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.     

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。      

Phenolic acids composition and antioxidant activity of canola extracts in cooked beef,chicken and pork

Crude polyphenol extracts (15 or 100 mg gallic acid equivalents (GAE)/kg meat) from canola meal reduced the formation of 2-thiobarbituric acid-reactive substances (TBARS) in pre-cooked beef (66–92%), pork (43–75%) and chicken (36–70%). The canola extract contained sinapic (99.7%), ferulic (0.28%) and p-hydroxybenzoic acids (0.07%).     

Chemical composition and antioxidant activities of Myrtus communis L. berries extracts

Myrtle (Myrtus communis L.) berries extracts were prepared with solvents at different polarity (water, ethanol, and ethyl acetate) and analysed using different in vitro tests in order to evaluate their antioxidant properties. Antiradical and total antioxidant activities were measured with DPPH and FRAP tests, respectively. Their ability to protect biological molecules was assessed using the cholesterol and LDL oxidation assays. In addition, phenolic compounds and unsaturated fatty acids composition was analysed by HPLC–DAD and HPLC–MS/MS. Ethanol and water extracts showed the highest amount of extracted compounds, but the highest antiradical and antioxidant activities were found in ethanol and ethyl acetate extracts. These extracts were also the ones with the highest content of phenolic compounds. In addition, our results showed a highly significant correlation between the amount of total phenols and antiradical (R² = 0.9993) or antioxidant activities (R² = 0.9985) in these extracts. HPLC–DAD and HPLC–MS analyses showed significant quantitative and qualitative differences among these three extracts. The ethyl acetate extract had the highest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu²⁺-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that because of these properties, myrtle berries could be used in dietary supplements preparations or as food additives.     

Phenolic composition,antioxidant and acetylcholinesterase inhibitory activities of Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) extracts

Total phenolic content, proanthocyanidins, gallotannins, flavonoids, and antioxidant activities of Sclerocarya birrea and Harpephyllum caffrum methanolic extracts were evaluated using in vitro assays. S. birrea young stem extract contained the highest levels of total phenolic content (14.15 ± 0.03 mg GAE/g), flavonoids (1.21 ± 0.01 mg CE/g) and gallotannins (0.24 ± 0.00 mg GAE/g). H. caffrum stem bark extract had the highest content of proanthocyanidins (1.47%). The EC₅₀ values of the extracts in the DPPH free radical scavenging assay ranged from 4.26 to 6.92 μg/ml, compared to 6.86 μg/ml for ascorbic acid. A dose-dependent linear curve was obtained for all extracts in the ferric-reducing power assay. Dichloromethane and methanol extracts exhibited dose-dependent acetylcholinesterase inhibitory activity. Similarly, all extracts exhibited high antioxidant activity comparable to butylated hydroxytoluene based on the rate of β-carotene bleaching (84.1–93.9%). The two Anacardiaceae species provide a source of natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial to the health of consumers.     

草果精油的化学组成、抗氧化及抑菌活性研究

以正己烷为溶剂提取草果精油,利用气相-质谱联用技术（GC-MS）分析其化学成分,同时研究了草果精油的抗氧化和抑菌活性。结果表明,草果精油成分比较复杂,其中有23种化合物被鉴定,主要成分为香叶醇（29.42%）、橙花叔醇（9.87%）、十八碳烯酸（8.62%）等。草果精油对DPPH和ABTS自由基均显示出了较好的清除效果,EC50值分别为3.84、3.20mg/mL;不同浓度的草果精油对5种测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2.0mg/mL。      

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。      

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。     

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.     

Chemical composition,cytotoxic and antioxidant activity of the leaf essential oil of Photinia serrulata

The leaf essential oil of Photinia serrulata was obtained by hydrodistillation and analyzed by GC and GC-MS. Seventy-one components were identified in the essential oil and the main components of the oil were 10-epi-γ-eudesmol (12.72%), pinene (6.85%), sabinene (5.93%), α-humulene (5.87%) and α-thujene (5.47%). The in vitro cytotoxicity of the oil on human cancer cell lines Hela, A-549 and Bel-7402 was examined. The oil was found to be very active against all the three human tumor cell lines tested with low IC₅₀ of 0.0427 μl/ml (Hela), 0.0219 μl/ml (A-549) and 0.0301 μl/ml (Bel-7402). The oil was also found to possess antioxidant activity as demonstrated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method.     

Chemical composition,antibacterial and antifungal activities of seed essential oil of Ferulago angulata

The aim of this study was to determine the chemical composition and the in vitro antimicrobial effects of seed essential oil of Ferulago angulata. The oil analyses by GC and GC/MS resulted in the identification of 39 compounds representing 91.07% of the oil. The major constituents were (Z)-β-ocimene (19.93%), α-pinene (15.50%), p-cymene (7.67%), sabinene (7.49%), β-phellandrene (5.5%), and α-phellandrene (4.95%). The oil was also screened for its antimicrobial properties against six bacteria (Erwinia amylovora, Xanthomonas oryzae, Pseudomonas syringae, Pectobacterium carotovorum, Ralstonia solanacearum, Bacillus thuringiensis) and six fungi (Alternaria alternata, Culvularia fallax, Macrophomina phaseolina, Fusarium oxysporum, Cytospora sacchari, Colletotrichum tricbellum). According to the results of antibacterial activity, B. thuringiensis (with 8 µL mL^?1 minimal inhibitory concentration (MIC) and 15 µL mL^?1 minimum bactericidal concentration (MBC)) was the most sensitive bacterium; P. carotovorum and R. solanacearum (with 20 µL mL^?1 MIC and 30< MBC) were the most resistant bacteria. Additionally, a broad differentiation against all of the tested fungi showed that the most susceptible and resistant fungi after 6 days at the highest concentration (800 µL L^?1) were F. oxysporum (100.0 ± 0.00%) and C. tricbellum (52.50 ± 1.67%) of growth inhibition, respectively.     

