In vitro study of antioxidant capacity and antibacterial activity on oral anaerobes of a grape seed extract

Grape seeds are considered rich sources of polyphenolic compounds that show antioxidant or antimicrobial effects. The aim of the present work was to investigate the effect of a grape seed extract (GSE) on two oral anaerobes closely associated with periodontal diseases and its antioxidant action.     

Antiproliferative activity of peels,pulps and seeds of 61 fruits

Fruits are wildly consumed and considered to have various health benefits. The aim of this study was to supply new information on the antiproliferative function of selected fruits for nutritionists and the general public. The in vitro antiproliferative activities of the peels, pulps and seeds of 61 fruits on four cancer cell lines, A549 (human lung cancer cells), MCF-7 (human breast cancer cells), HepG2 (human hepatoma cells) and HT-29 (human colon cancer cells) were evaluated by MTT assay. The results revealed that different fruits and different parts of one fruit exhibited different antiproliferative capacities. Nine of the 162 samples from 61 fruits showed remarkable inhibitory effects toward the four cancer cell lines, and all decreased the viability of the cancer cell lines in a dose-dependent manner. The results suggested that some fruits (such as honey peach, salak, orange, and Peru ground cherry) may serve as potential dietary supplement for the prevention and treatment of cancer because of strong antiproliferative activities against the cancer cell lines.     

Antioxidant and antibacterial activity of leaves of Etlingera species (Zingiberaceae) in Peninsular Malaysia

Methanolic extracts from fresh leaves of five Etlingera species were screened for total phenolic content (TPC), antioxidant activity (AOA), and antibacterial activity. Analysis of TPC was done using the Folin–Ciocalteu method. Evaluations of AOA included 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging ability, ferric-reducing antioxidant power (FRAP), ferrous-ion chelating (FIC) ability, and β-carotene bleaching (BCB) activity. Antibacterial activity was screened using the disc-diffusion method. Highest TPC, ascorbic acid equivalent antioxidant capacity (AEAC), and FRAP were found in leaves of E. elatior and E. rubrostriata. Leaves of E. maingayi, with the lowest TPC, AEAC, and FRAP, had the highest FIC ability and BCB activity. Ranking of TPC and AOA of different plant parts of E. elatior was in the order: leaves > inflorescences > rhizomes. Leaves of highland populations of Etlingera species displayed higher values of TPC and AEAC than those of lowland counterparts. Leaves of Etlingera species exhibited antibacterial activity against Gram-positive but not Gram-negative bacteria.     

Radical scavenging and antibacterial properties of the extracts from different Thymus pulegioides L. chemotypes

Radical scavenging and antibacterial properties of large thyme extracts isolated from five chemotypes of Thymus pulegioides L. growing wild in Lithuania were studied. The chemotypes were defined according to the main essential oil components: linalool (L), geranial/geraniol/neral (G/G/N), thymol (T), carvacrol/γ-terpinene/p-cymene (C/γT/pC) and thymol/carvacrol/γ-terpinene/p-cymene (T/C/γT/pC). The contents of phenolic compounds, flavonoids and flavonols were determined. It was found that the extracts of phenolic chemotypes containing remarkable concentrations of thymol and/or carvacrol were stronger DPPH and ABTS free radical scavengers in the model systems. The antibacterial activity of the extracts depended on the plant chemotype, extract preparation, solvent used and finally the sensitivity of bacteria. Bacillus cereus, Micrococcus luteus, Staphylococcus epidermidis and Staphylococcus aureus were the most sensitive to the all extracts applied, whereas Escherichia coli, Salmonella typhimurium and Enterobacter aerogenes remained resistant.     

Antioxidant and antibacterial activities of Nephelium lappaceum L. extracts

Ether, methanolic and aqueous extracts of lyophilized rambutan (Nephelium lappaceum L.) peels and seeds were evaluated for phenolic contents, antioxidant and antibacterial activities. High amounts of phenolic compounds were found in the peel extracts and the highest content was in the methanolic fraction (542.2 mg/g dry extract). Several potential antioxidant activities, including reducing power, β-carotene bleaching, linoleic peroxidation and free radical scavenging activity, were evaluated. The peel extracts exhibited higher antioxidant activity than the seed extracts in all methods determined (P < 0.05). The methanolic fraction was found to be the most active antioxidant as shown by their 50% DPPH inhibition concentration, 4.94 μg/mL. The results indicated this fraction exhibited greater DPPH radical scavenging activity than BHT and ascorbic acid (0.32 g dry extract/g BHT or ascorbic acid). Antibacterial activity against eight bacterial strains was assessed by disc diffusion and broth macrodilution methods. All peel extracts exhibited antibacterial activity against five pathogenic bacteria. The most sensitive strain, Staphylococcus epidermidis, was inhibited by the methanolic extract (MIC 2.0 mg/mL).     

