In Vitro Antioxidant and Antiglycation Properties of Methanol Extract and Its Different Solvent Fractions of Musa paradisiaca L. (Cv. Nendran) Inflorescence

Methanolic extract of Musa paradisiaca inflorescence and its different solvent fractions, petroleum ether, ethyl acetate, butanol, and water were studied for their total phenolic and flavonoid content, free radical scavenging, and antiglycation activities, and these properties were compared with standard antioxidant compounds. Ethyl acetate fraction exhibited higher antioxidant and antiglycation properties than other fractions. IC₅₀ values of ethyl acetate fraction for 1,1-diphenyl-2-picrylhydrazyl method, 2,2-azinobis-3 ethylbenzothiazoline-6-sulphonic acid method, superoxide radical scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, and antiglycation activities were 9.80, 13.50, 26.40, 19.71, 25.73, and 31.00 μ g/ml, respectively. Total phenolic content of ethyl acetate (21.52 mg GAE/g) was significantly higher than other fractions. There was positive linear correlation between antioxidant activity and total phenolic content.      

Antioxidant, antibiofilm, and anticholinesterase activities of fermented Deodeok (Codonopsis lanceolata) extracts

This study was designed to evaluate the antioxidant, antimicrobial, antibiofilm, and anticholinesterase activities of different solvent fractions from non-fermented (NF) and Lactobacillus rhamnosus fermented deodeok (Codonopsis lanceolata) (LRF). The highest amounts of total phenols and flavonoids were observed in chloroform fraction from NF (72 and 31 mg RE/g) and LRF (79 and 24 mg RE/g). The ferric reducing antioxidant power (FRAP) values were highly correlated with the DPPH scavenging activity, showing that the highest FRAP values were observed in chloroform fractions from NF (35 mM Fe(II)/g) and LRF (50 mM Fe(II)/g). Staphylococcus aureus biofilm cells were highly susceptible to chloroform fraction, showing 1.8 log reductions. The highest anticholinesterase activity was observed in chloroform and ethyl acetate fractions from LRF (1.5 mg/mL<EC₅₀<2.5 mg/mL). The results provide useful information for improving pharmacological activities and also suggest new direction for developing biologically active compounds from medicinal plants.     

Effects of Various Heat Treatments on Phenolic Profiles and Antioxidant Activities of Pleurotus eryngii Extracts

Free (FP) and bound phenolics (BP) were extracted from freeze dried (FD), oven dried (OD), as well as boiling treated (BT) Pleurotus eryngii samples. Free, bound, total phenolics were quantified using Folin–Ciocalteau assay. Qualitative and quantitative analysis of phenolic compounds were carried out using high‐performance liquid chromatography (HPLC) coupled with diode array detector (DAD), and a total of 8 phenolic compounds were detected. Free phenolic contents followed the order: Freeze‐dried free phenolics (FDFP) > Oven‐dried free phenolics (ODFP) > Boiling‐treated free phenolics (BTFP), and ranged from 95.42 (BTFP) to 442.50 (ODPF) μg gallic acid equivalents (GAE)/g dry weight (DW). Bound and total phenolic contents followed the order: FD > OD > BT, and ranged from 218.33 (BTBP) to 774.17 (FDBP) and 313.75 (BT total phenolics) to 1090.42 (FD total phenolics) μg GAE/g DW. Bound phenolics contributed 49.76% (OD), 69.59% (BT), and 71% (FD) of the total phenolic contents. All free and bound phenolic extracts were investigated for their antioxidant activities by 3 different assays, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity, reducing power, and superoxide anion radical scavenging activity. FDFP showed strongest DPPH radical scavenging activity (IC₅₀ at 32.61 μg/mL), ODFP showed strongest reducing power (IC₅₀ at 26.31 μg/mL), and BTBP showed strongest superoxide anion radical scavenging activity (IC₅₀ at 14.07 μg/mL).     

