Evaluation of polyphenolic fingerprints and antioxidant profiles of wild fruits

High‐performance thin‐layer chromatography and UV–vis spectrometry, coupled with multivariate exploratory techniques, have been investigated to fingerprint some local wild fruit extracts. The study was conducted using extracts of sea buckthorn (Hippophae rhamnoides), bilberry (Vaccinium myrtillus), cranberry (Vaccinium oxycoccos), rose hip (Cynosbati fructus), blackberry (Rubus fruticosus), raspberry (Rubus idaeus) and less‐known berries such as cornelian cherry (Cornus mas) and blackthorn (Prunus spinosa), all acquired from local markets. The extracts were firstly subjected to chromatographic separation coupled with digital image analysis and secondly to spectrophotometric analysis. Also, the DPPH˙ scavenging profiles were investigated through the UV–vis spectrum (200–700 nm), and RSA%–time profiles were determined for the first time using these samples, at different concentrations.     

Phytochemicals,vitamin C and sugar content of Thai wild fruits

The objective of the present study was to generate information about the potential health-enhancing properties of selected Thai wild fruits. Nineteen varieties of wild fruits, collected from the natural forest in north-eastern Thailand, were analysed for phytochemicals, anti-oxidant activity, vitamin C and sugar content. The results showed that Diospyros decandra Lour. exhibited the highest content of total phenolic compounds (215 mg GAE/g) and total flavonoid content (187 mg RE/g). Terminalia chebula Retz. had higher anti-oxidant activities than other fruits, as measured by 1,1-diphenyl-2-picrylhydrazyl radical scavenging (99% inhibition) and ferric reducing/anti-oxidant power assays (63 mmol FeSO₄/g). The sum of sugars (sucrose, glucose, fructose and galactose) ranged from 33 to 430 mg/g fresh weight, being dominated by glucose (ranging from 7.5 to 244 mg/g) and fructose (ranging from 5.3 to 193 mg/g). The highest content of vitamin C was found in Phyllanthus emblica Linn. (2.2 mg/g). Thai wild fruits, which were investigated in this study, have been shown to be a novel rich source of phytochemicals.     

Comparison of the contents of the main antioxidant compounds and the antioxidant activity of white grapefruit and his new hybrid

The aim of this study was to compare the main antioxidant compounds content and the antioxidant activity of white grapefruit and his new hybrid (Jaffa Sweeties). Total phenols were measured colorimetrically using the Folin-Ciocalteu reagent, phenolic acids—by HPLC, anthocyanins and flavonoids—spectrophotometrically. The antioxidant activity of these fruits was determined by total antioxidant activity (TAA) and nitric oxide (NO) methods. Trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were more abundant in white grapefruit than in his hybrid. However, on a fresh weight basis, grapefruit's hybrid has a higher total phenol content as well as a higher antioxidant capacity in comparison with white grapefruit. A linear relationship existed between TAA and anthocyanins (R²=0.8068), TAA and flavonoids (R²=0.9320) and TAA and total phenols (R²=0.9446). Our findings indicate the following: (1) Both studied fruits contain a high concentration of natural antioxidants that have not only a high antioxidant activity, but also a good antioxidant quality. (2) The total phenol content and the antioxidant potential are significantly higher in the grapefruit hybrids than in white grapefruits.     

Anti-inflammatory activity of methanolic extracts from edible mushrooms in LPS activated RAW 264.7 macrophages

Nowadays there is a great interest in the use of edible mushrooms as functional food since they are rich in bioactive compounds. Although their immunomostimulant activity has been largely demonstrated, their potential anti-inflammatory activity has been scarcely explored. We have investigated the anti-inflammatory activity of methanolic extracts from different edible mushrooms species: Agaricus bisporus, Boletus edulis, Cantherellus cibarius, Cratarellus cornucopioides, Lactarius deliciosus and Pleurotus ostreatus, in activated macrophages. The species that exhibited higher anti-inflammatory activities were A. bisporus, C. cibarius and L. deliciosus, inducing inhibition of NO production and iNOS, IL-1β and IL6 mRNAs expression in response to LPS stimulation. C. cornucopioides only induced inhibition of NO production and iNOS expression, and the other species did not present anti-inflammatory effects. Therefore, some edible mushrooms species have a potential anti-inflammatory capacity in vitro, suggesting that they could be regarded as a potential source of natural anti-inflammatory agents.     

