Comparison of various easy-to-use procedures for extraction of phenols from apricot fruits

Zítka, Ondřej; Sochor, Jiří; Rop, Otakar; Skaličková, Sylvie; Šobrová, Pavlína; Zehnálek, Josef; Beklová, Miroslava; Krška, Boris; Adam, Vojtěch; Kizek, René

dc.title	Comparison of various easy-to-use procedures for extraction of phenols from apricot fruits	en
dc.contributor.author	Zítka, Ondřej
dc.contributor.author	Sochor, Jiří
dc.contributor.author	Rop, Otakar
dc.contributor.author	Skaličková, Sylvie
dc.contributor.author	Šobrová, Pavlína
dc.contributor.author	Zehnálek, Josef
dc.contributor.author	Beklová, Miroslava
dc.contributor.author	Krška, Boris
dc.contributor.author	Adam, Vojtěch
dc.contributor.author	Kizek, René
dc.relation.ispartof	Molecules
dc.identifier.issn	1420-3049 Scopus Sources, Sherpa/RoMEO, JCR
dc.date.issued	2011-04
utb.relation.volume	16
utb.relation.issue	4
dc.citation.spage	2914
dc.citation.epage	2936
dc.type	article
dc.language.iso	en
dc.publisher	MDPI AG	en
dc.identifier.doi	10.3390/molecules16042914
dc.relation.uri	http://www.mdpi.com/1420-3049/16/4/2914/
dc.subject	polyphenols	en
dc.subject	apricot	en
dc.subject	high performance liquid chromatography	en
dc.subject	CoulArray electrochemical detector	en
dc.subject	UV-VIS detector	en
dc.description.abstract	Phenols are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potential antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. The objective of this study was to investigate a suitable method for determination of protocatechuic acid, 4-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferulic acid, quercetin, resveratrol and quercitrin from apricot samples. A high-performance liquid chromatograph with electrochemical and UV detectors was used. The method was optimized in respect to both the separation selectivity of individual phenolic compounds and the maximum sensitivity with the electrochemical detection. The lowest limits of detection (3 S/N) using UV detection were estimated for ferulic acid (3 mu M), quercitrin (4 mu M) and quercetin (4 mu M). Using electrochemical detection values of 27 nM, 40 nM and 37 nM were achieved for ferulic acid, quercitrin and quercetin, respectively. It follows from the acquired results that the coulometric detection under a universal potential of 600 mV is more suitable and sensitive for polyphenols determination than UV detection at a universal wavelength of 260 nm. Subsequently, we tested the influence of solvent composition, vortexing and sonication on separation efficiency. Our results showed that a combination of water, acetone and methanol in 20: 20: 60 ratio was the most effective for p-aminobenzoic acid, chlorgenic acid, caffeic acid, protocatechuic acid, ferulic acid, rutin, resveratrol and quercetin, in comparison with other solvents. On the other hand, vortexing at 4 C produced the highest yield. Moreover, we tested the contents of individual polyphenols in the apricot cultivars Mamaria, Mold and LE-1075. The major phenolic compounds were chlorgenic acid and rutin. Chlorgenic acid was found in amounts of 2,302 mg/100 g in cultivar LE-1075, 546 mg/100 g in cultivar Mamaria and 129 mg/100 g in cultivar Mold. Generally, the cultivar LE-1075 produced the highest polyphenol content values, contrary to Mold, which compared to cultivar LE-1075 was quite poor from the point of view of the phenolics content.	en
utb.faculty	Faculty of Technology
dc.identifier.uri	http://hdl.handle.net/10563/1002176
utb.identifier.rivid	RIV/70883521:28110/11:43865340!RIV12-MSM-28110___
utb.identifier.obdid	43865342
utb.identifier.scopus	2-s2.0-79955532496
utb.identifier.wok	000289236200013
utb.identifier.coden	MOLEF
utb.source	j-wok
dc.date.accessioned	2011-08-16T15:06:36Z
dc.date.available	2011-08-16T15:06:36Z
dc.rights	Attribution-NonCommercial-NoDerivs 3.0 Unported
dc.rights.uri	https://creativecommons.org/licenses/by-nc-nd/3.0/
dc.rights.access	openAccess
utb.contributor.internalauthor	Rop, Otakar
utb.fulltext.affiliation	Ondrej Zitka 1, Jiri Sochor 1, Otakar Rop 2, Sylvie Skalickova 1, Pavlina Sobrova 1, Josef Zehnalek 1, Miroslava Beklova 3, Boris Krska 4, Vojtech Adam 1 and Rene Kizek 1,* 1 Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic 2 Department of Food Technology and Microbiology, Faculty of Technology, Tomas Bata University in Zlin, Namesti T. G. Masaryka 275, CZ-762 72 Zlin, Czech Republic 3 Department of Veterinary Ecology and Environmental Protection, University of Veterinary and Pharmaceutical Sciences, Palackeho 1-3, CZ-61242 Brno, Czech Republic 4 Department of Fruit Growing, Faculty of Horticulture, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic * Author to whom correspondence should be addressed; E-Mail: kizek@sci.muni.cz; Tel.: +420-5-4513-3350; Fax: +420-5-4521-2044.
