Antibacterial and Antioxidant Activities in Extracts of Fully Grown Cladodes of 8 Cultivars of Cactus Pear

The antimicrobial and antioxidant activities of some cultivars of the nopal cactus have not been determined. In this study, 8 cultivars of nopal cacti from Mexico were assayed for phenolic content, antioxidant activities, and antimicrobial activities against Campylobacter Jejuni, Vibrio cholera, and Clostridium Perfringens. Plant material was washed, dried, and macerated in methanol. Minimum bactericidal concentrations (MBCs) were determined using the broth microdilution method. Antioxidant activities were quantitatively determined using spectrophotometric methods. The MCBs of the nopal cacti ranged from 1.1 to 12.5 mg/mL for c. jejuni, 4.4 to 30 mg/mL for V. cholera, and 0.8 to 16 mg/mL for C. perfringens in the cultivars Cardon Blanco, Real de Catorce, and Jalpa, respectively. High quantities of total phenols and total flavonoids were found in the Jalpa cacti (3.80 mg of gallic acid equivalent GAE/g dry weight [DW] and 36.64 mg of quercetin equivalents [QE]/g DW, respectively). 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activities (RSA) were correlated to bioactive compound contents. The Villanueva cacti had the highest %RSA at 42.31%, and the lowest activity was recorded in Copena V1 at 19.98%. In conclusion, we found that some of the 8 cactus pear cultivars studied may be used for their antioxidant compounds or antimicrobials to control or prevent the contamination of foods.     

Optimization of Microwave-Assisted Extraction of Phenolic Antioxidants from Grape Seeds (Vitis vinifera)

Grape seeds (Vitis vinifera) are rich in phytochemicals that have antioxidant properties. The influence of independent variables such as microwave power (100, 150, and 200 W), extraction time (2, 4, and 6 min), and solvent concentration (30%, 45%, and 60% ethanol) and their interactions on total phenols and the antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP)) were determined; and the microwave-assisted extraction (MAE) process was optimized using a central composite design. The total phenols that were expressed as gallic acid equivalents (GAE), catechin equivalents (CAT), and tannic acid equivalents (TAE) were significantly influenced by the solvent concentration and the time of extraction. A numerical optimization was carried out to obtain the overall conditions for MAE of phenolic antioxidants from grape seed. The response variables were maximized for 6 min of MAE of grape seed (GS) with 32.6% ethanol at 121 W with a desirability function of 0.947. The predicted extraction yields were 13?±?0.89, 21.6?±?1.59, and 15.9?±?1.32 mg GAE, CAT, and TAE, respectively per gram of GS. The predicted antioxidant activity per gram of dry weight GS was 80.9% for the inhibition of DPPH and 135 μM ascorbic acid equivalents for FRAP test. The predicted response values were significantly correlated with the observed ones as follows: GAE r?=?0.995, CAT r?=?0.990, TAE r?=?0.996, DPPH r?=?0.996, and FRAP r?=?0.996.     

Antioxidant activities of organic grape, pomace, juice, must, wine and their correlation with phenolic content

The highest values of antioxidant activity (AOA), inhibition of low‐density lipoproteins (LDL‐diene, LDL‐MDA) and total phenols were determined in pomace (82.30 and 82.60%), grapes (68.91%) and must [2750 mg L^?1 gallic acid equivalents (GAE)], respectively. For all parameters (AOA, iLDL‐diene, iLDL‐MDA, total phenols) the highest values were obtained in Cabernet Sauvignon and Merlot grape varieties. Positive correlations were determined between AOA and iLDL‐diene (r = 0.809); AOA and total phenols (r = 0.528); total phenols and iLDL‐diene (r = 0.451) with significance of P < 0.005. The results of principal component analysis demonstrated that the location of iLDL‐diene and AOA is the same for pomace, must and red wines. The total phenols are found in the same place in red wines, red grapes, pomace and must. The results emphasize the importance of must, pomace and red wine for inhibiting LDL‐oxidation.     