Phenolic extracts from Crataegus × mordenensis and Prunus virginiana: Composition,antioxidant activity and performance in sunflower oil

The prevailing stigmatization of synthetic antioxidants and the inefficiency of endogenous antioxidants like tocopherols during high temperature processing of edible oils necessitate the search for effective natural antioxidants. Here, polyphenolic extracts from chokecherry and hawthorn fruits were screened for possible antioxidative application in fats/oils. Extracts were successively partitioned on sephadex columns and fractions were screened for radical scavenging activity using DPPH and β-carotene assays. Furthermore, sunflower oil fortified with extracts was assessed for stability using accelerated storage at 65 °C, Rancimat at 120 °C, and frying at 180 °C. Phenolic extracts showed significantly high radical scavenging and antioxidant activity in the oil. At the end of storage, hydroperoxide formation in sunflower oil was reduced by up to 50%, and the induction period significantly increased in the presence of extracts. Similarly, a significantly high frying stability was observed for the fortified samples, suggesting that the phenolic extracts can offer effective natural alternative to synthetic antioxidants during frying.     

Phenolic profiles and antioxidant activities of commercial beers

The phenolic profiles and corresponding antioxidant activities of 34 commercial beers in Chinese markets were evaluated. Results found remarkable variations in total and individual phenolic contents as well as antioxidant activity across beer brands. Gallic and ferulic acids were the dominant phenolic compounds identified in the tested beer samples and both of them accounted for >50% of the total phenolic compounds. Results from Pearson correlation analysis suggested that five antioxidant activity assays positively correlated well (p < 0.01) with each other and showed significant positive correlations (p < 0.05) with (+)-catechin, protocatechuic, and caffeic acids contents. Stepwise linear regression further demonstrated that different phenolic components responsible for beer antioxidant activity were dependent on the method used, and that ferulic acid, syringic acid, (+)-catechin, caffeic acid, protocatechuic acid and (−)-epicatechin together made 55.0–88.1% of contribution to the antioxidant activity of beer.     

Phenolic content and profiles of selected wild fruits of Zimbabwe: Ximenia caffra, Artobotrys brachypetalus and Syzygium cordatum

The phenolic compound content and profiles of three wild fruits found in Zimbabwe were tentatively identified using the traditional colorimetric methods and high-performance liquid chromatography (HPLC). The fruits assayed were: Ximenia caffra , Artobotrys brachypetalus and Syzygium cordatum . Ximenia caffra fruit peels contained the highest amounts of total phenolics amounting to 1205 μg g⁻¹ in fresh weight, flavonols amounting to 27 μg g⁻¹ and phenolic acids on HPLC tentative identification showed higher concentrations compared with the profiles of the other fruits. Syzygium cordatum fruit peels contained the least amounts of phenolics amounting to 20 μg g⁻¹, flavonols amounting to 8 μg g⁻¹ and phenolic acids' HPLC profiles showed low concentrations. Comparing the peels and pulps of all the fruits, we detected more total phenolics in the peels of X. caffra as high as 1205 μg g⁻¹ and the pulps had 228 μg g⁻¹, more flavonols and phenolic acids while the peels of S. cordatum fruits contained the least with a total phenolic acid content of 20 μg g⁻¹, and had more flavonols in the pulps than the peels, 11 μg g⁻¹ and 8 μg g⁻¹, respectively. Ximenia caffra contained 1.2% and about 1% dry weight condensed tannins in peels and pulps, respectively. In S. cordatum we detected 0.2% and 0.3% dry weight condensed tannins in the peels and pulps, respectively.     