utb.fulltext.dates	Received: 9 March 2011 in revised form: 25 March 2011 Accepted: 31 March 2011 Published: 4 April 2011
utb.fulltext.references	1. Bruneton, J. Pharmacognosy, Phytochemistry, Medicinal Plants, 2nd ed.; Lavoisier: Paris, France, 1999. 2. Cartea, M.E.; Francisco, M.; Soengas, P.; Velasco, P. Phenolic Compounds in Brassica Vegetables. Molecules 2010, 16, 251-280. 3. Ferretti, G.; Bacchetti, T.; Belleggia, A.; Neri, D. Cherry Antioxidants: From Farm to Table. Molecules 2010, 15, 6993-7005. 4. Sochor, J.; Zitka, O.; Skutkova, H.; Pavlik, D.; Babula, P.; Krska, B.; Horna, A.; Adam, V.; Provaznik, I.; Kizek, R. Content of Phenolic Compounds and Antioxidant Capacity in Fruits of Apricot Genotypes. Molecules 2010, 15, 6285-6305. 5. Sisa, M.; Bonnet, S.L.; Ferreira, D.; Van der Westhuizen, J.H. Photochemistry of Flavonoids. Molecules 2010, 15, 5196-5245. 6. Ghasemzadeh, A.; Jaafar, H.Z.E.; Rahmat, A. Elevated Carbon Dioxide Increases Contents of Flavonoids and Phenolic Compounds, and Antioxidant Activities in Malaysian Young Ginger (Zingiber officinale Roscoe.) Varieties. Molecules 2010, 15, 7907-7922. 7. Kelsey, N.A.; Wilkins, H.M.; Linseman, D.A. Nutraceutical Antioxidants as Novel Neuroprotective Agents. Molecules 2010, 15, 7792-7814. 8. Rechner, A.R.; Wagner, E.; Van Buren, L.; Van de Put, F.; Wiseman, S.; Rice-Evans, C.A. Black tea represents a major source of dietary phenolics among regular tea drinkers. Free Radic. Res. 2002, 36, 1127-1135. 9. Gonzalez-Gallego, J.; Garcia-Mediavilla, M.V.; Sanchez-Campos, S.; Tunon, M.J. Fruit polyphenols, immunity and inflammation. Br. J. Nutr. 2010, 104, S15-S27. 10. Galleano, M.; Pechanova, O.; Fraga, C.G. Hypertension, Nitric Oxide, Oxidants, and Dietary Plant Polyphenols. Curr. Pharm. Biotechnol. 2010, 11, 837-848. 11. Fang, Z.X.; Bhandari, B. Encapsulation of polyphenols - a review. Trends Food Sci. Technol. 2010, 21, 510-523. 12. Michalowicz, J.; Duda, W.; Pol, J. Environ. Stud. Pol. J. Environ. Stud. 2007, 16, 347-362. 13. Chen, H.L.; Yao, J.; Wang, F.; Zhou, Y.; Chen, K.; Zhuang, R.S.; Choi, M.M.F.; Zaray, G. Toxicity of three phenolic compounds and their mixtures on the gram-positive bacteria Bacillus subtilis in the aquatic environment. Sci. Total Environ. 2010, 408, 1043-1049. 14. Shadnia, H.; Wright, J.S. Understanding the toxicity of phenols: Using quantitative structureactivity relationship and enthalpy changes to discriminate between possible mechanisms. Chem. Res. Toxicol. 2008, 21, 1197-1204. 15. Lepoittevin, J.P.; Benezra, C. Allergic contact-dermatitis caused by naturally-occurring quinones. Pharm. Weekblad-Sci. Ed. 1991, 13, 119-122. 16. Saito, S.; Kawabata, J. Effects of electron-withdrawing substituents on DPPH radical scavenging reactions of protocatechuic acid and its analogues in alcoholic solvents. Tetrahedron 2005, 61, 8101-8108. 17. Hatzipanayioti, D.; Karaliota, A.; Kamariotaki, M.; Aletras, V.; Petropouleas, P. Theoretical and spectroscopic investigation of the oxidation and degradation of protocatechuic acid. Chem. Phys. 2006, 325, 341-350. 