Physiological components of kiwifruits with in vitro antioxidant and acetylcholinesterase inhibitory activities

Five domestic kiwifruit varieties, Bidan (BD), Chiak (CA), Haegeum (HG), Haehyang (HH), and Mansoo (MS), in Korea and two imported varieties, Hayward (HW) and Hort16A (HT), from New Zealand were evaluated main active component groups in the fruit extracts involved in antioxidant and anti-dementia activities. HW, HT, and HH exhibited higher soluble solid content. BD, HG, and HH contained high total phenolics (TP), whereas two imported kiwifruits and green kiwifruits (MS and CA) had low TP content. BD showed the highest antioxidant and antidementia activities among kiwifruits studied. Vitamin C (Vc) in kiwifruit extracts had the highest correlation with antioxidant activities. TP in kiwifruits had the highest correlation with acetylcholinesterase inhibitory activity. Butyrylcholinesterase activity was not significantly correlated with TP or Vc content, but the butyrylcholinesterase activity was significantly correlated with total flavonoids. The results above suggest that domestic varieties have a potential source of Vc and phenolic bioactivities.     

高良姜醇提物的抗氧化、酶抑制活性及其与活性成分的相关性

以新鲜高良姜为原料,制备甲醇提取物,分别采用Folin-Ciocalteu法和AlCl3比色法测定多酚和总黄酮含量,并利用DPPH法、ABTS法和FRAP法评价抗氧化功能,同时检测对胰脂肪酶和α-葡萄糖苷酶的抑制功能。结果显示,高良姜醇提物中多酚和总黄酮分别为62.91mg GAE/g DW和13.12mg QE/g DW。当醇提物浓度达到50mg/mL时,对DPPH自由基的清除率达到95.78%,半抑制浓度IC_(50)为6.37mg/mL;对ABTS自由基的清除率达到99.03%,IC_(50)为2.24mg/mL。FRAP值为428.92μmol Fe~(2+)/g DW。醇提物对胰脂肪酶和α-葡萄糖苷酶抑制活性的IC_(50)值分别为205.87,1.32mg/mL。表明高良姜醇提物含有丰富的多酚和黄酮,具有较强的体外抗氧化活性、胰脂肪酶和α-葡萄糖苷酶抑制功能,在降脂降糖药品与功能性食品的开发与应用方面具有很好的前景。     

Chemical composition,angiotensin I-converting enzyme (ACE) inhibitory,antioxidant and antimicrobial activities of the essential oil from Periploca laevigata root barks

The present study describes the chemical composition, and antimicrobial, antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of essential oil from Periploca laevigata root barks (PLRB), an aromatic plant widely distributed in Tunisia and used as a traditional medicinal plant. Gas chromatography/mass spectrometry was used to determine the composition of the PLRB oil. Forty-three components were identified in the essential oil and the main compounds were benzaldehyde (56%), methyl 4-methoxysalicylate (6.55%) and carvacrol (4.75%). The PLRB essential oil exhibited a dose-dependent manner of inhibitory activity toward ACE. The highest ACE inhibitory activity (54%) was observed at a concentration of 30 μg/ml. The PLRB oil was also found to possess antioxidant activities, as evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, β-carotene bleaching and reducing power assays. The antimicrobial activity of the essential oil was also investigated on several microorganisms. The inhibition zones and minimal inhibitory concentration (MIC) values of bacterial strains were in the range of 12–46 mm and 50–300 μg/ml, respectively. The inhibitory activity of the PLRB essential oil against Gram-positive bacteria was significantly higher than against Gram-negative. It also exhibited remarkable activity against several fungal strains.     

