Table 1.
Metabolites identified according to LC-MS and NMR analyses.
| Identified VIP metabolite | NMR | LC-MS | ID metrics (class) |
|||
|---|---|---|---|---|---|---|
| VIP Score | Ratio S/R | Ionization mode | VIP Score | Ratio S/R | ||
| Amino acids | ||||||
| Isoleucine | 1.82–1.89 | 1.61–1.67 | Pos | 2.40 | 2.47 | II (9) |
| Leucine | 1.11–1.43 | 1.23–1.32 | ||||
| Valine | 1.93–2.10 | 4.35–4.55 | - Neg | − 2.15 | 4.99–5.26 | I (9) |
| Lysine | 1.12–1.03 | 1.12–1.13 | (9) | |||
| Arginine | 1.16–1.49 | 1.16–1.47 | (7) | |||
| Proline | 1.23–1.49 | 0.75–0.63 | (3) | |||
| Glutamate | 1.43–1.39 | 0.68–0.71 | Pos - Neg | 1.12–1.48 | 0.72–0.70 | I (5) |
| Methionine | 1.33 | 1.22 | Pos - Neg | 1.83–1.60 | 1.41–1.52 | I (9) |
| Alanine | 1.81 | 0.88 | Pos | 1.33 | 0.72 | II (9) |
| Beta-Alanine | 1.10 | 1.41 | (5) | |||
| Aspartate | 1.03–1.13 | 1.11–1.16 | (9) | |||
| Asparagine | 1.21 | 0.82 | (5) | |||
| Phenylalanine | Pos - Neg | 2.57–2.13 | 2.29–2.08 | I | ||
| Tyrosine | 1.40–1.53 | 1.44–1.52 | Neg | 1.58 | 2.10 | I (9) |
| Glycine | Detected but not VIP | Pos | 1.73 | 1.38 | I (9) | |
| Citrulline | 1.01–2.00 | 0.84–0.81 | (5) | |||
| Tryptophan | 2.17 | 6.98 | (5) | |||
| Saccharides | ||||||
| Trehalose* | 1.74–1.69 | 0.85–0.85 | Pos | 1.96 | 0.74 | II (9) |
| Trehalose 6-P* | Pos - Neg | 2.27–2.04 | 0.52–0.54 | II (9) | ||
| Cellobiose* | 1.82–1.01 | 1.26–1.21 | Pos | 1.96 | 0.74 | II (9) |
| Cellobiose 6-P* | Pos - Neg | 2.27–2.04 | 0.52–0.54 | II (9) | ||
| Glycogen | 1.80–1.76 | 0.65–0.84 | (9) | |||
| Alpha-glucose | 1.71–1.69 | 1.52–2.19 | (9) | |||
| Fructose | 1.15–1.22 | 1.59–1.79 | (2) | |||
| Maltose | 1.40 | 1.65 | (2) | |||
| Xylose | Neg | 1.54 | 0.45 | II (9) | ||
| Amines | ||||||
| Putrescine | 1.16–1.23 | 1.32–1.16 | (7) | |||
| Carnitine | 1.16 | 1.06 | Pos | 1.48 | 1.76 | I (9) |
| Spermidine | Pos | 1.04 | 1.46 | I | ||
| Lipids | ||||||
| Palmitoleic acid | Pos - Neg | 1.77–1.52 | 0.36–0.41 | I | ||
| Lyso PE (16:1) | Pos - Neg | 2.07–1.71 | 0.44–0.50 | II (3) | ||
| Lyso PC (16:1) | Pos | 1.59 - | 0.65 | II (3) | ||
| Lyso PE (16:0) | Pos - Neg | 1.97–1.72 | 0.41–0.36 | I | ||
| Lyso PC (16 :0) | Pos | 1.73 | 0.41 | II (3) | ||
| Lyso PE (18:1) | Pos - Neg | 2.07–1.55 | 0.40–0.39 | I | ||
| Miscellaneous | ||||||
| Acetate | 1.01 | 0.84 | (6) | |||
| Lactate | 1.09 | 1.41 | (9) | |||
| Succinate | 1.05 | 1.40 | (6) | |||
| Citrate | 1.33–1.28 | 1.15–1.22 | (3) | |||
| Beta-hydroxybutyrate | 1.59–1.44 | 1.25–1.26 | (5) | |||
| Pipecolic acid | 1.96–1.59 | 1.46–1.25 | (4) | |||
| Pantothenic acid | 1.05–1.02 | 1.40–1.21 | Pos - Neg | 2.31–1.76 | 1.90–1.92 | I (9) |
| Inosinic acid | 1.73–1.41 | 0.71–0.72 | (9) | |||
| Nicotinamide ribotide | 1.19–1.03 | 0.86 | (3) | |||
| AMP | 1.73–1.38 | 0.72–0.76 | (9) | |||
| ATP | 2.09–2.17 | 0.43–0.40 | (9) | |||
| NADH | 1.37–1.38 | 0.75–0.76 | (2) | |||
| UMP | 2.04–1.92 | 0.43–0.45 | Neg | 2.03 | 0.47 | (9) |
| Glycerol | 1.03 | 0.90 | (9) | |||
| Glycerol 3-P | Neg | 1.65 | 0.49 | I | ||
| Betaine | 2.13 | 4.46 | Pos | 2.70 | 5.14 | I (2) |
| Glutathione | 1.08 | 1.28 | (9) | |||
| Peptides | ||||||
| Alanyl-alanine | Pos | 2.01 | 0.65 | I | ||
| Isoleucyl/leucyl-histidine | Pos | 1.99 | 2.35 | II (3) | ||
| Isoleucyl/leucyl-aspartic acid | Pos | 2.58 | 6.14 | II (3) | ||
| Valyl-isoleucine/leucine | Pos | 1.74 | 4.89 | II (3) | ||
| Valyl-serine | Pos | 1.17 | 0.71 | I | ||
| Valyl-aspartic acid | Pos | 2.00 | 1.95 | I | ||
| Gln-Asp-Thr-Pro | Pos | 2.32 | 4.31 | II (3) | ||
| Arg-Cys-Ser-Trp | Pos | 1.85 | 0.57 | II (3) | ||
VIP scores indicate the relative influence of the corresponding metabolites on the discrimination between the two conditions (with and without H2O2) for both analytical techniques. Ratios S (in the presence of H2O2)/R (in the absence of H2O2) were determined from relative intensities in profiles at 50 min. Classes and scores are according to Sumner et al.59,60.
*Under our analytical conditions, Trehalose/Cellobiose and Trehalose 6-P/Cellobiose 6-P were not differentiated.