常见6种杂粮与2种主粮的抗氧化活性比较研究

目的：比较常见6种杂粮：荞麦(甜荞、苦荞)、小米、糜米(粳性、糯性)、玉米、薏米、燕麦与2种主粮：大米、小麦食用部分的总酚、黄酮含量及其存在形式和抗氧化活性差异,并分析总酚、黄酮含量与抗氧化活性之间的相关性。方法：采用Folin-Ciocalteu法测定总酚含量,NaNO2-Al(NO)3测定黄酮含量;DPPH自由基法、ABTS+ ·法、β-胡萝卜素-亚油酸乳化液法和还原力法评价样品的抗氧化能力。结果：总酚含量由高至低为：苦荞、甜荞、燕麦、薏米、玉米、小米、粳性糜米、小麦、糯性糜米、大米,并且除小米、糯性糜米外其他样品提取物的多酚主要以自由态存在,占总酚的64.18%～98.70%;黄酮含量最高的为薏米、燕麦次之,且均多以自由态存在;杂粮的抗氧化活性高于主粮,其中苦荞清除DPPH自由基能力、ABTS+ ·能力和总还原力最强,甜荞次之,而小米抑制β-胡萝卜素褪色能力最强;同时,抗氧化活性与总酚含量之间具有良好的线性关系,与黄酮含量的相关性不明显。结论：杂粮的总酚含量及总抗氧化活性高于主粮,其中苦荞最为突出,因此,推荐增加日常杂粮食用量以弥补主粮膳食中多酚物质含量过低的不足。     

Nutritional composition and flavonoids content of flour from different buckwheat cultivars

Thirty nine buckwheat cultivars were collected from China, of which twenty one were tartary buckwheat and others were common buckwheat. Flour samples from these cultivars were analysed for colour properties, nutritional composition and flavonoid content. Buckwheat cultivars exhibited high variations for each of these parameters. The flour of common buckwheat showed a higher whiteness index than that of tartary buckwheat and contained very low levels of flavonoids. On average, the tartary buckwheat flour contained a higher level of ash (2.38%) and lower levels of total starch (70.22%), amylose (22.32%), resistant starch (17.66%) than the common buckwheat flour (2.17%, 73.69%, 23.01%, 18.69% respectively) (P < 0.05) whereas the contents of proteins, fats and crude fibres of the tartary buckwheat flour were similar to those of common buckwheat flour. The Mei‐Hua‐Shan tartary buckwheat flour contained the highest level of total flavonoids and quercetin (22.74 mg g^?1 and 2.38 mg g^?1, respectively).     

液态发酵对西农9940苦荞主要成分及其抗氧化活性的强化作用

利用液态发酵技术富集苦荞渣中的营养物质,测定分析西农9940苦荞粉及其经液态发酵后所得苦荞渣的蛋白质、粗脂肪、矿物质、粗纤维、灰分、总黄酮、总酚含量以及氨基酸和脂肪酸组成,并以总还原能力、1,1-二苯基-2-三硝基苯肼(1,1-dipheny1-2-picryl-hydrazyl,DPPH)自由基和2,2'-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐自由基(2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)radical,ABTS+·)清除能力为指标对抗氧化活性进行综合评价。结果表明苦荞渣的蛋白质、粗脂肪、灰分、粗纤维、矿物质含量均显著提高,且液态发酵过程不改变苦荞粉的氨基酸及脂肪酸组成。苦荞渣的总酚含量为1 343.22 mg/100 g,显著高于苦荞粉559.76 mg/100 g,总黄酮含量为2 186.06 mg/100 g,显著低于苦荞粉2 464.10 mg/100 g,芦丁和槲皮素含量的测定也进一步证明发酵后苦荞渣的总黄酮含量显著降低,但其总还原能力、DPPH自由基和ABTS+·清除能力显著高于苦荞粉,说明经过发酵后苦荞渣的抗氧化能力更强。     

Distribution of phenolic compounds in the graded flours milled from whole buckwheat grains and their antioxidant capacities