18. Kampa, M.; Alexaki, V.I.; Notas, G.; Nifli, A.P.; Nistikaki, A.; Hatzoglou, A.; Bakogeorgou, E.; Kouimtzoglou, E.; Blekas, G.; Boskou, D.; Gravanis, A.; Castanas, E. Antiproliferative and apoptotic effects of selective phenolic acids on T47D human breast cancer cells: potential mechanisms of action. Breast Cancer Res. 2004, 6, R63-R74. 19. Ueda, J.I.; Saito, N.; Shimazu, Y.; Ozawa, T. A comparison of scavenging abilities of antioxidants against hydroxyl radicals. Arch. Biochem. Biophys. 1996, 333, 377-384. 20. An, L.J.; Guan, S.; Shi, G.F.; Bao, Y.M.; Duan, Y.L.; Jiang, B. Protocatechuic acid from Alpinia oxyphylla against MPP+-induced neurotoxicity in PC12 cells. Food Chem. Toxicol. 2006, 44, 436-443. 21. Akberova, S.I. New biological properties of p-aminobenzoic acid. Biol. Bull. 2002, 29, 390-393. 22. Shuang, S.M.; Yang, Y.; Pan, J.H. Study on molecular recognition of para-aminobenzoic acid species by alpha-, beta- and hydroxypropyl-beta-cyclodextrin. Anal. Chim. Acta 2002, 458, 305-310. 23. Schmidt, T.C.; Petersmann, M.; Kaminski, L.; vonLow, E.; Stork, G. Analysis of aminobenzoic acids in waste water from a former ammunition plant with HPLC and combined diode array and fluorescence detection. Fres. J. Anal. Chem. 1997, 357, 121-126. 24. Clifford, M.N. Chlorogenic acids and other cinnamates - nature, occurrence and dietary burden. J. Sci. Food Agric. 1999, 79, 362-372. 25. Boerjan, W.; Ralph, J.; Baucher, M. Lignin biosynthesis. Annu. Rev. Plant Biol. 2003, 54, 519-546. 26. Kono, Y.; Kashine, S.; Yoneyama, T.; Sakamoto, Y.; Matsui, Y.; Shibata, H. Iron chelation by chlorogenic acid as a natural antioxidant. Biosci. Biotechnol. Biochem. 1998, 62, 22-27. 27. Halliwell, B.; Gutteridge, J.M.C. Role of free-radicals and catalytic metal-ions in human-disease - an overview. Methods Enzymol. 1990, 186, 1-85. 28. Mori, H.; Tanaka, T.; Shima, H.; Asu, T.K.; Takahashi, M. Inhibitory effect of chlorogenic acid on methylazoxymethanol acetate-induced carcinogenesis in large-intestine and liver of hamsters. Cancer Lett. 1986, 30, 49-54. 29. Tsuchiya, T.; Suzuki, O.; Igarashi, K. Protective effects of chlorogenic acid on paraquat-induced oxidative stress in rats. Biosci. Biotechnol. Biochem. 1996, 60, 765-768. 30. Zhao, Z.H.; Moghadasian, M.H. Bioavailability of hydroxycinnamates: a brief review of in vivo and in vitro studies. Phytochem. Rev. 2010, 9, 133-145. 31. Maurya, D.K.; Devasagayam, T.P.A. Antioxidant and prooxidant nature of hydroxycinnamic acid derivatives ferulic and caffeic acids. Food Chem. Toxicol. 2010, 48, 3369-3373. 32. Kono, Y.; Shibata, H.; Kodama, Y.; Sawa, Y. The suppression of the N-nitrosating reaction by chlorogenic acid. Biochem. J. 1995, 312, 947-953. 33. Kasai, H.; Fukada, S.; Yamaizumi, Z.; Sugie, S.; Mori, H. Action of chlorogenic acid in vegetables and fruits as an inhibitor of 8-hydroxydeoxyguanosine formation in vitro and in a rat carcinogenesis model. Food Chem. Toxicol. 2000, 38, 467-471. 34. Shibata, H.; Sakamoto, Y.; Oka, M.; Kono, Y. Natural antioxidant, chlorogenic acid, protects against DNA breakage caused by monochloramine. Biosci. Biotechnol. Biochem. 