Radical Scavenging Components Research Articles

Home-based preparation approaches altered the availability of health beneficial components from carrot and blueberry.

This study investigated the effects of different home food preparation methods on availability of total phenolic contents (TPC) and radical scavenging components, as well as the selected health beneficial compounds from fresh blueberry and carrot. High performance liquid chromatography (HPLC) analysis revealed that ground carrots using blenders released significantly greater amount of β‐carotene than their chopped counterpart, and blueberry samples prepared with different commercial blenders/grinders released different levels of cyaniding‐3‐O‐glucoside and malvidin‐3‐O‐glucoside. Furthermore, microwaving was able to significantly alter the releasable amounts of cyaniding‐3‐O‐glucoside and malvidin‐3‐O‐glucoside from blueberries. In addition, carrots and blueberries processed using different blenders and chopping with or without microwaving differed in their available levels of TPC, and radical scavenging components against DPPH •, oxygen radicals and HO •, as well as their potential anti‐inflammatory activities. Taking together, these results indicated that home food preparation approaches may alter the availability of health components from carrots and blueberries. The results also suggested that the influence may depend on the fruit and vegetable type, but not the price of blenders/grinders.

Isolation and Identification of Radical Scavenging Components of Seeds of Desmodium styracifolium

In order to promote comprehensive utilization of Desmodium styracifolium resources, bioassay-guided fractionation and a chemical investigation of D. styracifolium seeds, were conducted, which resulted in the isolation of a new flavonol acylglycoside (1) together with eight known compounds (2–9). Their structures were identified by spectroscopic techniques (1D/2D NMR and MS). All the compounds were isolated for the first time from the genus Desmodium except for 3 and 8.

Activity-guided isolation of antioxidants from the leaves of Terminalia arjuna

An activity-guided isolation and purification process was used to identify the l,l-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging components of the food plant (Terminalia arjuna) of Antheraea mylitta. Dry leaves of T. arjuna were extracted with different solvents and tested for their antioxidant activity against DPPH•. The acetone–water (8:2) extract expressed strong DPPH radical-scavenging activity, and was subjected to column chromatography over silica gel. Gallic acid, apigenin, luteolin, quercetin, epicatechin, ellagic acid and 1-O-β-galloyl glucose were isolated as active components and characterised by using different spectroscopic techniques.

Activity-guided isolation of antioxidants from the roots of Rheum emodi

An activity-guided isolation and purification process was used to identify the DPPH free radical scavenging components of Rheum emodi. The activity-guided isolation revealed that eugenol, gallic acid, quercetin, rutin, epicatechin, desoxyrhapontigenin, rhapontigenin and mesopsin are the major phenolic compounds responsible for the antioxidant activity of the roots of R. emodi.

Activity-guided isolation of antioxidant xanthones from Swertia chirayita (Roxb.) H. Karsten (Gentianaceae)

An activity-guided isolation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) radical-scavenging components of Swertia chirayita. A dry, whole plant of S. chirayita was extracted with different solvents and tested for its DPPH radical-scavenging activity. The acetone : water (8 : 2) extract showed the highest total phenolic content (TPC) and DPPH radical-scavenging activity, which was column chromatographed to obtain decussatin, swertianin, bellidifolin, isobellidifolin, amarogentin, swertianolin and mangiferin as active components. Good correlation was observed between TPC and DPPH scavenging activity among the extracts. The unique structure of xanthones, including the catecholic moiety and the completely conjugated system, enables them to be promising antioxidants.

Activity-guided isolation and identification of free radical-scavenging components from various leaf extracts of Sorbus aria (L.) Crantz

Nine phenolics were obtained from the leaves of Sorbus aria (L.) Crantz by activity-directed isolation: isorhamnetin 3-O-β-glucopyranoside (1), astragalin (2), isoquercitrin (3), hyperoside (4), kaempferol 3-O-β-glucopyranoside-7-O-α-rhamnopyranoside (5), quercetin 3-O-β-glucopyranoside-7-O-α-rhamnopyranoside (6), rutin (7), chlorogenic acid (8) and neochlorogenic acid (9). The isolates were identified by spectral methods (UV, 1H- and 13C-NMR, COSY, HMQC and HMBC), and their free radical-scavenging activity was tested using the l,l-diphenyl-2-picrylhydrazyl (DPPH) method. The antioxidant potential of the different extracts obtained in the fractionation process was evaluated using the DPPH test in relation to the HPLC contents of the isolates 1–9, total phenolics and total proanthocyanidins. Among the analytes tested, superior activity was expressed by isoquercitrin (3, EC50 = 2.76 mg L−1) and the ethyl acetate extract (EC50 = 2.99 mg L−1). Five strongly active isolates 3, 6, 7, 8 and 9 were found to be major components and to be principally responsible for the radical-scavenging activity of S. aria extracts.