Whole buckwheat grains were milled into 16 flour fractions using the gradual milling system and the phenolic compounds and the antioxidant capacity of each flour fraction were investigated. The phenolic and flavonoid contents of both free and bound phenolic extracts of buckwheat flour fractions significantly increased in the order from the fraction number 1 (phenolics less rich fraction) to the fraction number 16 (phenolics rich fraction). The phenolic compounds in buckwheat existed primarily in free form, whereas the flavonoids existed in grain in insoluble bound forms, bound to cell wall materials. The amounts of ferulic acid and rutin increased from 2.5 and 2.5 μg/g flour of the phenolics less rich fraction to 609.5 and 389.9 μg/g flour of the phenolics rich fraction of grain, respectively. The higher phenolic contents in the phenolics rich fractions exhibited the stronger antioxidant capacity than the phenolics less rich fractions. As a result, the flour milled from the outer layers of buckwheat grains with large amount of phenolic compounds and antioxidant capacity are considered to have significant health benefits.     

Antioxidant activity of commercial buckwheat flours and their free and bound phenolic compositions

Commercial buckwheat flours were investigated for their antioxidant activities, free, and bound phenolic compositions using spectrophotometer, LC–ESI-IT-MS, and LC–ESI-Q-TOF-MS. Farinetta flour contained the highest free and bound phenolic contents, followed by Supreme, whole buckwheat, and Fancy flour, respectively. The 50% ethanol extraction achieved significantly higher free phenolic content compared with water and absolute alcohol. The absolute ethanol extraction contained considerable more bound phenolic and flavonoid compounds. A high extraction temperature increased the phenolic contents. The optimal solvent to solids ratio was 50:1, and the optimal extraction time was 5 h for flavonoids. The spectral method was reproducible for analysing the total flavonoid contents. The LC–ESI-Q-TOF-MS studies on whole buckwheat flour showed that p-coumaric and gallic acids were found in the bound phenolics along with isoquercitrin but were not present in the free phenolic compounds. The free flavonol-glycosides were found in whole buckwheat flour but not in any other buckwheat flours.     

Comparative evaluation of the antioxidant potential of some Iranian medicinal plants

Medicinal plants are a source for a wide variety of natural antioxidants. In the study reported here, we have conducted a comparative study between five medicinal plants having the same geographic origin: the Hamadan region in the west of Iran and growing in the same natural conditions. The amount of total phenolics and total flavonoids for parts of these plants used in Iranian popular medicine were evaluated. Furthermore, antioxidant activities for these parts using vitamin C equivalent antioxidant capacity (VCEAC) test were also evaluated. The results show that the antioxidant activities varied greatly among the different plant parts used in this study and some plants are rich in natural antioxidants especially leaves of Lavandula officinalis and of Melissa officinalis. A positive correlation between total phenolic or flavonoid contents and VCEAC was found with a correlation coefficient of R² = 0.961 and R² = 0.817, respectively. These findings show that phenolics in these plants provide substantial antioxidant activity.     

Antioxidant and protective properties of six Tanacetum species against hydrogen peroxide-induced oxidative stress in K562 cell line: A comparative study

The antioxidant activities of ethanolic extract of six species of Tanacetum (T. budjnurdense, T. hololeucum, T. chiliophyllum, T. sonboli, T. tabrisianum, T. kotschyi) from Iran were examined by employing various established in vitro assay systems. The results showed that all Tanacetum extracts displayed antioxidant activities, with IC₅₀ values ranging from 59.55 to 157.24 μg/ml, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The extract of T. hololeucum, with an IC₅₀ value of 59.55 μg/ml was nearly two or three times more active than the other used Tanacetum extracts. The amounts of total phenolics and total flavonoids were also determined by spectrophotometer. A similar order of the amounts of phenolics and flavonoids in all plant extracts were found. The results showed that the extent of antioxidant activities is in accordance with the amounts of phenolics and flavonoids existing in all plant extracts. Regarding high performance liquid chromatography (HPLC) data, caffeic acid, ferulic acid, luteolin, apigenin and rutin were detected as major phenolic compounds in all the species investigated. Pretreatment of K562 cells with various concentrations of Tanacetum extracts (10–100 μg/ml) for 16 h prevent cell damage and enhanced activity of antioxidant enzymes induced by a treatment with H₂O₂. Moreover, lower level of glutathione caused by hydrogen peroxide in K562 cells were partly recovered by a pretreatment of cells with various Tanacetum species extract. These results may show the significant protection effect of Tanacetum sp. against oxidation of the cells.     

