龙眼核提取物的体外抗氧化及抑菌活性研究

探讨龙眼核中不同极性部位的体外抗氧化和抑菌活性,并筛选其有效部位。以Folin-Ciocalteu比色法测定龙眼核95%乙醇提取物中4种不同极性萃取物的总酚含量,并利用ABTS法、DPPH法、邻苯三酚自氧化法、邻二氮菲—Fe2+氧化法测定评价各萃取物的抗氧化活性,同时采用牛津杯法测定比较4种萃取物的抑菌活性。结果表明:乙酸乙酯萃取物的总酚含量最高,达到(693.51±9.52)mg/g;在不同的自由基体系中,4种萃取物均对·O-2的清除作用最弱,但对清除ABTS·+、DPPH·、·OH均表现出较强的效果,龙眼核各萃取物抗氧化能力的结果为乙酸乙酯萃取物氯仿萃取物正丁醇萃取物水层剩余物;除水层对沙门氏菌和大肠杆菌均无明显抑制作用外,4种萃取物对沙门氏菌、大肠杆菌、金黄色葡萄球菌均具有不同强度的抑制作用,其中乙酸乙酯层的抑菌活性最为突出。由结果可推断乙酸乙酯萃取物含有丰富的多酚类物质,可作为一种天然的抗氧化剂和抑菌剂,具有很大的药用价值和应用前景。     

Antioxidant and antibacterial activities of various seabuckthorn (Hippophae rhamnoides L.) seed extracts

Seabuckthorn (Hippophae rhamnoides L.) seeds were successively extracted with chloroform, ethyl acetate, acetone and methanol (MeOH) using a Soxhlet extractor for 8 h each. The crude extracts were screened for antioxidant and antibacterial activities. The reducing power and antioxidant activities evaluated in various in vitro models (1,1-diphenyl-2-picrylhydrazine and liposome model system) showed the highest activity for MeOH extract. The MeOH extract was also found to posses maximum antibacterial activity. The MIC values, with respect to MeOH extract for Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Listeria monocytogenes, Yersinia enterocolitica, were found to be 200, 300, 300, 300, and 350 ppm, respectively. These results indicated the possibility of using seabuckthorn seeds for medicinal uses and food preservation.     

Bioactive compounds and antioxidant activities of Brazilian hop (Humulus lupulus L.) extracts

Bioactive compounds from Brazilian hop (Humulus lupulus L.) cultivars were extracted by ultrasound and their phenolic profile compared with commercial hop from the USA. The most effective extraction conditions (solution of ethanol 49%, at 52 °C and a solid/liquid ratio of 1 g per 34 mL) for the total phenolic compounds (TPC) were determined using a Central Composite Rotatable Design. The Brazilian hop showed higher content of TPC (33.93 ± 0.67 mg GAE g⁻¹), total flavonoids (54.47 ± 0.10 mg QE g⁻¹) and higher antioxidant activity (ABTS: EC₅₀ 21.29 ± 1.36 μL mL⁻¹; DPPH: EC₅₀ 3.91 ± 0.17 μL mL⁻¹) when compared with the USA hop. The main phenolic compounds present in the extracts were the flavonoids isoquercitrin and quercetin. The antioxidant properties of the Brazilian hop extract had not been reported yet in the literature for this raw material, thus showing potential to be incorporated in polymeric films used as active packaging.     

Antibacterial and antioxidant activities of grape (Vitis vinifera) seed extracts

Grape seeds were powdered and the fatty material was extracted in a Soxhlet extractor with petroleum ether (60–80 °C) for 6 h. The defatted powder was extracted with acetone:water:acetic acid (90:9.5:0.5) and methanol:water:acetic acid (90:9.5:0.5) for 8 h each separately. The extracts were concentrated under vacuum to obtain crude extracts, which were analyzed by high performance liquid chromatography with UV detection at 280 nm. Monomeric procyanidin was found to be the major compound being at 48 and 40% in acetone:water:acetic acid (90:9.5:0.5) and methanol:water:acetic acid (90:9.5:0.5) extracts, respectively. These extracts were tested for antibacterial activity by pour plate method against Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. It was found that, Gram-positive bacteria were completely inhibited at 850–1000 ppm, while Gram-negative bacteria were inhibited at 1250–1500 ppm concentration. Radical-scavenging activity of grape seed extracts of acetone:water:acetic acid (90:9.5:0.5) and methanol:water:acetic acid (90:9.5:0.5) were compared with BHA at 25 and 50 ppm concentrations by HPLC method using 1, 1-diphenyl-2-picrylhydrazyl (DPPH). The antioxidant capacities of grape seed extracts were determined by the formation of phosphomolybdenum complex method. It was found that acetone:water:acetic acid (90:9.5:0.5) extract was better radical scavenger than methanol:water:acetic acid (90:9.5:0.5) extract.     

