Extraction and Separation of the Bright-Greenish-Yellow Fluorescent Material from Aflatoxigenic Aspergillus spp. Infected Cotton Lint by HPLC−UV/FL

To isolate the bright-greenish-yellow-fluorescence (BGY-F) material associated with aflatoxin contamination on cotton lint, various in vitro chemical and in vivo natural BGY-F reaction products were prepared. BGY-F material was obtained from reactions involving (1) kojic acid (KA) and H2O2, (b) KA, peroxidase, and H2O2, (c) fresh cotton locules treated with KA and H2O2, (d) detached cotton locules inoculated with an aflatoxigenic Aspergillus flavus spore suspension, and (e) live developing cotton bolls inoculated with aflatoxigenic A. flavus. BGY-F preparations separated on TLC resulted in the same R f value (0.52), indicating the possibility of the same compound. Under HPLC conditions, at a 380 nm wavelength setting, BGY-F retention times ranged 5.74−6.09 min; under fluorescent detection at 435 nm (excitation) and 494 nm (emission), retention times ranged from 5.75 to 6.09 min. Apparently, in all methods used to form the BGY-F compound, both in vivo and in vitro, only one compound with specific chromatographic characteristics was produced, and the product is likely an oxidized form of KA. Keywords: Cotton; Gossypium hirsutum L.; bright-greenish-yellow fluorescence (BGY-F); Aspergillus flavus; aflatoxin; HPLC − UV/F