柠檬果皮精油主要组分抑菌及抗氧化活性研究

探讨尤力克柠檬果皮精油(LEO)的3个主要组分dl-柠檬烯、γ-萜品烯、α-松油醇的单体物及其复配物的抗氧化与抑菌效果;主要测定该3个组分的DPPH自由基和羟自由基清除能力,以及其对大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌的抑菌圈大小及最低抑菌浓度(MIC)。结果表明,dl-柠檬烯、γ-萜品烯、α-松油醇对羟自由基有一定的清除效果,清除率为48.45%~77.94%;对DPPH自由基的清除效果均高于同浓度的LEO。抑菌活性试验结果表明dl-柠檬烯、γ-萜品烯、α-松油醇对3种测试菌都表现出抑菌作用,但抑制效果均低于同浓度的LEO,其中α-松油醇对大肠杆菌和枯草芽孢杆菌的抑制效果最好,MIC分别为3.9,1.0μL/mL;dl-柠檬烯对金黄色葡萄球菌抑菌效果最好,最低抑菌浓度为1.0μL/mL。dl-柠檬烯、γ-萜品烯、α-松油醇的复配物较单体的抑菌作用更佳。表明作为主要组分的dl-柠檬烯、γ-萜品烯、α-松油醇对LEO抗氧化与抑菌活性的表现有一定影响。     

白酒酒醅中两种多肽的鉴定及其抗氧化和降血压功能评价

为追溯白酒中多肽的来源,采用超滤、半制备型高效液相色谱等方法对古井贡酒酒醅水溶性提取物中的多肽进行分离纯化,并利用高效液相色谱-四级杆-飞行时间质谱仪对所得多肽进行结构鉴定。在体外水平对多肽的抗氧化功能力和血管紧张素转化酶抑制活性进行测定。结果表明,氨基酸序列分别为Lys-Gly-Pro(KGP)和Val-Pro-Asp(VPD)的2种多肽首次从酒醅中发现,且与标准抗氧化剂Trolox相比,2种多肽均表现出了很强的ABTS自由基清除能力(KGP为1. 12μmol TE/μmol KGP; VPD为1. 36μmol TE/μmol VPD)和氧化自由基吸收能力(KGP为1. 11μmol TE/μmol KGP; VPD为1. 17μmol TE/μmol VPD)。此外,2种多肽也表现出了ACE抑制活性,KGP与VPD的半抑制浓度IC_(50)分别为2. 91和2. 11 mmol/L。该研究为深入挖掘酒醅中生物活性成分进而通过改进蒸馏工艺以提升白酒的健康功能提供了参考。     

糙米酵素乳饮料的功能成分及其抗氧化活性研究

将发芽糙米粉制成糙米酵素,经过一系列工艺制成风味独特的糙米酵素乳饮料。对其功能成分进行分析后并对其抗氧化活性进行研究。结果表明:糙米酵素乳饮料中的γ-氨基丁酸含量为0.225 mg/L,谷胱甘肽含量为48.9 mg/kg。其抗氧化性研究表明当质量浓度为1.0 mg/mL时,糙米酵素乳饮料对DPPH·的清除率高达83%,对超氧阴离子(O^2-·)的清除率为48%。     

Brazilian red propolis: unreported substances, antioxidant and antimicrobial activities

BACKGROUND: Chloroform, ethyl acetate and methanol extracts of a sample of red propolis from the state of Alagoas (northeast Brazil) were analyzed by gas chromatography–mass spectrometry and high‐performance liquid chromatography–diode array detection–electrospray ionization‐mass spectrometry. Antimicrobial and antioxidant activities were also obtained. RESULTS: The propolis sample contained low content of narigenin‐8‐C‐hexoside, this being the first report of a C‐glycoside in propolis. The main constituent found was characterized as 3,4,2′,3′‐tetrahydroxychalcone. Other important constituents were the chalcone isoliquiritigenin, the isoflavans (3S)‐vestitol, (3S)‐7‐O‐methylvestitol, the pterocarpan medicarpin, the phenylpropenes trans‐anethol, methyl eugenol, elimicin, methoxyeugenol and cis‐asarone, and the triterpenic alcohols lupeol and α‐ and β‐ amyrins. The methanol extract exhibited high antioxidant activities by 2,2‐diphenyl‐1‐picrylhydrazyl and β‐carotene/linoleic acid assay methods, and antimicrobial activity toward Gram‐positive and Gram‐negative bacteria. CONCLUSION: Structures are suggested for new substances never before seen in any kind of propolis. This is the first report of 3,4,2′,3′‐tetrahydroxychalcone and a flavone C‐glycoside in a propolis sample. Copyright © 2011 Society of Chemical Industry     

