxidant properties of persimmon (Diospyros kaki L. cv. Daebong) seeds

The aim of this study was to investigate the antioxidant activities of persimmon seed extracts (PSE) using different solvents such as ethanol, methanol, acetone, and their aqueous 80% solvents. The EC₅₀ values of the extracts from absolute ethanol (EE) and methanol (ME) in 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical–scavenging assay were 49.71 and 51.15 μg mL^?1, respectively, while the EC₅₀ of butylated hydroxyanisole (BHA) was 70.82 μg mL^?1. However, the EC₅₀ value of reducing power for the absolute acetone extract (AE) was higher (210.06 μg mL^?1) than that of BHA (212.67 μg mL^?1). Although the absolute ME had the highest antioxidant activity, it exhibited the lowest total phenolics and flavonoids. In contrast, the antioxidant activities of the aqueous solvent extracts showed a good correlation with total phenolics and flavonoids when compared to the absolute solvent extracts. The results showed that PSE could potentially be used as an inexpensive source of natural antioxidant in food and pharmaceutical industries.     

Phenolic compounds,lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)

Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p‐coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg^?1 fresh weight, while naringenin levels were lower than 12.55 mg kg^?1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg^?1 fresh weight, followed by caffeic acid, while p‐coumaric and ferulic acids showed similar concentrations lower than 5 mg kg^?1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg^?1 fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg^?1, with the exception of Liso (less than 20 mg kg^?1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry     

Phenolic content and antioxidant activity of olive extracts

The phenolic component of freeze-dried olive fruit was fractionated by high-performance liquid chromatography using ultraviolet, atmospheric pressure chemical ionisation (APCI) and electrospray ionisation (ESI) detection. The fractions together with several standards were tested for antioxidant activity in an aqueous and a lipid system. The negative ion mode of APCI and ESI showed less fragmentation than positive ion mode. The latter was generally more useful in obtaining fragmentation data and hence structural information. Some olive phenolics notably tyrosol exhibited a low ionisation efficiency in both APCI and ESI. There was no simple relationship between antioxidant activity and chemical structure. The ranking of antioxidant activity was strongly dependent on both the test system and on the substrate demonstrating the need to examine activity in both aqueous and lipid systems. Significant antioxidant activity was seen in most olive fractions and this was related to phenolic content. The kinetics of the oxidation process are complex and suggest that multiple pathways may be involved at different antioxidant concentrations.