Compositions, antioxidant and antimicrobial activities of Helichrysum (Asteraceae) species collected from Turkey

The methanolic extracts of 16 Helichrysum species were investigated for their in vitro antioxidant, radical scavenging and antimicrobial activities. All the extracts showed strong antioxidant and radical scavenging activity. The highest total antioxidant capacity as ascorbic acid equivalents (AAE) of 194.64 mg/g dry extract was obtained for Helichrysum noeanum in the phosphomolybdenum assay. The highest IC₅₀ value (7.95 μg/ml) was observed for the extract of Helichrysum stoechas subsp. barellieri in the DPPH assay. The total phenolic contents of the extracts ranged from 66.74 to 160.63 mg gallic acid equivalents (GAE)/g dry extract. The major component present in the extracts was identified as chlorogenic acid followed by apigenin-7-glucoside and apigenin by HPLC analysis. All the extracts showed significant antimicrobial activity against microorganisms containing 13 bacteria and two yeasts in the agar diffusion method.     

不同品种青砖茶化学成分与抗氧化活性的比较分析

本研究第一次分析比较了赤壁群体种、中茶108、槠叶齐和丹桂品种所制青砖茶在感官品质、化学成分及抗氧化活性方面的差异。采用顶空固相微萃取-气相色谱-质谱仪联用技术,对4个品种青砖茶样品挥发性成分进行了分析鉴定。结果表明,不同品种青砖茶的化学成分含量有明显差异;总抗氧化能力、抑制羟自由基能力和DPPH自由基清除能力以中茶108、槠叶齐和丹桂所制青砖茶较高;相关性分析表明青砖茶茶汤的抗氧化活性主要与茶多酚、儿茶素类化合物总量以及咖啡碱总量具有较大的相关性,其中与表没食子儿茶素没食子酸酯(EGCG)和苹果酸的相关性最强;可溶性糖、反-2-癸烯醛、壬醛与感官评分呈极显著正相关,而没食子酸、3-甲基呋喃、苯乙酮、异佛尔酮等与感官评分呈极显著负相关;不同品种青砖茶的醛类、酮类和醇类化合物具有明显的差异,其中丹桂品种所制青砖茶的品种香明显,与其芳香醛和酮类物质含量较高相关;感官审评结果显示,4个品种所制青砖茶的品质无显著差异。通过对不同品种青砖茶的主要品质化学成分含量、抗氧化活性以及感官品质等分析,为青砖茶品种选育及其应用提供参考依据。     

ORAChromatography and total phenolics content of peanut root extracts

A large number of compounds have been reported in peanut plants. Many of these compounds are phytoalexins, which are produced by plants experiencing environmental stress and often exhibit antioxidant activity. It is difficult to determine which of the many compounds has the greatest impact on total antioxidant capacity in a mixture. The objectives of this research were to examine the oxygen-radical absorbing capacity (ORAC) value and total phenolic contents of peanut root extracts and peanut root extract fractions collected via HPLC. Peanut roots were extracted from four different cultivars (Brantley, NC-12, Phillips, and Wilson) with 70% aqueous ethanol with ultrasonic assistance. Each cultivar was sampled in duplicate. The extracts were fractionated into 18 3-min fractions by HPLC using a C-18 column. Fractions and crude extracts were freeze dried. ORAC values and total phenolic content were then determined for all fractions and crude extracts. Fractions had a significant effect on the μM TE/mg gallic acid equivalents (GAE). ORAC values ranged from -46.89 μM TE to 185 μM TE in HPLC fractions. ORAChromatography can be used to focus on antioxidants in complex samples.     