三种红树植物醇提取物抗菌及抗氧化活性研究

比较3种红树植物黄槿、白骨壤、桐花树不同溶剂萃取物体外对5种常见细菌的抑菌作用与清除自由基作用。利用乙醇浸提法和溶剂萃取法提取分离,得到4种不同溶剂萃取物。以5种常见的细菌作为供试菌,采用纸片扩散法、微孔板2倍稀释法比较3种红树植物萃取物的抑菌活性。采用硫酸亚铁一水杨酸法氧化法、DPPH反应法和邻苯三酚自氧化法比较体外清除自由基作用。结果显示:3种红树植物萃取物对5种供试细菌的抑菌活性的强弱顺序为黄槿>白骨壤>桐花树。水萃取物的抑菌效果较其他显著。3种红树植物水萃取物对金黄色葡萄球菌的MIC在11.2~15.6 mg/m L之间。清除自由基的强弱依次为DPPH自由基>超氧阴离子自由基>羟基自由基。桐花树具有较强的DPPH自由基清除作用,且乙酸乙酯萃取物>正丁醇萃取物>石油醚萃取物、水萃取物。结果表明黄槿水萃取物具有极强的抑菌作用,极性很强;而桐花树乙酸乙酯萃取物具有较强的清除DPPH自由基作用。      

In vitro antibacterial and antioxidant activities of Orthosiphon stamineus Benth. extracts against food-borne bacteria

Extracts of the Orthosiphon stamineus plant were tested for antimicrobial and antioxidant activities against selected food-borne bacteria in vitro. Whole O. stamineus plants (powdered) were extracted using various concentrations (0%, 25%, 50%, 75%, and 100%) of methanol. O. stamineus extracted with 50% methanol, 75% methanol and fraction 5 of a 50% methanolic extract demonstrated inhibitory activity against Vibrio parahaemolyticus. The inhibition observed with these O. stamineus extracts was comparable to the inhibition seen with the natural food preservative 5% lactic acid; this is likely due to the high concentration of rosmarinic acid found in the O. stamineus extracts. This study showed that the highest concentration of rosmarinic acid had the best antibacterial and free radical scavenging activities. This suggests that rosmarinic acid content is closely associated with antibacterial and free radical scavenging activities of O. stamineus extracts.     

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.     

秦皮不同溶剂提取物总酚含量及抗氧化活性

分别以水、加0.5%纤维素酶水和50%乙醇溶液为提取剂,超声辅助提取秦皮,采用Folin-Ci-ocalteu法测定提取物中总酚含量,同时利用清除DPPH.和羟自由基(.OH)法评价秦皮提取物的抗氧化活性。结果表明,不同溶剂水、50%乙醇和加0.5%纤维素酶水的秦皮提取物中总酚含量分别41.68mg/g、49.32mg/g和51.51mg/g;对DPPH.的半清除率(IC50)分别为0.29mL、0.22mL和0.17mL;对.OH的半清除率(IC50)分别为2.4mL、2.0mL和1.3mL。秦皮不同溶剂提取物都具有较强的抗氧化活性,其大小顺序为:加酶水提物>醇提物>水提物,抗氧化活性与提取物中总酚含量成正相关。     

Phenolic profile,antioxidant, anticholinesterase,and anti-tyrosinase activities of the various extracts of Ferula elaeochytris and Sideritis stricta

In this study, the antioxidant, anticholinesterase, and anti-tyrosinase properties of (hexane, acetone, methanol, and water) extracts of Ferula elaeochytris and Sideritis stricta were determined with the total phenolic and flavonoid contents. The phenolic profile of the methanol and water extracts was analysed using HPLC-DAD. Protocatechuic acid was found as the major phenolic compound in the methanol (116.3 ± 3.1 µg/g) and water extracts (69.4 ± 1.3 µg/g) of F. elaeochytris. Coumarins (253.9 ± 4.1 µg/g) and catechin hydrate (175.2 ± 2.9 µg/g) were the most abundant phenolic compounds in the methanol and water extracts of S. stricta. β-carotene–linoleic acid, DPPH^?, ABTS^?+, CUPRAC, and metal-chelating assays were used to evaluate antioxidant properties of the extracts. The methanol and water extracts of F. elaeochytris and the acetone and methanol extracts of S. stricta containing the highest amount of total phenolic and flavonoid contents showed the highest antioxidant activities in β-carotene–linoleic acid, DPPH^?, ABTS^?+, and CUPRAC assays. The enzyme inhibitory potential of extracts was investigated against key enzymes involved in neurodegenerative (acetylcholinesterase (AChE) and butyrylcholinesterase (BChE)) and skin (tyrosinase) disorders. In the cholinesterase inhibitory assays, the hexane extracts of two species exhibited the best activity against AChE, while the hexane extract of F. elaeochytris and the methanol extract of S. stricta observed to be the most active against BChE. As for anti-tyrosinase activity results of extracts, the only acetone and methanol extracts showed mild inhibitory activity for both species.