Quantitative analysis of the S‐alk(en)yl‐L‐cysteine sulphoxides in onion (Allium cepa L.)

Abstract

Quantitative analysis of each of the S-alk(en)yl-L-cysteine sulphoxides was achieved by the following procedure. A methanol : chloroform : water extract of onion tissue was purified by electrophoresis. Alk(en)yl-L-cysteine sulphoxides were separated by thinlayer chromatography (t.l.c,) on commercial silica-gel plates and were reacted with ninhydrin, the spot intensity being measured by an integrating densitometer. The synthetic analogue ( k )-S-1-butyl-L-cysteine sulphoxide was used as an internal standard in each extract.In white bulb onion (cv. Southport White Globe), ( & )-S-1-propyl-L-cysteine sulphoxide is the predominant flavour precursor at a concentration of 2.9 f 0.4 mg g-1 fresh weight. rt -S-1-methyl-L-cysteine sulphoxide and ( 2 ) trans-S-1-propenyl-Lcysteine sulphoxide are present at the lower concentrations of 0.9 f 0.25 mg g-l fresh weight and 0.6 f 0.15 mg g-1 fresh weight respectively.Stable n-butyl, trifluoroacetyl derivatives of standards and of the alk(en)yl-Lcysteine sulphoxides in extracts, were formed. Subsequent g.c.-m.s. enabled parent ions and fragmentation patterns to be recorded and allowed the conclusive identification of the endogenous alk(en)yl-L-cysteine sulphoxides.

Interactions among genotype, environment and agronomic practices on production and quality of storage onion (Allium cepa L.) - A review

“…6 Lancaster, Kelly 1983;Thomas, Parkin 1994;Hovius et al 2005;Lee et al 2009b Quercetin (mg/kg FW) of ACSOs from the same content of sulphur compounds in the tissues (Lee et al 2009b). The content of total ACSOs in onion bulbs varies between 0.12 and 4.60 mg/g FW (Lancaster, Kelly 1983;Thomas, Parkin 1994;Hovius et al 2005;Lee et al 2009b). Moreover, the content of major flavour precursors in bulbs increases linearly with the increase of pungency level: the most pungent cultivars can contain about eightfold more 1-PeCSO (0.07 to 0.65 mg/g FW) and threefold more MCSO (0.03 to 0.16 mg/g FW) than the least pungent onions (Lee et al 2009b).…”

Characterization of Amino Acid and S-alk(en)yl-L-cysteine Sulfoxide Production in Japanese Bunching Onion Carrying an Extra Chromosome of Shallot

“…Several reports (Lancaster and Kelly, 1983;Yoo and Pike, 1998) have indicated that AlCSO was undetectable in shallot and A. fistulosum. The differences were due to the detection sensitivity of the methods of analysis.…”

“…There is growing interest in optimizing breeding and production to produce fresh or processed products with defined flavor and health characteristics (Griffiths et al, 2002). When their tissues are damaged, Allium plants produce distinct sulfur volatiles through the hydrolysis of S-alk(en)yl-L-cystein sulfoxides (ACSOs), flavor precursors biosynthetically derived from cysteine, by the action of alliinase (Lancaster and Kelly, 1983). The existence of four ACSOs in the Allium species, S-methyl (Me)-, S-propyl (Pr)-, S-2-propenyl (allyl, Al)-, and S-1-propenyl (Pe)-CSOs, has been reported (Freeman and Whenham, 1975;Granroth, 1968;Lancaster and Kelly, 1983).…”

“…When their tissues are damaged, Allium plants produce distinct sulfur volatiles through the hydrolysis of S-alk(en)yl-L-cystein sulfoxides (ACSOs), flavor precursors biosynthetically derived from cysteine, by the action of alliinase (Lancaster and Kelly, 1983). The existence of four ACSOs in the Allium species, S-methyl (Me)-, S-propyl (Pr)-, S-2-propenyl (allyl, Al)-, and S-1-propenyl (Pe)-CSOs, has been reported (Freeman and Whenham, 1975;Granroth, 1968;Lancaster and Kelly, 1983). These ACSO compounds and their derivatives show a number of activities that are beneficial to human health, such as antidiabetic (Kumari et al, 1995), antihyperglycemic (Roman-Ramos et al, 1995), and antiplatelet activities (Ali et al, 1999).…”

Quercetin-4′-glucoside: a physiological inhibitor of the activities of dominant glutathione S-transferases in onion (Allium cepa L.) bulb

“…On the other hand, the onion plant is a rich source of a variety of sulfur compounds (Lancaster and Shaw 1989;Jones et al 2004) and flavonoids (Bilyk et al 1984;Rhodes and Price 1996). Among the sulfur compounds, GSH and cysteine derivatives are important biosynthetics in Allium plants (Lancaster and Kelly 1983;Jones et al 2004), and some GSH and cysteine derivatives have been reported to inhibit the activities of GSTs in pumpkin (Hossain et al 2007b). Similarly, quercetin is the main flavonoid in onion (Leighton et al 1992), the content being 5-10 times higher than that in other vegetables (Lachman et al 2003).…”