Antioxidant activity of the ethanolic extract from the bark of Chamaecyparis obtusa var. formosana

BACKGROUND: Chamaecyparis obtusa var. formosana (Taiwan hinoki) is an endemic conifer in Taiwan and the purpose of this study is to evaluate the antioxidant activity of various fractions obtained from the bark of this plant material. The ethanolic extract of the bark was sequentially separated into three fractions, including n‐hexane, ethyl acetate and ethanol soluble fractions, by liquid–liquid partition. Then the antioxidant activities of crude extract and three fractions along with 13 subfractions obtained from the ethyl acetate (EA) soluble fraction were tested for several antioxidant assays. RESULTS: The total phenolic content of the samples varied from 27.71 to 102.86 mg GAE g^?1 dry weight for fractions, and from 49.94 to 206.46 mg GAE g^?1 for subfractions (where GAE is milligrams of gallic acid per gram of extract). The Trolox equivalent antioxidant capacity (TEAC) ranged from 0.15 to 0.26 mmol L^?1 Trolox equivalents. The EA soluble fraction was found to be the best antioxidant‐rich fraction in terms of DPPH and reducing power assays. With further data analysis it was found that there was a positive correlation between the total phenolic content of extracts and TEAC is R² = 0.61. CONCLUSION: Results from various antioxidant assays showed that the EA fraction possessed strong antioxidant activity. This would provide additional information about the antioxidant activity of bark extract of this plant species. Copyright © 2008 Society of Chemical Industry     

野生桃金娘主要抗氧化成分及其抗氧化能力

本实验研究了野生桃金娘（Rhodomyrtus tomentosa）的抗氧化能力、总多酚含量、总黄酮含量、抗坏血酸含量和花青素类成分。采用超高效液相串联光电二极管阵列（photo-diode array,PDA）检测器和离子肼质谱法（ultra performance liquid chromatography coupled to photo-diode array and ion-trap mass spectrometry,UPLC-PDAIT-MS）鉴定花青素类化合物,通过高通量的自由基清除方法测定抗氧化能力。结果表明：野生桃金娘具有较高的抗氧化能力。每克桃金娘的1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力相当于67.2 μmol的抗坏血酸和28.5 μmol没食子酸;过氧化氢自由基清除能力（PSC单位）相当于23.2 μmol的抗坏血酸和14.3 μmol没食子酸;2,2’-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azinobis（3-ethylbenzothi azoline-6-sulfonic acid） ammonium salt,ABTS）自由基（ABTS+·）清除能力相当于30.4 μmol的抗坏血酸和7.8 μmol没食子酸;对三价铁的还原能力相当于28.7 μmol的抗坏血酸和3.1 μmol没食子酸。野生桃金娘的总多酚含量和总黄酮含量分别是4 976 mg 没食子酸/100 g（以干质量计）和49.7 mg儿茶酚/100 g（以干质量计）,总抗坏血酸含量是9 mg/100 g（以鲜质量计）。总花青素含量相当于414 mg矢车菊素/100 g（以干质量计）,共有飞燕草素3-O-葡萄糖苷等7 种花青素类化合物被鉴别出来。     

油梨品种和部位间抗氧化及乙酰胆碱酯酶抑制活性比较

研究不同品种油梨之间的多酚含量及其抗氧化和乙酰胆碱酯酶抑制活性差异,以期为油梨高价值产品开发提供理论依据。测定热研1号、福尔特、哈斯、里德4种油梨的果皮、果肉、果核3个部位乙醇提取物的总酚含量、抗氧化及乙酰胆碱酯酶抑制活性。结果显示:4种油梨3个部位的总酚含量为9.6~27.8 mg GAE/g干物质。抗氧化及乙酰胆碱酯酶抑制活性均与样品质量浓度存在剂量关系。其中里德的果皮与果核对1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐自由基清除活性以及乙酰胆碱酯酶抑制活性均较强,热研1号与福尔特的果皮、果核对·OH清除活性最强。同一品种内,果皮与果核的活性较强,果肉的活性较差。因此,在产品开发过程中应尽可能地提高果皮、果核这些不可食用部位的利用率,达到变废为宝、提高产品附加值的目的。     

Proximate composition, total phenolic content, and antioxidant activity of seagrape (Caulerpa lentillifera)

