石榴皮提取物的抗氧化作用研究

分别以水、甲醇、丙酮和乙酸乙酯为溶剂,对石榴皮中的多酚进行了提取,得到4种提取物。采用油脂过氧化值(POV)法和二苯三硝基苯肼(DPPH)自由基法研究了提取物的抗氧化活性。结果显示,4种提取物均具有抗油脂过氧化和清除DPPH自由基的能力,其抗氧化活性随添加量的增加而增加。4种提取物中,丙酮提取物的抗油脂过氧化作用最大,其次为水提取物和甲醇提取物,乙酸乙酯提取物的抗油脂过氧化作用最小。当丙酮提取物添加量为猪油质量的0.1%时,其抗油脂过氧化活性接近添加量为0.02%茶多酚或BHT。4种提取物对DPPH自由基的清除能力大小顺序依次为:水提取物、丙酮提取物、甲醇提取物和乙酸乙酯提取物。浓度为0.0175 mg/mL的水提取物对DPPH自由基的清除率高达85.2%,高于BHT,但略低于茶多酚。石榴皮多酚是一种有效的天然抗氧化剂。     

山楂不同溶剂提取物的抗氧化活性及对DNA和蛋白质氧化损伤的保护作用

研究山楂甲醇、乙醇、丙酮、乙酸乙酯、氯仿、石油醚等不同极性溶剂提取物的总多酚、总黄酮含量及其成分组成,并分析比较不同提取物的体外抗氧化活性及其对DNA和蛋白质氧化损伤的保护效果。结果表明,山楂的不同溶剂提取物中总多酚、总黄酮含量及其生物活性不同。其中,甲醇提取物中总多酚和总黄酮含量均最高,清除DPPH自由基、ABTS自由基能力和铁还原能力最强,对蛋白质和DNA氧化损伤的保护作用亦优于其他提取物。山楂甲醇提取物主要活性成分为表儿茶素、原花青素B2、绿原酸和槲皮素。山楂提取物的总多酚、总黄酮含量与其抗氧化活性、DNA和蛋白质氧化损伤的保护效果均具有较高的相关性。     

Extraction,optimisation and characterisation of phenolics from Thymus vulgaris L.: phenolic content and profiles in relation to antioxidant,antidiabetic and antihypertensive properties

The objectives of this study were to examine varying extraction conditions of Thymus vulgaris L. as related to phenolic content and profiles of the extracts and their antioxidant, antihypertensive and antidiabetic properties. Phenolics were extracted under various conditions pertaining to free and bound phenolics, solvent type and combination of extraction time and temperature, and these extracts were evaluated in terms of their antioxidant activities and inhibitory activities of angiotensin‐converting enzyme (ACE), α‐glucosidase and α‐amylase. The acetone–water solvent mixture (1:1; v/v) produced the extract with the greatest phenolic content, antioxidant activity and inhibitory activities of ACE and α‐glucosidase. The optimal extraction temperature for maximum phenolic content and antioxidant activity associated with methanol extraction was 60 °C, whereas a lower temperature at 40 °C was required to maximise inhibitory activities for ACE, α‐glucosidase and α‐amylase. An inverse relationship was seen between antioxidant and glucosidase inhibitory activities vs. the ACE and α‐amylase inhibitory activities, which suggests the need for extractions to be directed to specific bioactivities of thyme extracts. Generally, the results indicate major differences in phenolic profiles among the tested extraction conditions with thymol as the predominant phenolic seen in most extractions, while gallic acid, rosmarinic acid or diosmin also predominated in other extracts. Extracts with the same predominant phenolic compound and similar phenolic content showed major disparities in their ACE, glucosidase and α‐amylase inhibitory activities, indicating that the major phenolic profiles of thyme extracts may not be necessarily related to the degree of inhibition of ACE, glucosidase and α‐amylase enzymes.     