Total phenolic compounds and antioxidant capacities of major fruits from Ecuador

Seventeen fruits from Ecuador were analysed for total soluble phenolic compounds content and for antioxidant capacity, using three different methods (DPPH, FRAP and ABTS⁺). For the total phenolic content measured by the Folin–Ciocalteu method, three groups, having <100, 200–500 and >1000 mg GAE/100 g FW, were clearly distinguishable. Andean blackberry, capulí cherry peel and banana passion fruit were classified in the third group, with concentrations of 2167, 1494 and 1010 mg of GAE/100 g FW, respectively. Antioxidant capacity analyses revealed the same classes. FRAP and ABTS⁺ gave comparable results and were highly correlated (y = 0.691x + 6.78; r² = 0.908). Spectrophotometric measurements showed that the Andean blackberry and capulí peel but not banana passion fruit contained high levels of anthocyanins (λ_max = 520 nm).     

Nutraceutical properties and toxicity studies of fruits from four Cactaceae species grown in Argentine Northwestern

Fruits are known as good sources of phytochemicals, essential to prevent degenerative diseases like cancer and cardiovascular diseases. They contain a variety of antioxidants, which are useful to scavenge radical oxygen species (ROS). Considering the importance of natural products as a functional food, comparative studies between the antioxidant activity (AOA) and antimutagenic properties as well as phytochemical profile of Cactaceae fruits (Lepismium lorentzianum, Lepismium lumbricoides, Rhipsalis floccosa, and Pfeiffera ianthothele) from Argentinean Yungas, were performed. Different assays were applied: ABTS radical scavenging capacity, inhibition of lipid peroxidation using ??-carotene-linoleate model system and mutagenicity/antimutagenicity by Ames test. A pigment like betalain was detected in fruits of both Lepismium species; L. lorentzianum aqueous extracts showed a higher pigment content (60.6 mg BE/100 g FM) than L. lumbricoides (9.2 mg BE/100 g FM). Fruit preparations of L. lorentzianum (aqueous and ethanolic extractions) showed significantly higher total phenolic compound and pigments content than the other berries. In all preparations, high antioxidant activity was demonstrated. Lepismium species were more active than Rhipsalis and Pfeiffera (SC_50ABTS values between 1.3 and 4.5 ??g/ml and IC_{50 ??-carotene-linoleate} values between 9 and 45.8 ??g/ml). A significant correlation between pigment and phenolic compounds content and AOA was observed. The preparations showed no sign of mutagenicity at tested concentrations (until 50 ??g/plate). A significant antimutagenic effect was observed for L. lumbricoides, and a weak effect was shown for P. ianthothele and R. floccosa. Because of the diversity and abundance of bioactive phytochemicals found in these species, food, cosmetic, and pharmaceutical applications could be proposed.     

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.     

Nutritional properties of commercially grown native Australian fruits: Lipophilic antioxidants and minerals

A high level of antioxidant activity of lipophilic fractions obtained from commercially grown native Australian fruits, as evaluated in the oxygen radical absorbance capacity assay for lipophilic antioxidants (ORAC-L), was identified for the first time. The level of contribution of lipophilic fractions varied from 5.8% (quandong) to 30.7% (riberry) of the total oxygen radical scavenging capacity (ORAC-T). Vitamin E components - ??-tocopherol, ??-tocopherol and ??-tocopherol and lutein - were identified as the main sources of this activity. Among the evaluated sources, Kakadu plum emerges as a fruit with unique nutritional qualities: it exhibited a superior ORAC-T value (430.0 ??M trolox eq/g fresh weight, TEq/g FW) with 26.7% contribution of the lipophilic fraction. The major compounds of Kakadu plum's lipophilic fraction were ??-tocopherol (1.022 ± 0.1 mg/100 g, FW), lutein (0.26 ± 0.01 mg/100 g FW) and chlorophyll a and b (2.72 ± 0.1 and 0.54 ± 0.1 mg/100 g FW, respectively). With regards to mineral content, the levels of major minerals, such as potassium, phosphorus, calcium, magnesium, and trace elements such as iron, zinc, manganese, selenium and copper as well as cobalt, nickel, aluminium and led in native Australian fruits are similar to the levels of these elements in a range of vegetables and frutis produced and consumed elsewhere.     

