Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey

TH Kwok, G Kirkpatrick, HI Mohd Yusof, I Portokalakis, P Nigam, R Owusu-Apenten

Research output: Contribution to journalArticle

Abstract

Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and otherdicarbonyl compounds from Manuka honey.Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted asreagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively.Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i)regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 μM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 μM, and (v) a day-to-day precision of 16.0 and 18.3%, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99).Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey isfeasible proposition. Further work is needed for method validation.
LanguageEnglish
Pages1-6
JournalJournal of Advances in Biology and Biotechnology
Volume7
Issue number1
Early online date14 Jun 2016
DOIs
Publication statusE-pub ahead of print - 14 Jun 2016

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Pyruvaldehyde
Acetylcysteine
Colorimetric analysis
Assays
Glyoxal
Sugars
Monitoring

Keywords

  • Rapid determination
  • dicarbonyl compounds
  • n-acetyl cysteine
  • carbonyl reagents
  • 2
  • 4-
  • dinitrophenylhydrazine
  • methylglyoxal
  • 3-deoxy-D-glucosone
  • Advanced glycation endproducts (AGES)

Cite this

Kwok, TH., Kirkpatrick, G., Mohd Yusof, HI., Portokalakis, I., Nigam, P., & Owusu-Apenten, R. (2016). Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey. 7(1), 1-6. https://doi.org/10.9734/JABB/2016/26592
Kwok, TH ; Kirkpatrick, G ; Mohd Yusof, HI ; Portokalakis, I ; Nigam, P ; Owusu-Apenten, R. / Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey. 2016 ; Vol. 7, No. 1. pp. 1-6.
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abstract = "Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and otherdicarbonyl compounds from Manuka honey.Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted asreagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively.Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i)regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 μM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 μM, and (v) a day-to-day precision of 16.0 and 18.3{\%}, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99).Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey isfeasible proposition. Further work is needed for method validation.",
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Kwok, TH, Kirkpatrick, G, Mohd Yusof, HI, Portokalakis, I, Nigam, P & Owusu-Apenten, R 2016, 'Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey', vol. 7, no. 1, pp. 1-6. https://doi.org/10.9734/JABB/2016/26592

Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey. / Kwok, TH; Kirkpatrick, G; Mohd Yusof, HI; Portokalakis, I; Nigam, P; Owusu-Apenten, R.

Vol. 7, No. 1, 14.06.2016, p. 1-6.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey

AU - Kwok, TH

AU - Kirkpatrick, G

AU - Mohd Yusof, HI

AU - Portokalakis, I

AU - Nigam, P

AU - Owusu-Apenten, R

PY - 2016/6/14

Y1 - 2016/6/14

N2 - Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and otherdicarbonyl compounds from Manuka honey.Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted asreagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively.Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i)regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 μM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 μM, and (v) a day-to-day precision of 16.0 and 18.3%, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99).Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey isfeasible proposition. Further work is needed for method validation.

AB - Aims: Realization of a rapid colorimetric assay for monitoring levels of methylglyoxal and otherdicarbonyl compounds from Manuka honey.Methods: N-acetyl cysteine (NAC) and 2, 4-dinitrophenylhydrazine (DNPH) were adopted asreagents for methylglyoxal colorimetric analysis of honey at 288 or 525 nm, respectively.Results and Discussion: NAC and DNPH produced linear responses for methylglyoxal with:(i)regression coefficient (R2) equal to 0.99 or 0.97, (ii) molar absorptivity (measure of sensitivity) equal to 287±11 or 14189±498 M-1 cm-1, (iii) a minimum detectable concentration (MDC) of 0.18 mM vs 7.3 μM, (iv) upper linearity limit of linearity (ULL) equal to 4mM or 83 μM, and (v) a day-to-day precision of 16.0 and 18.3%, respectively. Low interferences occurred with reducing sugars, glyoxal or 3-deoxy-D-glucosone. For honey with a unique manuka factor (UMF) rating 5+ to UMF18+, the net concentration of dicarbonyl compounds ranged from 1069 mg-methylglyoxal equivalence per kg (mg MeGEq /kg) to 2208 (mg MeGEq /kg) using the NAC assay. For the DNPH assay, the apparent dicarbonyl concentration was 350 to 1009-mg MeGEq /kg honey. Measures of methylglyoxal equivalences were strongly correlated with the UMF rating for honeys (R2=0.98-0.99).Conclusion: The proposed colorimetric analysis of methylglyoxal equivalence in Manuka honey isfeasible proposition. Further work is needed for method validation.

KW - Rapid determination

KW - dicarbonyl compounds

KW - n-acetyl cysteine

KW - carbonyl reagents

KW - 2

KW - 4-

KW - dinitrophenylhydrazine

KW - methylglyoxal

KW - 3-deoxy-D-glucosone

KW - Advanced glycation endproducts (AGES)

U2 - 10.9734/JABB/2016/26592

DO - 10.9734/JABB/2016/26592

M3 - Article

VL - 7

SP - 1

EP - 6

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Kwok TH, Kirkpatrick G, Mohd Yusof HI, Portokalakis I, Nigam P, Owusu-Apenten R. Rapid Colorimetric Determination of Methylglyoxal Equivalents for Manuka Honey. 2016 Jun 14;7(1):1-6. https://doi.org/10.9734/JABB/2016/26592