不同提取剂对余甘子提取物抗氧化活性的影响

以丙酮、甲醇、乙醇和水4种提取剂提取余甘子中化学成分,分析4种提取物的多酚含量、对氧自由基的吸收能力、对超氧阴离子自由基的抑制能力和对羟自由基的清除能力。结果表明,不同提取剂的余甘子提取物对自由基均有一定的清除能力,其中以丙酮和甲醇提取物的多酚含量最高,对自由基的清除能力最强,其次是乙醇>水。所以,选用丙酮或者甲醇为提取剂,对余甘子提取物多酚含量和抗氧化活性研究效果最好。     

A comparative study on the polyphenolic content,antibacterial activity and antioxidant capacity of different solvent extracts of Brassica oleracea vegetables

Brassica vegetables are rich in polyphenols, flavonoids and glucosinolates. Investigation was undertaken to optimise the best solvents among 60% ethanol, acetone and methanol for the extraction of polyphenols from Brassica vegetables. Furthermore, different properties such as antibacterial activity and antioxidant capacity were also investigated. Results showed that a 60% methanolic extract showed the highest total phenolic content which was 23.6, 20.4 and 18.7 mg gallic acid equivalents (GAE) g^?1 extract for broccoli, Brussels sprouts and white cabbage, respectively. The hydroxybenzoic acid content of various solvent extracts ranged from 5.86 to 8.91 GAE g^?1 extract for broccoli, 2.70 to 5.44 GAE g^?1 extract for Brussels sprouts and 3.69 to 4.86 GAE g^?1 extract for white cabbage, while the hydroxycinnamic acid content ranged from 0.78 to 1.26 chlorogenic acid equivalents (CAE) g^?1 extract for broccoli, 1.41 to 3.45 CAE g^?1 extract for Brussels sprouts and 0.49 to 1.14 CAE g^?1 extract for white cabbage. A concentration‐dependent antioxidative capacity was confirmed for different reactive oxygen species, and moderate antibacterial activity was observed against a number of Gram‐negative and Gram‐positive food spoilage and food pathogenic bacteria. Solvents significantly affected polyphenolic content and its different properties, and the methanol was found to be the best solvent for the extraction of polyphenols from studied Brassica vegetables.     

三叶青茎部不同溶剂提取物的功能成分、抗氧化及酪氨酸酶抑制活性研究

目的 以三叶青茎部为原料,探究三叶青不同溶剂提取物的功能成分、抗氧化及酪氨酸酶抑制活性。方法 采用乙醇超声法提取三叶青,获得醇提液及残渣。醇提液依次用石油醚、乙酸乙酯、正丁醇对其进行分步萃取,残渣则采用蒸馏水多次提取,最终得到4种提取物。分别测定4种提取物总酚、总黄酮、总皂苷、总多糖、抗氧化及酪氨酸酶抑制活性,并进行相关性分析。结果 4种提取物中乙酸乙酯萃取物总酚、总黄酮、总皂苷含量最高,分别为40.22%±1.01%、38.56%±0.64%、6.15%±0.21%,正丁醇萃取物总多糖含量最高,为9.29%±0.25%。各萃取物均具有抗氧化和酪氨酸酶抑制活性,其中乙酸乙酯萃取物清除1,1-二苯基-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、超氧阴离子、2-苯基-4,4,5,5-四甲基咪唑啉-3-氧代-1-氧(2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl,PTIO)自由基、羟自由基能力和铁离子还原能力(ferric reducing antioxidant power, FRA...     

Antioxidant and tyrosinase inhibitory activities of different parts of guava (<Emphasis Type="Italic">Psidium guajava</Emphasis> L.)