厚朴籽不同溶剂萃取物抗氧化活性比较分析

为研究厚朴籽抗氧化成分,测定厚朴籽90%乙醇粗提物及其石油醚、乙酸乙酯、正丁醇和水萃取物的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除活性,2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(2,2-azino-bis(3-ethylbenzthiazoline-6-sulonic acid),ABTS)自由基清除活性和铁离子还原能力(ferric reducing antioxidant power,FRAP),同时测定其总酚及总黄酮含量。结果发现,乙酸乙酯萃取物的总酚和总黄酮的含量最高,含量依次为(253.64±7.25)和(179.11±0.61)mg/g。厚朴籽乙醇粗提物和萃取物具有一定抗氧化活性,其中乙酸乙酯萃取物的抗氧化活性最强,DPPH自由基清除活性显著(P<0.05)高于阳性对照BHT,其IC₅₀仅为(29.33±2.31)μg/mL;乙酸乙酯萃取物ABTS自由基清除活性与V_C相当,IC₅₀分别(30.33±1.53)和(31.67±3.06)μg/mL;厚朴籽乙醇粗提物和萃取物对铁离子的还原能力较低,均显著(P<0.05)低于阳性对照V_C和BHT。相关性显示,厚朴籽三种体外抗氧化活性均与总酚和总黄酮极显著相关(P<0.01)。以上结果表明,乙酸乙酯可以富集厚朴籽酚类物质,为下一步厚朴籽抗氧化物质分离奠定了理论依据。     

Antioxidant activity of the ethanolic extract from the bark of Chamaecyparis obtusa var. formosana

BACKGROUND: Chamaecyparis obtusa var. formosana (Taiwan hinoki) is an endemic conifer in Taiwan and the purpose of this study is to evaluate the antioxidant activity of various fractions obtained from the bark of this plant material. The ethanolic extract of the bark was sequentially separated into three fractions, including n‐hexane, ethyl acetate and ethanol soluble fractions, by liquid–liquid partition. Then the antioxidant activities of crude extract and three fractions along with 13 subfractions obtained from the ethyl acetate (EA) soluble fraction were tested for several antioxidant assays. RESULTS: The total phenolic content of the samples varied from 27.71 to 102.86 mg GAE g^?1 dry weight for fractions, and from 49.94 to 206.46 mg GAE g^?1 for subfractions (where GAE is milligrams of gallic acid per gram of extract). The Trolox equivalent antioxidant capacity (TEAC) ranged from 0.15 to 0.26 mmol L^?1 Trolox equivalents. The EA soluble fraction was found to be the best antioxidant‐rich fraction in terms of DPPH and reducing power assays. With further data analysis it was found that there was a positive correlation between the total phenolic content of extracts and TEAC is R² = 0.61. CONCLUSION: Results from various antioxidant assays showed that the EA fraction possessed strong antioxidant activity. This would provide additional information about the antioxidant activity of bark extract of this plant species. Copyright © 2008 Society of Chemical Industry     

Antioxidant and anti-inflammatory activities of ethyl acetate extracts of chub mackerel (Scomber colias): a thorough seasonal evaluation

The seasonal variation of key bioactivities in ethyl acetate extracts of chub mackerel (Scomber colias), an underutilised fish species, was evaluated through a complete monthly sampling. The phenolic content had a seasonal variation, ranging from 39 ± 5 mg GAE/100 g ww (February) to 340 ± 6 mg GAE/100 g ww (October). Ferric reducing antioxidant power (FRAP) increased from 1.3 ± 0.4 μmol Fe²⁺ Eq/g ww (January) to 10.3 ± 0.1 μmol Fe²⁺ Eq/g ww (September). ABTS had no antioxidant activity between June and December, being the highest value in February, 64.3 ± 6.3 μmol Trolox Eq/100 g ww. For phenolic content and FRAP, there was a strong seasonality, which was similar to that of the lipid content. Therefore, correlations were high, being R² 0.95 for lipid vs. phenolic contents. Anti-inflammatory activity did not show large changes throughout most part of the year, remaining high in the 70–80% of COX-2 inhibition. This finding and the seasonality of the antioxidant properties warrant further research.     

Phenolic Compounds and Antioxidant Capacities of 10 Common Edible Flowers from China

The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe²⁺ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC₅₀) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.     

Antioxidant phenolic compounds from Smilax sebeana Miq.

Methanol extract and sub-fractions of Smilax sebeana rhizomes and roots were analyzed to evaluate the compounds involved in antioxidant activity. In all separated fractions of the different polarity solvents, ethyl acetate fraction showed the highest antioxidant activity and total phenolic content. This fraction was subjected to the sephadex LH-20 column and preparative HPLC for purification. Six phenolic compounds, chlorogenic acid (1), 4-formylphenol (2), epicatechin (3), cinchonain IIa (4), Ia (5) and Ib (6) were isolated and identified by spectroscopic analyses and further evaluated their potential antioxidant activities by DPPH and superoxide radical scavenging assays. Compared with synthetic antioxidant Trolox, except 4-formylphenol, the other isolated five compounds exhibited excellent antioxidant activities. This is the first report on the chemical constituents of S. sebeana which potentially involved in antioxidant activity. The results suggest that the ethyl acetate extract of S. sebeana might be used as a readily accessible source of natural antioxidant.     

