Food Chemistry 155 (2014) 112–119

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Food Chemistry

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In vitro antioxidant properties and anthocyanin compositionsof elderberry extracts

http://dx.doi.org/10.1016/j.foodchem.2014.01.0280308-8146/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding author. Tel.: +90 (222) 335 0580; fax: +90 (222) 335 3616.E-mail address: ecz.halegamze@gmail.com (H.G. Duymus�).

Hale Gamze Duymus� a,⇑, Fatih Göger a, K. Hüsnü Can Bas�er a,b,c

a Anadolu University, Faculty of Pharmacy, Department of Pharmacognosy, 26470 Eskisehir, Turkeyb King Saud University, College of Science, Botany and Microbiology Department, P.O. Box 2455, Riyadh 11451, Saudi Arabiac Technology Transfer Office, Bahcesehir University, 34354 Besiktas-_Istanbul, Turkey

a r t i c l e i n f o

Article history:Received 9 September 2013Received in revised form 5 December 2013Accepted 13 January 2014Available online 23 January 2014

Keywords:Sambucus nigraElderberryHPLCLC/MS–MSRadical scavenging activityAntioxidant activity

a b s t r a c t

In this study, dried elderberry fruits growing wild in Turkey were macerated using different solvents andan infusion was prepared according to traditional methods. All extracts were investigated for their totalphenolic content, total monomeric anthocyanins, qualitative–quantitative determination of cyanidin-3-glucoside (by HPLC–UV analysis), anthocyanin compositions (by LC/MS–MS), free radical scavengingactivity (DPPH and ABTS) and inhibition of b-carotene/linoleic acid co-oxidation. An extract with 70% eth-anol was found to be richer in cyanidin-3-glucoside when compared to the other extracts. The infusionwas found to be as rich as the 70% ethanol extract. Ethanol and acetone extracts (both 70%) were foundto be more active in the free radical activity and b-carotene bleaching assays. Water extract showed goodABTS� radical scavenging activity when compared with ascorbic acid.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Current research into free radicals has confirmed that foods richin antioxidants play an essential role in the prevention of cardio-vascular diseases, cancers and neurodegenerative diseases (Hamid,Aiyelaagbe, Usman, Ameen, & Lawal, 2010; Sharma, Jha, Dubey, &Pessarakli, 2012). Therefore, natural antioxidants and colourantspresent in foods have attracted interest because of their safetyand potential nutritional and therapeutic effects. These naturalcompounds can also be alternatives to synthetic dyes (Espin,Soler-Rivas, Wichers, & Garcia-Viguera, 2000).

Anthocyanins belong to the most common class of phenoliccompounds which occur naturally in fruits and vegetables as glyco-sides, containing glucose, galactose, rhamnose, xylose or arabinoseattached to an aglycon nucleus (Wang & Stoner, 2008). Nowadays,the potential health benefits associated with consumption of antho-cyanins are the focus of much research. Intake of anthocyanin isincreasing because extracts and juices with high anthocyanin con-tents from fruits and vegetables such as grape, various berries andred carbage are becoming more and more popular.

The anthocyanin content of berries from Sambucus, Lonicera andViburnum species have received great attention. Especially juicesand extracts from the elderberry, known as Sambucus nigra L., have

been used in biological studies (Abuja, Murkovic, & Pfannhauser,1998; Bitsch et al., 2004; Bratu, Guiu, Samarineanu, Gaidargiu, &Porta, 2003; Murkovic, Adam, & Pfannhauser, 2000; Netzel et al.,2005; Roschek, Fink, McMichael, Li, & Alberte, 2009; Wu, Gu, Prior,& McKay, 2004). Elderberries general grow wild in several coun-tries in Europe and are also cultivated on a small scale in somenorthern European countries (Akbulut et al., 2009). Elderberryhas also been used to colour jams, jellies and wines in Europe(Inami, Tamura, Kikuzaki, & Nakatani, 1996). The dried ripe or freshberries are recommended for the treatment of constipation, as adiuretic and diaphoretic in upper respiratory tract infections, andto alleviate pain. For the treatment of these complaints, juice ortea are consumed. The infusion, prepared from 10 g dried berriesstanding in cold water for several minutes, is then slowly heatedup and boiled briefly. Before filtering, a drawing-time of5–10 min is recommended (Vlachojannis, Cameron, & Chrubasik,2009). In Turkey, S. nigra occurs sporadically in western and east-ern parts, particularly in the northern coastal strip. Elderberry bark,root, stem and fruits have been used particularly by the rural pop-ulation as medicine and food (Baytop, 1984). But the consumptionof elderberry is not very common and only a few studies have beenreported (Akbulut, Ercis�li, & Tosun, 2009; Yenen & Özgen, 1997).However, none of these studies focus on elderberry anthocyanincomposition and identification by liquid chromatography.