Phenolic content and antioxidant activity of cantaloupe (cucumis melo) methanolic extracts

The objectives of this study were to determine phenolic content and antioxidant activity of methanolic extracts from different parts of cantaloupe (leaf, stem, skin, seed and flesh). The flesh extract afforded the highest yield (89.6 ± 0.3%) whilst the lowest yield was obtained from the seed (13.7 ± 0.5%) (p < 0.05). The leaf extract showed the highest total phenolic content (26.4 ± 0.3 mg GAE/g extract) and total flavonoid content (69.7 ± 3.37 μg RE/g extract) accompanied with best antioxidant activity through all antioxidant assays (p < 0.05). In addition, the stem extract also exhibited good antioxidant activity. Thus, these results suggest that methanolic extracts of cantaloupe leaf and stem may serve as a potential source of natural antioxidant for food and nutraceutical application.     

The antioxidant properties of whey permeate treated fresh-cut tomatoes

The aim of this research was to analyse the effects of three types of cheese whey permeate treatment on the antioxidant properties of fresh-cut tomatoes. Tomatoes were treated with whey permeate concentrate (PC), delactosed permeate (DP) and delactosed concentrate (DC), stored at 4 °C for 10 days and compared to samples treated with the industry standard, chlorine (120 ppm). Samples treated with DP retained significantly higher antioxidant activity (FRAP) and total phenols (TP), when compared with those treated with PC and DC. DP showed significantly higher results than chlorine for DPPH, FRAP and TP. In DPPH assay, all whey permeate-treated samples showed similar antioxidant activity, while ascorbic acid and lycopene were unaffected by treatment. Among the three whey permeates, delactosed permeate showed the best results in maintaining the antioxidant properties of tomato, suggesting it could be used to enhance the antioxidant activity of fresh-cut tomato and retain the antioxidant components during storage.     

Comparative study of phytochemicals and antioxidant potential of wild edible mushroom caps and stipes

A comparative study of the organic acids and phenolics composition and of the total alkaloids content of entire wild edible mushrooms (Russula cyanoxantha, Amanita rubescens, Suillus granulatus and Boletus edulis) and correspondent caps and stipes was performed. All species presented oxalic, citric, malic and fumaric acids, with A. rubescens exhibiting the highest total organic acids content. Organic acids were preferably fixed in the cap. Among phenolics, only p-hydroxybenzoic acid was found in A. rubescens and S. granulatus, in very low amounts. B. edulis was the species that presented the highest total alkaloid amounts. Except for this species, alkaloids mainly accumulated in the cap. All of the species exhibited a concentration-dependent scavenging ability against DPPH^·. B. edulis revealed the highest antioxidant capacity. The cap seemed to be the part with highest antioxidant potential. Some relationships between chemical composition and antioxidant capacity were considered.     

陕西苦菜叶总黄酮的提取及抗氧化活性的测定

苦菜总黄酮的提取及抗氧化活性的研究可提高我国野生资源利用和活性成分的开发。以苦菜为原料,采用超声波辅助提取法对苦菜叶总黄酮的提取工艺进行优化,采用分光光度法测定提取物的还原力,对羟基自由基（·OH）、超氧阴离子（O2-·）、DPPH自由基（DPPH·）的清除作用进行研究。结果表明:超声波辅助提取的优化工艺参数为乙醇体积分数80%、提取温度70℃、料液比1∶35、超声时间40min,此条件下总黄酮的提取含量为64.62mg/g。苦菜叶黄酮对羟基自由基、超氧阴离子、DPPH自由基具有良好的清除能力,同时还具有较强的还原能力,活性大小与提取物的浓度呈明显的线性关系。      