The proximate composition of seagrape (Caulerpa lentillifera) from culture ponds in Penghu, Taiwan was analyzed. The phenolic content and the antioxidant activities including the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity, ferric ion-reducing activity, hydrogen peroxide scavenging activity, and ferrous ion chelating (FIC) activity of the ethanolic extracts of dry seagrape samples using 2 drying methods of freeze drying and thermal drying were compared with the ethanolic extract of Oolong tea as a reference. The contents (dry weight basis) of carbohydrate, crude protein, crude lipid, crude fiber, and ash of seagrape obtained from culture ponds in Taiwan were 64.00%, 9.26%, 1.57%, 2.97%, and 22.20%, respectively. The total phenolic content (1.30 mg gallic acid equivalent [GAE]/g dry weight) of the ethanolic extract of thermally dried seagrape was significantly lower (P < 0.05) than that (2.04 mg GAE/g dry weight) of freeze-dried seagrape, and both were significantly lower than that (13.58 mg GAE/g dry weight) of Oolong tea. At the same phenolic content, the antioxidant activities of freeze-dried seagrape were significantly higher (P < 0.05) than those of thermally dried seagrape. Compared with Oolong tea, seagrape, irrespective of drying method used, generally had strong hydrogen peroxide scavenging activity; but it was weak in DPPH radical scavenging activity, ferric ion-reducing activity, and FIC activity. The antioxidant activity of seagrape and Oolong tea was significantly influenced by their phenolic contents. PRACTICAL APPLICATION: The proximate composition, total phenolic content, and antioxidant activity of seagrape (Caulerpa lentillifera) in Taiwan were determined in this research to indicate nutritionally of this edible seaweed to human health, and compared these results to previous studies.     

Textural Characteristic,Antioxidant Activity,Sugar, Organic Acid,and Phenolic Profiles of 10 Promising Jujube (Ziziphus jujuba Mill.) Selections

Abstract: Ten promising jujubes were analyzed for textural characteristic (hardness), antioxidant activity, sugar, organic acid, and phenolic profiles. Total phenolic content (TP) measured by Folin–Ciocalteu method ranged from 275.6 to 541.8 mg of gallic acid equivalents per 100 g fresh weight (mg GAE/100 g FW). Four sugars (rhamnose, fructose, sucrose, and glucose), 3 organic acids (malic, citric, and succinic acids), and 11 phenolic compounds (gallic acid, protocatechuic acid, cinnamic acid, chlorogenic acid, caffeic acid, ferulic acid, ellagic acid, catechin, epicatechin, rutin, and quercetin) were identified and quantified by high‐performance liquid chromatography in jujube fruits. The results showed that ascorbic acid and proanthocyanidins contents were positively correlated with hardness, and antioxidant activity was well correlated with TP content. Among 10 jujube cultivars, Zizyphus jujuba cv. Qingjianmuzao is good for direct consumption containing high levels of total soluble solids, total sugars, fructose, and glucose, while Zizyphus jujuba cv. Jiaxianmuzao could be an important dietary source of natural antioxidants. Practical Application: Genotype is the main factor influencing the composition of bioactive compounds in jujubes. Zizyphus jujuba cv. Qingjianmuzao is good for direct consumption, while Zizyphus jujuba cv. Jiaxianmuzao could be an important dietary source of natural antioxidants for prevention of diseases caused by oxidative stress.     