Anticancer,antioxidant, and antimicrobial activities of anemone (Anemone cathayensis)

This study was performed to evaluate the anticancer, antioxidant, and antimicrobial activities of fractions and isolated compounds from anemone (Anemone cathayensis). Fourteen compounds were isolated from extracts. Anticancer activities of fractions and compounds were determined by MTT assay, and all tested fractions showed inhibition activity on human breast cancer cells (MDA-MB-231). The fraction 6 displayed the strongest anticancer activity, and inhibition percent was 50.32%. The antioxidant effect of fractions was evaluated by using DPPH scavenging assays. Fraction 5 had a higher DPPH radical scavenging activity with low IC₅₀ value of 30.578 μg/mL. The antimicrobial activity of the fractions was evaluated against 3 microorganisms using the agar well diffusion method. The fractions also showed moderate antimicrobial activity. These results suggest that anemone could hold a good potential source for human health.     

Angiotensin-I converting enzyme inhibitory and antioxidant activities of egg protein hydrolysates produced with gastrointestinal and nongastrointestinal enzymes

Egg is a well-known rich source of bioactive peptides. In this study, egg protein (egg white and egg yolk proteins) hydrolysates were produced with gastrointestinal enzymes (pepsin and pancreatin) or nongastrointestinal enzymes (thermolysin and alcalase), and fractionated by ultrafiltration and cation exchange chromatography. Angiotensin-I converting enzyme (ACE) inhibitory and antioxidant activities, amino acid composition and molecular weight distribution were studied, and the physicochemical properties were related with the bioactivities. Our results showed that egg protein hydrolysates produced with non-GI enzymes (thermolysin and alcalase) showed significantly higher ACE inhibitory activity, whereas similar or even lower antioxidative activities, than those of hydrolysates produced with GI enzymes. ACE-inhibitory activity significantly correlated with the amino acid composition, especially the proportion of positively charged amino acid, whereas antioxidant activities correlated with the proportion of low molecular weight peptides under 500 Da. Understanding the relationship between the bioactivities and physicochemical properties of the hydrolysates/fractions is important to facilitate the development technologies for preparing fractions with improved bioactivities.     

Functional properties of melanoidins: In vitro antioxidant,antimicrobial and antihypertensive activities

Melanoidins formed at the last stage of the Maillard reaction have been pointed out to possess certain functional properties such as antioxidant, antimicrobial and antihypertensive activities. In order to gain more insights on these functional properties different soluble melanoidins and melanoidin fractions isolated from several amino acid–glucose model systems has been analysed In the case of antioxidant and antimicrobial properties, low molecular weight compounds bounded to melanoidins (BMC fraction) exerts antioxidant and antimicrobial activities usually higher than those of the pure melanoidins to whom they are linked. Contrary, in the case of antihypertensive activity it has been found that the main activity is related to the melanoidin core, not to BMC fraction. In addition it has been found no correlation, except for ABTS assay, among colour and antioxidant, antimicrobial or antihypertensive activity, supporting the idea that melanoidin chromophores are not responsible for these actions.     