Antioxidant properties of methanolic extracts from Diospyros mespiliformis (jackal berry), Flacourtia indica (Batoka plum), Uapaca kirkiana (wild loquat) and Ziziphus mauritiana (yellow berry) fruits

Four wild fruits, Diospyros mespiliformis, Flacourtia indica, Uapaca kirkiana and Ziziphus mauritiana, were extracted with methanol and analysed for radical-scavenging effect of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power and anion radical effect on superoxide anion using colorimetric method. There was an increase in the radical-scavenging effect, reducing power and superoxide anion radical-scavenging effect as the concentration of sample increased. Diospyros mespiliformis had high DPPH radical-scavenging capacity. The peels of F. indica and U. kirkiana had higher DPPH radical-scavenging effects, reducing power and superoxide-scavenging effects compared with the pulp while the pulp of Z. mauritiana had high DPPH radical-scavenging effects, reducing power and superoxide-scavenging effects compared with the peel.     

Phenolic composition of Flacourtia indica, Opuntia megacantha and Sclerocarya birrea

The phenolic acid composition of the peel and pulp of the fruits of Flacourtia indica (Burm. f.) Merr., Opuntia megacantha (L.) Mill and Sclerocarya birrea (A. Rich.) Hochst., from Zimbabwe, were analysed using traditional colorimetric as well as HPLC methods. The total phenolics, flavanoids and condensed tannin levels varied with species. Sclerocarya birrea pulp had the highest total phenolics, flavanoids and condensed tannins, i.e., 2262 μg GAE/g, 202 μg catechin/g and 6.0% condensed tannins, respectively. Flacourtia indica pulp contained the least total phenolics, flavanoids and condensed tannins 334 μg GAE/g, 41 μg catechin/g and 1.4%, respectively. There were no significant differences in the total phenolics between the peels and the pulps of the individual fruits. However, significant differences were noted in the flavanoids and the condensed tannins between the peels and pulps of the fruits assayed. Ferulic acid, caffeic acid and vanillic acid were the dominant phenolic acids in the three fruits. There were differences between the phenolic acids in the peels and the pulps of the fruits.     

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.     

Strawberries from integrated pest management and organic farming: Phenolic composition and antioxidant properties

Consumer awareness, pesticide and fertilizer contaminations and environmental concerns have resulted in significant demand for organically grown farm produce. Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins and other phenolic compounds. The present study evaluated the influence that organic farming (OF) and integrated pest management (IPM) practise exert on the total phenolic content in 22 strawberry samples from four varieties. Postharvest performance of OF and IPM strawberries grown in the same area in the centre of Portugal and harvested at the same maturity stage were compared. Chemical profiles (phenolic compounds) were determined with the aid of HPLC-DAD/MS. Total phenolic content was higher for OF strawberry extracts. This study showed that the main differences in bioactive phytochemicals between organically and IPM grown strawberries concerned their anthocyanin levels. Organically grown strawberries were significantly higher in antioxidant activity than were the IPM strawberries, as measured by DPPH and FRAP assays.     

Phenolic acid profiles and antioxidant activities of wheat bran extracts and the effect of hydrolysis conditions

Four different types of wheat bran were extracted and analyzed for phenolic acids using the Folin–Ciocalteu method and HPLC. The extracts and their hydrolysis products were also evaluated for their antioxidant activities. The total phenolic content of the red wheat bran was higher than that of the white wheat. We found that the majority of the phenolic acids existed in a bound form in wheat bran. These phenolic acids can be released by hydrolyzing the bran under alkaline or acidic conditions; however, the former was more efficient in the release of free phenolic acids than the latter. Ferulic, vanillic, and syringic acids were the major individual phenolic acids in the studied wheat bran. The main portion of the total ferulic acid was from alkaline hydrolysis. The alkaline hydrolysable fractions had greater antioxidant activities, while the acid hydrolysable fractions showed lower activities in both the red and white bran. The antioxidant activity of bran extract was stronger than that of free phenolic acids.