Antioxidant and Xanthine Oxidase Inhibitory Activities of Persicaria hydropiper

Five different polarity fractions of methanolic extract from Persicaria hydropiper, which are consumed as vegetables, were evaluated for its total phenolic content, and antioxidant activities by 1,1-diphenyl-2-picrylhydrazyl radical scavenging, ferric thiocyanate, and xanthine oxidase inhibition assays. Particularly, higher phenolic content was exhibited by butanol and ethyl acetate fractions with the values of 224.38 and 68.95 mg GAE/100 g dry extract, respectively. Both butanol and ethyl acetate fractions exhibited higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with IC₅₀ values of 28.61 and 25.55 μg/ml. Meanwhile, both fractions also were shown to inhibit xanthine oxidase activity compared to other fractions with IC₅₀ values of 28.72 and 165.25 μg/ml. As for the ferric thiocyanate method, all the fractions except hexane fraction showed similar activity against lipid peroxidation and were comparable to butylated hydroxyl toluene, with percentage of inhibition from 95 to 98%.     

Polyphenol contents and in vitro antioxidant activities of lyophilised aqueous extract of kiwifruit (Actinidia deliciosa)

The aim of this study was to determine the antioxidant potency and total phenolic and flavonoid contents of kiwifruit (Actinidia deliciosa) in vitro by analysing the radical scavenging activity of lyophilised water extract from kiwifruit (LEK) for 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), and superoxide anion radical (O₂⁻) as well as the total reducing power by FRAP and CUPRAC assays and the metal chelating activities. LEK showed efficient radical scavenging activity with DPPH, ABTS, DMPD, and O₂⁻ radicals; ferric (Fe³⁺) and cupric (Cu²⁺) ion reducing power and metal chelating activities. Moreover, the amounts of phenolic compounds, such as caffeic acid, ferulic acid, syringic acid, ellagic acid, catechol, pyrogallol, p-hydroxy benzoic acid, vanillin, p-coumaric acid, gallic acid, quercetin, ??-tocopherol and ascorbic acid, in LEK were quantified by LC-MS-MS. The results show that pyrogallol (2070.0 mg/kg LEK) is the main phenolic compound responsible for the antioxidant and radical scavenging activities of LEK. Finally, total phenolic and flavonoid contents were determined as gallic acid (GAE) and quercetin equivalents (QE). The GAE and QE values in LEK were 16.67 ± 2.83 ??g GAE/mg and 12.95 ± 0.52 ??g QE/mg, respectively. The results suggest that consumption of kiwifruit (A. deliciosa) can be beneficial effects due to its antioxidant properties.     

青海藜麦资源酚类物质及其抗氧化活性分析

为了明确青海藜麦资源酚类物质含量及其抗氧化活性的差异,筛选出酚类物质和抗氧化活性高的藜麦资源,采用化学法分析了90份藜麦资源中游离酚类、结合酚类含量,通过DPPH·、ABTS+·清除力及FRAP铁还原力指标评价各组分的体外抗氧化活性。结果表明:不同藜麦酚类物质含量均存在较大差异,且结合酚类物质含量差异较大,游离酚类物质含量相对较小,游离酚类和结合酚类物质在清除DPPH·、ABTS+·、FRAP方面存在明显差异,其中结合酚类具有较强的清除DPPH·、ABTS+·能力,分别达4732.56、3371.97 μmol Trolox Eq/100 g DW;游离酚类的FRAP还原能力相对较强,达1408.64 μmol Trolox Eq/100 g DW。白色、黄色藜麦的结合酚类物质清除DPPH·、ABTS+·能力显著高于红色藜麦,分别达4657.41、5065.66 μmol Trolox Eq/100 g DW,3532.37、3350.72 μmol Trolox Eq/100 g DW;红色藜麦的酚类物质FRAP铁还原力最强(3264.42 μmol Trolox Eq/100 g DW)。聚类分析表明,参试的大部分青海藜麦资源结合酚类物质含量较低,DPPH·、ABTS+·清除力较弱,但FRAP铁还原力较强,其中有6个藜麦资源的结合酚类物质含量最高,5个藜麦资源的抗氧化活性最强。此结果为功能性藜麦新品种的选育提供了优质资源和指导意义。     

Antioxidant activity and phenolic content of phenolic rich fractions obtained from black cumin (Nigella sativa) seedcake