Antioxidant activity of methanolic extracts from some grains consumed in Korea

The objectives of this study were to determine antioxidant activity of the methanolic extracts from some grains and to investigate relationships between antioxidant activities and antioxidant contents in the extracts. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical cation scavenging activities, inhibitory effect on lipid peroxidation, chelating activity and reducing power have been used to investigate the relative antioxidant activities of the extracts from grains. The concentrations of total polyphenolics and carotenoids in the extracts were measured by spectrophotometric methods and vitamin E analysis was carried out by HPLC. The methanolic extracts prepared from red sorghum and black rice showed significantly higher antioxidant activities and contained higher polyphenolic contents than other grains such as white rice, brown rice, mungbean, foxtail millet, prosomillet, barley, and adlay. Polyphenolic compounds were the major naturally occurring antioxidants in grains. The correlation coefficient between total polyphenolic content and ABTS radical cation scavenging activity in the extracts was >0.99. However, no relationship was found between antioxidant activities and carotenoids and vitamin E derivatives.     

Antiproliferative and antioxidant properties of anthocyanin-rich extract from açai

An anthocyanin-rich extract, generated from açai (AEA), was investigated for its antioxidant properties and antiproliferative activity against C-6 rat brain glioma cells and MDA-468 human breast cancer cells. AEA has an ORAC value of 2589 μmoles trolox equivalents (TE)/g dried powder and a DPPH radical-scavenging activity of 1208 μmoles TE/g, suggesting that AEA is an exceptional source of natural antioxidants. In addition, AEA remarkably suppresses proliferation of C-6 rat brain glioma cells, but has no effect on the growth of MDA-468 human breast cancer cells. Further experiments demonstrated that the AEA treatment dose-dependently inhibited the growth of C-6 rat glioma cells with an IC₅₀ of 121 μg/ml. The DNA ladder fragmentation results indicated that AEA induced apoptosis of C-6 rat brain glioma cells. To compare açai with other anthocyanin-rich extracts, a number of berry extracts, including blueberry, strawberry, raspberry, blackberry and wolfberry, were assessed for potential antiproliferative activity against C-6 rat brain glioma cells. However, none of them showed suppressing effect. The results suggest that the active antiproliferative constituents in AEA are unlikely to be anthocyanins normally found in common berries.     

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.     

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.     

Synergistic antioxidant and antibacterial activity of rosemary plus butylated derivatives

Antioxidant and antibacterial activity of a methanol rosemary extract (RE) containing 30% carnosic acid (CA), 16% carnosol (COH) and 5% rosmarinic acid (RA) was studied in vitro alone and in combination with the antioxidant food additives butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). The antioxidant efficiency of the extract, CA, and RA, was determined by a kinetic analysis of the 2,2-diphenyl-2-picrylhydrazyl hydrate radical (DPPH·) scavenging activity. RE showed two different rate slopes in the reduction of DPPH· vs. time curve, which correlated with the distinct behaviours of RA and CA; pure RA reached the plateau more rapidly than CA. A synergistic antioxidant effect between RE and BHT was demonstrated by isobolographic analysis and a synergistic interaction of RE with BHA to inhibit Escherichia coli and Staphylococcus aureus growth was observed. Therefore, rosemary not only enhances the antioxidant efficiency of BHA and BHT, but also the antibacterial effect of BHA; allowing a decrease from 4.4 to17 folds in the amounts of the synthetic compounds used.     

桦褐孔菌多糖的分离纯化及体外抗氧化活性研究

目的 分离纯化桦褐孔菌多糖(Inonotus obliquus polysaccharide, IOP),分析其结构并对其抗氧化活性进行评价。方法 以桦褐孔菌为原材料,采用水提醇沉工艺,经大孔树脂吸附法除杂脱色得到IOP;通过DEAE-52纤维素柱对IOP进行分离纯化,得到4个多糖组分:IOP-1、IOP-2、IOP-3和IOP-4,通过Sephadex G-100凝胶柱纯化得率较高的组分IOP-1,得到均一多糖IOP-1a。对IOP-1a进行结构鉴定,并考察其体外抗氧化能力。结果 IOP-1a相对分子质量为12040Da;由7种单糖组成:葡萄糖、半乳糖、木糖、甘露糖、鼠李糖、阿拉伯糖和岩藻糖(0.341:0.246:0.150:0.102:0.842:0.559:0.213),红外光谱显示IOP-1a含有β型糖苷键、羰基、羟基等官能团。体外抗氧化实验表明,IOP和IOP-1a均有较好的抗氧化能力。结论 从IOP中分离纯化得到的中性组分IOP-1a具有较好的抗氧化活性。     

