Toxicology 166 (2001) 161 – 170 Partial chemical/structural elucidation of anti-mutagenic compounds from corn A. Burgos-Herna ´ndez *, R. Lo ´ pez-Garcı ´a 1 , H. Njapau, D.L. Park 2 Department of Food Science, Louisiana State Uniersity Agricultural Center, Baton Rouge, LA 70803 -4200, USA Received 4 April 2001; received in revised form 25 June 2001; accepted 3 July 2001 Abstract In this study, corn fractions obtained from an isolation process of anti-mutagenic factors in our previous research work (Burgos-Herna ´ndez et al., 2001), were subjected to several analyses for chemical/structural elucidation. The anti-mutagenic activity of these fractions was tested against aflatoxin B 1 (AFB 1 ) and 1-methyl-3-nitro-1-nitro- soguanidine (MNNG), a mutagen that does not require bioactivation. Two concentrations of this agent in the corn fractions were tested for anti-mutagenicity in the Salmonella /microsomal mutagenicity assay, using tester strain TA100 with no metabolic activation. Corn fractions tested showed evidence of anti-mutagenic activity by producing a dose – response type of relationship between a constant amount of MNNG and several concentrations of tested corn fraction. Five different varieties of yellow corn were tested in order to determine if the anti-mutagenic factors were intrinsic to corn. Variety of the corn did not show an effect on the reduction of the mutagenic potential of AFB 1 suggesting that anti-mutagenic compounds are intrinsic to corn. Four corn fractions, previously obtained after the isolation process were analyzed by MALDI-MS and GC-MS. MALDI-MS showed the presence of two groups of molecules or molecular fragments. The molecular mass of one group ranged from 250 to 370 m/z, the other ranged from 540 to 640 m/z. GC-MS identified linoleic acid as one of the compounds responsible for the anti-mutagenic activity present in corn. © 2001 Published by Elsevier Science Ireland Ltd. Keywords: Anti-mutagenic compounds; Corn; Characterization; Salmonella TA 100 and TA 98; Spectrometry; Linoleic acid www.elsevier.com/locate/toxicol Abbreiations: AFB 1 , aflatoxin B 1 ; DMSO, dimethyl sulfoxide; MNNG, 1-methyl-3-nitro-1-nitrosoguanidine; TLC, thin layer chromatography. * Corresponding author. Present address: Departamento de Investigacio ´ n y Posgrado en Alimentos, Universidad de Sonora, Apartado Postal 1658, Hemosillo, C.P. 83000 Sonora, Me ´xico. Tel.: +52-6-213-4907; fax: +52-6-212-5488. E-mail address: aburgos@guayacan.uson.mx (A. Burgos-Herna ´ndez). 1 Present address: Departamento de Ciencias Quı ´micas, Universidad La Salle, Benjamı ´n Franklin 47, Mexico, D.F., C.P. 06140. 2 Present address: Center of Food Safety and Applied Nutrition, Food and Drugs Administration, Building FB-8, Rm 4815, Mail Stop HFS-345, Washington, DC, USA. 0300-483X/01/$ - see front matter © 2001 Published by Elsevier Science Ireland Ltd. PII:S0300-483X(01)00466-8