The antioxidant activities of crude methanolic extract (CME) and its fractions using ethyl acetate (EAF), hexane (HF) and water (WF) of black cumin seedcake were investigated. DPPH radical scavenging activity, β-carotene–linoleate bleaching, and inhibition of corn oil oxidation were used to evaluate the antioxidant capacity. The total phenolics were found to be 78.8, 27.8, 32.1 and 12.1 mg gallic acid equivalents (GAE)/g in EAF, CME, WF and HF, respectively. The CME and EAF exhibited the highest DPPH followed by WF and HF. The extract/fractions showed high effect on reducing the oxidation of β-carotene. The effect of extract/fractions on the oxidative stability of corn oil at 70 °C was tested in the dark and compared with butylated hydroxyanisole (BHA). The oil peroxide and anisidine values were generally lower with addition of PRFs in comparison to a control. The predominant phenolic compounds identified by HPLC–DAD in CME and WF of black cumin seedcake were hydroxybenzoic, syringic and p-cumaric acids.     

Tea and herbal infusions: Their antioxidant activity and phenolic profile

Tea and herbal infusions have been studied for their polyphenolic content, antioxidant activity and phenolic profile. The total phenolics recovered by ethyl acetate from the water extract, were determined by the Folin–Ciocalteu procedure and ranged from 88.1 ± 0.42 (Greek mountain tea) to 1216 ± 32.0 mg (Chinese green tea) GAE (Gallic acid equivalents)/cup. The antioxidant activity was evaluated by two methods, DPPH and chemiluminescence assays, using Trolox and quercetin as standards. The EC₅₀ of herbal extracts ranged from 0.151 ± 0.002 mg extract/mg DPPH (0.38 quercetin equivalents and 0.57 Trolox equivalents), for Chinese green tea, to 0.77 ± 0.012 mg extract/mg DPPH (0.08 quercetin equivalents and 0.13 Trolox equivalents), for Greek mountain tea. Chemiluminescence assay results showed that the IC₅₀ ranged from 0.17 ± 3.4 × 10⁻³ μg extract/ml of the final solution in the measuring cell (1.89 quercetin and 5.89 Trolox equivalents) for Chinese green tea, to 1.10 ± 1.86 × 10⁻² g extract/ml of the final solution in the measuring cell (0.29 quercetin and 0.90 Trolox equivalents) for Greek mountain tea. The phenolic profile in the herbal infusions was investigated by LC-DAD-MS in the positive electrospray ionization (ESI⁺) mode. About 60 different flavonoids, phenolic acids and their derivatives have been identified.     

Antioxidant activities and related polyphenolic constituents of the methanol extract fractions from Broussonetia papyrifera stem bark and wood

Broussonetia papyrifera radix, fruits, leaves, and stems exhibit antioxidant, antinociceptive, antityrosinase, anti-inflammatory, and antiplatelet activities. However, study of the antioxidant activity of stem bark has been limited. In this work the antioxidant activity of stem bark and wood extracts were compared using different methods, and their phenolic constituents were analyzed. The bark ethyl acetate fraction exhibited the highest 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical, hydroxyl radical scavenging activity, and the highest total phenolic and flavonoid contents. Both bark and wood n-butanol fractions showed stronger superoxide anion radical scavenging activity and reducing potential than other fractions. The bark and wood hexane fraction provided the highest level of ion chelating power. The high performance liquid chromatography (HPLC) analysis reveals there are more phenolic compounds in bark than in wood. These findings suggest that bark exhibits a higher antioxidant capacity than wood and that ethyl acetate and n-butanol fractions of B. papyrifera bark are potential natural resources for pharmacology of functional foods.     

不同干燥方式对苹果蟠桃纸的感官品质和理化特性的影响

为了研究不同干燥方式对苹果蟠桃纸的感官品质和理化特性的影响,本文采用五种干燥方式（烘箱热风干燥、烤箱干燥、微波炉干燥、烤箱-烘箱联合干燥、烤箱-微波炉联合干燥）制备苹果蟠桃纸,考察不同干燥方式制备的苹果蟠桃纸在感官评定、质构、色泽、褐变度、总酚和维生素C含量、抗氧化活性等方面的差异。结果表明,烘箱热风干燥的产品的形态、口感、色泽、风味更能吸引感官评定人员,感官评定分数为最高（86.7）,总酚类含量最高（5.66 mg GAE/g dw）、抗氧化活性较强（DPPH自由基清除率66.00%,FRAP法测定的总还原能力0.32 mmol Trolox/g dw）,但维生素C含量较低（4.56 mg/100 g）、褐变程度较高。微波炉干燥的苹果蟠桃纸维生素C含量最高（9.78 mg/100 g）,但感官评定分数最低为66.7,总酚含量（4.11 mg GAE/g dw）和抗氧化活性最低（DPPH自由基清除率58.00%,FRAP法测定的总还原能力 0.18 mmol Trolox/g dw）。烤箱-烘箱联合干燥和烤箱-微波炉联合干燥的产品则没有突出优势。综上,建议在苹果蟠桃纸生产中不采用微波炉干燥,采用烘箱热风干燥。     