The aim of this study was to determine the anthocyanincomposition and to evaluate the antioxidant capacity of elderberry

H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119 113

extracts. Five extracts were prepared with solvents of differentpolarities and an infusion of elderberry fruits was investigated forits antioxidant activity in in vitro test systems. Furthermore, the totalphenol and total monomeric anthocyanin were also analysed usingspectrophotometric techniques. Anthocyanin contents of the ex-tracts were also characterized by HPLC–UV and LC–MS/MS analyses.

2. Materials and methods

2.1. Plant material and reagents

Air-dried mature fruits of elderberry were obtained from ‘EvçayCompany’, Yalova, Turkey in 2009. Chromatographic standardswere purchased from Sigma Chemical Company. Ultra-pure waterwas used throughout and was prepared using a Millipore Milli-RO12 plus system (Millipore Corp., MA, USA). All remaining reagentswere of the highest purity available and obtained from the SigmaChemical Company (St. Louis, MO, USA).

2.2. Preparation of the extracts

Ground elderberries (5 g) were macerated with 100 ml of water,70% ethanol, 70% acetone and methanol at room temperature byusing a shaker 3 times (48, 48, 24 h) during 5 days in the dark. HCl(0.1%) in methanol extracts were prepared by using an ultrasonicbath at room temperature for 30 min, 3 times. The infusion was pre-pared according to traditional methods (Vlachojannis et al., 2009)and freeze dried. The extracts were evaporated to dryness at 35 �Cby a rotary evaporater and stored at�18 �C. Prior to analysis, an ali-quot of each extract was dissolved and filtered through a 0.45 lmmembrane (Whatman, UK) and used in all the test systems.

2.3. Total phenols

Total phenols were estimated as gallic acid equivalents (GAE),expressed as mg gallic acid/100 g extract (Singleton, Orthofer, &Lamuela-Raventos, 1999). To ca. 6.0 ml H2O, 100 ll of samplewas transferred into a 10.0 ml volumetric flask, to which 500 llundiluted Folin–Ciocalteu reagent was added subsequently. After1 min, 1.5 ml of a 20% (w/v) Na2CO3 solution was added and thevolume was made up to 10.0 ml with H2O. After 2 h incubationat 25 �C, the absorbance was measured at 760 nm and comparedto a gallic acid calibration curve. The data are presented as theaverage of triplicate analyses.

2.4. Total monomeric anthocyanins

Total monomeric anthocyanins were measured according to the‘pH differential method’ in triplicate (Giusti & Wrolstad, 2000). Allextracts were dissolved in suitable solvents and used as stock solu-tions. Appropriate dilution factors for each sample were deter-mined by diluting with 0.025 M potassium chloride buffer (pH1.0) until the absorbance of the sample at 510 nm was within thelinear range of the spectrophotometer. For each sample, two dilu-tions were prepared, both with 0.025 M potassium chloride buffer(pH 1.0) and with 0.4 M sodium acetate buffer (pH 4.5) dilutingeach by the previously determined dilution factor. These dilutionswere equilibrated for 15 min. The absorbance of each dilution wasmeasured at 510 nm and at 700 nm (to correct for haze), against ablank cell filled with distilled water.

The absorbance of the diluted sample (A) was calculated asfollows:

A ¼ A510 � A700ð ÞpH 1:0 � A510 � A700ð ÞpH 4:5: ð1Þ

The monomeric anthocyanin concentration in the original sam-ple was calculated using the following formula:

Monomeric anthocyanin pigment ðmg=lÞ¼ A�MW� DF� 1000ð Þ e� 1ð Þ= : ð2Þ

Anthocyanin content was calculated as cyanidin-3-glucoside,where MW = 449.2 and e = 26,900.