다공성 합성흡착제를 이용한 복분자 딸기(Rubus coreanus) 농축액의 항산화 효과

4종류의 다공성 합성흡착제(Sepabeads 207, 700, 850, Diaion HP 20)를 사용하여 Rubus coreanus 과실의 물 추출물로부터 과당 및 비polyphenol성분을 효과적으로 제거하여 DPPH라디칼 소거능 및 화학발광법을 이용한 superoxide 라디칼 소거능이 증가된 농축물을 효율적으로 얻을 수 있었다. 또한, 실시간 HPLC <TEX>$ABTS^{{\cdot}+}$</TEX> 활성분석 시스템을 활용하여 6개의 항산화 능력을 갖는 활성피크를 확인할 수 있었으며 이들 대상으로 LC-MS/MS분석을 실시하여 5개의 anthocyanin인 cyanidin-3-sambubioside, cyanidin-3-glucoside, cyanidin-3-xylosylrutinoside, cyanidin-3-rutinoside, pelargonidin-3-rutinoside를 mass pattern 및 분자량 확인 과정을 통해 잠정적 화학구조 동정을 하였다. 수율과 항산화 효능을 고려해 볼 때, 4종의 합성흡착제 중에서 Diaion HP 20이 가장 우수한 결과를 나타내었다. 이처럼 적절한 합성흡착제의 선택으로 표적물질에 대한 polyphenol성 물질의 농축뿐만 아니라 생리학적 활성증대효과를 가져올 수 있어 적절한 합성흡착제의 선택은 식품 및 의약품의 정제 및 분리에 유용하게 활용될 수 있음이 확인되었다. This study was carried out to develop a method of removing unnecessary sugars and high-molecular weight soluble components from water extract by using various highly porous polymer resins: these resins are widely used as adsorbents for polyphenolic compounds. Each anthocyanin-rich fraction (ARF) that was eluted from column packed with 4 different resins (SEPABEADS SP207, 700, 850 and Diaion HP 20) was obtained from an aqueous extract of the ripe fruits of Rubus coreanus, which is well-known in Korea as "Bok-bun-ja". Among the above mentioned resins, Diaion HP20 had the highest efficacy and provided maximum yield of the ARF. The ARF eluted from the column packed with HP 20 exhibited the strongest antioxidant activity in vitro. Bioactive phytochemicals extracted from Rubus coreanus were investigated using the on-line HPLC-<TEX>$ABTS^{{\cdot}+}$</TEX> system, and the resulting 6 peaks were identified as radical-scavenging components. By using liquid chromatography-mass spectrometry, 5 peaks were obtained, and these were identified as cyanidin-3-sambubioside, cyanidin-3-glucoside, cyanidin-3-xylosylrutinoside, cyanidin-3-rutinoside and pelargonidin-3-rutinoside. These results indicate that the use of appropriate porous resin (Diaion HP 20) leads to an increase in the yield of bioactive components and enhancement of their biological properties.

Activity‐Guided Isolation and Identification of Radical Scavenging Components in Gao‐Cha Tea

Gao-Cha is a traditional Chinese health tea made from Acer ginnala. We performed a components and radical scavenging activity analysis to identify any medicinal components in this tea. High performance thin layer chromatography (HPTLC)-1,1-Diphenyl-2-picryhydrazyl (HPTLC-DPPH) assay showed that the methanolic extract contained strong radical scavengers. Quantitative analysis revealed that the IC(50) of the extract against 1 mM DPPH was 52.7 ± 0.6 μg/mL. Bioactive-guided isolations led to procurement of 3 radical scavengers with IC(50)s of 17.5 ± 2.1, 29.3 ± 2.5, and 21.6 ± 1.7 μg/mL, respectively. Analysis of the high resolution-electric spray ionization-mass spectrometer and (1)H, (13)C, distortionless enhancement by polarization transfer at 135°, heteronuclear quantum coherence, correlating spectroscopy coupling, and heteronuclear multiple bond coherence (HMBC) data revealed that the compounds were methyl 3, 4, 5-trihydroxybenzoate (1), quercetin-3-O-α-rhamnopyranoside (2), and 2,6-bis (3,4,5-trihydroxybenzoyl)-aceritol (3). Bioactive combined components analysis revealed that, apart from compounds 1, 2, and 3, the tea possibly contained radical scavengers: ginnalin A (4) and B (5), 2″-O-Galloylquercitrin (6) and 3″-O-Galloyl-quercitrin (7). Compounds 2, 6, and 7 were isolated from Acer ginnala for the first time. The positions of the 2 galloyl moieties in compound 3 were unambiguously established by the HMBC spectrum for the first time.