柠檬籽中类柠檬苦素反胶团萃取工艺优化及抑菌活性分析

目的 探究羟丙基甲基纤维素(hydroxypropyl methyl cellulose, HPMC)辅助反胶团萃取柠檬籽中类柠檬苦素的可行性,并对提取物质的抑菌活性进行分析。方法 以初提液中类柠檬苦素含量为响应值,通过正交试验确定初提液制备的最优参数;以Placktett-Burman(P-B)试验筛选影响类柠檬苦素反胶团萃取效率的主要因素,并结合Box-Behnken(B-B)试验确定最优工艺条件;通过测定最小抑菌浓度(minimal inhibitory concentration,MIC)、最小杀菌浓度(minimum bactericidal concentration, MBC)、碱性磷酸酶(alkaline phosphatase, AKP)活性考查类柠檬苦素对青霉菌和绿霉菌的抑菌活性。结果 初提阶段影响类柠檬苦素提取效率的最优条件为提取时间1.5 h、液料比30:1(mL/g)、HPMC添加量0.5%、pH 6.5,该条件下提取率为(3.34±0.02) mg/g。P-B试验结合B-B试验结果表明,类柠檬苦素萃取的最优配方为双十八烷基二甲基氯化铵(dioctadecyl...     

Egyptian chia seeds (Salvia hispanica L.) during germination: Upgrading of phenolic profile,antioxidant, antibacterial properties and relevant enzymes activities

Food Science and Biotechnology - Little studies on chia sprouts were not deeply address the polyphenols profiles and their functional properties during long period of germination. This study aims...     

Polyphenolic profile,antioxidant properties and antimicrobial activity of grape skin extracts of 14 Vitis vinifera varieties grown in Dalmatia (Croatia)

The aim of the present study was to determine polyphenolic composition, related antioxidative and antimicrobial properties of grape skin extracts from 14 grape varieties (seven white and seven red grape) grown in Dalmatia (Croatia). The content of total phenols, flavonoids, catechins, flavanols and individual polyphenols ((+)-catechin, (−)-epicatechin, epicatechin gallate, procyanidin B1 and procyanidin B2, quercetin glucoside, resveratrol monomers, piceid and astringin) was variety dependent. Antioxidant properties were determined as DPPH radical-scavenging ability (IC₅₀), ferric reducing/antioxidant power (FRAP), Fe²⁺-chelating activity (IC₅₀), and using β-carotene bleaching assay. The high antioxidant capacity of all extracts, both red and white, has been observed and related to the relative amounts of polyphenolic compounds with good antioxidant properties. The antimicrobial activity was screened by broth microdilution test using Gram-positive (Staphylococcus aureus, Bacillus cereus) and Gram-negative bacteria (Escherichia coli O157:H7, Salmonella Infantis, Campylobacter coli). It was confirmed against all tested organisms. Minimum inhibitory concentrations (MICs), were found in the range 0.014–0.59 mg of gallic acid equivalents (GAE)/ml, with lower MICs of white cultivars, especially against Campylobacter and Salmonella.     

柚提取物含量测定及其抗氧化、抑菌活性研究

采用水蒸气蒸馏法、超声波辅助溶剂萃取法以及酸提醇沉法分别提取柚叶、柚皮、柚肉、柚籽中精油、总黄酮和果胶,采用气相色谱-质谱（GC-MS）、Na NO2-Al（NO3）3法和咔唑-硫酸法分别对精油成分和总黄酮、果胶含量进行分析。通过精油、总黄酮和果胶的总还原力及清除1,1-二苯基-2-苦基肼（DPPH·）能力的测定实验评价其抗氧化活性,通过滤纸片扩散法评价其抑菌活性。结果表明:柚皮中精油和总黄酮含量最高;柚肉中果胶含量最高;柚皮精油共鉴定出25种化合物,其主要成分为D-柠檬烯（77.96%）,β-月桂烯（12.40%）和β-蒎烯（2.14%）;柚三种活性成分（精油,总黄酮和果胶）均具有较强的还原力,对DPPH·的IC50（清除率达到50%时的浓度）分别为1.53%、0.07%和0.21%,表现出较强的抗氧化活性;对3种受试菌（大肠杆菌、金黄色葡萄球菌和沙门氏菌）均有抑制活性,且随着物质浓度的增加,对受试菌的抑菌效果逐渐增强。该研究结果为柚资源的合理开发和回收再利用以及生物杀菌剂、天然食品抗氧化剂和防腐剂的开发提供了理论依据。      

Determination of antibacterial effects and total phenolic contents of grape (Vitis vinifera L.) seed extracts

In the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.     