1999, 63, 1295-1297. 35. Akagi, K.; Hirose, M.; Hoshiya, T.; Mizoguchi, Y.; Ito, N.; Shirai, T. Modulating effects of ellagic acid, vanillin and quercetin in a rat medium-term multiorgan carcinogenesis model. Cancer Lett. 1995, 94, 113-121. 36. Kappachery, S.; Paul, D.; Yoon, J.; Kweon, J.H. Vanillin, a potential agent to prevent biofouling of reverse osmosis membrane. Biofouling 2010, 26, 667-672. 37. Kumar, S.S.; Ghosh, A.; Devasagayam, T.P.A.; Chauhan, P.S. Effect of vanillin on methylene blue plus light-induced single-strand breaks in plasmid pBR322 DNA. Mutat. Res. Genet. Toxicol. Environ. Mutagen. 2000, 469, 207-214. 38. Aruoma, O.I.; Evans, P.J.; Kaur, H.; Sutcliffe, L.; Halliwell, B. An evaluation of the antioxidant and potential pro-oxidant properties of food-additives and of trolox-c, vitamin-e and probucol. Free Rad. Res. Commun. 1990, 10, 143-157. 39. Utsumi, H.; Fujii, K.; Irie, H.; Furusaki, A.; Nitta, I. Crystal structure of p-coumaric acid. Bull. Chem. Soc. Jpn. 1967, 40, 426-426 40. Castelluccio, C.; Paganga, G.; Melikian, N.; Bolwell, G.P.; Pridham, J.; Sampson, J.; Riceevans, C. Antioxidant potential of intermediates in phenylpropanoid metabolism in higher-plants. FEBS Lett. 1995, 368, 188-192. 41. Sharma, R.D. Isoflavones and hypercholesterolemia in rats. Lipids 1979, 14, 535-540. 42. Gaberscik, A.; Voncina, M.; Trost, T.; Germ, M.; Bjorn, L.O. Growth and production of buckwheat (Fagopyrum esculentum) treated with reduced, ambient, and enhanced UV-B radiation. J. Photochem. Photobiol. B-Biol. 2002, 66, 30-36. 43. Rozema, J.; Bjorn, L.O.; Bornman, J.F.; Gaberscik, A.; Hader, D.P.; Trost, T.; Germ, M.; Klisch, M.; Groniger, A.; Sinha, R.P.; Lebert, M.; He, Y.Y.; Buffoni-Hall, R.; de Bakker, N.V.J.; van de Staaij, J.; Meijkamp, B.B. The role of UV-B radiation in aquatic and terrestrial ecosystems - an experimental and functional analysis of the evolution of UV-absorbing compounds. J. Photochem. Photobiol. B-Biol. 2002, 66, 2-12. 44. Korkmaz, A.; Kolankaya, D. Protective Effect of Rutin on the Ischemia/Reperfusion Induced Damage in Rat Kidney. J. Surg. Res. 2010, 164, 309-315. 45. Abeywardena, M.Y.; Head, R.J. Dietary polyunsaturated fatty acid and antioxidant modulation of vascular dysfunction in the spontaneously hypertensive rat. Prostagland. Leuk. Essent. Fatty Acids 2001, 65, 91-97. 46. Wojcicki, J.; Barcewwiszniewska, B.; Samochowiec, L.; Rozewicka, L. Extractum-fagopyri reduces atherosclerosis in high-fat diet fed rabbits. Pharmazie 1995, 50, 560-562. 47. Bingjiang, L.; Wei, M.; Dan, L. Photoprotective effects of ferulic on human keratinocyte HaCaT cells: Proteomic identification of proteins associated with cutaneous cancer. J. Invest. Dermatol. 2010, 130, 796. 48. Zhang, L.W.; Al-Suwayeh, S.A.; Hsieh, P.W.; Fang, J.Y. A comparison of skin delivery of ferulic acid and its derivatives: Evaluation of their efficacy and safety. Int. J. Pharm. 2010, 399, 44-51. 49. Yabe, T.; Hirahara, H.; Harada, N.; Ito, N.; Nagai, T.; Sanagi, T.; Yamada, H. Ferulic acid induces neural progenitor cell proliferation in vitro and in vivo. Neuroscience 2010, 165, 515-524. 