The antioxidant and the tyrosinase inhibitory activities of 4 different solvents (acetone, ethanol, methanol, and water) for preparation of extracts from guava (branch, fruit, leaf, and seed) were evaluated by measuring total phenolic contents (TPC), DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power (RP), and tyrosinase inhibitory activity. The extracts of branch and leaf showed relatively higher antioxidant properties than those of fruit and seed. The highest TPC (141.28 mg/g gallic acid equivalents), DPPH radical scavenging activity (IC₅₀=34.01 μg/mL), ABTS radical scavenging activity (IC₅₀=3.23 μg/mL), and RP (IC₅₀= 75.63 μg/mL) were found in acetone extract of leaf, while water extract of seed had the lowest antioxidant activity. The tyrosinase inhibitory activity of ethanol extract from guava leaf was 69.56%, which was the highest activity among the extracts. These results indicate that useful bioactive substances exist in the guava branch as well as leaf extracts.     

高粱米不同溶剂提取物的抗氧化活性研究

研究不同极性溶剂对高粱米提取物中活性物质含量及抗氧化活性的影响.结果表明,不同溶剂对高梁米中多酚、黄酮含量及抗氧化活性有明显的影响.80％丙酮提取物中的多酚、黄酮含量最高,分别为6.49 mg GA/g和61.2 mg/100 g,表现出较好的抗氧化能力.其次80％甲醇和80％乙醇提取物也表现出较好的抗氧化能力.与此相反,正己烷提取物中的多酚、黄酮含量最低,分别为1.30 mg GA/g和9.6 mg/100 g,抗氧化能力较差.相关性分析表明,提取物中的多酚、黄酮含量与其抗氧化能力有较高的相关性,说明高梁米不同提取物抗氧化能力的差异主要来源于提取物中抗氧化物质的量的差异.     

体外模拟胃肠消化过程中山楂的活性成分及抗氧化性规律

为了研究体外模拟山楂胃肠消化过程中的活性成分及抗氧化性变化规律。本实验通过体外模拟山楂口腔消 化液、胃消化液、肠消化液、肠透析液以及山楂提取液5 种样品,测定其黄酮、多酚、多糖和有机酸含量变化,及 5 种样品对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、2,2’-联氮-二（3-乙基-苯并噻 唑-6-磺酸）二铵盐（2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonate),ABTS）自由基、羟自由基清除能力及铁离 子还原能力。结果表明：5 种样品在模拟消化过程中活性成分具有相似的变化趋势,其中经口腔和胃消化后多糖和 有机酸比消化前含量显著增加;5 种样品清除DPPH自由基、ABTS＋?及还原铁离子能力的变化趋势相似,其中口腔 和胃消化液抗氧化能力最强,肠透析液抗氧化能力最弱,而清除羟自由基能力的结果略有不同。从本研究中可以看 出山楂在体内的消化产物具有较好的抗氧化活性。     

红薯叶不同溶剂提取物抗氧化性及活性成分鉴定

研究不同极性溶剂对红薯叶中酚类化合物的提取以及提取物抗氧化性的影响,并鉴定提取物中的主要抗氧化成分组成。分别采用极性不同的7 种溶剂（蒸馏水、甲醇、无水乙醇、丙酮、正丁醇、乙酸乙酯和氯仿）从红薯叶中提取多酚,并评价提取物中总酚、总黄酮和花青素的含量,以及对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力和还原能力,最后运用高效液相色谱-串联质谱（high performance liquidchromatography tandem mass spectroscopy,HPLC-MS/MS）技术分析抗氧化活性最好的提取物中多酚的主要组成成分。结果表明：提取溶剂的极性对红薯叶中多酚类化合物的提取效率和提取物抗氧化活性有很大的影响,水提物具有最高的粗提物得率（（37.13±1.60）%）,而甲醇提取物中总酚含量（13.80 mg GAE/g）和总黄酮含量（（5.68±0.35）mg QE/g）最高,且具有最好的DPPH自由基清除能力（IC50为0.32 mg/mL）与还原能力（ρ0.5为0.95 mg/mL）。采用HPLC-MS/MS从红薯叶甲醇提取物中鉴定9 种、初步鉴定3 种酚类化合物,鉴定的化合物为咖啡酸、对羟基苯甲酸、1-咖啡酸奎宁酸、3-咖啡酸奎宁酸、异绿原酸A、异绿原酸B、异绿原酸C、3,4,5-三咖啡酰奎尼酸和金丝桃苷。     

