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NMR protocol for determination of oxidation susceptibility of serum lipids and application of the protocol to a chocolate study.

Tynkkynen T, Mursu J, Nurmi T, Tuppurainen K, Laatikainen R, Soininen P - Metabolomics (2011)

Bottom Line: The oxidation susceptibility of serum lipids decreased in the HPC group, and there was a significant difference between the WC and HPC groups (P = 0.031).Furthermore, arachidonic, docosahexaenoic, docosapentaenoic and palmitic acids, gamma-glutamyl transferase, hemoglobin, HDL, phosphatidylcholine and choline containing phospholipids explained about 60% of the oxidation susceptibility values.ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0323-2) contains supplementary material, which is available to authorized users.

View Article: PubMed Central - PubMed

ABSTRACT
A protocol for determination of oxidation susceptibility of serum lipids based on proton nuclear magnetic resonance ((1)H NMR) spectroscopy is presented and compared to the commonly used spectrophotometric method. Even though there are methodological differences between these two methods, the NMR-based oxidation susceptibility correlates well (r(2) = 0.73) with the lag time determined spectrophotometrically. In addition to the oxidizability of serum lipids, the NMR method provides also information about the lipid profile. The NMR oxidation assay was applied to the chocolate study including fasting serum samples (n = 45) from subjects who had consumed white (WC), dark (DC) or high-polyphenol chocolate (HPC) daily for 3 weeks. The oxidation susceptibility of serum lipids decreased in the HPC group, and there was a significant difference between the WC and HPC groups (P = 0.031). According to the random forest analysis, the consumption of the HPC chocolate induced changes to the amounts of HDL, phosphatidylcholine, sphingomyelin, and nervonic, docosahexaenoic and myristic acids. Furthermore, arachidonic, docosahexaenoic, docosapentaenoic and palmitic acids, gamma-glutamyl transferase, hemoglobin, HDL, phosphatidylcholine and choline containing phospholipids explained about 60% of the oxidation susceptibility values. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0323-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


The correlations between the variables (VARBASE+END) (shown in Table 2) and the NMR oxidation susceptibility (NMROXBASE+END) values (black) and the lag time (LAGBASE+END) values (grey). Since the NMR oxidation susceptibility values and the lag time values are inversely correlated, the inverse correlation coefficients for the spectrophotometric method are presented in order to ease the comparison. P-values are indicated with one (0.001 < P ≤ 0.05) or two (P ≤ 0.001) asterisks
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Fig6: The correlations between the variables (VARBASE+END) (shown in Table 2) and the NMR oxidation susceptibility (NMROXBASE+END) values (black) and the lag time (LAGBASE+END) values (grey). Since the NMR oxidation susceptibility values and the lag time values are inversely correlated, the inverse correlation coefficients for the spectrophotometric method are presented in order to ease the comparison. P-values are indicated with one (0.001 < P ≤ 0.05) or two (P ≤ 0.001) asterisks

Mentions: Random forest approach was also used to assess the determinants for the oxidation susceptibility of serum lipids for the chocolate study samples. The analysis included the baseline and end-point values of the variables (Table 2). The correlation coefficients between the baseline and end-point variables (VARBASE+END) and the corresponding NMR oxidation susceptibility values (NMROXBASE+END) as well as between the variables (VARBASE+END) and the lag time values (LAGBASE+END) are shown in Fig. 6. Due to the inverse correlation of the values of the NMR oxidation method and the spectrophotometric assay, the signs of the correlation coefficients are opposite for these two methods. To ease the comparison, the signs of the coefficients of the spectrophotometric method were inversed. As can be seen from Fig. 6, the correlation coefficients for the NMR oxidation method and the spectrophotometric assay are very similar and most of the correlations are relatively weak (less than /0.4/). The NMROXBASE+END values have the strongest correlations with gamma-glutamyl transferase (γ-GT), arachidonic acid and hemoglobin (Spearman’s correlation coefficients −0.498, 0.477 and −0.449, respectively, P < 0.001 for all) whereas the LAGBASE+END values correlate strongest with phosphatidylcholine, HDL and γ-GT (Spearman’s correlation coefficients 0.544, 0.528 and −0.525, respectively, P < 0.001 for all). For example, the positive correlation coefficient of arachidonic acid means that the NMR oxidation susceptibility increases when the amount of arachidonic acid increases. For the spectrophotometric method, the high amount of arachidonic acid corresponds to a short lag time value.Fig. 6


NMR protocol for determination of oxidation susceptibility of serum lipids and application of the protocol to a chocolate study.

