title: Isolation of the antioxidant pyranonigrin-A from rice mold starters used in the manufacturing process of fermented foods.
abstract: Rice mold starters prepared from Aspergillus species are commonly used for the manufacture of koji in the production of oriental fermented foods. Methanol extracts of rice mold starters fermented by the Aspergillus species, A. awamori, A. kawachii, A. oryzae, A. saitoi, and A. sojae, were examined for their antioxidative activity by using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging system. The extracts of A. awamori, A. kawachii, and A. saitoi exhibited higher activity than those of A. oryzae and A. sojae. An antioxidant was isolated from the extract of A. saitoi and identified as pyranonigrin-A by 1H-NMR, 13C-NMR, and FAB-MS analyses. The antioxidative activity of pyranonigrin-A was approximately equivalent to that of ferulic acid, an antioxidant in cereal grain. It was present in rice mold starters prepared by A. awamori, A. kawachii, and A. saitoi, although there was no pyranonigrin-A in the A. oryzae and A. sojae starters. The results suggest that the content of pyranonigrin-A in rice mold starters has a correlation with the antioxidative activity, and that it is induced in rice mold starters at the sporulation stage.
authors.affiliation: Faculty of Human Wellness, Tokaigakuen University, Japan. miyakeyo@tokaigakuen-u.ac.jp
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Miyake
authors.forename: Chihiro
authors.initials: C
authors.lastname: Ito
authors.forename: Masataka
authors.initials: M
authors.lastname: Itoigawa
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Osawa
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D001230:Aspergillus / Q000145:classification / Q000378:metabolism*; D002247:Carbon Isotopes / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000378:metabolism; D005285:Fermentation; D005516:Food Microbiology; D016166:Free Radical Scavengers / Q000378:metabolism; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D011758:Pyrroles / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D045730:Soy Foods / Q000382:microbiology*; D013045:Species Specificity; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000975:Antioxidants; D002247:Carbon Isotopes; D003373:Coumaric Acids; D016166:Free Radical Scavengers; D011753:Pyrones; D011758:Pyrroles; C522144:pyranonigrin A; C004999:ferulic acid