Microalgae of different phyla display antioxidant, metal chelating and acetylcholinesterase inhibitory activities

Methanol and hexane extracts from Tetraselmis chuii, Nannochloropsis oculata, Chlorella minutissima and Rhodomonas salina were evaluated for total phenolic contents, radical scavenging activity (RSA), metal chelating potential against copper and iron ions and acetylcholinesterase (AChE) inhibition. Only the methanol extracts contained phenolic compounds. The hexane extracts had the highest RSA. The extracts had a higher capacity to chelate Fe²⁺ ions, more pronounced in the lowest concentration of the hexane extracts with values ranging from 73.3 ± 3.3% (R. salina) to 97.5 ± 1.1% (N. oculata). The highest AChE inhibitory activity was found in the hexane extracts at 10 mg/ml of C. minutissima (79.3 ± 1.9%), T. chuii (85.7 ± 0.7%) and R. salina (81.5 ± 7.5%). GC-MS analysis indicated polyunsaturated fatty acids and steroids as the most abundant compounds in the hexane extracts. The species under study provide a valuable source of antioxidants, metal chelators and AChE inhibitors.     

植物中抗氧化活性成分及其提取技术的研究

天然的抗氧化剂能有效的清除自由基从而保护机体健康。从植物中寻找高效、廉价、低毒的天然抗氧化剂成为目前抗氧化剂发展的一个必然趋势,而对于建立更简捷、高效的提取、分离、纯化及鉴定技术的需求越来越强烈。就植物中抗氧化活性物质及其提取技术的基本原理、应用和发展方向等进行阐述。     

几种黑豆成分、体外抗氧化及酶抑制作用对比

目的：挑选黑豆药用与食用的适宜品种。方法：测定了9种黑豆的总酚酸、总黄酮、缩合单宁、总花色苷、总多糖和总蛋白质含量,并对黑豆提取物的体外抗氧化活性以及对α-淀粉酶、胰脂肪酶、乙酰胆碱酯酶、酪氨酸酶的抑制作用进行比较。结果：总酚酸、总黄酮、缩合单宁、总花色苷含量为马料豆＞小黑豆＞黑豆;总多糖含量为小黑豆＞黑豆＞马料豆;总蛋白含量为马料豆＞黑豆＞小黑豆;抗氧化活性为马料豆＞小黑豆＞黑豆。体外试验发现,小黑豆与黑豆对多种酶均有抑制作用,强度各不相同。结论：不同品种黑豆的生物活性物质含量和功能存在差异。黑豆更适合食用,马料豆和小黑豆药用价值更高。     

Identification of polyphenols in tobacco leaf and their antioxidant and antimicrobial activities

Crude polyphenols were extracted from tobacco leaf by 80% ethanol solution with ultrasonic treatment and then purified by a macroporous resin. The polyphenols from tobacco leaf (PTL) were subjected to analyses by reverse-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS). The dominant polyphenols in tobacco leaf were identified as chlorogenic acid and rutin. Furthermore, the antioxidant activities of PTL were investigated, including scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (5.02 μg/ml IC₅₀ value), hydroxyl radicals (49.6 μg/ml IC50 value) and superoxide anion radicals (44.0 μg/ml IC₅₀ value), inhibition activity of lipid peroxidation (132 μg/ml IC₅₀ value) and reducing power. The proliferation inhibition activities on Escherichia coli, Staphylococcus aureus and Bacillus subtilis were also measured for evaluating the antimicrobial activity of PTL. The diameters of inhibition zones were 20.23 ± 0.42, 17.66 ± 0.86 and 12.89 ± 0.29 mm, respectively. The results showed that PTL had great potential as antioxidant and antimicrobial agent.     