Antioxidant activity of sage extracts in rapeseed oil irradiated with UV‐rays

The antioxidant activities of sage acetone oleoresin and its methanol‐water fractions were tested in rapeseed oil at 0.1% concentrations and 80°C temperature after irradiation with UV‐rays (exposition 0.5 h). It was determined that even little doses of UV irradiation induce oxidation process in rapeseed oil samples both with additives and without them. The antioxidant activity of a synthetic antioxidant BHT was much lower than that of the sage fractions at 80°C and forced air oven conditions. This finding proves the advantage of sage extracts in comparison with BHT at high temperatures. It was also found that methanol‐water fraction separated from acetone oleoresin had the highest antioxidant activity in terms of the formation of primary and secondary oxidation products. Oil sample with this additive had the highest protection factor (PF = 4.53) when the oil was not irradiated with UV rays. The data obtained showed that all sage extracts had very strong antioxidant activity (PF > 3).     

丙酮法提取菜籽饼多酚及体外抗氧化性研究

以菜籽饼为原料,探讨了采用丙酮法提取菜籽饼多酚的工艺及丙酮多酚提取液的体外抗氧化性。以多酚得率为考察指标,选择丙酮体积分数、提取温度、料液比及提取时间进行单因素及正交试验,确定了丙酮法提取菜籽饼多酚的最优工艺条件:提取温度70℃,料液比1∶12,提取时间30 min,丙酮体积分数35%,在此条件下菜籽饼多酚得率为20.64 mg/g。以鞣酸、维生素C为对照,通过测定丙酮多酚提取液的还原能力及对DPPH.的清除能力,结果表明,丙酮多酚提取液具有一定的体外抗氧化能力。     

Encapsulation of polyphenolic antioxidants from medicinal plant extracts in alginate–chitosan system enhanced with ascorbic acid by electrostatic extrusion

In this study the encapsulation of raspberry leaf, hawthorn, ground ivy, yarrow, nettle and olive leaf extracts was performed by electrostatic extrusion in alginate-chitosan microbeads, with ascorbic acid being used for the dissolution of chitosan. The original and encapsulated plant extracts were characterized for their polyphenol content and composition, mineral content and antioxidant capacity. Raspberry leaf encapsulating microbeads exhibited the highest total phenol content and antioxidant capacity, followed by hawthorn, while olive leaf microbeads contained the lowest total phenol content. High encapsulation efficiency was obtained for all extract encapsulating microbeads (80-89%). Nettle extract-containing microparticles were characterized with the largest particle size and irregular shape, due to a high content of microelements (copper, strontium, and zinc), which affected the geling process of alginate. Although the antioxidant stability of hydrogel microcapsules was deteriorated during refrigerated storage, which might be attributed to the instability of ascorbic acid, the obtained microbeads deliver significant biological activity and antioxidant potential which may increase the daily intake of antioxidants when implemented in a food product.     

Microwave‐assisted extraction optimised with response surface methodology and antioxidant activity of polyphenols from hawthorn (Crataegus pinnatifida Bge.) fruit

Microwave‐assisted extraction (MAE) of polyphenols from hawthorn (Crataegus pinnatifida Bge.) fruit was investigated, and the best combination of extraction parameters was obtained using response surface methodology (RSM). The optimised procedure was achieved by soaking the sample powder with 83% ethanol for 90 min at solid–liquid ratio of 1–20, and then microwave irradiation for 13 min at power of 440 W. Under this condition, an extraction yield of 23.5% was obtained and the percentage of phenolic compounds in the extract reached 41.2%. The total content of polyphenols in hawthorn fruit was 96.9 ± 4.3 mg gallic acid equivalents per gram of dry weight measured by Folin‐Ciocalteu reagent method, and the main phenolic compounds were determined as procyanidin B₂, epicatechin, chlorogenic acid, procyanidin C₁ and rutin. Biological studies showed that the extract possessed a strong inhibitory effect against DPPH, hydroxyl radicals and lipid peroxidation, as well as strong reducing power.     