檀香叶提取物抗氧化及抗菌活性初步研究

研究檀香(Sandalwood)叶不同溶剂提取物的抗氧化及抗菌活性,为檀香叶资源开发利用提供依据。采用4种不同溶剂提取檀香叶中抗氧化、抗菌活性成分;采用清除DPPH自由基方法测定抗氧化活性,采用平板打孔法测定抗菌活性。结果表明:檀香叶80%乙醇、水、乙酸乙酯提取物可以清除DPPH自由基;80%乙醇提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌有抗菌作用,但对霉菌、啤酒酵母没有抑菌作用。乙醇提取物经不同温度、不同光照时间处理后,其抗氧化、抗菌活性较稳定。乙醇提取物经不同pH处理后,抗氧化物质在pH6～8范围内稳定,抗菌物质在pH3～7范围内稳定,碱性条件下不稳定。檀香叶乙醇提取物化学成分标识结果表明:檀香叶乙醇提取物中含有多糖、鞣质、黄酮类、酚类物、有机酸以及氨基酸、多肽、蛋白质等成分。结论:80%乙醇、水、乙酸乙酯提取物具有抗氧化活性,其中,80%乙醇提取物抗氧化活性最好。只有80%乙醇提取物具有抗菌活性。     

Anti-inflammatory and antioxidant activities of red pepper (Capsicum annuum L.) stalk extracts: Comparison of pericarp and placenta extracts

Red pepper stalks, an agricultural waste product, are casually discarded at landfills where they oxidize and harm the local ecology. To our knowledge, no feasible method has been designed to evaluate the bioavailability of red pepper stalks. Therefore, the present study focused on the stalk waste investigating its superoxide dismutase (SOD) activity and inhibitory effect on nitric oxide (NO) production in macrophages. Interestingly, by comparison with red pepper pericarp and placenta extracts, the stalks were found to have higher phenolic, flavonoid, and capsaicin contents. Chromatographic data showed differences in the amounts of phenolic compounds in various parts of red pepper. At a concentration of 100 μg/mL, the stalk, placenta, and pericarp had SOD activities of 52.3%, 7.4%, and 10.4%, respectively. A very high level of chlorogenic acid (3.82 mg/g d w) and p-coumaric acid (2.98 mg/g d w) gave the stalks of red peppers the most powerful antioxidant activity among the three tested parts. The high phenolic and SOD activity-containing stalks also had the most significant NO inhibitory effect (53.5%) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These results demonstrated that there is an opportunity to develop a new anti-inflammatory agent from agricultural wastes.     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Radical scavenging and antimicrobial activity of horsetail (Equisetum arvense L.) extracts

A reversed-phase high performance liquid chromatography (RP-HPLC) separation on C₈ column and quantitative method were developed to analyse hydroxyl derivatives of benzoic and cinnamic acid and flavonoids in horsetail ( Equisetum arvense L.) extracts. Total phenolic content of n -butanol, ethyl acetate and water extracts, determined by the Folin-Ciocalteu method, was 96.4, 26.4 and 15.4 mg g⁻¹ of dry extracts, respectively. The antioxidative activity of horsetail extracts was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reactive hydroxyl radicals by electron spin resonance spectroscopy. The results demonstrated that the free radical scavenging activity (versus both DPPH and hydroxyl radicals) depended on the type and concentration of applied extracts; the highest DPPH (EC₅₀ = 0.65 mg mL⁻¹) and hydroxyl radical scavenging activities (EC₅₀ = 0.74 mg mL⁻¹) were obtained in the case of n -butanol extract. The radical scavenging activity of extracts significantly correlated with total phenolic content. The antimicrobial tests showed that ethyl acetate and n -butanol extracts inhibited the growth of tested bacteria.     

