title: Isolation of methyl syringate as a specific aflatoxin production inhibitor from the essential oil of Betula alba and aflatoxin production inhibitory activities of its related compounds.
abstract: Methyl syringate was isolated from the essential oil of Betula alba as an aflatoxin production inhibitor. It inhibited aflatoxin production of Aspergillus parasiticus and Aspergillus flavus with IC(50) values of 0.9 and 0.8 mM, respectively, without significantly inhibiting fungal growth. Methyl syringate reduced mRNA levels of genes (aflR, pksA, and omtB) [corrected] encoding proteins required for aflatoxin biosynthesis. Methyl gallate, methyl 3,4,5-trimethoxybenzoate, and methyl 3-O-methylgallate inhibited both aflatoxin production and fungal growth of A. parasiticus and A. flavus. However, their acids and syringic acid did not inhibit aflatoxin production and growth of A. parasiticus significantly, although gallic acid inhibited aflatoxin production of A. flavus with selectivity. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of methyl syringate was much weaker than that of gallic acid. These results showed that methyl syringate has a unique inhibitory activity toward aflatoxin production with a different mode of action from that of gallic acid.
authors.affiliation: Department of Applied Biological Chemistry, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Usuma
authors.initials: U
authors.lastname: Jermnak
authors.forename: Tomoya
authors.initials: T
authors.lastname: Yoshinari
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Rie
authors.initials: R
authors.lastname: Tsuyuki
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Nagasawa
authors.forename: Shohei
authors.initials: S
authors.lastname: Sakuda
mesh_terms: D000348:Aflatoxins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D001231:Aspergillus flavus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029662:Betula / Q000737:chemistry*; D001713:Biphenyl Compounds; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D009822:Oils, Volatile / Q000378:metabolism; D010851:Picrates; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism
chemical_list: D000348:Aflatoxins; D001713:Biphenyl Compounds; D009822:Oils, Volatile; D010851:Picrates; D012333:RNA, Messenger; C506133:methyl syringate; D005707:Gallic Acid; C025525:3-O-methylgallic acid; C004931:1,1-diphenyl-2-picrylhydrazyl