50. de Boer, V.C.J.; Dihal, A.A.; van der Woude, H.; Arts, I.C.W.; Wolffram, S.; Alink, G.M.; Rietjens, I.; Keijer, J.; Hollman, P.C.H. Tissue distribution of quercetin in rats and pigs. J. Nutr. 2005, 135, 1718-1725. 51. Cushnie, T.P.T.; Lamb, A.J. Antimicrobial activity of flavonoids. Int. J. Antimicrob. Agents 2005, 26, 343-356. 52. Seufi, A.M.; Ibrahim, S.S.; Elmaghraby, T.K.; Hafez, E.E. Preventive effect of the flavonoid, quercetin, on hepatic cancer in rats via oxidant/antioxidant activity: Molecular and histological evidences. J. Exp. Clin. Cancer Res. 2009, 28, 1-8 53. Kaindl, U.; Eyberg, I.; Rohr-Udilova, N.; Heinzle, C.; Marian, B. The dietary antioxidants resveratrol and quercetin protect cells from exogenous pro-oxidative damage. Food Chem. Toxicol. 2008, 46, 1320-1326. 54. Orsolic, N.; Knezevic, A.H.; Sver, L.; Terzic, S.; Basic, I. Immunomodulatory and antimetastatic action of propolis and related polyphenolic compounds. J. Ethnopharmacol. 2004, 94, 307-315. 55. Arts, I.C.W.; Hollman, P.C.H. Polyphenols and disease risk in epidemiologic studies. Am. J. Clin. Nutr. 2005, 81, 317S-325S. 56. Knekt, P.; Kumpulainen, J.; Jarvinen, R.; Rissanen, H.; Heliovaara, M.; Reunanen, A.; Hakulinen, T.; Aromaa, A. Flavonoid intake and risk of chronic diseases. Am. J. Clin. Nutr. 2002, 76, 560-568. 57. Benkovic, V.; Kopjar, N.; Knezevic, A.H.; Dikic, D.; Basic, I.; Ramic, S.; Viculin, T.; Knezevic, F.; Orsolic, N. Evaluation of radioprotective effects of propolis and quercetin on human white blood cells in vitro. Biol. Pharm. Bull. 2008, 31, 1778-1785. 58. Rahman, M.M.; Bak, I.; Das, D.K. Effectiveness of Resveratrol Against Cardiovascular Disease. Mini-Rev. Org. Chem. 2010, 7, 256-261. 59. Toklu, H.Z.; Sehirli, O.; Ersahin, M.; Suleymanoglu, S.; Yiginer, O.; Emekli-Alturfan, E.; Yarat, A.; Yegen, B.C.; Senser, G. Resveratrol improves cardiovascular function and reduces oxidative organ damage in the renal, cardiovascular and cerebral tissues of two-kidney, one-clip hypertensive rats. J. Pharm. Pharmacol. 2010, 62, 1784-1793. 60. Chicoine, L.G.; Stewart, J.A.; Lucchesi, P.A. Is Resveratrol the Magic Bullet for Pulmonary Hypertension? Hypertension 2009, 54, 473-474. 61. Tiwari, V.; Sharma, S.; Kulkarni, S.K.; Chopra, K. Amelioration of oxidative stress and renal dysfunction by insulin and its combination with curcumin or resveratrol: Role of TGF-beta. Indian J. Pharmacol. 2008, 40, 90-90 62. Thandapilly, S.J.; Wojciechowski, P.; Behbahani, J.; Louis, X.L.; Yu, L.P.; Juric, D.; Kopilas, M.A.; Anderson, H.D.; Netticadan, T. Resveratrol Prevents the Development of Pathological Cardiac Hypertrophy and Contractile Dysfunction in the SHR Without Lowering Blood Pressure. Am. J. Hypertens. 2010, 23, 192-196. 63. Khalil, A.; Berrougui, H. Mechanism of action of resveratrol in lipid metabolism and atherosclerosis. Clin. Lipidol. 2009, 4, 527-531. 64. Kaeberlein, M. Resveratrol and rapamycin: are they anti-aging drugs? Bioessays 2010, 32, 96-99. 