Chemical Composition and Bioactivities of Two Common Chaenomeles Fruits in China: Chaenomeles speciosa and Chaenomeles sinensis

Contents of total flavonoids, total phenolics, total triterpenes, total condensed tannin and total saponins in peels, flesh and endocarps of Chaenomeles speciosa (CSP) and Chaenomeles sinensis (CSS) were determined by colorimetric method, while 5 phenolics (vanillic, gallic, chlorogenic, ferulic and p‐coumaric acids), 2 triterpenes (oleanolic and ursolic acids), and 3 flavonoids (rutin, catechin and epicatechin) were identified and quantified by high‐performance liquid chromatography‐mass spectrometry (HPLC‐MS) and HPLC, and antioxidant and α‐glucosidase inhibitory activities of them also were evaluated as well as their digestive characteristics. In the correlation analysis, total phenolics, vanillic acid, catechin, ursolic acid and oleanolic acid all contribute to DPPH^· scavenge capacity, gallic acid contributes to total ferric reducing antioxidant power, while total triterpenes, total saponins, chlorogenic acid and ferullic acid contribute to α‐glucosidase inhibitory activity. In the principal component analysis, endocarps of CSP and CSS both show better quality than their peels and flesh, respectively. In vitro digestion can increase contents of total flavonoids, total condensed tannin and total saponins, while contents of total phenolics and total triterpenes decreased greatly. Our study would contribute to the full use of discarded parts of the 2 Chaenomeles and be helpful to establish a good foundation for further research of CSP and CSS.     

Profile of antioxidant and antibacterial activities of different solvent extracts from Rabdosia rubescens

The objective of this work was to investigate the antioxidant and antibacterial activities of different extracts from Rabdosia rubescens and to further evaluate the antibacterial mechanism of extracts. The results showed that 80% acetone extracts had the highest contents of total polyphenols (8.09 mg GAE g^?1) and flavonoids (5.69 mg RE g^?1) and exhibited the strongest antioxidant activities, followed by 80% methanol and 80% ethanol, and the lowest for hexane extracts. Others except for hexane extracts showed different antibacterial activities against Gram‐positive strains, while no inhibitory effects were found on tested Gram‐negative bacterial strains. Among these extracts, 80% acetone and ethanol extracts had relatively higher antibacterial activities with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 5 and 10 mg mL^?1. The antibacterial mechanism of ethanol extracts against Staphylococcus aureus might be described as it disrupts cell wall, increases cell membrane permeability and then leads to the leakage of cell constituents.     

Influence of solvent and temperature on extraction of phenolic compounds from grape seed,antioxidant activity and colour of extract

This study was aimed to investigate the influence of solvent (water and ethanol in concentration: 50%, 70% and 96%) and extraction temperature (25–80) °C on polyphenols extraction of grape seed (Vitis vinifera L. cv. “Frankovka”) cultivated in Eastern Croatia. The best results were reached using 50% ethanol at 80 °C. The most abundant individual polyphenolic compound was catechin which makes the average of 45.11% of the total phenolic content followed by epicatechin (34.45%), procyanidin B₂ (12.90%), gallic acid (5.34%), gallocatechin (1.58%), epicatechin gallate (1.01%). The antioxidant activity of extracts was determined by DPPH‐method and it was highly dependent on extraction solvent and temperature. The total extractable proanthocyanidins content of extract had the highest positive correlation (r = 0.994) with antioxidant activity, which indicated that these compounds might be the most important antioxidant in examined grape seed extracts. Relationship between phenolic content and colour of extracts was observed.     

