In vitro efficacy of mycotoxins adsorption by natural mineral adsorbents

Abstract

The paper describes in vitro model for evaluation of natural mineral adsorbents ability to adsorb mycotoxins. Bentonite, diatomite and zeolite were prepared in the Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade. A total of six mycotoxins: aflatoxin B1 (AFL), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZON), diacetoxyscirpenol (DAS) and T-2 toxin were tested in vitro. For adsorption experiments crude extracts of mycotoxins, produced in the Department of Microbiology of Bio-ecological Center in Zrenjanin, were used. The ability for binding mycotoxins was evaluated in the electrolyte 0.1 M K2HPO4 which pH value was adjusted to 3.0 and 6.9, respectively. Mass ratio of individual mycotoxin and natural mineral adsorbent was 1:5000. The experimental mixtures were incubated for 1 hour on a rotary shaker (185 rpm) at room temperature (22-25oC). After incubation the extractions of unadsorbed mycotoxins from the filtrates were performed with organic solvents, and their quantifications were done by thin-layer chromatography (TLC). By the use of TLC method it was noted that bentonite, diatomite and zeolite binded more than 95% of applicated AFL. In the case of OTA only diatomite adsorbed that toxin - adsorption index was 66.67%. Binding of DON has been observed only at pH 3.0 of electrolyte. Its adsorption index varied from 25.00 to 50.00% depending on the type of mineral adsorbent. Effect of electrolyte pH value on the binding of ZON was not so expressed. Its adsorption index ranged from 12.20 to 37.00%. In the case of type A trichothecenes (DAS and T-2 toxin) bentonite, diatomite, and zeolite binded only T-2 toxin. The amount of adsorbed T-2 toxin ranged from 16.66 to 33.33%. The obtained results point out the need for activation or processing of natural mineral adsorbens, especially bentonite and zeolite, in order to increase the efficiency of adsorption of the wider spectrum of mycotoxins.U radu je prikazan in vitro model za evaluaciju sposobnosti za adsorpciju mikotoksina prirodnih mineralnih adsorbenata: bentonita, diatomita i zeolita pripremljenih u Institutu za tehnologiju nuklearnih i drugih mineralnih sirovina, Beograd. Testirano je ukupno sest mikotoksina: aflatoksin B1 (AFL), ohratoksin A (OTA), dezoksinivalenol (DON), zearalenon (ZON), diacetoksiscirpenol (DAS) i T-2 toksin. Za eksperimente adsorpcije su korisceni sirovi ekstrakti mikotoksina, proizvedeni u Odeljenju mikrobiologije Bio-ekoloskog centra, Zrenjanin. Sposobnost za in vitro vezivanje mikotoksina je ocenjivana u elektrolitu 0,1 M K2HPO4 cija je pH vrednost podesena na 3,0 odnosno 6,9. Maseni odnos pojedinacnih mikotoksina i prirodnih mineralnih adsorbenasa je iznosio 1:5000. Eksperimentalne smese su inkubirane tokom 1 sata na rotacionoj tresilici (185 o/min) i sobnoj temperaturi (22-25oC). Nakon inkubacije vrsena je ekstrakcija neadsorbovanih mikotoksina iz filtrata organskim rastvaracima i kvantifikacija istih metodom tankoslojne hromatografije. Koriscenom metodom je konstatovano da su bentonit, diatomit i zeolit vezali vise od 95% aplicirane kolicine AFL. U slucaju OTA samo je diatomit adsorbovao ovaj mikotoksin - indeks adsorpcije je bio 66,67%. Vezivanje DON-a je konstatovano samo pri pH vrednosti 3,0 elektrolita. Njegov indeks adsorpcije je varirao od 25,00-50,00% u zavisnosti od vrste mineralnog adsorbenta. Uticaj pH vrednosti elektrolita na vezivanje ZON-a nije bio izrazen. Indeks adsorpcije ovog mikotoksina je iznosio od 12,20-37,00%. Od trihotecena tipa A (DAS i T-2 toksin) bentonit, diatomit i zeolit su vezivali samo T-2 toksin. Kolicina adsorbovanog T-2 toksina je bila od 16,66 do 33,33%. Dobijeni rezultati ukazuju na potrebu aktivacije ili oplemenjivanja prirodnih mineralnih adsorbenata, posebno bentonita i zeolita, u cilju povecanja efikasnosti adsorpcije sireg spektra mikotoksina. PR Projekat Ministarstva nauke Republike Srbije, br. III-46005 and TR-31023