Analysis of solvent effects on polyphenols profile,antiproliferative and antioxidant activities of mulberry (Morus alba L.) extracts

A systematic study about the solvent effect on the mulberry polyphenol (MP) profile, antioxidant and antiproliferation capacities against human hepatoma HepG2 cells was conducted. Results indicated that MP profiles showed significant differences as a function of solvents including AA/W (acetic acid/water), MeOH/AA/W (methanol/ acetic acid/water), EtOH/AA/W (ethanol/ acetic acid/water) and ME2CO/AA/W (acetone/ acetic acid/water). Among the solvents, EtOH/AA/W took advantage in obtaining MP with the highest yield (49.81 mg GAE g^?1 dw), and cellular antioxidant capacity in the PBS no‐wash protocol (63.2 μmolQE/100 g), as well as low cell cytotoxicity (≥50.0 mg mL^?1). ME2CO/AA/W was the best choice for extracting MP with the most various compositions (two phenolic acids, four anthocyanins and four flavonols), greatest potential in inhibiting proliferation of HepG2 cells (EC₅₀ = 28.2 mg mL^?1) and highest intracellular antioxidant activity (38.0 μmolQE/100 g). Results provide baseline information for efficient solvent extraction to obtain MP that is promising as natural antioxidants and antitumor agents.     

Evaluation of antioxidant activities of Iranian sumac (R. coriaria L.) fruit and spice extracts with different solvents

The antioxidant capacity and phenolic content of three sumac (Rhus coriaria L.) samples, including brown sumac fruit, brown sumac powder and red sumac powder were investigated in the present study. Methanol, ethanol, distilled water, and a mixture of methanol and ethanol (1:1) were used as solvent systems. Antioxidant activities of extracts were screened using 1,1-diphenyl-2-picrylhydrazyl DPPH radical scavenging method. Phenolic content was determined through Folin–Ciocaltaeu procedure. The efficiency of the solvents used to extract phenols from the samples varied considerably. The phenolic content of brown sumac powder ranged from 2.906 to 2.997 gallic acid equivalents/100 g (GAE/100 g), while that of the brown sumac fruit was 2.438–2.529 GAE/100 g, and that of the red sumac powder was 2.172–2.263 GAE/100 g. Findings indicated that water extracts of sumac have effective antioxidant and radical scavenging activities as compared to other extracts.     

Antioxidant and antimicrobial activities of Smilax china L. leaf extracts

Antioxidant and antimicrobial activities of Smilax china L. leaf extracts obtained with methanol, ethanol, acetone, and water were investigated. Antioxidant activity was evaluated by determining the DPPH radical scavenging activity, ABTS radical scavenging activities, total phenol content (TPC), and reducing power (RP). The highest DPPH, ABTS radical scavenging activity, and RP were found in the ethanol extract, which also showed the highest TPC (105.81±0.48 μg gallic acid equivalents/mL). The antimicrobial activity of all the extracts against foodborne microorganisms was determined by paper disc method. All the extracts inhibited the growth of Listeria monocytogenes, Staphylococcus aureus, and Salmonella Typhimurium, however, no antimicrobial activity was observed against Escherichia coli O157:H7. The results indicated that Smilax china L. possessed antioxidant and antimicrobial substances, and suggested that the ethanol extract can be applied into food and cosmetic industry.     

Phenol content related to antioxidant and antimicrobial activities of Passiflora spp. extracts

Methanolic extracts were prepared from different organs of plants from five Passiflora species obtained by zygotic embryo culture and evaluated for their capacity to quench DPPH and ABTS^•+ radicals in comparison to that of Trolox, a water soluble vitamin-E analogue. Moreover their antimicrobial activity against E. coli was tested by agar diffusion and turbidity assays. P. nitida, P. foetida, and P. palmeri showed antimicrobial activity. P. nitida and P. palmeri also showed high antioxidant activity. P. tenuifila and P. coriacea demonstrated antioxidant power but not antimicrobial activity. The phenolic content of the different extracts was studied and quantified by spectrophotometric methods, HPLC, and mass spectrometry. High antioxidant activity correlated with high amounts of o-diphenol and catechin. An unknown component, tentatively identified as structural isomer of isoschaftoside, appeared to correlate with antimicrobial activity.     