Phenols,proanthocyanidins, flavones and flavonols in some plant materials and their antioxidant activities

Methanol extracts prepared from five plant materials native to the Mediterranean area, namely olive tree (Olea europaea) leaf, St. John's wort (Hypericum perforatum), hawthorn (Crataegus laevigata), oregano (Origanum vulgare) and laurel leaf (Lauris nobilis), were examined for their phenolic components. Total phenolic content was determined by the Folin–Ciocalteu method. The content of proanthocyanidins in acid-hydrolysed extracts was determined spectrophotometrically. The contents of free flavones (apigenin and luteolin) and flavonols (kaempferol, myricetin and quercetin) were determined by HPLC analysis. The time of hydrolysis of flavones, flavonols and proanthocyanidins was optimised.Antioxidant activities of apigenin, luteolin, kaempferol, myricetin, quercetin and of plant extracts were examined. Antioxidative activities were studied in sunflower oil at 98 °C, by measuring peroxide value, and in an aqueous emulsion system of β-carotene and linoleic acid by measuring the absorbance of the sample. Among flavones and flavonols investigated, only myricetin inhibited oxidation of sunflower oil. All other flavones and flavonols showed pro-oxidative activity. Oppositely, in the emulsion system, only apigenin showed pro-oxidative activity while other flavones and flavonols and plant extracts inhibited oxidation of β-carotene.     

Total phenolic content,antiradical, antioxidant and antimicrobial activities of Rhododendron honeys

Fifty Rhododendron honey samples obtained from Black Sea Region of Turkey were screened for total phenolic content by the modified Folin–Ciocalteu method, for potential antioxidant activity using phosphomolybdenum assay and by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) method for antiradical activity. The antimicrobial activity was studied by the agar diffusion method, using eleven bacteria and two yeasts.     

Phytochemical composition and in vitro antimicrobial and antioxidant activities of essential oils of three endemic Soqotraen Boswellia species

The chemical composition of three essential oils obtained from the barks of three endemic Boswellia species namely, Boswellia dioscorides, Boswellia elongata and Boswellia socotrana which were collected from the Soqotra Island (Yemen), was investigated. In parallel to that evaluation of their antimicrobial and antioxidant activities was also carried out. The investigation led to the identification of 72, 70 and 67 constituents for B.dioscorides, B. elongata, and B. socotrana, respectively. The B. dioscorides oil was found to have a high content of monoterpene hydrocarbons (32.8%) with α-thujene (9.3%) and α-pinene (8.3%) as main components. Whereas, the essential oil of B. elongata was characterised by high diterpene content (31.7%), in which incensol (14.8%) was found to be the major constituent. On the other hand, the oil obtained from the B. socotrana was found to be predominated of monoterpene hydrocarbons (26.4%) and oxygenated monoterpenes (30.7%) with p-cymene (13.0%), 2-hydroxy-5-methoxy-acetophenone (16.3%) and camphor (11.6%). All essential oils possessed antimicrobial activity especially against Gram-positive bacteria with MIC-values between 1.8 and 17.2 mg/ml. Furthermore, the DPPH-radical scavenging assay exhibited only weak antioxidant activities (28%) at 1.0 mg/ml.     

Effects of nicotinic acid derivatives on tyrosinase inhibitory and antioxidant activities

The tyrosinase inhibitory and antioxidant activities of four nicotinic acid derivatives, namely, nicotinamide, methyl nicotinate, nicotinic acid hydroxamate (NAH), N-methyl nicotinic acid hydroxamate (NAH-M), and kojic acid, were studied. The tyrosinase inhibitory activity was found to follow the trend: NAH > kojic acid > NAH-M > methyl nicotinate > nicotinamide. The concentrations of half-inhibition (IC₅₀) of NAH against monophenolase and diphenolase activity were 2 and 1 μM, respectively; the inhibition mode was a mixed-type in the former and an uncompetitive type in the latter. In the antioxidant activity assays, NAH and NAH-M, but not nicotinamide or methyl nicotinate, showed dose-dependent DPPH radical scavenging activity, and their corresponding IC₅₀ values were 65.81 and 125 μM, respectively. NAH and NAH-M also showed hydroxyl radical scavenging activity and anti-low-density-lipoprotein peroxidation. These results indicate that NAH and NAH-M have the potential to be useful in cosmetics or food processing, and therefore, they should be investigated further.