Phytochemical,antioxidant, and antibacterial activities of fermented Citrus unshiu byproduct

Food Science and Biotechnology - Citrus unshiu is an economically important fruit on Jeju Island, Korea, but byproducts are a major source of agricultural waste. The aim of this study is to examine...     

Chemical composition and antibacterial activities of lupin seeds extracts

Determination of influence of lupin natural phenolic compounds on antibacterial properties of its seeds was carried out. Raw material were seeds of Lupinus albus, L. luteus, and L. angustifolius. The methods included the determination of the content of proteins, total phenolic compounds, free phenolic acids, and tannins as well as antibacterial properties with ethanol extracts. The content of total phenolic compounds was smaller in testas than in cotyledons and the highest levels are observed in bitter cultivars of Lupinus albus cv. Bac and L. angustifolius cv. Mirela. Lupin tannins mainly occurred in cotyledons of the white lupin, predominantly in the bitter cultivar Bac. Free phenolic acids were mainly found in testas. Only extracts from the testas displayed antibacterial properties, which excludes the possibility of alkaloid influence on the results. The results suggest that inhibition of test bacteria growth depended mainly upon the content of the total phenolic compounds.     

荔枝核水提物抗氧化和抑菌作用的研究

以荔枝核为原料,经过粉碎,采用传统中药水煎法制备得到荔枝核水提物。通过测定还原能力、总抗氧化能力以及水提物对1,1-二苯基-2-三硝基苦肼自由基(DPPH.)、羟自由基(.OH)、超养阴离子自由基(O2-.)的清除能力来评价水提物的抗氧化活性。同时,通过侧定抑菌圈直径大小和最小抑菌浓度研究的荔枝核水提物对金黄色葡萄球菌的抑菌效果。实验结果表明:荔枝核水提物有较好的抗氧化性,对DPPH.、.OH、O2-.的IC50分别是0.1819mg/mL、16.3652mg/mL、31.6767mg/mL。同时荔枝核水提物表现出一定的还原能力和抗氧化能力。通过抑菌实验,得出荔枝核水提物对金黄色葡萄球菌有抑制效果。当水提物的浓度为3.125%,抑菌圈直径为8.8±0.58mm。荔枝核水提物对金黄色葡萄球菌的最小抑菌浓度为6.25%。     

In-vitro antioxidant activities of an ethanolic extract of the oyster mushroom,Pleurotus ostreatus

The antioxidant potential of an ethanolic extract of the oyster mushroom, Pleurotus ostreatus, was investigated. The extract exhibited the most potent radical-scavenging activity at a maximum concentration of 10 mg/ml, and the scavenging effects were 56.20% and 60.02% on hydroxyl and superoxide radicals, respectively. The IC₅₀ values of the extract were found to be 8 mg/ml for hydroxyl and superoxide radicals. Ascorbic acid used as a standard was highly effective in inhibiting hydroxyl and superoxide radicals, showing IC₅₀ values of 6 mg/ml and 4 mg/ml respectively. At a maximum concentration of 10 mg/ml, the extract effected 56.12% inhibition of lipid peroxidation and 60.68% chelation of ferrous ions; also, at a maximum concentration 10 mg/ml, the extract manifested significant (p < 0.05) reducing power (1.367) which exceeded even that of butylated hydroxyl toluene (1.192). Increasing concentrations of the extract were found to cause progressively decreasing intensity of fluorescence 2, 3-diazabicyclo [2, 2, 2] oct-2-ene (DBO). In addition, the known antioxidants were identified as components of the extract. The data generated by this study strongly suggest that an ethanolic extract of the oyster mushroom, P. ostreatus, has potent antioxidant activity.Industrial relevanceThe present study suggests that an ethanolic extract of the mushroom, Pleurotus ostreatus, could serve as an easily accessible item of food rich in natural antioxidants, as a possible food supplement or even as a pharmaceutical agent. Hence this study is considerable relevant to the food and pharmaceutical industries.     