In vitro antioxidant, antimicrobial, and antitumor activities of bitter almond and sweet apricot (Prunus armeniaca L.) kernels

The aim of this study was to investigate in vitro antioxidant, antimicrobial, and antitumor activities of water, methanol, and ethanol extracts of sweet apricot and bitter almond kernels. The fruit extracts were evaluated for their antioxidant activities using various antioxidant methodologies including phosphomolybdenum assay (total antioxidant capacity), free radical scavenging assay, ferric ion reducing power, and β-carotene/linoleic acid bleaching test system. The antioxidant capacity of the sweet apricot kernels was better than those recorded for bitter almond ones. The highest total antioxidant activity (59.53 mg/g dry extract), ferric ion reducing power (1.626), antioxidant index (67%), total phenolic content (3.290 mg/g dry extract), and total lycopene content (4.70mg/mL) were detected in the aqueous extract of sweet apricot kernels. The antimicrobial activities of the above extracts were also tested against some pathogenic microorganisms using a disc-diffusion method. Additionally, the extracts of sweet apricot and bitter almond kernels could inhibit the growth of human breast (MCF-7), colon (HCT-116), and hepatocellular (Hep-G2) carcinoma cell lines in a dose-dependent manner with different sensitivity between cell lines. The overall results indicate promising baseline information for the potential uses of apricot (Prunus armeniaca L.) fruit extracts in the treatment of infectious diseases and tumors.     

Antimicrobial and antioxidant activity of crude onion (Allium cepa,L.) extracts

Antioxidant and antimicrobial activity of the ethyl acetate and water subfractions of methanolic extracts of three Spanish onion varieties were assayed. Flavonoids were mainly present in ethyl acetate subfraction being 34.92 ± 0.75, 7.95 ± 0.16, 0.38 ± 0.01 μmol of rutin eq. g^?1 D.W. and its antioxidant capacity was 74.86 ± 1.77, 24.59 ± 0.67, 4.55 ± 0.44 μmol Trolox g^?1 D.W. of Grano de Oro, Fuentes de Ebro and Calçot de Valls varieties, respectively. The antimicrobial activity of flavonol standards and onion extracts was evaluated against some food spoiler microorganisms. Quercetin and kaempferol were inhibitory against gram positive bacteria such as Bacillus cereus, Staphylococcus aureus, Microcroccus luteus and Listeria monocytogenes. Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa were less sensible to the antimicrobial effect of both flavonol standards and Candida albicans was totally resistant. Among the onion extracts tested only ethyl acetate subfraction showed antimicrobial inhibition.     

The in vitro antioxidant and antimicrobial activities of the essential oil and various extracts of Origanum syriacum L var bevanii

The present work examines the in vitro antioxidant and antimicrobial properties of the essential oil and various extracts from the herbal parts of Origanum syriacum L var bevanii. Polar subfractions of methanol extracts from both deodorised and non‐deodorised materials showed the highest DPPH (2,2‐diphenyl‐l‐picrylhydrazyl) radical‐scavenging activity, with IC₅₀ values of 21.40 and 26.98 µg ml^?1 respectively, whereas the IC₅₀ of the essential oil was 134.00 µg ml^?1. The antioxidant potential of the extracts appeared to be closely related to the presence of polar phenolics. However, the inhibitive effect on linoleic acid oxidation might be promoted by the presence of non‐polar phenolics, as both hexane and dichloromethane extracts showed high antioxidant activities. The antimicrobial activity of the essential oil was superior to those of the other extracts. Nineteen compounds representing 962 g kg^?1 of the essential oil were identified; carvacrol (669 g kg^?1) was the main component. Overall, the results suggest that the essential oil and extracts from the herbal parts of O syriacum could be used as natural preservative ingredients in the food industry. Copyright © 2004 Society of Chemical Industry     