Effect of semi-drying on the antioxidant components of tomatoes

Three tomato cultivars (Excell, Tradiro, and Flavourine) grown under hydroponic conditions in a commercial greenhouse in New Zealand were semi-dried at 42 °C. The semi-dried tomatoes contained low levels of 5-hydroxymethyl-2-furfural and were significantly (p < 0.05) darker (lower CIELAB L* values) and had a higher mean a*/b* value (1.6) than the fresh tomatoes (1.2). The mean total phenolics in the semi-dried samples of tomatoes (300 mg gallic acid equivalents, GAE/100 g dry matter (DM)) was significantly lower than that of fresh tomatoes (404 mg GAE/100 g DM). The mean total flavonoid, and lycopene contents in the fresh samples (206 mg rutin equivalents/100 g DM, 63 mg/100 g DM, respectively) also showed a significant decrease after semi-drying (179 mg rutin equivalents/100 g, 54 mg/100 g DM, respectively). Ascorbic acid content in fresh tomatoes (284 mg/100 g DM) decreased to 223 mg/100 g DM after drying. The total antioxidant activity of the semi-dried tomatoes (1783 μmole trolox equivalents antioxidant capacity (TEAC)/100 g DM) was significantly (p < 0.05) lower than that of the fresh samples (2730 μmole TEAC/100 g DM).     

Volatiles,polysaccharides and total polyphenols in Chinese rose tea infusions and their antioxidant activities

Rose tea is a kind of popular beverage in many Asian countries. In this study, the contents of volatiles, polysaccharides and total polyphenols in three species of Chinese rose tea infusions [Kuishui Rose (KSR), Pinying Rose (PYR) and Jinbian Rose (JBR)] were determined, respectively. Meantime, the volatiles from those three tea infusions were analyzed by GC‐MS, and their antioxidant activities were tested by 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging assay. As results, 17, 15, and 20 components were identified in their volatiles, respectively. The contents of volatiles, polysaccharides and total polyphenols, and the antioxidant activity of PYR tea infusion were higher than those of other two tea infusions. To elucidate the contributions of those main constituents in rose tea for its activity, correlation coefficients between them were analyzed, displaying that the polysaccharides and polyphenols are the main antioxidants in rose tea infusion, whose correlation coefficients were greater than 0.9.

Practical applications

As a kind of beverage with health care function, the activities and active ingredients of rose tea have mainly focused on polyphenols and their antioxidant so far. The current studies on the contents of volatiles, polysaccharides and total polyphenols and the antioxidant activities of rose tea infusions from three species in China could provide an useful comparison of the difference of antioxidant activities and constituents in those three rose teas and a basic data for quality control of rose tea.     

A comprehensive study of polyphenols contents and antioxidant potential of 39 widely used spices and food condiments

Spices and condiments are rich sources of potent antioxidants. In the present investigation, total equivalent antioxidant capacities (TEAC) of 39 spices were studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging, and cupric reducing antioxidant capacity (CUPRAC) assays. Their total phenolic contents (TPC) and total flavonoid contents (TFC) were also determined. TEAC, TPC, and TFC varied significantly (P?<?0.05) among these spices. ABTS, DPPH, and CUPRAC assay values of studied spices ranged from 1.42 to 112.94 mg ascorbic acid equivalents (AAE)/g, 1.14 to 91.09 mg Trolox equivalents (TE)/g, and 0.52 to 54.47 mg TE/g, respectively (dry weight basis; DW). Based on Folin–Ciocalteu assay, TPC ranged from 2.93 to 160.55 mg of gallic acid equivalents (GAE)/g DW. Strong correlations between TPC and TEAC values (R?=?0.966, 0.825, and 0.954 for ABTS, DPPH, and CUPRAC, respectively) were found. This indicates that phenolic compounds are potent antioxidants in these spices. Principal component analysis (PCA) indicated that cloves (flower buds of Syzygium aromaticum) had the most distinct and potent antioxidant capacity, followed by allspice (fruits of Pimenta dioica) and cinnamon (bark of Cinnamomum verum). Results of the present study provide adequate evidence that polyphenols are responsible for their compelling antioxidant capacities of studied spices. Thus, consumption of antioxidant-rich spices such as cloves, allspice, and cinnamon can significantly prevent oxidative stress in the human body.     