Evaluation of antioxidant,antibacterial and anti-tyrosinase activities of four Macaranga species

The methanolic fresh leaf extracts of Macaranga gigantea, Macaranga pruinosa, Macaranga tanarius and Macaranga triloba were screened for their antioxidant properties (AOP), tyrosinase inhibition and antibacterial activities. Total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferric-ion reducing power (FRAP), ferrous-ion chelating (FIC) and lipid peroxidation inhibition (LPI) activities were used to evaluate the AOP. Modified 3,4-dihydroxy-L-phenylalanine (L-DOPA) method was used to determine tyrosinase inhibition activity, whereas antibacterial activity was determined using the disc-diffusion technique. TPC screening of the same species from different collection sites showed no significant difference between sites. M.triloba showed the highest ascorbic acid equivalent antioxidant activity (AEAC), FRAP and LPI values. M. tanarius, which showed the lowest TPC, AEAC, FRAP and LPI activities, exhibited the best FIC activity. M. pruinosa showed the best tyrosinase inhibition activity, whereas M. triloba showed the best antibacterial activity against Gram-positive bacteria species, with minimal inhibition dosage (MID) values as low as 10 μg/disc.     

Influence of roasting on chemical profile,antioxidant and antibacterial activities of dried chili

Food Science and Biotechnology - Roasted dried chili, used to improve texture and taste, is important for various cuisines. The effect of roasting at 90&nbsp;°C for 25&nbsp;min on the...     

柠檬果皮精油的化学组成、抗氧化及抑菌活性研究

采用GC-MS法分析经水蒸气蒸馏法所提柠檬果皮精油的化学组分,并对其抗氧化与抑菌活性进行了研究。实验结果表明:鉴定出23种挥发性成分,占精油总量的94.57%,主要为dl-柠檬烯(42.93%)、γ-萜品烯(8.41%)、α-松油醇(6.39%)和E-柠檬醛(6.09%)等;柠檬精油对OH自由基有较好的清除效果,清除率可达95.14%;而对DPPH自由基的清除率在实验条件下最高为34.81%,远低于同浓度的PG和TBHQ。200mg/kg添加量的柠檬精油可延缓猪油和花生油的贮藏期,但略差于同浓度TBHQ和VE的抗氧化效果。抑菌活性实验结果表明柠檬精油对6种供试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度(MIC)为0.1μL/m L。     

新疆凤仙花色素抑菌及抗氧化活性研究

以凤仙花为植物材料,采用滤纸片法以四种常见致病菌(金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌和变形杆菌)为供试菌,测定凤仙花色素的体外抑菌作用;以还原力、清除DPPH自由基、羟基自由基的能力测定色素的抗氧化性能。结果表明凤仙花色素对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌和变形杆菌的最低抑菌浓度(MIC)分别为1.563%、3.125%、3.125%、1.563%,其抑菌活性随着浓度的增大而逐渐增强;凤仙花色素具有较好的还原力、清除DPPH自由基和羟基自由基能力。     

迷迭香叶对葵花籽抗氧化性的影响研究

通过在煮制葵花籽过程中加入迷迭香叶,采用Schaal烘箱法研究迷迭香叶添加量、煮制时间、烘烤时间对葵花籽酸价、过氧化值和感官评分的影响。并根据单因素试验结果,以过氧化值为指标进行正交试验得出在添加25%迷迭香叶、煮制120 min、烘烤100 min的工艺条件下,葵花籽产品抗氧化效果和感官品质最好。     

Comparisons of physicochemical properties and antioxidant activities among pumpkin (Cucurbita moschata L.) flour and isolated starches from fresh pumpkin or flour

Physicochemical properties (pasting and thermal properties, swelling power, water solubility and antioxidant activities) and chemical composition of pumpkin flour (PF) and starches, isolated from fresh pumpkin (SFF) or flour (SFP) were compared. SFP and SFF had similar proximate composition and amylose content. Drying process during PF preparation modified starch properties. PF exhibited greater antioxidant activities (DPPH, ABTS and FRAP), but had lower β‐carotene than fresh pumpkin. SFF and SFP had higher amylose content than PF, and exhibited a B‐type X‐ray diffraction pattern with spherical and dome‐like starch granules. Peak viscosity of SFP was relatively higher than that of SFF, probably due to lower swelling power and water solubility, which indicated increased granular rigidity in the SFP starch structure. Compared with SFF and SFP, PF had significantly higher onset (T_o), peak (T_p) and conclusion (T_c) temperatures due to a lower starch content and relatively higher fibre content, which resulted in lower gelatinisation enthalpy (ΔH).     