A new antioxidant compound from Capparis spinosa

An activity-directed fractionation and purification process was used to isolate 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging components from fruits of Capparis spinosa L. (Capparaeae). Ethyl acetate and aqueous fractions showed greater DPPH• scavenging activities compared to the petroleum ether fractions. The ethyl acetate fraction was subjected to purification using column chromatography. A new antioxidant cappariside (4-hydroxy-5-methylfuran-3-carboxylic acid, 1), together with seven known organic acids (2–8) for the first time from plants of genus Capparis and four known organic acids (9–12) were isolated from C. spinosa. The structures were elucidated by extensive analysis of 1D- and 2D-NMR spectroscopic. In addition, compounds 1, 2, 4, 5, 9, 10 and 12 indicated strong scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with a SC50 value of 0.204 ± 0.002, 0.007 ± 0.0, 0.011 ± 0.0, 0.044 ± 0.0016, 0.032 ± 0.0, 0.090 ± 0.001, and 0.350 ± 0.017 mM, respectively.

Free radical scavenging and anti-acne activities of mangosteen fruit rind extracts prepared by different extraction methods

The ethanol extracts of mangosteen fruit rinds prepared by several extraction methods were examined for their contents of bioactive compounds, DPPH-scavenging activity, and anti-acne producing bacteria against Propionibacterium acnes and Staphylococcus epidermidis. The dried powder of the fruit rind was extracted with 95% ethanol by maceration, percolation, Soxhlet extraction, ultrasonic extraction, and extraction using a magnetic stirrer. Soxhlet extraction promoted the maximum contents of crude extract (26.60% dry weight) and α-mangostin (13.51%, w/w of crude extract), and also gave the highest anti-acne activity with MIC 7.81 and 15.63 μg/mL and MBC 15.53 and 31.25 μg/mL against P. acnes and S. epidermidis, respectively. Ethanol 70% and 50% (v/v) were also compared in Soxhlet extraction. Ethanol 50% promoted the extract with maximum amounts of total phenolic compounds (26.96 g gallic acid equivalents/100 g extract) and total tannins (46.83 g tannic acid equivalents/100 g extract), and also exhibited the most effective DPPH-scavenging activity (EC50 12.84 μg/mL). Considering various factors involved in the process, Soxhlet extraction carried a low cost in terms of reagents and extraction time. It appears to be the recommended extraction method for mangosteen fruit rind. Ethanol 50% should be the appropriate solvent for extracting free radical-scavenging components, phenolic compounds, and tannins, while 95% ethanol is recommended for extraction of α-mangostin, a major anti-acne component from this plant.

Activity guided isolation of antioxidants from the leaves of Ricinus communis L.

An activity-guided isolation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) free radical scavenging components of the food plant ( Ricinus communis L.) of Eri silkworm. Dry leaves of R. communis L. were extracted with different solvents and tested for their antioxidant activity against DPPH •. The MeOH:water (8:2) extract showed strong DPPH radical-scavenging activity, and was subjected to column chromatography over silica gel. Gallic acid, quercetin, gentisic acid, rutin, epicatechin and ellagic acid were isolated as active components and characterised by different spectroscopic techniques.

Activity-guided Isolation and Identification of Free Radical-scavenging Components from Ethanolic Extract of Boneset (Leaves of Eupatorium Perfoliatum)

Activity-directed fractionation and isolation procedures were used to identify the antioxidant components of Boneset (Eupatorium perfoliatum). Dried powdered leaves were extracted with ethanol and subsequently fractionated into light petroleum, chloroform, ethyl acetate, and n-butanol fractions. The ethyl acetate fraction, which showed the strongest antioxidant activity, reducing power and highest phenolic content, was subjected to Sephadex LH-20 chromatography followed by repetitive preparative TLC to afford protocatechuic acid as the major antioxidant constituent, together with small amounts of other antioxidants (hyperoside, quercetin and rutin). Similar treatment of the n-butanol fraction, the second most potent fraction, yielded predominantly rutin and a trace amount of hyperoside as active constituents. The identity of the compounds was established based on direct comparison of spectral data (UV, IR, 1D- and 2D-NMR and MS) with those of authentic samples and literature values.