2.5. Qualitative–quantitative chromatographic analysis

2.5.1. HPLC–UV analysisThe liquid chromatographic apparatus (Shimadzu LC 10Avp, Ant

Ltd. S�ti., Istanbul, Turkey) consisted of an in-line degasser, pumpand controller coupled to a Shimadzu UV–Vis Spectrophotometerequipped with an automatic injector interfaced to Class VP chro-matography manager software (Shimadzu, Japan). Separationswere performed on a 250 � 4.6 mm i.d., 5 lm particle size, octa-decyl silica gel analytical column (Supelco, PA, USA) operating at40 �C at a flow rate of 0.4 ml/min. Detection was carried out at520 nm. Elution was carried out using a binary gradient of formicacid/water (8.5/91.5, v/v) (solvent A) and tetrahydrofuran/formicacid/acetonitrile/methanol/water (5/8.5/22.5/22.5/41.5, v/v/v/v/v)(solvent B). The composition of B was increased from 15% to 30%in 10 min, increased to 40% in 10 min and increased to 100% in5 min, then the composition was decreased to 15% in 5 min. Cyani-din-3-glucoside in all extracts was identified by comparison of itsretention time to that of authentic standards under identical anal-ysis conditions and UV spectra. A 10 min equilibrium time wasallowed between injections. All standard and sample solutionswere injected in triplicate.

2.5.2. HPLC–UV–MS–MS analysisThe identification of some of the anthocyanins present in the

elderberry extracts was carried out by means of their molecularweight and their fragments. For this, HPLC with UV detection andtandem mass spectrometry was used (HPLC–UV–MS–MS). Theanalytical conditions used were those described by Bermudez-Sotoand Thomas-Barberan (2004), with some modifications. Samples ofeach elderberry extract (5 ll) were analysed using an HPLC systemequipped with a model LC20AD Shimadzu pump and a modelSPD20A Shimadzu UV Detector. The samples were injected bymeans of a model SIL20A Shimadzu Autosampler. Separations werecarried out using an Intersil ODS-3 column (4.6 � 250 mm, 5 lmparticle size). The CTO20A Shimadzu Column Oven was kept at40 �C. The mobile phase was water with 1% formic acid (v/v) (sol-vent A) and HPLC grade methanol (solvent B) at a flow rate of1 ml min�1. The linear gradient started with 3% solvent B reaching5% at 5 min, 8% solvent B at 10 min, 13% solvent B at 15 min, 15%solvent B at 19 min, 40% solvent B at 47 min, 65% solvent B at64 min, 80% solvent B at 65 min and 98% solvent B, followed by66 min at isocratic elution until 69 min. At 70 min the gradientreached the initial conditions again. HPLC chromatograms were re-corded at 380 and 520 nm. The Shimadzu HPLC–UV system wasconnected directly to a 3200 Q TRAP mass spectrometer (MS) (ABSciex, Toronto, Canada). The software used for data acquisitionand analysis was Analyst 1.5. The chromatographic conditionswere used as described above. For enhanced mass scan (EMS),the MS was operated in positive polarity at a scan rate of1000 Da/s within the mass range of 200–800 amu. Mass scan(MS) and daughter (MS–MS) spectra were measured from m/z100 up to m/z 800. Collision-induced fragmentation experimentswere performed in the ion trap using nitrogen as the collisiongas, with the collision energy set at 30–100. The parameters wereas follows: Collision Energy Spread (CES) = 15, Declostiring Poten-tial (DP) = 45, Enterance Potential (EP) = 10, Curtain gas (CUR) = 10and Temperature (TEM) = 600. For the IDA experiment, the criteriawere arranged for ions greater than 200.000 m/z and smaller than

Table 1Extract yield, total phenols, monomeric anthocyanins, and HPLC qualitative and quantitative data for elderberry.

Sample Yielda Spectrophotometric results HPLC results

Total phenolsb Total anthocyaninsc Cyanidin-3-glucosided Total anthocyaninse

(A) 260 8974 ± 37 878.5 ± 15 100.5 ± 0.72 1247 ± 53(B) 432 7594 ± 3 1066.6 ± 55 254.3 ± 5.03 1326 ± 48(C) 404 4917 ± 63 408.6 ± 85 42.4 ± 0.02 285 ± 20(D) 328 8206 ± 167 651.1 ± 26 175.4 ± 0.63 890 ± 50(E) 602 6399 ± 80 600 ± 16 68.1 ± 0.07 650 ± 15(F) 161 6715 ± 21 734.2 ± 33 202.9 ± 1.87 951 ± 40