香蕉皮单宁的提取及其提取物的抑菌抗氧化活性

以香蕉皮为原料,采用微波提取法,以单宁提取率为评价指标,在单因素试验基础上,通过响应面法优化了香蕉皮单宁提取工艺;滤纸片法测定了单宁对细菌、霉菌和酵母菌的抑菌性能;通过对O-2·和·OH的清除能力,确定了香蕉皮单宁的抗氧化能力。结果表明:香蕉皮单宁微波提取的最优工艺条件为,乙醇体积分数75%、提取时间为80 s、微波功率375 W、料液比1∶30(g∶m L),在此条件下单宁的提取率为87.04%;抑菌试验结果显示,香蕉皮单宁对大肠杆菌、金黄色葡萄球菌、根霉、青霉及酵母菌都有一定的抑菌效果,对大肠杆菌的最低抑菌浓度为0.78 mg/m L,金黄色葡萄球菌和酵母菌为6.25 mg/m L,霉菌为1.56 mg/m L;香蕉皮单宁对超氧阴离子自由基和羟自由基具有较好的清除能力,并在低浓度时(<1.0 mg/m L)抗氧化性要高于Vc,在浓度为1.8mg/m L时,香蕉皮单宁对超氧阴离子和羟自由基的清除率可达(66.04±3.926)%和(73.14±4.128)%。     

沙枣黄酮提取工艺、抗氧化及抑菌活性研究

利用单因素和正交实验研究了沙枣黄酮的提取工艺,采用DPPH自由基清除法、Rancimat实验研究沙枣黄酮的抗氧化性能,用滤纸片法检测其抑菌活性.结果显示,沙枣黄酮最佳提取工艺为:料液比1∶18、超声时间10min,乙醇浓度60％,超声功率320W,在此条件下沙枣黄酮得率达5.28％;抗氧化实验表明,沙枣黄酮有较好的抗氧化活性,且在同浓度下,其抗氧化活性强于VC;抑菌实验结果显示,沙枣黄酮对六种供试菌种均有抑制效果.对大肠杆菌、金黄色葡萄球菌的最小抑菌浓度为1.0g/L;对枯草芽孢杆菌、青霉、毛霉、黑曲霉的最小抑菌浓度为1.5g/L.     

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.     

南瓜多糖硫酸酯化衍生物的制备及抗氧化研究

采用氯磺酸一吡啶法,对南瓜粗多糖和分离得到的南瓜AP1多糖进行硫酸酯化;采用邻二氮菲-金属铁离子-H2O2体系和邻苯三酚自氧化法,测定南瓜多糖对羟自由基和超氧阴离子自由基的清除作用.结果表明,四种南瓜多糖均能有效清除羟基自由基,并随着浓度的增加,清除作用加强,且水提南瓜粗多糖对羟基自由基清除作用显著高于其它三种多糖.南瓜粗多糖和南瓜AP1多糖对超氧阴离子自由基的清除作用不明显,经硫酸酯化后的多糖能有效清除超氧阴离子自由基,并呈量效关系.实验结果表明,硫酸酯化南瓜多糖具有抗氧化性.     