Antioxidant phenolic compounds from walnut kernels ( Juglans regia L.)

An activity-directed fractionation and purification process was used to isolate 1,1-diphenyl-2-picrylhydrazyl radical (DPPH ) scavenging components from Juglans regia kernels. Ethyl acetate and n-butanol fractions showed greater DPPH scavenging activities compared to those of water and petroleum ether fractions. The ethyl acetate fraction was subjected to purification using column chromatography. Seven phenolic compounds, pyrogallol (1), p-hydroxybenzoic acid (2), vanillic acid (3), ethyl gallate (4), protocatechuic acid (5), gallic acid (6) and 3,4,8,9,10-pentahydroxydibenzo[ b, d]pyran-6-one (7), containing significant antioxidant activities were isolated and identified in J. regia by spectroscopic methods for the first time in this study. The relative order of DPPH scavenging capacity for these compounds was 7 > 6 ⩾ 4 ⩾ 1 > Trolox ⩾ 5 > 3 > 2. The results of this study suggested that the antioxidant activities of these phenolic compounds may be influenced by the number of hydroxyls in their aromatic rings.

Study on the Hydroxyl Radical Scavenging Activity Changes of Ginseng and Ginsenoside-Rb2 by Heat Processing

The free radical scavenging activities of Panax ginseng C.A. MEYER are known to increase by heat processing. Phenolic acids and Maillard reaction products (MRPs) have been suggested as active free radical scavenging components from our previous research, but heat processing-induced chemical and activity changes of ginsenosides considering the Maillard reaction have not yet been fully elucidated. In this study, we investigated the hydroxyl radical (.OH) scavenging activity changes of ginsengs and ginsenoside-Rb2 (Rb2)) by heat processing using an electron spin resonance spectrometer. Especially, Rb2 was heat processed with the same amount of glycine, a frequently used amino acid in the Maillard reaction model system. As a result, the .OH scavenging activities and brown compound levels of ginseng and glycine-Rb2 mixture were increased by heat processing. However, the increase in .OH scavenging activities were not in accordance with the extents of browning. On the other hand, less-polar ginsenosides such as Rg3, Rg5, and Rk1 were generated from the glycine-Rb2 mixture by heat processing. The sugar moieties at carbon-20 of Rb2 were separated by the steaming process, less-polar ginsenosides were produced, and then the separated sugar moieties were thought to form MRPs with glycine. From the .OH scavenging activity tests of Rb2, glycine, less-polar ginsenosides, and maltol, the increase in .OH scavenging activity was thought to be more closely related to the generation of .OH scavenging ginsenosides such as 20(S)-Rg3 and Rg5 by heat processing than MRPs.

Stereospecificity in hydroxyl radical scavenging activities of four ginsenosides produced by heat processing

The activity-guided fractionation of sun ginseng (SG, heat processed Panax ginseng C. A. Meyer at 120 °C) was carried out to identify its main active hydroxyl radical ( OH) scavenging components. As a result, the n-BuOH fraction mainly consisting of ginsenosides showed the strongest activity. Of several ginsenosides of SG, the OH scavenging activities of relatively high contents of 20( S)-Rg 3, 20( R)-Rg 3, Rk 1, and Rg 5 were compared. Rg 5 and 20( S)-Rg 3 showed strong OH scavenging IC 50 values of 0.15 and 0.44 mM, respectively, and these activities were prominently higher than each of their respective isomers. Therefore, stereospecificity exists in the OH scavenging activities of ginsenosides produced by heat processing. Especially, the double bond at carbon-20(22) or the OH group at carbon-20 geometrically close to OH at carbon-12 is thought to increase the OH scavenging activity of ginsenosides.

Activity-guided isolation and identification of free radical-scavenging components from an aqueous extract of Coleus aromaticus

An activity-directed fractionation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) free radical-scavenging components of Coleus aromaticus Benth. Fresh leaves of C. aromaticus were extracted with water and then separated into hexane, ethyl acetate, and water fractions. Among these, only the ethyl acetate phase showed strong DPPH radical-scavenging activity in vitro, when compared with water and hexane phases. The ethyl acetate fraction was then subjected to separation and purification using Sephadex LH-20 chromatography. Three compounds showing strong DPPH radical-scavenging activity were shown, by spectral methods ( 1H NMR, 13C NMR, and MS) and by comparison with literature values, to be rosmarinic acid, chlorogenic acid and caffeic acid. In addition, HPLC identification and quantification of isolated compounds were also performed. Rosmarinic acid was found as a major component and principally responsible for the radical-scavenging activity of C. aromaticus.