(A) Water extract; (B) 70% ethanol extract; (C) methanol extract; (D) 70% acetone extract; (E) acidified methanol; (F) infusion.a Extract yields expressed as milligrams of extract per gram (dry weight) of fruits.b Total phenols expressed as gallic acid equivs. milligrams of gallic acid per 100 gram (dry weight) of extract.c Total monomeric anthocyanins expressed as cyanidin-3-glucoside equivs. milligrams of cyanidin-3-glucoside per 100 gram (dry weight) of extract.d Values (mg/100 g extract) are expressed as means ± standard error.e Total anthocyanins expressed as cyanidin-3-glucoside equivs. milligrams of cyanidin-3-glucoside per 100 g of extract by HPLC method.

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0 32.5 min0

100000

200000

300000

400000

500000

600000

700000uV

A

B

Fig. 1. (A) The HPLC–UV chromatogram of elderberry extract with absorbance at 520 nm; (B) the HPLC–UV chromatogram of cyanidin-3-glucoside standard.

114 H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119

800.000 m/z, and excluded former target ions after 3.0 occur-rence(s) for 3.000 s.

2.6. The antioxidant activity

2.6.1. 1,1-Diphenyl-2-picrylhydrazyl (DPPH�) radical scavengingactivity

Serial dilutions were carried out with the stock solutions(10 mg/ml�1) of the extracts to obtain the concentrations of 10,5, 25 � 10�1, 125 � 10�2, 625 � 10�3, 3125 � 10�4 mg/ml�1.Diluted solutions were mixed with DPPH (equal amounts) andallowed to stand for 30 min for any reaction to occur. The UVabsorbance was recorded at 517 nm. The experiment was per-formed in triplicate and the average absorption was noted for eachconcentration. The same procedure was followed for the positivecontrol, ascorbic acid. The percentage inhibition was calculatedusing Eq(3). The IC50 value, which is the concentration of the testmaterial that inhibits 50% of the free radical concentration, wascalculated as mg/ml�1 (Kumarasamy et al., 2007):

Percentage inhibition ¼Abscontrol � Abssample� �

Abscontrol

� �� 100: ð3Þ

2.6.2. TEAC assay (Trolox Equivalent Antioxidant Capacity)This assay assesses the capacity of a compound to scavenge

the stable ABTS radical in comparison to the antioxidant activityof Trolox, a water-soluble form of vitamin E that is used as a stan-dard. The blue–green ABTS was produced through the reaction of7 mM ABTS with 2.5 mM sodium persulfate (Na2S2O8) (final

concentrations) in the dark at room temperature for 12–16 h be-fore use. The concentrated ABTS solution was diluted with etha-nol to a final absorbance of 0.7–0.8 at 734 nm. A 10-ll portionof sample (concentrations of 0.6, 0.3 and 0.1 mg/ml�1) was addedto 990 ll of ABTS solution, and the reduction in absorbance wasmeasured 1 min after addition of Trolox (final concentration1–20 lM) and up to 40 min after addition of the each extract.The stock solution of Trolox (2.5 mM) was prepared in ethanol.Absorbance was measured on a UV/spectrophotometer(Papandreou et al., 2006).

2.6.3. Determination of inhibition of b-carotene/linoleic acid co-oxidation

Antioxidant activity of the elderberry extracts was determinedaccording to b-carotene bleaching methods (Oomah & Mazza,1996; Velioglu, Mazza, Gao, & Oomah, 1998). Briefly, 1 ml of b-car-otene (0.2 mg/ml�1 dissolved in chloroform; Sigma Chemical Co.,St. Louis, MO) was added to a flask containing linoleic acid(40 mg) and Tween 80 (400 mg). Chloroform was evaporated un-der a stream of nitrogen. Distilled water (50 ml) was added andshaken vigorously. A control was prepared without sample or stan-dards with same procedure. Blanks of control and sample were alsoprepared without b-carotene. Their absorbance were measured ona spectrophotometer at 470 nm. The samples were then subjectedto thermal autoxidation by keeping them in a constant tempera-ture water bath at 50 �C for 2 h. The rate of bleaching of b-carotenewas monitored by taking the absorbance at 15 min intervals. Anti-oxidative activity was calculated according to Eq.(4):

AA%¼ 1� Ab0sample�Abs120sample� �

= Ab0control�Abs120controlð Þ� �

�100: ð4Þ

Table 2HPLC–MS–MS data for elderberry extracts.