体外模拟胃肠消化中山楂多酚及抗氧化活性的变化

本实验研究了山楂多酚、黄酮及抗氧化活性在体外模拟胃肠道环境下的变化规律,并利用高效液相色谱法测定了胃肠消化对山楂中5 种主要单体酚类化合物的影响。结果表明：山楂多酚在模拟胃液消化中稳定性较好,总多酚、黄酮含量及抗氧化能力均无显著性变化（P＞0.05）;而在模拟肠液消化中山楂多酚易发生降解,总多酚、黄酮含量在0.5 h内分别降低16.26%和7.46%,抗氧化能力也随之降低10.25%。高效液相色谱测定结果显示,5 种单体酚类化合物含量在胃液消化中无显著性变化（P＞0.05）;而在肠液消化中变化情况不相一致,其中金丝桃苷和异槲皮苷含量无显著性变化（P＞0.05）,表儿茶素在0.5 h内完全降解,绿原酸和原花青素B2在0.5 h内分别显著下降40.78%和28.99%（P＜0.05）。     

Enhancement of antioxidant activity,total phenolic and flavonoid content of black soybeans by solid state fermentation with Bacillus subtilis BCRC 14715

In the present study, a solid state fermentation of black soybeans with Bacillus subtilis BCRC 14715 was performed. The effect of fermentation on the changes of total phenolic and flavonoid content and antioxidant activities including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect, and Fe²⁺-chelating ability exerted by various solvent (water, 80% methanol, 80% ethanol, 80% acetone) extracts of black soybeans was examined. It was found that fermentation enhanced the total phenolic and flavonoid content as well as antioxidant activity of the black soybean extract. Among the various extracts examined, the acetone extract of fermented black soybeans showed the highest total phenolic and flavonoid content. The acetone extract and the methanol extract of fermented black soybeans showed the highest DPPH free radical-scavenging effect and Fe²⁺-chelating ability, respectively. Analysis of extraction yields showed that the active principle associated with the DPPH radical-scavenging effect was most efficiently extracted from black soybeans using water, regardless of fermentation. Water and methanol effectively extract the Fe²⁺-chelating principles from non-fermented and fermented black soybeans, respectively.     

INHIBITORY POTENTIAL OF WINE AND TEA AGAINST α-AMYLASE AND α-GLUCOSIDASE FOR MANAGEMENT OF HYPERGLYCEMIA LINKED TO TYPE 2 DIABETES

ABSTRACT

Natural α‐amylase and α‐glucosidase inhibitors from food‐grade plants offer an attractive strategy to manage postprandial hyperglycemia for type 2 diabetes management via control of starch breakdown and intestinal glucose absorption. In this study, four random sources of red and white wines as well as four types of teas were investigated for α‐amylase and α‐glucosidase inhibitory potential. Water extracts of black tea had the highest α‐glucosidase inhibitory activity, followed by white tea and oolong tea. All the randomly selected red wines had significant α‐glucosidase inhibitory activity compared to white wine. The α‐glucosidase inhibitory activity of the tea and wines correlated to the phenolic content, antioxidant activity and phenolic profile of the extracts. Further, these extracts had less or no α‐amylase inhibitory activity, indicating potential to overcome the side effects of undigested starch. This research has relevance for managing hyperglycemia and related oxidation‐linked dysfunction and concurrently reducing problems of undigested starch.

PRACTICAL APPLICATIONS

In this study anti‐diabetic‐relevant potential of wines and teas were confirmed in four types of red and white wines as well as four types of commonly available teas using in vitro enzyme assays for alpha‐glucosidase and alpha‐amylase inhibitory activities. In vitro inhibitory activities of these enzymes provide a strong biochemical rationale for further in vivo studies and dietary management strategy for type 2 diabetes through the control of glucose absorption. Further this phenolic antioxidant‐enriched dietary strategy using specific beverage combinations can generate a whole food profile that has the potential to reduce hyperglycemia‐induced pathogenesis and also associated complications linked to cellular oxidation stress.