苦荞芽粉馒头体外消化后抗氧化能力研究

为研究苦荞芽粉馒头在人体消化、吸收过程中抗氧化能力的变化规律,模拟体外口腔、胃肠道消化吸收,通过比较不同梯度样品馒头总酚和总黄酮含量、DPPH·和ABTS+·的清除能力和抑制β-胡萝卜素褪色能力来比较苦荞芽粉馒头、苦荞馒头和小麦馒头体外消化吸收3个阶段的抗氧化性差异。各样品组的馒头在经过口腔消化之后,多酚和黄酮类物质逐渐释放,并在胃肠道消化之后达到最大值,但吸收率较低;苦荞芽粉馒头的胃肠道消化液和吸收液抗氧化性均显著高于相同比例添加量的苦荞和小麦馒头。馒头消化液的总酚和总黄酮含量与DPPH·、ABTS+·清除能力和抑制β-胡萝卜漂白能力呈正相关性,其中总酚与消化液抗氧化性极显著相关。苦荞芽粉馒头的胃肠道消化液和吸收液具有较强抗氧化活性,并优于相同梯度的苦荞原粉馒头和小麦馒头。研究为新型苦荞营养保健食品的开发提供依据。     

Comparisons of flavonoids and anti-oxidative activities in seed coat,embryonic axis and cotyledon of black soybeans

Flavonoids contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities and the ferric-reducing antioxidant power (FRAP) were compared in three black soybean varieties CRWD, Tainan 3 and Tainan 5. Varietal differences in antioxidant contents existed among the tested varieties. Variety CRWD accumulated more total phenolics (7.49 mg g⁻¹) and isoflavones (1.77 mg g⁻¹) than varieties Tainan 3 (7.05 mg g⁻¹ total phenolics and 1.58 mg g⁻¹ isoflavones) and Tainan 5 (4.38 mg g⁻¹ total phenolics and 0.63 mg g⁻¹ isoflavones). CRWD also accumulated more proanthocyanidins in seed coat than Tainan 3 and Tainan 5. CRWD also demonstrated greater DPPH and FRAP activities than the other two cultivars. Stepwise regressions indicated that both DPPH and FRAP activities were correlated well with the total contents of phenolics and flavonoids, with total phenolics being the most important anti-oxidative factor. The present results indicate that CRWD has greater anti-oxidative responses than Tainan 3 or Tainan 5, and is useful in functional food and other applications.     

Buckwheat—the source of antioxidant activity in functional foods

Antioxidant activities of buckwheat seeds, dehulled seeds, hulls, straws and leaves were evaluated and compared with those of oats and barley. Schaal oven test at 70 °C with gravimetric indication and lard as the substrate was applied. Protection factors ranged from 1.3 to 8.0 and increased in the order: buckwheat straws < buckwheat hulls = oats <barley <buckwheat seeds <buckwheat dehulled seeds <buckwheat leaves. Methanol extract of buckwheat seeds showed higher antioxidant activity in comparison with petrolether extract, protection factors amounted to 2.9 and 1.9, respectively Total phenolics, rutin and tocol contents in tested samples were determined and related to the antioxidant activities. Statistically significant relationship between total phenolics content as well as rutin content and antioxidant activity of buckwheat material was observed (R² = 0.987, P <0,002, R² = 0.972, P<0.002, respectively) Significant correlation between tocol content and antioxidant activity was not found.     