Peak HPLC Rt (min) Molecular ion (MS) Fragment (MS–MS) Structure A B C D E Fm/z+ m/z+

X 26.70 611 449, 287 Cyanidin-3,5-diglucoside + + + + + +743 581, 449, 287 Cyanidin-3-sambubioside-5-glucoside + + + + + +

Y 33.08 449 287 Cyanidin-3-glucoside + + + + + +581 449, 287 Cyanidin-3-sambubioside + + + + � +

Z 52.64 633 487, 331 Quercetin-3-rutinoside Na+ adduct + + + + � +

(A), water extract; (B), 70% ethanol extract; (C), methanol extract; (D), 70% acetone extract; (E), Acid. methanol extract; (F), infusion.

Fig. 2. LC chromatogram at 520 nm and EMS–EPI spectra of the X peak at tR 26.7 min.

H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119 115

2.7. Statistical analysis

Data are presented as mean values ± standard deviation. All thestatistical analyses were carried out using SPSS 10.0.1. (SPSS Inc.,Chicago, IL). Analysis of variance (ANOVA) was performed by ANO-VA procedures. Significant differences between means weredetermined by Tukey’s pairwise comparison test at a level ofp < 0.05. IC50 values were estimated using a non-linear regressionalgorithm.

3. Results and discussion

3.1. Fraction yields, total phenols, total monomeric anthocyanins andcompositional analysis

Ground elderberries were macerated with water, 70% ethanol,70% acetone, ethanol and methanol at room temperature. Acidifiedmethanol (0.1% HCl Inc.) extracts were prepared using an ultra-sonic bath at room temperature for 30 min in triplicate. The

Fig. 3. LC chromatogram at 520 nm and EMS-EPI spectra of the Y peak at tR 33.08 min.

116 H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119

infusion was prepared according to traditional methods. The re-sults of fractionation, total phenols, total monomeric anthocyaninsand the amount of cyanidin-3-glucoside of extracts are presentedin Table 1. According to the data presented in Table 1, water, 70%acetone, 70% ethanol, infusion, acidified methanol and methanolextracts contained the highest amount of total phenol content,respectively. The highest yields were obtained also from the acid-ified methanol, 70% ethanol and methanol extracts.

The results of the qualitative–quantitative analyses of the ex-tracts, carried out using an HPLC apparatus coupled with a UVdetector, are presented in Table 1, with a selected chromatogramshown in Fig. 1. Cyanidin-3-glucoside was identified and quanti-fied at 520 nm. Cyanidin-3-glucoside was identified by comparisonof the retention time and UV spectra of authentic standard, whilequantitative data were calculated from their calibration curves.The 70% ethanol, infusion and 70% acetone extracts were foundto be the richest in cyanidin-3-glucoside, as measured by HPLC.In addition, total anthocyanins of each extract obtained from chro-matogram at 520 nm were quantified as cyanidin-3-glucosideequivalents (Table 1). When the spectroscopic total anthocyaninanalysis data was compared with that from the HPLC method,the total anthocyanins measured by HPLC were higher than thoseobserved in the spectroscopic method, except for the methanolextract. Correlation was determined on the anthocyanin values

obtained by the pH differential method and HPLC. The correlationbetween these two methods was significant (r2 = 0.9302).

All extracts were determined for their total phenolic andanthocyanin contents by spectrophotometric methods. Cyanidin-3-glucoside was also identified and calculated in the extracts byHPLC. Other anthocyanins in the extracts were identified by LC–MS–MS. In order to achieve ionisation of the anthocyanins, HPLCconditions reported by Bermudez-Soto and Thomas-Barberan(2004) were employed with some modifications. Four differentcyanidin glycosides, such as cyanidin-3,5-diglucoside, cyanidin-3-sambubioside-5-glucoside, cyanidin-3-sambubioside and cyani-din-3-glucoside were detected in the 520 nm chromatogram, whilequercetin-3-rutinoside Na+ adduct was detected in the 380 nmchromatogram. These compounds were identified by their UVspectra, their molecular weights and their fragmentation patterns.At 520 nm, MS fragmentation ions at m/z 287 were attributed tocyanidin derivatives (Table 2). The X peak (Fig. 2) was confirmedas cyanidin-3,5-diglucoside (m/z+ 611, MS2 fragments at 449,287) and cyanidin-3-sambubioside-5-glucoside (m/z+ 743, MS2

fragments at 581, 449, 287). The Y peak (Fig. 3) was characterizedas cyanidin-3-sambubioside (m/z+ 581, MS2 fragments 449, 287)and cyanidin-3-glucoside (m/z+ 449, MS2 fragment 287). The Zpeak (Fig. 4) obtained from the 380 nm chromatogram was identi-fied as quercetin-3-rutinoside Na+ adduct (m/z+ 633, MS2