Saskatoon berries ( Amelanchier alnifolia Nutt.) scavenge free radicals and inhibit intracellular oxidation

Two cultivars (Thiessen and Smoky) of Saskatoon berries ( Amelanchier alnifolia Nutt.) possess free radical scavenging activities in a concentration-dependent manner, whereas Thiessen presented higher ( p < 0.05) activity compared to Smoky due to its relatively abundant anthocyanin content. Total anthocyanin content significantly corresponded to free radical scavenging activities ( p < 0.05). Solvent fractionation revealed that the free radical scavenging components, i.e., anthocyanin, predominantly occurred in the ethyl acetate and n-butanol extracted fractions, suggesting that active components are more likely to occur in glycoside forms. HPLC further confirmed the existence of cyanidin-3- O-galactoside and cyanidin-3- O-glucoside as leading anthocyanins in the Saskatoon berries. Furthermore, Saskatoon berries extracts from both cultivars suppressed peroxy-radical induced intracellular oxidation in a concentration-dependent manner without affecting cell viability. The obtained results provided useful information for the future application of Saskatoon berries in the nutraceutical industry.

An Improved HPLC Post-Column Methodology for the Identification of Free Radical Scavenging Phytochemicals in Complex Mixtures

The importance of natural antioxidants principally relates to their health-promoting properties. The discovery of new sources of established compounds or more potent compounds is a costly exercise and any technique capable of aiding this procedure would be highly significant. An approach combining chromatographic separation, component analysis and post-column identification of free radical scavenging has been reported. However, its effectiveness is dependent upon various factors and the number of samples analyzed without operator intervention is restricted. A more applicable technique using a 10% to 100% methanol with 2% acetic acid mobile phase and a citric acid-sodium citrate buffered methanolic 1,1-diphenyl2-picrylhydrazyl free radical reagent is presented, whereby free radical scavengers can be detected within crude extracts of variable polarity without special considerations. As an illustration, acetone, 70% (aq.) methanol and acetonitrile-soluble extracts were prepared from sage (Salvia officinalis L.) for extraction of polar and non-polar radical scavengers and analyzed. Radical scavenging components were identified as carnosic, caffeic and rosmarinic acids and luteolin-7-O-glycoside. Others radical scavengers were tentatively identified as benzoic and hydroxycinnamic acid derivatives, flavonoids and diterpenoids. Through the application of this technique, carnosic acid and rosmarinic acid were identified as the principal free radical scavengers.

Antimicrobial and antioxidative enrichment of oak ( Quercus robur) bark by rotation planar extraction using ExtraChrom®

The multifunctional ExtraChrom® instrument was used in the extraction of antimicrobial and radical scavenging components from oak ( Quercus robur L.) bark. Milled and sieved oak bark was extracted with 80% (v/v) methanol solution in water on the ExtraChrom® instrument using step-gradient in the preparative separation. Extracts were tested using agar diffusion method on Staphylococcus aureus, Enterobacter aerogenes and Candida albicans. Some extracts showed moderate bactericidal, fungicidal, bacteriostatic and fungistatic activity. The composition related to activity of the fractions and extracts was screened simultaneously by thin-layer chromatography (TLC) detected by UV and by spraying the plate with radical scavenging reagent 1,1-diphenyl-2-picrylhydrazyl (DPPH) to detect antioxidant activity. Thus, we could demonstrate the antiradical and antimicrobial activity of oak beneficial in the storage of wine against the oxidation and human microbial exposure.

Polymeric procyanidins as radical-scavenging components in red-hulled rice.

The extracts from white-, black-, and red-hulled rice were prepared by sequential extraction with six different polar solvents, and their radical-scavenging activities were measured by methods using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH*) and tert-butyl hydroperoxyl radical (t-BuOO*). The extracts prepared with highly polar solvents, methanol and deionized water, exhibited higher DPPH* and t-BuOO* scavenging activities in all three cultivars. In addition, the acetone extract from red-hulled rice exhibited a high DPPH* and t-BuOO* scavenging activity, while no such activity was detected for the acetone extracts from white- and black-hulled rice. The major components responsible for the radical scavenging in the acetone extract from red-hulled rice were identified as procyanidins by acidic hydrolysis, vanillin assay, and Sephadex LH-20 chromatography. GPC analysis of the acetylated procyanidins revealed that the average molecular weight is about 5000, in a range of about 500-18,000.