doctoral thesis
Prevention of genotoxic effect of ochratoxin and aflatoxin B1 by Echinacea L. and Castanea Mill. extracts

Huska Jukić (2012)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Applied Chemistry and Ecology
Sub-department of Biochemistry and Toxicology
Metadata
TitleSprječavanje genotoksičnog učinka ohratoksina i aflatoksina B1 ekstraktima vrsta roda Echinacea L. i Castanea Mill.
AuthorHuska Jukić
Mentor(s)Tomislav Klapec
Ivan Kosalec
Abstract
Cilj ovoga rada bio je ispitati sadržaj polifenola u ekstraktima vrsta Echinacea purpurea (L.) Moench kao i Castanea sativa Mill. te odrediti njihov antioksidativni i antigenotoksični učinak. Antioksidativna aktivnost ekstrakata i glavnih sastavnica je utvrđena primjenom elektronske spinske rezonancije i spektrofotometrijskih metoda hvatanja DPPH, superoksidnog i hidroksilnog radikala. Ispitan je i redoks učinak i citotoksičnost ekstrakata u kulturi stanica raka kolona (SW480). Antigenotoksični i antimutageni učinak procijenjen je kometnim i Amesovim testom uz mutagene i genotoksične mikotoksine – aflatoksin B1 (AFB1) i ohratoksin A (OTA). Provedena je i senzorska analiza tretiranih uzoraka kikirikija i grožđica za preliminarnu procjenu primjenjivosti tretmana ekstraktima. Ekstrakt herbe ehinaceje je sadržavao više ukupnih polifenola u odnosu na ekstrakt lista kestena (10,57 % prema 6,74 %). Ekstrakt ehinaceje je sadržavao višestruko veću količinu fenolnih kiselina (prvenstveno cikorijska i kaftarinska kiselina), dok je ekstrakt kestena bio najbogatiji taninima i flavonoidima (derivati galne i elaginske kiseline). Ekstrakt kestena je pokazao znatno veću sposobnost neutralizacije DPPH radikala (EC50 = 1,87 μg/mL) u odnosu na ekstrakt ehinaceje (EC50 = 15,67 μg/mL). Slični rezultati utvrđeni i ispitivanjem hvatanja hidroksilnog i superoksidnog radikala, pri čemu je ekstrakt kestena bio desetak puta učinkovitiji. Utvrđena je i snažna antioksidativna aktivnost dominantnih sastavnica koja ukazuje na fenolne kiseline (ehinaceja) i elaginsku kiselinu (kesten) kao sastojke koji najviše doprinose učinku ekstrakata. Inhibitorni učinak ekstrakata ehinaceje na mutageno djelovanje aflatoksina B1 zabilježeno je samo kod najniže koncentracije na soju bakterije Salmonella typhimurium osjetljivom na pomak okvira čitanja. S druge strane, utvrđen je snažan inhibitoran učinak ekstrakta kestena, izraženiji na soju osjetljivom na pomak okvira čitanja. Supresija genotoksičnog učinka AFB1 i OTA utvrđena je i kometnim testom, pri čemu je ustanovljena značajna redukcija dužine repa, repnog intenziteta i repnog momenta u leukocitima istovremeno tretiranim mikotoksinima i različitim koncentracijama ekstrakata. Dok ekstrakt ehinaceje tek pri dužoj inkubaciji i višim koncentracijama djeluje citotoksično na stanice raka kolona, ekstrakt kestena je pokazao znatno snažniji učinak već kod najniže koncentracije. Ispitivanjem supresije oksidativnog stresa ekstraktima u kulturi stanica raka zabilježeno je podsticanje oksidativnog stresa kod nižih koncentracija i redukcija pri višim koncentracijama, a slično djelovanje je ustanovljeno i u stanicama tretiranim vodikovim peroksidom. Rezultati upućuju na indukciju antioksidantne zaštite stanica. Senzorska analiza tretiranih kikirikija je utvrdila koncentraciju ekstrakta koja nije izazvala značajnije promjene organoleptike u odnosu na kontrolni uzorak. Tretirane grožđice su bile promijenjenog mirisa i arome, iako bez utjecaja na prihvatljivost samog proizvoda. Dodatak ovdje ispitanih ekstrakata potencijalnog antigenotoksičnog učinka hrani bi, dakle, pored uloge u povećanju održivosti samih namirnica antioksidantnim djelovanjem, mogao modulirati toksičnost prisutnih mikotoksina nakon konzumacije.