65. Wagner, C.; Fachinetto, R.; Corte, C.L.D.; Brito, V.B.; Severo, D.; Dias, G.; Morel, A.F.; Nogueira, C.W.; Rocha, J.B.T. Quercitrin, a glycoside form of quercetin, prevents lipid peroxidation in vitro. Brain Res. 2006, 1107, 192-198. 66. Jung, M.; Park, M. Acetylcholinesterase inhibition by flavonoids from agrimonia pilosa. Molecules 2007, 12, 2130-2139. 67. Materska, M.; Perucka, I. Antioxidant activity of the main phenolic compounds isolated from hot pepper fruit (Capsicum annuum L.). J. Agric. Food Chem. 2005, 53, 1750-1756. 68. Davis, R.A.; Simpson, M.M.; Nugent, R.B.; Carroll, A.R.; Avery, V.M.; Rali, T.; Chen, H.; Qurallo, B.; Quinn, R.J. Pim2 inhibitors from the Papua New Guinean plant Cupaniopsis macropetala. J. Nat. Prod. 2008, 71, 451-452. 69. Ibrahim, N.A.; El-Seedi, H.R.; Mohammed, M.M.D. Phytochemical investigation and hepatoprotective activity of Cupressus sempervirens L. leaves growing in Egypt. Nat. Prod. Res. 2007, 21, 857-866. 70. Liu, Y.; Murakami, N.; Ji, H.; Abreu, P.; Zhang, S. Antimalarial flavonol glycosides from Euphorbia hirta. Pharm. Biol. 2007, 45, 278-281. 71. Fukai, T.; Sakagami, H.; Toguchi, M.; Takayama, F.; Iwakura, I.; Atsumi, T.; Ueha, T.; Nakashima, H.; Nomura, T. Cytotoxic activity of low molecular weight polyphenols against human oral tumor cell lines. Anticancer Res. 2000, 20, 2525-2536. 72. Dai, J.; Mumper, R.J. Plant Phenolics: Extraction, Analysis and Their Antioxidant and Anticancer Properties. Molecules 2010, 15, 7313-7352. 73. Naczk, M.; Shahidi, F. Extraction and analysis of phenolics in food. J. Chromatogr. A 2004, 1054, 95-111. 74. Stalikas, C.D. Extraction, separation, and detection methods for phenolic acids and flavonoids. J. Sep. Sci. 2007, 30, 3268-3295. 75. Kartsova, L.A.; Alekseeva, A.V. Chromatographic and Electrophoretic Methods for Determining Polyphenol Compounds. J. Anal. Chem. 2008, 63, 1024-1033. 76. Yang, L.; Jiang, J.G.; Li, W.F.; Chen, J.; Wang, D.Y.; Zhu, L. Optimum extraction Process of polyphenols from the bark of Phyllanthus emblica L. based on the response surface methodology. J. Sep. Sci. 2009, 32, 1437-1444. 77. Cork, S.J.; Krockenberger, A.K. Methods and pitfalls of extracting condensed tannins and other phenolics from plants - insights from investigations on eucalyptus leaves. J. Chem. Ecol. 1991, 17, 123-134. 78. Khanna, S.K.; Viswanat, P.N.; Krishnan, P.S.; Sanwal, G.G. Extraction of total phenolics in presence of reducing agents. Phytochemistry 1968, 7, 1513-1517 79. Ragazzi, E.; Veronese, G. Quantitative-analysis of phenolic compounds after thin-layer chromatographic separation. J. Chromatogr. 1973, 77, 369-375. 80. Rodriguez-Arcos, R.C.; Smith, A.C.; Waldron, K.W. Effect of storage on wall-bound phenolics in green asparagus. J. Agric. Food Chem. 2002, 50, 3197-3203. 81. Barroso, C.G.; Rodriguez, M.C.; Guillen, D.A.; PerezBustamante, J.A. Analysis of low molecular mass phenolic compounds, furfural and 5-hydroxymethylfurfural in Brandy de Jerez by highperformance liquid chromatography diode array detection with direct injection. J. Chromatogr. A 1996, 724, 125-129. 