Fig. 4. LC chromatogram at 380 nm and EMS–EPI spectra of the Z peak at tR 52.64 min.

H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119 117

fragments at 487, 331). The results are given in Table 2.Cyanidin-3,5-diglucoside, cyanidin-3-sambubioside-5-glucosideand cyanidin-3-glucoside were identified in all extracts. Cyani-din-3-sambubioside and quercetin-3-rutinoside Na+ adduct weredetected in all the extracts except for the acidified methanol ex-tract. These compounds were evaluated according to LC/MS–MSresults of Bermudez-Soto and Thomas-Barberan (2004).

3.2. DPPH� radical scavenging activity

The 1,1-diphenyl-2-picrylhydrazyl (DPPH�) radical is a stableradical, with an absorption maximum at 517 nm. When reducedto the hydrazine derivative by an antioxidant via electron or hydro-gen atom transfer reactions, this absorption maximum decreases(Lu & Foo, 2001). IC50 values, defined as the concentration requiredto scavenge 50% of the available free radicals, were estimated bynonlinear regression for all the extracts. All the extracts showedfree radical scavenging activity in this test. According to the results,the 70% acetone extract was the most active free radical scavengerof them all (IC50 value 117 lg/ml�1). The water extract was the sec-ond active free radical scavenger with an IC50 value of 123 lg/ml�1

However, none of the extracts were as active as the positive con-trol, ascorbic acid (IC50 value of 8 lg/ml�1). The order of DPPH� rad-ical scavenging ability for the fractions was as follows: 70%

acetone > water > 70% ethanol > infusion > acidified methanol >methanol. Also cyanidin-3-glucoside at 1 mg/ml�1 concentrationshowed 80% inhibition, whereas ascorbic acid at the same concen-tration exhibited 94% inhibition on DPPH� radical. These phenolicshave antioxidant activity and they are considered to be responsiblefor the antioxidant activity.

3.3. Inhibition of b-carotene/linoleic acid co-oxidation

Food lipids and cell membranes contain unsaturated fatty acids,linoleic and arachidonic acids, which can be easily oxidised withoxidative agents. Therefore, unsaturated fatty acid–base mediumin antioxidant activity tests are important to determine the activ-ities of test samples. The b-carotene–linoleic acid bleaching assayis such a model, widely used to investigate the oxidation of unsat-urated fatty acids, especially in the cell wall and food products(Kosar, Goger, & Baser, 2008).

The b-carotene/linoleic acid oxidation method evaluates theinhibitory activity of free radicals generated during the peroxida-tion of linoleic acid. The method is based on spectrophotometricdiscolouration measurements or oxidation of b-carotene-inducedoxidative degradation products of linoleic acid. In the b-carotene/linoleic acid co-oxidation assay, the degree of lipid peroxidationis measured. The inhibition percentages of all extracts of

118 H.G. Duymus� et al. / Food Chemistry 155 (2014) 112–119

elderberry are calculated. According to results, some extracts couldinhibit the oxidation of linoleic acid. The 70% ethanol extract hadthe best activity (58% inhibition). The hierarchy of theextracts were 70% ethanol > infusion > 70% acetone > methanol >water > acidified methanol. None of the extracts of elderberry werefound to be as active as the positive control BHT. Cyanidin-3-gluco-side at 1 mg/ml�1 concentration had 43% inhibition on theoxidation of linoleic acid. According to these results, cyanidin-3-glucoside is thought to be responsible for this activity.