Keywordspolyphenols antioxidant activity genotoxicity extract peanut
Parallel title (English)Prevention of genotoxic effect of ochratoxin and aflatoxin B1 by Echinacea L. and Castanea Mill. extracts
Committee MembersDaniela Čačić Kenjerić (committee chairperson)
Tomislav Klapec (committee member)
Ivan Kosalec (committee member)
Ivica Strelec (committee member)
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Applied Chemistry and Ecology
Sub-department of Biochemistry and Toxicology
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
UDK615
APPLIED SCIENCES. MEDICINE. TECHNOLOGY
Pharmacology. Therapeutics. Toxicology
Study programme typeuniversity
Study levelpostgraduate
Study programmeFood Engineering
Academic title abbreviationdr. sc.
Genredoctoral thesis
Language Croatian
Defense date2012-03-16
Parallel abstract (English)
The purpose of this thesis is to examine polyphenol content in Echinacea purpurea (L.) Moench and Castanea sativa Mill. extracts, and to determine antioxidant effects of those extracts, trough electron spin resonance and colorimetric method of DPPH•; a superoxide hydroxyl radical. Redox effect and cytotoxicity of the extract in colon cancer cell culture SW480 has also been tested. Antigenotoxic antimutagenic effect has been evaluated using comet and Ames test, with mutagenic and genotoxic micotoxines AFB1 and OTA present. Sensory analysis of peanut and raisin samples has also been performed for the preliminary evaluation of extract treatment. Echinacea herb extract contained higher total polyphenol content than chesnutt leaves extract (10,57% compared to 6,74%). Echinacea herb extract had significantly higher phenolic acid content (cicoric and caftarinic acid), while chestnut extract was rich in tanine and flavonide compounds. Chestnut extract had higher capability to neutralize DPPH radicals (EC50 = 1,87 μg/mL) compared to Echinacea extract (EC50 = 15,67 μg/mL). Similar results were obtained when hydroxyl and superoxide radical capture capability was examined; chestnut extract was about 10 times more effective. Strong antioxidative activity of dominant compounds has been established, which points out to presence of phenolic acids and elaginic acid in Echinacea and chestnut respectively, as well as other compounds which contribute to the extract effect. Inhibitory effect of Echinacea extract on mutagenic effect of aflatoxin B1 has been recorded at the lowest concentrations, when Salmonella typhimurium bacteria has been treated. On the other hand there was a strong inhibitory effect demonstrated by the chestnut extract, once it was applied to the appropriate bacteria culture. The suppression of genotoxic effect of AFB1 and OTA has been determined using the comet test, whereby significant reduction of the tail length has been determined, as well as tail moment and intensity in leukocytes treated by mycotoxines and different concentrations of extracts simultane ously. Chestnut extract has shown strong effects even at low concentrations, while Echinacea extract had cytotoxic effect on colon cancer cells only after prolonged exposure at high concentrations. When suppression of the oxidative stress trough extract application has been examined, it has been established that there is oxidative stress relation with lower concentrations, while reduction has been established at high concentrations; similar effects have been established once cells were treated with hydrogen peroxide. The results suggest induction of antioxidative protection of the cell. Sensory analysis of treated peanuts has established the concentration with no significant effects on organoleptics compared with the control sample. Treated raisins had a change in aroma and scent, but without substantial effect on the consumability of the product itself. These additives not only would extend the useful life of various food products; they can also serve as a modulator for toxicity of various micotoxins after those food products have been consumed.
Parallel keywords (Croatian)polifenoli antioksidacijska aktivnost kikiriki ekstrakt genotoksičnost
Extent217 str.: ilustr., graf. prikazi: 30 cm
Versionaccepted version
Resource typetext
Access conditionAccess restricted to students and staff of home institution
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
Noteaccepted version
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:362347
CommitterSanda Hasenay