82. Dekic, S.; Milosavljevic, S.; Vajs, V.; Jovic, S.; Petrovic, A.; Nikicevic, N.; Manojlovic, V.; Nedovic, V.; Tesevic, V. Trans- and cis-resveratrol concentration in wines produced in Serbia. J. Serb. Chem. Soc. 2008, 73, 1027-1037. 83. Kivilompolo, M.; Oburka, V.; Hyotylainen, T. Comprehensive two-dimensional liquid chromatography in the analysis of antioxidant phenolic compounds in wines and juices. Anal. Bioanal. Chem. 2008, 391, 373-380. 84. Benova, B.; Hajek, T. Utilization of coulometric array detection in analysis of beverages and plant extracts. In 5th Symposium by Nordic Separation Science Society; Kaljurand, M., Ed.; Elsevier Science Bv: Amsterdam, The Netherlands, 2010; Volume 2, pp. 92-100. 85. Krafczyk, N.; Glomb, M.A. Characterization of phenolic compounds in rooibos tea. J. Agric. Food Chem. 2008, 56, 3368-3376. 86. Kahoun, D.; Rezkova, S.; Veskrnova, K.; Kralovsky, J.; Holcapek, M. Determination of phenolic compounds and hydroxymethylfurfural in meads using high performance liquid chromatography with coulometric-array and UV detection. J. Chromatogr. A 2008, 1202, 19-33. 87. Jouki, M.; Khazaei, N. Compare of extraction of phenolic compounds from Pistacia atlantica in different solvents. In Advances in Biomedical Research, Proceedings; Anninos, P., Rossi, M., Pham, T.D., Falugi, C., Bussing, A., Koukkou, M., Eds.; World Scientific and Engineering Acad and Soc: Athens, Greece, 2010; pp. 361-365. 88. Turkmen, N.; Velioglu, Y.S.; Sari, F.; Polat, G. Effect of extraction conditions on measured total polyphenol contents and antioxidant and antibacterial activities of black tea. Molecules 2007, 12, 484-496. 89. Krygier, K.; Sosulski, F.; Hogge, L. Free, esterified, and insoluble-bound phenolic-acids .1. Extraction and purification procedure. J. Agric. Food Chem. 1982, 30, 330-334. 90. Rababah, T.M.; Banat, F.; Rababah, A.; Ereifej, K.; Yang, W. Optimization of Extraction Conditions of Total Phenolics, Antioxidant Activities, and Anthocyanin of Oregano, Thyme, Terebinth, and Pomegranate. J. Food Sci. 2010, 75, C626-C632. 91. Rodrigues, S.; Pinto, G.A.S.; Fernandes, F.A.N. Optimization of ultrasound extraction of phenolic compounds from coconut (Cocos nucifera) shell powder by response surface methodology. Ultrason. Sonochem. 2008, 15, 95-100. 92. Gribova, N.Y.; Filippenko, T.A.; Nikolaevskii, A.N.; Belaya, N.I.; Tsybulenko, A.A. Optimization of Conditions for the Extraction of Antioxidants from Solid Parts of Medicinal Plants. J. Anal. Chem. 2008, 63, 1034-1037. 93. Bors, W.; Michel, C. Chemistry of the antioxidant effect of polyphenols. In Alcohol and Wine Health and Disease; Das, D.K., Ursini, F., Eds.; New York Acad Sciences: New York, NY, USA, 2002; Volume 957, pp. 57-69. 94. Dragovic-Uzelac, V.; Levaj, B.; Mrkic, V.; Bursac, D.; Boras, M. The content of polyphenols and carotenoids in three apricot cultivars depending on stage of maturity and geographical region. Food Chem. 2007, 102, 966-975. 95. Long, G.L.; Winefordner, J.D. Limit of Detection. Anal. Chem. 1983, 55, A712-A724.
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