Determination of selected biogenic amines in Acacia rigidula plant materials and dietary supplements using LC–MS/MS methods
Highlights
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- Tyramine, tryptamine and phenethylamine are the primary amines in A. rigidula leaves.
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- Amine profiles of A. rigidula dietary supplements differed from those of the plant.
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- A positional isomer of amphetamine was found in about half of the supplements.
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- The positional isomer was identified as β-methylphenethylamine.
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- Confirmation by independent analytical methods are critical in identifications.
Abstract
Extracts of Acacia rigidula
leaves are used in weight-loss products sold in vitamin shops and over
the internet with little or no published data about their potential
biological effects. In our chemical investigations on authenticated A. rigidula
plant material, we established a rapid and sensitive LC–MS/MS method
for the quantitative determination of several phenethylamine, tyramine
and tryptamine derivatives. Stable isotopically labeled compounds were
used as internal standards for quantitative analysis. We found total
calculated contents of 6 biogenic amines in A. rigidula leaf of 18.6 and 32.9 μg/g. The content of selected amines in 21 dietary supplements labeled as containing A. rigidula
was determined by a second LC–MS/MS method. Our study revealed
significant differences in the amine profiles of authenticated plant
materials and dietary supplements. β-Methylphenethylamine, a non-natural
compound, was found in 9 of the 21 dietary supplement products.
β-Methylphenethylamine was found at levels of 960–60,500 μg/g while
phenethylamine was found at levels of 710–171,620 μg/g.
β-Methylphenethylamine is a positional isomer of amphetamine and our
results showed that it can be misidentified as amphetamine during LC–MS
analysis. An independent GC–MS analysis was used to confirm the presence
of β-methylphenethylamine and the absence of amphetamine in dietary
supplements labeled as containing A. rigidula. This study
demonstrates that confirmations by independent analytical methods are
essential to verify findings of unusual or unexpected compounds in
dietary supplements.
Graphical abstract
Keywords
- Acacia rigidula;
- Biogenic amines;
- Dietary supplement;
- β-Methylphenethylamine;
- Amphetamine
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+1 240 402 1795; fax: +1 301 436 2622.
Published by Elsevier B.V.