Antioxidant, anti-inflammatory activity, and phytochemical constituents of ficus (Ficus amplissima Smith) bark

In the present investigation, phenolics (36.6 g gallic acid equivalents (GAE)/100 g extract), tannin (21.6 g GAE/100 g extract), and flavonoid content (67.5 g rutin equivalents/100 g extract) were found to be highest in acetone extract. Ficus (Ficus amplissima) acetone extract showed maximum antioxidant activity in phosphomolybdenum (958.8 mg ascorbic acid equivalents/g extract), DPPH (1.6 μg/mL), ferric reducing antioxidant power (2,993 mmol Fe (II)/g extract), and metal chelating (39.7 mg EDTA equivalents/g extract) assays. In anti-inflammatory study, 400 mg/kg acetone extract showed maximum reduction in the paw volume compare to indomethacin. GC-MS analysis indicated that bark contain rich source of non-polar compounds like Lup-20(29)-en-3-yl acetate (33.04%). Hence, Ficus can be valuable source for antioxidant and anti-inflammatory and seemed to be applicable in medicine.     

Relative antioxidant and cytoprotective activities of common herbs

Many studies have been carried out on bioactivities of individual herbs, however, no collective study on their comparative antioxidant and cytoprotective activities against oxidative damage has been reported. We selected 17 common commercial herbs and studied their relative phenolic contents, antioxidant activities, and cytoprotective activities on gap–junction intercellular communication and antioxidative enzymes in vitro under the same conditions. Total polyphenol content ranged from 464 to 870 gallic acid equivalents (GAE) mg/100 g and total flavonoid content from 212 to 494 catechin equivalents (CE) mg/100 g. Among the samples, chamomile, rosehip, hawthorn, lemon verbena, and green tea contained relatively high total phenolics (769–844 mg GAE/100 g) and flavonoids (400–4 mg CE/100 g). Chamomile also showed the highest antioxidant activity with 960 mg/100 g of vitamin C equivalent (VCE), followed by hawthorn (929 mg VCE/100 g) and black tea (916 mg VCE/100 g). Total phenolic and total flavonoids showed a higher correlation with antioxidant activity. Most of herbs enhanced cell viability and showed protective effects against oxidative stress induced by hydrogen peroxide in Chinese hamster lung fibroblast (V79-4) cells. Furthermore, herbs used in this study showed higher protective effect on gap–junction intercellular communication (GJIC) as compared to gallic acid and catechin, and also enhanced activity of the antioxidative enzymes such as superoxide dismutase (SOD) and catalase (CAT) in a dose-dependent manner.     

Physicochemical Properties and Antioxidant Capacity of Chinese Olive (Canarium album L.) Cultivars

In this study, the physicochemical characteristics and antioxidant potentials of 10 Chinese olive cultivars were investigated. Considerable differences were found between cultivars in weight, edible yield, water content, size, shape, total soluble solids, and total titratable acidity. The major sugars and organic acids in all the cultivars were glucose, fructose, and malic acid. Phenolics were the most abundant antioxidants (1174.0 to 1799.6 mg gallic acid equivalents/100 g fresh weight). Twelve phenolic compounds were identified and quantified by UPLC‐MS/MS. Six compounds were identified first in the Chinese olive, with 3‐O‐galloylquinic acid and geraniin isomers as the most abundant compounds. The results also indicated that the phenolic content (TPC) correlated with the antioxidant properties of Chinese olive fruit extracts. A principal component analysis indicated that the Tantou and Tanxiang cultivars were a valuable source, with high TPC and antioxidant activity, whereas Maken22, Changying, and Green changying cultivars may be eaten fresh and had high sugar and low phenolic contents. This information will be useful for selecting suitable cultivars for industry and the market.     