Anti-oxidative characterisation of NaN3-induced common bean mutants

The contents of total phenolics, total anthocyanins, total proanthocyanidins and antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl radicals scavenging activity, ferric reducing antioxidant power, lipid peroxidation inhibition ability and ABTS⁻ radical-scavenging activity assays. These were compared in the seed coats of common bean (Phaseolus vulgaris L.) cultivar Hwachia and its eighteen NaN₃-induced mutants. NaN₃-induced mutants generally accumulated more total phenolics (19% more), total anthocyanins (65% more) and total proanthocyanidins (4% more) than Hwachia (containing 29.94 mg g⁻¹ total phenolics, 0.31 mg g⁻¹ total anthocyanins and 12.94 mg g⁻¹ total proanthocyanidins, respectively). Anthocyanidins including delphinine, cyanidin and pelargonidin were detectable in seed coat, each with different levels depending on the tested accessions. Significant correlations (average of 0.847 across all comparisons, p < 0.01) were found between the tested antioxidant activities, total phenolics, total anthocyanins and total proanthocyanidins. Mutants SA-11-2, SA-13-2 and SA-34-2 that are enriched with antioxidants may be useful in food and other applications.     

Antioxidant and antiproliferative activities of common edible nut seeds

Frequent consumption of nuts has been linked to a lowered risk of cardiovascular disease. Phytochemicals, especially phenolics, in nuts may be considered to be the major bioactive compounds for health benefits. Nine types of tree nuts and peanuts commonly available in the United States were evaluated for total phenolic and flavonoid contents, antioxidant, and antiproliferative activities. The profiles of total phenolics and flavonoids, including both soluble free and bound forms, were investigated by utilizing solvent extraction, base digestion, and solid-phase extraction methods. Walnuts had the highest total phenolic and flavonoid contents (1580.5 ± 58.0 mg/100 g, 744.8 ± 93.3 mg/100 g, respectively). Walnuts also possessed the highest total antioxidant activity (458.1 ± 14.0 μmol of vitamin C equiv/g of nut). Both soluble phenolic and flavonoid contents were positively correlated with total antioxidant activity (R² = 0.9901, p < 0.05; and R² = 0.9749, p < 0.05, respectively). The proliferation of HepG₂ and Caco-2 cells was significantly inhibited in a dose-dependent pattern after exposure to the extracts of nuts, with walnuts and pecans exhibiting the highest antiproliferative activity. These results provide new knowledge about health functions of nuts and may influence consumers toward purchasing nuts exhibiting greater potential health benefits.     

Antioxidant properties and phytochemical composition of China-grown pomegranate seeds

Four cultivars of Shanxi-grown pomegranate seeds were investigated for their phytochemical composition and antioxidant properties. Pomegranate seed oils were extracted and analysed for their fatty acid profiles, and tocopherol and carotenoid contents. The defatted flours were extracted with 50% acetone or 80% methanol, and evaluated for levels of phenolics, flavonoids and proanthocyanidins, and scavenging capacities against DPPH and ABTS⁺ and their ferric ion reducing abilities. Pomegranate seed oil was rich in punicic acid (73.5-78.8 g/100 g oil) and total tocopherols (5.3-12.0 μmol/g). The 50% acetone and 80% methanol were appropriate solvents for extraction of total phenolic and total flavonoid, respectively. The four cultivars were significantly different in levels of phenolics, flavonoids, proanthocyanidins and their antioxidant properties (P < 0.05), generally flowing an order: Suanshiliu > Tianhongdan > Sanbaitian ≈ Jingpitian. This study will assist in the cultivar selection of the above pomegranate seeds for commercial production to meet the market demand.     