Hypocholesterolaemic and antioxidant activities of chickpea (Cicer arietinum L.) protein hydrolysates

BACKGROUND: Some dietary proteins possess biological properties which make them potential ingredients of functional or health‐promoting foods. Many of these properties are attributed to bioactive peptides that can be released by controlled hydrolysis using exogenous proteases. The aim of this work was to test the improvement of hypocholesterolaemic and antioxidant activities of chickpea protein isolate by means of hydrolysis with alcalase and flavourzyme. RESULTS: All hydrolysates tested exhibited better hypocholesterolaemic activity when compared with chickpea protein isolate. The highest cholesterol micellar solubility inhibition (50%) was found after 60 min of treatment with alcalase followed by 30 min of hydrolysis with flavourzyme. To test antioxidant activity of chickpea proteins three methods were used: β‐carotene bleaching method, reducing power and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging effect since antioxidant activity of protein hydrolysates may not be attributed to a single mechanism. Chickpea hydrolysates showed better antioxidant activity in all assays, especially reducing power and DPPH scavenging effect than chickpea protein isolate. CONCLUSION: The results of this study showed the good potential of chickpea protein hydrolysates as bioactive ingredients. The highest bioactive properties could be obtained by selecting the type of proteases and the hydrolysis time. Copyright © 2012 Society of Chemical Industry     

沙棘籽粕多酚提取工艺优化、组分分析及抗氧化性能研究

为提高沙棘籽粕中蛋白质和多酚的利用率,在确保蛋白质溶出率低的情况下,优化了沙棘籽粕多酚的提取工艺条件。同时,采用HPLC对沙棘籽粕多酚提取液的组分进行了分析,并研究了沙棘籽粕多酚的抗氧化性。结果表明,沙棘籽粕多酚提取的最佳工艺条件为:80%甲醇溶液为提取溶剂,超声提取方式,超声频率40 k Hz,超声功率150 W,料液比1∶25,提取温度20℃,提取时间20min。在最佳提取条件下,多酚得率为(7. 83±0. 03)%。沙棘籽粕多酚提取液共检出没食子酸、儿茶素、芦丁、杨梅素、槲皮素、山奈酚6种多酚类物质,其中芦丁含量最高,为(1. 623±0. 224) mg/g(以沙棘籽粕质量计)。沙棘籽粕多酚具有较强的抗氧化性,对DPPH自由基和羟自由基均具有显著清除能力,半数抑制浓度(IC₅₀)分别为0. 057、0. 147 mg/m L。     

Effect of milling time on antioxidant compounds and activities of methanol extracts of sorghum [Sorghum bicolor (L.) Moench]

Antioxidant compounds and activities of methanol extracts of sorghum for different milling times were investigated. Total polyphenol, flavonoid, and tannin contents were measured using spectrophotometric methods. Methanol extracts were also evaluated for antioxidant activities based on DPPH and ABTS radical-scavenging activities. As milling rates increased, milling recovery and a value decreased, while L and b values increased. The extraction yield, antioxidant compound contents, and antioxidant activities of sorghum grain decreased with increasing milling rates. Methanol extracts from sorghum bran generally showed higher antioxidant activities than extracts from sorghum grain. The antioxidant content was higher in sorghum bran extracts than in grain extracts. A significant (p<0.05) correlation was observed between free radical-scavenging activity and the content of polyphenolic compounds. Sorghum bran exhibited antioxidant activities that may have important health benefits.     

Correlation analysis between phenolic levels of Brazilian propolis extracts and their antimicrobial and antioxidant activities

Propolis extracts are currently used for the treatment of oronasal infections and as antioxidant agents. Ethanolic commercial Brazilian propolis extracts were assayed for their ability to inhibit the growth of Staphylococcus aureus and also for their ability to scavenge DPPH radicals. These activities were correlated with their total phenolic and flavonoid levels. In one group of extracts there was a strong linear relationship between total phenol contents and the measured activities, while in the other group this relationship was weaker. It was also found that flavonoid levels had a greater influence on the antioxidant activity of these extracts than on their antimicrobial profiles.