Inhibitory effect of raspberries on starch digestive enzyme and their antioxidant properties and phenolic composition

Seven primocane fall-bearing raspberry (Rubus idaeus L.) cultivars, Nova (red), Dinkum (red), Heritage (red), Autumn Britten (red), Josephine, Anne (yellow), Fall Gold (yellow) were analysed for potential health promoting properties including their inhibitory effect on starch and fat digestive enzymes, antioxidant activities, and phenolic composition. The tested raspberry extracts showed no detectable inhibition of pancreatic α-amylase and lipase. However, all the extracts exhibited potent inhibition of α-glucosidase with IC₅₀ from 16.8 to 34.2 μg/mL. Four phenolic compounds, ellagic acid, cyanidin-diglucoside, pelargonidin-3-rutinoside, and catechin were identified as the active α-glucosidase inhibitors. The raspberry extracts also possessed significant antioxidant activities with oxygen radical absorbance capacities (ORAC) ranging from 136.7 to 205.2 μmol Trolox equivalents (TE)/g dry weight fruit and DPPH radical scavenging activities from 305 to 351 μmol TE/g. The total phenolic content of raspberry cultivars varied significantly from 40.9 to 98.5 mg of gallic acid equivalents/g dry weight. The anthocyanin content varied widely from 0.1 to 9.5 mg cyanidin 3-glucoside equivalents/g. Nine phenolic acids were quantified in raspberries and their total amounts varied from 157.3 to 713.5 μg/g. The enzyme inhibition and antioxidant properties of raspberry cultivars were not correlated with their total phenolic, anthocyanin, and phenolic acid content. Overall, ‘Dinkum’ and ‘Josephine’ raspberry varieties possess higher total phenolic content, ORAC, DPPH radical scavenging activity, and α-glucosidase inhibitory activity than other five cultivars.     

The Study of Phenolic Compounds as Natural Antioxidants in Wine

Plant phenolics present in fruit and vegetables, and that are particularly rich in red wine, have received considerable attention because of their potential antioxidant activity. Human consumption of antioxidants has many alleged health benefits, including protection against cardiovascular diseases, and, most recently, cancer. Red wines contain a variety of polyphenolic antioxidants. Five samples of commercial red wines from Spain and four phenolic compounds of red wine: gallic acid, trans-resveratrol, quercetin and rutin, have been studied. The total phenolics content and the total antioxidant activity (TAA) of wines was determined. The total phenolic content, determined according to the Folin-Ciocalteu method, varied from 1800 to 2300?mg/L, expressed as gallic acid equivalents (GAE). The antioxidative effects of wine phenolics were determined using a system based on the inhibition by antioxidants of the absorbance of the radical cation. The relationship between antioxidant activity of phenolic compounds, as hydrogen donating free radical scavengers, and their chemical structures was studied. Furthermore, the total antioxidant activity of the wines investigated was well correlated with phenol content. Thus, the results confirm that red wine polyphenols are, in vitro, significant antioxidants.     

Ascorbic acid improves the antioxidant activity of European grape juices by improving the juices' ability to inhibit lipid peroxidation of human LDL in vitro

Antioxidant activities of red and white European grape juices towards copper induced lipid oxidation of human low-density lipoproteins (LDL) were examined in vitro . LDL lipid peroxidation was assessed spectrophotometrically by monitoring the development of conjugated lipid hydroperoxides at 234 nm. Red grape juice concentrate inhibited lipid peroxidation of LDL by prolonging the lag phase by 2.7 times relative to a control when evaluated at a total phenolic concentration of 10 μM gallic acid equivalents (GAE). Both red grape juices tested blocked lipid peroxidation of LDL at 20 μM GAE. White grape juice exerted prooxidant activity at 5–20 μM GAE. The antioxidant activity, inhibition of lipid peroxidation of LDL in vitro , was correlated with the juices' levels of total phenols ( r  > 0.98, P  < 0.01), anthocyanins ( r  > 0.99, P  < 0.01), flavan-3-ols ( r  > 0.97, P  < 0.05), and hydroxybenzoates ( r  > 0.96, P  < 0.05) when the phenolic composition of each grape juices was analysed by HPLC. 5 μM ascorbic acid alone did not exert antioxidant activity towards LDL, but combinations of 5 μM ascorbic acid with 5 μM GAE juice phenols eliminated the prooxidant activity of white grape juice, and significantly improved the antioxidant activities of red grape juices.