贵州不同品种苦荞品质及其对荞麦面条加工的影响

通过对贵州地区不同品种苦荞的灰分、水分、粗蛋白、粗脂肪、淀粉、直链淀粉、总糖、粗纤维、总黄酮、出粉率等指标进行测定,并结合不同品种苦荞粉对苦荞面条感官品质、蒸煮损失、拉伸特性、质构特性的影响,筛选出适宜加工苦荞面条的苦荞品种。结果表明:10个品种总黄酮含量均值可达2.07 g/100 g,黔苦7号中总黄酮含量(2.95±0.11)g/100 g显著多于其他品种(P<0.05),粗蛋白含量均值为10.91 g/100 g,黔苦7号粗蛋白含量最高(12.09±0.77)g/100 g,直链淀粉含量均值达到22.85 g/100 g,出粉率均值达到70.32%。在苦荞粉添加量40%,小麦粉添加量60%,面团含水量35%的条件下制作苦荞面条,黔苦7号感官评分最高,拉伸阻力最大,弹性较好,更适用于苦荞面条加工。     

Radical scavenging and reducing properties of extracts of cashew shoots (Anacardium occidentale)

The total phenolic content and antioxidant activities of methanol, hexane and ethyl acetate extracts of the shoots of Anacardium occidentale were measured. Total phenolic content was assessed by the Folin–Ciocalteau assay whereas antioxidant activities were assessed by measuring the ability of the extracts to scavenge the ABTS^·+ and DPPH^· radicals, superoxide anion radicals and nitric oxide radicals as well as their ability to reduce ferric ions. Results indicated that the methanol extract of A. occidentale was the most potent reducing agent and radical-scavengers compared to the other two extracts. The ethyl acetate extract exhibited some antioxidant activities whereas the hexane extract is the least reactive. The order of the antioxidant potency of the plant extract is methanol > ethyl acetate > hexane. The methanol extract contained more than 7 fold of total phenolic content compared to the hexane and ethyl acetate extracts indicating the likely possibility that the observed antioxidant activities were partly contributed by the phenolics. The results suggest that the shoots of A. occidentale are a source of natural antioxidants.     

Antioxidant activities of extract and fractions from Tuber indicum Cooke & Massee

The antioxidant activities of ethanolic crude extract (ECE) and its four different solvent sub-fractions (namely, petroleum ether fraction (PEF), ethyl acetate fraction (EAF), n-butyl alcohol fraction (BAF) and the rest fraction (RF)) from Tuber indicum were investigated using several in vitro antioxidant assays. ECE and four sub-fractions possessed different antioxidant and radical-scavenging activities in different assays. BAF showed the most potent radical-scavenging activity on DPPH radicals, superoxide anion radicals and reducing power, with EC₅₀ values of 1.38, 0.96, 16.0 mg/ml, respectively. EAF exhibited the highest hydroxyl radical-scavenging and ferrous ion chelating activities with EC₅₀ values of 3.31 and 0.70 mg/ml, respectively. The total phenolics (TP) and total flavonoids (TF) were also determined. BAF had the highest TP and TF contents, and the next was EAF. These results showed that the amounts of phenolics and flavonoids were in accordance with higher effectiveness in scavenging radicals and chelating ferrous ions.     

Systematic evaluation of natural phenolic antioxidants from 133 Indian medicinal plants

Total antioxidant capacities of 133 Indian medicinal plant species sampled from 64 families were assessed by ABTS, DPPH and FRAP assays, and their total phenolic contents measured by Folin–Ciocalteu assay. These species exhibited a broad range of antioxidant activities, varying from 0.16 to 500.70 mmol TEAC/100 g DW in the ABTS assay. The antioxidant activity values similarly varied with the DPPH and FRAP assays. Significant and positive linear correlations were found between total antioxidant capacities and phenolic contents (R = 0.89–0.97), indicating that phenolics were the dominant antioxidant constituents in the tested medicinal plants. Preliminary identification of the major phenolic compounds from 83 selected medicinal plants by reversed-phase HPLC revealed phenolic acids, tannins, flavonoids, curcuminoids, coumarins, lignans, and quinines. The fruit of Terminalia chebula, pericarp of Punica granatum and gall of Rhus succedanea showed very high levels of hydrolysable tannins, and the gum of Acacia catechu presented very high levels of catechin and epicatechin in addition to tannins. Major phenolics in many of the medicinal plants were identified for the first time (e.g., Euphorbia lathyrus, Ipomoea turpethum, and Picrorrhiza kurroa). This systematic investigation of a large number of Indian medicinal plants proved important for understanding their chemical constituents and functionality in Ayurvedic medicine, and contributes to the search for natural sources of potent antioxidants.     