Tynkkynen T, Mursu J, Nurmi T, Tuppurainen K, Laatikainen R, Soininen P - Metabolomics (2011)

The correlations between the variables (VARBASE+END) (shown in Table 2) and the NMR oxidation susceptibility (NMROXBASE+END) values (black) and the lag time (LAGBASE+END) values (grey). Since the NMR oxidation susceptibility values and the lag time values are inversely correlated, the inverse correlation coefficients for the spectrophotometric method are presented in order to ease the comparison. P-values are indicated with one (0.001 < P ≤ 0.05) or two (P ≤ 0.001) asterisks
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3351613&req=5

Fig6: The correlations between the variables (VARBASE+END) (shown in Table 2) and the NMR oxidation susceptibility (NMROXBASE+END) values (black) and the lag time (LAGBASE+END) values (grey). Since the NMR oxidation susceptibility values and the lag time values are inversely correlated, the inverse correlation coefficients for the spectrophotometric method are presented in order to ease the comparison. P-values are indicated with one (0.001 < P ≤ 0.05) or two (P ≤ 0.001) asterisks
Mentions: Random forest approach was also used to assess the determinants for the oxidation susceptibility of serum lipids for the chocolate study samples. The analysis included the baseline and end-point values of the variables (Table 2). The correlation coefficients between the baseline and end-point variables (VARBASE+END) and the corresponding NMR oxidation susceptibility values (NMROXBASE+END) as well as between the variables (VARBASE+END) and the lag time values (LAGBASE+END) are shown in Fig. 6. Due to the inverse correlation of the values of the NMR oxidation method and the spectrophotometric assay, the signs of the correlation coefficients are opposite for these two methods. To ease the comparison, the signs of the coefficients of the spectrophotometric method were inversed. As can be seen from Fig. 6, the correlation coefficients for the NMR oxidation method and the spectrophotometric assay are very similar and most of the correlations are relatively weak (less than /0.4/). The NMROXBASE+END values have the strongest correlations with gamma-glutamyl transferase (γ-GT), arachidonic acid and hemoglobin (Spearman’s correlation coefficients −0.498, 0.477 and −0.449, respectively, P < 0.001 for all) whereas the LAGBASE+END values correlate strongest with phosphatidylcholine, HDL and γ-GT (Spearman’s correlation coefficients 0.544, 0.528 and −0.525, respectively, P < 0.001 for all). For example, the positive correlation coefficient of arachidonic acid means that the NMR oxidation susceptibility increases when the amount of arachidonic acid increases. For the spectrophotometric method, the high amount of arachidonic acid corresponds to a short lag time value.Fig. 6

Bottom Line: The oxidation susceptibility of serum lipids decreased in the HPC group, and there was a significant difference between the WC and HPC groups (P = 0.031).Furthermore, arachidonic, docosahexaenoic, docosapentaenoic and palmitic acids, gamma-glutamyl transferase, hemoglobin, HDL, phosphatidylcholine and choline containing phospholipids explained about 60% of the oxidation susceptibility values.ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0323-2) contains supplementary material, which is available to authorized users.

View Article: PubMed Central - PubMed

ABSTRACT
A protocol for determination of oxidation susceptibility of serum lipids based on proton nuclear magnetic resonance ((1)H NMR) spectroscopy is presented and compared to the commonly used spectrophotometric method. Even though there are methodological differences between these two methods, the NMR-based oxidation susceptibility correlates well (r(2) = 0.73) with the lag time determined spectrophotometrically. In addition to the oxidizability of serum lipids, the NMR method provides also information about the lipid profile. The NMR oxidation assay was applied to the chocolate study including fasting serum samples (n = 45) from subjects who had consumed white (WC), dark (DC) or high-polyphenol chocolate (HPC) daily for 3 weeks. The oxidation susceptibility of serum lipids decreased in the HPC group, and there was a significant difference between the WC and HPC groups (P = 0.031). According to the random forest analysis, the consumption of the HPC chocolate induced changes to the amounts of HDL, phosphatidylcholine, sphingomyelin, and nervonic, docosahexaenoic and myristic acids. Furthermore, arachidonic, docosahexaenoic, docosapentaenoic and palmitic acids, gamma-glutamyl transferase, hemoglobin, HDL, phosphatidylcholine and choline containing phospholipids explained about 60% of the oxidation susceptibility values. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0323-2) contains supplementary material, which is available to authorized users.

No MeSH data available.