Antiproliferative activity of peptides prepared from enzymatic hydrolysates of tuna dark muscle on human breast cancer cell line MCF-7

To produce and identify antiproliferative peptides, two commercial enzymes, papain (PA) and Protease XXIII (PR) were used to hydrolyse tuna dark muscle byproduct, and the protein hydrolysates were purified, before being evaluated for antiproliferative activities against human breast cancer cell line MCF-7. The results showed that the peptide fractions with the molecular weight ranging from 390 to 1400 Da possessed the greatest antiproliferative activity. The amino acid sequences of the two antiproliferative peptides isolated from PA and PR hydrolysates were Leu-Pro-His-Val-Leu-Thr-Pro-Glu-Ala-Gly-Ala-Thr (1206 Da) and Pro-Thr-Ala-Glu-Gly-Gly-Val-Tyr-Met-Val-Thr (1124 Da), whilst they show the dose-dependent inhibition effect of the MCF-7 cells with IC₅₀ values of 8.1 and 8.8 μM, respectively. We thus conclude that antiproliferative hydrolysates from tuna dark muscle byproduct may be useful ingredients in food and nutraceutical applications.     

Profile of phenolic compounds in Trifolium pratense L. extracts at different growth stages and their biological activities

Although Trifolium pratense (Red Clover) is considered to be one of the leading crops for livestock grazing, it could also be used as a potential source of bioactive compounds in phytopharmacy. The aim of this study was to investigate the phenolic content and its biological activity at the growth phases (30 cm, 50 cm, and bud) of this plant. The phenolic compounds in methanolic extracts of T. pratense leaves at three growth stages, obtained by Microwave Assisted Extraction, were quantified using the HPLC-ESI-MS/MS technique, and their antioxidant and antimicrobial activity were assessed. Isoflavonoids, genistein, and daidzein, as well as other phenols, p-hydroxybenzoic and caffeic acids, kaempferol 3-O-glucoside, quercetin 3-O-glucoside, and hyperoside were found in all the extracts, but the content of these compounds was the highest in the extract of the plant at the lowest growth stage (30 cm, vegetative). Therefore, this extract showed the best antioxidant potential and it was most effective against bacterial strains such as Escherichia coli and Enterobacter aerogenes. These results indicated that red clover has potential health benefits, and that growth phase contributes to its biological activity. The extract of red clover at the growth stage of 30 cm is a great source of bioactive compounds and could be used in phytotherapy and nutrition.     

Antioxidant and pro-oxidant in vitro evaluation of water-soluble food-related botanical extracts

The total phenol content, antioxidant and pro-oxidant activities of deodourised, water-soluble aniseed, basil, caraway, cardamon, fennel, ginger, juniper, laurel and parsley extracts were estimated using a number of in vitro assays. The laurel and basil extracts contained the highest phenol content of 107.3 ± 1.3 GAE [mg gallic acid equivalents/g (dry wt.) extract] and 98.5 ± 1.4 GAE, respectively, whilst the ginger extract contained the lowest content at 14.9 ± 0.9 GAE. Juniper, laurel and basil extracts were consistently better than the other extracts in terms of iron(III) reducing activity, inhibition of β-carotene-linoleate thermal co-oxidation and N,N-dimethyl-p-phenylenediamine and hydroxyl radical scavenging assays. Potential pro-oxidant activities of the extracts were assessed using both DNA and bovine serum albumin (BSA) as substrates. None of the extracts were capable of stimulating hydroxyl-mediated DNA fragmentation; however, the extracts could be categorised in the protein oxidation assay as extracts with (i) no significant (p > 0.05) effect, (ii) a significant (p < 0.05) protective effect or (iii) a significant (p < 0.05) pro-oxidant effect. The extracts from juniper, laurel and basil had a pro-oxidative effect upon BSA at a dose of 2 mg/ml, as estimated from the degree of carbonylation measured.