Antioxidant activity of microwave-assisted extract of Buddleia officinalis and its major active component

Buddleia officinalis Maxim, commonly used as rice dye for festivals, was extracted with ethanol using microwave-assisted extraction and Soxhlet extraction. The antioxidant activities of microwave-assisted extract of B. officialis (MEB) and Soxhlet extract of B. officianils (SEB) at the optimum extraction conditions were evaluated and compared with synthetic antioxidant butylated hydroxytoluene (BHT) employing DPPH free radical assay, ABTS assay, total antioxidant activity and reducing power. MEB and SEB had stronger antioxidant activities than BHT in all assays except reducing power, and the effects decreased as follows: MEB > SEB > BHT. The total phenolic contents of MEB and SEB reached 113.56 mg/g and 100.94 mg/g dry weight of extract, respectively, expressed as pyrocatechol equivalents, while the total flavonoids contents were 75.33 mg/g and 62.56 mg/g dry weight of extract, respectively, expressed as catechin equivalents (P < 0.05). Higher phenolic and flavonoids compounds may be major contributors to their higher antioxidant activities. Following activity-oriented separation, luteolin was isolated as an active principle, which exhibited excellent free radical scavenging activities with DPPH IC₅₀ 3.09 μg/ml and ABTS IC₅₀ 2.20 μg/ml.     

Antioxidant activities of Sideritis congesta Davis et Huber-Morath and Sideritis arguta Boiss et Heldr: Identification of free flavonoids and cinnamic acid derivatives

Different solvent extracts of endemic Sideritis (Labiatae) species, Sideritis congesta Davis et Huber-Morath and Sideritis arguta Boiss et Heldr, were analyzed for free flavonoids (quercetin, apigenin, myricetin and kaempferol) and cinnamic acid derivatives (rosmarinic acid, ferulic acid, caffeic acid, p-coumaric acid and chlorogenic acid) using HPLC-DAD. All the phenolics were quantified in acid-hydrolyzed extracts, except rosmarinic acid, chlorogenic acid and myricetin which were quantified in raw samples. Antioxidant activities of extracts of these two plants and many of their components in pure form were evaluated based on DPPH^. and ABTS^.+ assays. In general, S. arguta extracts displayed higher antioxidant activity than S. congesta extracts possibly due to their richness in antioxidant components of strong activity. Acetone extract of S. arguta, with its strikingly high TEAC value of 3.2 mM trolox and low IC₅₀ value of 38.3 ??g/mL showed the highest antioxidant potency among all extracts. ??-tocopherol, the positive control, displayed IC₅₀ and TEAC values of 33.8 ??g/mL and 2.9 mM trolox, respectively. No direct correlation was found between antioxidant activities and total phenolic contents of the plant extracts studied.     

Comparison of flavonoids profile in sprouts of common buckwheat cultivars and wild tartary buckwheat

In this study, major types of flavonoids in 7‐day sprouts of five common buckwheat cultivars grown in Poland (Hruszowska, Kora, Panda, Luba and Emka) and wild tartary buckwheat were investigated. Results demonstrated that sprouts of common buckwheat cultivars and wild tartary buckwheat contained both known and a newly discovered flavonol: quercetin 3‐O‐galactosyl‐rhamnoside. An exceptionally high content of this flavonoid was found in cotyledons of wild tartary buckwheat (30.79 ± 0.14 mg g^?1 DW), exceeding about 10 times level of rutin (3.16 ± 0.07 mg g^?1 DW). The results are not consistent with the data published so far on the content of flavonoids in sprouts of tartary buckwheat. Higher levels of flavonoids were measured in cotyledons than in hypocotyls with the exception of anthocyanins, which were present in higher amounts in hypocotyls. Cotyledons of common buckwheat sprouts were rich in C‐glycosides of luteolin and apigenin, the total content of which exceeded ca. 5 times the concentration of rutin.