金莲花黄色素抗氧化与抑菌活性的研究

研究金莲花黄色素的抗氧化与抑菌活性,为其综合利用提供科学依据。实验以清除DPPH·法和·OH法评价金莲花黄色素抗氧化活性,以滤纸片法测定其抑菌活性。抗氧化实验结果显示,金莲花黄色素对DPPH·和·OH的清除率与其质量浓度呈明显的量效关系,其对DPPH·和·OH的半清除率IC_(50)分别为18.04μg/m L和21.35μg/m L;常用抗氧化剂BHT对DPPH·和·OH的半清除率IC_(50)分别为30.18μg/m L和27.96μg/m L。抑菌实验结果显示,当金莲花黄色素质量浓度为0.2 mg/m L时,对金黄色葡萄球菌、枯草芽孢杆菌和大肠杆菌的抑菌圈直径分别可达14.4mm、12.3mm和9.5mm。结果表明,金莲花黄色素具有较强的抗氧化活性和一定的抑菌活性。金莲花黄色素是一种天然抗氧化剂的新资源。     

Evaluation and improvement of antioxidant and antibacterial activities of supercritical extracts from clove buds

For the first time, extracts from clove buds obtained by supercritical carbon dioxide extraction were screened for antioxidant and antibacterial activities. Additionally, antioxidant and antibacterial activities of extracts obtained by the supercritical extraction of the clove bud–oregano leaf mixtures were studied. Supercritical extract of pure clove had the highest eugenol (64%) and total phenolic content (530.56 mg GAE/g_extract). All extracts had antioxidant activity comparable to synthetic antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and formation of peroxides. Presence of 0.6% and 5% of oregano extract in the clove extracts obtained from the clove–oregano plant mixtures improved their antioxidant activity with respect to the extract from pure clove. Clove extract showed moderate antibacterial activities against selected Staphylococcus and Enterococcus bacterial strains. Presence of 50% of the oregano extract improved antibacterial activity of clove extract against all tested strains and resulted in a synergistic antibacterial activity against Methicillin-resistant Staphylococcus haemolyticus strain (MIC ? 1.25 μg/mL). Study demonstrated great potential of supercritical clove extract as natural functional ingredient and the possibility of increasing its antioxidant and antibacterial efficiencies in order to apply lower concentrations and to reduce undesirable flavour notes and toxicological effects in final products.     

板栗多糖的分离纯化及抗氧化活性研究

从板栗中分离纯化得到多糖并研究其抗氧化活性.采用沸水提取、Sevag法除蛋白、80%乙醇沉淀的方法从板栗中提取得到板栗多糖CPS.CPS经DEAE-纤维素柱分离纯化后,于蒸馏水洗脱液中得到一个纯化多糖组分CPS1.以VC为对照,试验了CPS与CPS1对羟自由基、超氧阴离子自由基、过氧化氢的清除能力及还原能力.结果表明,CPS与CPS1均具有一定的清除羟自由基、超氧阴离子自由基、过氧化氢的能力及还原能力,而且与多糖的浓度成正相关性.其中,CPS对过氧化氢的清除作用效果与VC相当.另外,经纯化精制后的CPS1对羟自由基、超氧阴离子自由基、过氧化氢的清除作用及还原能力均低于CPS.     

Enzymatic grafting of gallate ester onto chitosan: evaluation of antioxidant and antibacterial activities

The antioxidant octyl gallate (OG) has been successfully grafted onto chitosan by means of horseradish peroxidase biocatalyst. The maximum gallate incorporation onto chitosan determined by ¹H NMR spectroscopy was up to 16 molar%. The resulting materials displayed antioxidant capacities with DPPH radical inhibition percentage up to 23% upon the assay conditions. The grafting of the antioxidant on chitosan enhanced its antimicrobial activity. Minimal inhibitory concentration (MIC) for Escherichia coli was 0.5 g L^?1. The native medium molecular weight chitosan alone or grafted with the lowest OG incorporation (ca. 11 molar%) attained 100% inhibition of E. coli, whereas lower inhibition was observed for all other materials 50.7–68.9% corresponding a reduction in the counts from 10.6 to 5.23–3.30 Log CFU mL^?1. The inhibition of Listeria monocytogenes was significantly higher (59.8–100%) than that with the Gram negative bacterium reaching the MIC at 0.25 g L^?1 with a reduction in the counts from 12.6 Log CFU mL^?1 to 5.06–0 Log CFU mL^?1.