坛紫菜不同溶剂组分的抗氧化活性

为研究坛紫菜酚类化合物的抗氧化活性,通过提取和萃取得到坛紫菜4 种溶剂组分：石油醚、乙酸乙酯、正丁醇和水溶性组分,对其DPPH 自由基清除率和还原力大小进行比较,并研究其中多酚和黄酮类化合物的分布。结果表明：4 种溶剂组分在0.2～1.5g/L 质量浓度范围内与抗氧化活性均存在显著剂量效应关系,其DPPH 自由基清除率和还原力大小均为：乙酸乙酯＞正丁醇＞石油醚＞水溶性组分。在质量浓度为1.5g/L 时,乙酸乙酯组分的还原力吸光度为1.97,大于80% 茶多酚(1.90),接近于BHT(2.00)。对多酚类化合物和黄酮类化合物而言,同样是在乙酸乙酯组分中分布最多(分别为69.84mg GAE/g md 和299.49mg RE/g md),在水溶性组分中最少(分别为11.1mgGAE/g md 和32.36mg RE/g md),因此酚类化合物主要分布在中等极性溶剂中,而不是强极性溶剂中。研究还发现,1g/L 坛紫菜4 种溶剂组分的多酚类化合物含量与DPPH自由基清除率、还原力间的相关系数为：r =0.9311 和r=0.7530,而黄酮类化合物含量与DPPH 自由基清除率、还原力间的相关系数为r=0.8899 和r=0.7211,可见坛紫菜多酚类化合物为其抗氧化的主要活性成分。     

高钙菜黄酮的分级分离各级分的抗氧化活性

以抗坏血酸和叔丁基羟基茴香醚做阳性对照,采用二苯代苦味肼基自由基(DPPH·)、羟自由基(·OH)、超氧阴离子自由基(O₂-·)、还原力、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐阳离子自由基(ABTS+·)和总抗体外抗氧化模型,主成分分析综合评价高钙菜总黄酮各级分(乙酸乙酯相、正丁醇相、氯仿相和水相)的抗氧化活性。结果显示,在各体外抗氧化活性指标的测定中,各萃取相的抗氧化活性均随着黄酮浓度增加呈现上升趋势,其中ABTS+·的清除能力最强,高达99.72%±0.10%,与抗坏血酸清除能力相近。乙酸乙酯相的·OH清除率、O₂-·清除率、总抗氧化FRAP值、还原力及ABTS+·清除率要显著优于其它各萃取相,氯仿相的DPPH·清除率显著优于其它萃取相。主成分分析综合评价显示,乙酸乙酯相抗氧化活性最佳。显色反应结合红外光谱分析,初步判定乙酸乙酯相和正丁醇相可能为黄酮醇类。高钙菜总黄酮具有较强的抗氧化活性,可作为良好的健康食品原料开发及利用。     

Antioxidant Activities of Polyphenolic Compounds Isolated from Antidesma thwaitesianum Müll. Arg. Seeds and Marcs

ABSTRACT: Antidesma thwaitesianum Müll. Arg. or mao is widely used as commercial products of juice and wine in Thailand. As a result, waste products from the mao plant, such as mao seeds (MS) and mao marcs (MM), are plentiful. We aimed to purify and analyze polyphenolic content in both MS and MM and to investigate the radical scavenging activities of these polyphenolics against 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) and 2,2′‐Azinobis (3‐ethylbenzothiazoline 6‐sulphonate) (ABTS) radicals and thiobarbituric acid reactive products (TBARP). The results showed MS and MM to be an abundant source of polyphenols (97.32 to 130 mg gallic acid equivalents [GAE]/g) and proanthocyanidins. The radical scavenging activities of MS/MM against DPPH and ABTS radicals (IC₅₀ of 0.85 to 1.21 μg/mL) were significantly higher (P < 0.05) than that of standard trolox (IC₅₀ of 5.05 μg/mL). Activity of MS/MM extracts were 3.74 and 3.80 μg/mL trolox eq/g f.w. for the DPPH and ABTS assays, respectively. The oxidation of erythrocyte membranes using 2‐thiobarbituric acid demonstrated that the protective effect of MS/MM on lipid peroxidation is as strong as grape seed proanthocyanidin extract. These findings suggest that polyphenolic compounds and proanthocyanidins isolated from these mao extracts had much higher antioxidant activities than those of standard trolox and exhibited similar antioxidant potential to grape seed proanthocyanidin extract. These findings may also increase value of mao waste products and allow development of commercial health products.     

