Abstract
The content of dialk(en)yl thiosulfinates, including allicin, and their degradation
products has been determined by high performance liquid chromatography (HPLC), using
the respective determined extinction coefficients, for a number of commercially available
garlic products. Quantitation has been achieved for the thiosulfinates; diallyl, methyl
allyl, and dimethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides; the vinyldithiins;
and (E)- and (Z)-ajoene. The thiosulfinates were found to be released only from garlic cloves and
garlic powder products. The vinyldithiins and ajoenes were found only in products
containing garlic macerated in vegetable oil. The diallyl, methyl ally], and dimethyl
sulfide series were the exclusive constituents found in products containing the oil
of steam-distilled garlic. Typical steam-distilled garlic oil products contained about
the same amount of total sulfur compounds as total thiosulfinates released from freshly
homogenized garlic cloves; however, oil-macerated products contained only 20% of that
amount, while garlic powder products varied from 0 to 100%. Products containing garlic
powder suspended in a gel or garlic aged in aqueous alcohol did not contain detectable
amounts of these non-ionic sulfur compounds. A comparison of several brands of each
type of garlic product revealed a large range in content (4-fold for oil-macerates
and 33-fold for steam-distilled garlic oils), indicating the importance of analysis
before garlic products are used for clinical investigations or commercial distribution.
Key words
Allium sativum
- garlic analysis - dialk(en)yl thiosulfinates - HPLC analysis - allicin degradation
products
