Precursors and formation of pyrithione and other pyridyl-containing sulfur compounds in drumstick onion, Allium stipitatum

0359831 - BC 2012 RIV US eng J - Journal Article
Kubec, R. - Krejčová, P. - Šimek, Petr - Václavík, L. - Hajšlová, J. - Schraml, Jan
Precursors and formation of pyrithione and other pyridyl-containing sulfur compounds in drumstick onion, Allium stipitatum.
Journal of Agricultural and Food Chemistry. Roč. 59, č. 10 (2011), s. 5763-5770. ISSN 0021-8561. E-ISSN 1520-5118
R&D Projects: GA AV ČR IAA400720706
Grant - others:Grant Agency of South Bohemia(CZ) GAJU 067/2010/Z; Grant Agency of South Bohemia(CZ) GAJU 028/2010/P
Institutional research plan: CEZ:AV0Z50070508; CEZ:AV0Z40720504
Keywords : Allium stipitatum * S-(2-pyridyl)cysteine N-oxide * marasmin
Subject RIV: CE - Biochemistry
Impact factor: 2.823, year: 2011

Two novel, cysteine derivatives were isolated from the bulbs of Allium stipitatum (Allium sub) and shown to be S-(2-pyridyl)cysteine N-oxide and S-(2-pyridyl) glutathione N-oxide. The former compound is the first example of a naturally occurring alliinase substrate that contains an N-oxide functionality instead of the S-oxide group. In addition, S-methylcysteine S-oxide (methiin) and S-methyl thiomethyl)cysteine 4-oxide (marasmin) were found in the bulbs. The alliinase-mediated formation of pyridyl-containing compounds following disruption of A. stipitatum bulbs was studied by a combination of HPLC-MS, HPLC-PDA, DART-MS, and NMR techniques. No pyridyl-containing thiosulfinates are present in homogenized bulbs. Instead, various pyridine N-oxides such as N-hydroxypyridine-2(1H)-thione (pyrithione), 2-(methyldithio)pyridine N-oxide, 2-(methylthio) methyldithio]pyridine N-oxide, di(2-pyridyl) disulfide N-oxide, and di(2-pyridyl) disulfide N,N0-dioxide are reported.
Permanent Link: http://hdl.handle.net/11104/0197537