Antioxidant and Antibacterial Activities on Foodborne Pathogens of Artocarpus heterophyllus Lam. (Moraceae) Leaves Extracts

Abstract: Total water extract, ethyl acetate, and aqueous fractions from the leaves of Artocarpus heterophyllus were evaluated for phenolic content, antioxidant, and antibacterial activities against some foodborne pathogens such as E. coli, Listeria monocytogenes, Salmonella typhimurium, Salmonella enterica, Bacillus cereus, Enterococcus faecalis, and Staphylococcus aureus. The minimum inhibitory concentration (MICs) of extract and fractions determined by the agar dilution method were ranged from 221.9 μg/mL for ethyl acetate fraction to 488.1 μg/mL for total extract. In the agar diffusion method the diameters of inhibition were 12.2 for the total extract, 10.7 and 11.5 for ethyl acetate and aqueous fractions, respectively. A. heterophyllus showed significant antioxidant activity tested in different in vitro systems (DPPH, ABTS, FRAP, and Fe²⁺ chelating activity assay). In particular, in DPPH assay A. heterophyllus total extract exhibited a strong antiradical activity with an IC₅₀ value of 73.5 μg/mL while aqueous fraction exerted the highest activity in FRAP assay (IC₅₀ value of 72.0 μg/mL). The total phenols content by Folin–Ciocalteau method was determined with the purpose of testing its relationship with the antioxidant and antibacterial activities. Practical Application: The appearance of food is one of the major determinants of its appeal to consumers and consequently, sales of the product. Microbial contamination and lipid oxidation are the main factors that determine food quality loss and shelf-life reduction. Therefore, preventing microbial contamination and delaying lipid oxidation are highly relevant to food processors. The growth of microorganisms in food products may cause spoilage or foodborne diseases. Oxidative processes in food products lead to the degradation of lipids and proteins which, in turn, contribute to the deterioration in flavor, texture, and color of the products. A. heterophyllus leaves extracts demonstrated interesting biological properties that suggest its use as a new potential source of natural antioxidant and antimicrobial agent.     

Screening of 70 medicinal plant extracts for antioxidant capacity and total phenols

The total phenolic content and related total antioxidant capacity of 70 medicinal plant infusions was analyzed. Infusions were prepared in common way in which teas are prepared for human consumption. The total phenolics were measured by Folin–Ciocalteau assay. The total antioxidant capacity was estimated by Ferric Reducing/Antioxidant Power (FRAP) assay. To make practical comparison of relative antioxidant potential of phenolics extracted from selected medicinal plants, the phenol antioxidant coefficient (PAC) was calculated for each infusion. The total phenolic content of medicinal plant infusions ranges from 9 to 2218 mg/L. The FRAP range from 0.06 to 25 mM/L. There was significant linear correlation between total phenolic content and FRAP. According to their antioxidant capacity, 70 medicinal plant extracts can be divided in five groups: (a) very low FRAP (<1 mM/L) n = 9; (b) low FRAP (1–5 mM/L), n = 37; (c) good FRAP (5–10 mM/L), n = 15; (d) high FRAP (10–20 mM/L), n = 8; and (e) very high FRAP (>20 mM/L), n = 1 medicinal plant extract. The PAC was ranging from 1.1 to 3.9 (average 2.4). The best results were obtained for Melissae folium infusions: high phenolic concentration, very high FRAP (>20 mM/L) and PAC > 3. The effect of infusion time and infusion temperature on the phenolic content, FRAP, and free radical scavenging ability was tested. DPPH radical scavenging ability of Melissae folium phenolics was similar to (+)-catechin but not as good as for quercetin. Compared to Trolox and vitamin C, Melissae folium phenolics were more efficient free ABTS radical scavengers. The results indicate that Melissae folium infusions could be an important dietary source of phenolic compounds with high antioxidant capacity comparable with red wine or beverages like tea.