3.4. TEAC assay (Trolox Equivalent Antioxidant Capacity)

In this assay, the capacity of elderberry extracts to scavenge theABTS radical (ABTS�+) was assessed. This assay is based on the scav-enging of the relatively stable blue/green ABTS radical (ABTS�+),converting it into a colourless product. The degree of decolouriza-tion reflects the amount of ABTS�+ that has been scavenged and canbe determined spectrophotometrically. The TEAC value is assignedby comparing the scavenging capacity of an antioxidant to that ofTrolox (Badarinath et al., 2010). The TEAC values at 30 min werecalculated, the Trolox calibration curve was linear (r2 0.996) andTEAC values of all extracts were calculated according to this curve.The TEAC values of the extracts ranged between 0.89 and1.97 mmol Trolox equivalents/l. According to our results, the 70%acetone extract (1.96 mM) was as effective as ascorbic acid(1.97 mM) on ABTS�+ radical scavenging. Cyanidin-3-glucoside at1 mg/ml�1 conc. had a lower activity than ascorbic acid at the sameconcentration, whereas it showed better activity than the infusion(1.23 mM), methanol (1.0 mM), acidified methanol (0.89 mM) and70% ethanol (1.52 mM) extracts. The water extract (1.85 mM) wasas active as cyanidin-3-glucoside (1.87 mM).

Several berries are used as natural colourants in different indus-tries and elderberries draw attention because of their anthocyanin-rich content and high antioxidant activity. In elderberry fruits,cyanidin-3-glucoside, cyanidin-3-sambubioside, cyanidin-3,5-dig-lucoside and cyanidin-3-sambubioside-5-glucoside are the mainanthocyanins (Inami et al., 1996; Nakajima, Tanaka, Seo, Yamazaki,& Saito, 2004; Wu et al., 2004). The antioxidant and antiradicalactivities of the juice and extracts of elderberry have been re-ported. Espin et al. (2000) determined the antiradical activity onDPPH� radical of commercial elderberry juice and other fruit ex-tracts by a spectrophotometric method. According to their results,3-monoglycoside (97%) and cyanidin 3,5-diglycoside (3%) identi-fied in the juice had a lower DPPH� radical scavenging activitywhen compared with vitamin E, BHT and BHA. Lugasi and Hovari(2003) reported that elderberry juice had a total polyphenol con-centration of 5680 mg/l and this was significantly higher than thatof high quality red wines. Hydrogen-donating ability and thereducing power found to be the highest in the juice of elderberryexhibited both antioxidant and DPPH� scavenging propertiesstrongly correlated with the total polyphenol content. In anotherstudy, the potent antiradical activity of some berry extracts orcommercial juice were determined and their anthocyanin compo-sition was analysed by LC/PDA/ESI–MS. Cyanidin-3-glucoside,cyanidin-3-sambubioside, cyanidin-3-sambubioside-5-glucosideand cyanidin-3,5-diglucoside were identified in the commercialjuice of elderberry. All extracts were treated by DPPH� and com-pared with Trolox. According to the results, all the extracts showedlower DPPH� radical scavenging activity than Trolox (Nakajimaet al., 2004). Elderberry juice concentrate was found to have a richphenolic content and high free-radical scavenging activity againstboth ABTS�+ and DPPH� radicals. Cyanidin-3-sambubioside wasthe most abundant anthocyanin in the elderberry juice concentrate(Bermudez-Soto & Thomas-Barberan, 2004). The alcoholic extracts(80% ethanol in water) from the leaves, berries and flowers ofS. nigra act as antioxidants, neutralizing the activities of free

radicals and inhibiting the co-oxidation reactions of linoleic acidand b-carotene. Cyanidin-3-sambubioside, cyanidin-3-glucoside,rutin, isoquercitrin and astragalin were also identified in elder-berry extracts (Dawidowicz, Wianowska, & Baraniak, 2006).

According to our results, the highest total phenolic content wascalculated in the water extract, which had a similar TEAC activitywhen compared to cyanidin-3-glucoside. Furthermore, the waterextract was as effective as the 70% acetone extract on DPPH� radicalscavenging activity. The infusion of berries was found to possessgood antiradical activity correlated with its cyanidin-3-glucoside,total phenol and anthocyanin contents. The methanol extract wasfound to have the lowest total phenolic, total anthocyanin andcyanidin-3-glucoside levels when compared with the other ex-tracts. Because of this, the methanol extract showed the lowestantiradical and antioxidant activity in all the tested assays.

In conclusion, water and aqueous alcoholic extracts were foundto be rich in phenolic and anthocyanin contents. These extractsshowed high free radical scavenging activity against both ABTSand DPPH radical suggesting their possible use as antioxidants.

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