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Table 1 1H NMR signals of identified metabolites in N. oleracea fractions

From: Antioxidants and α-glucosidase inhibitors from Neptunia oleracea fractions using 1H NMR-based metabolomics approach and UHPLC-MS/MS analysis

Metabolites

1H NMR signals

Fractions

Phytosterol

0.68 (s), 2.02 (m), 5.3 (m)

CF

Fatty acids

0.88 (m), 1.24–1.35 (m), 1.66 (m),

2.34 (t, J = 7.5 Hz)

HF, CF

Alanine

1.48 (d, J = 6.5 Hz)

HF, CF

Leucine

0.95 (t, J = 6.0 Hz), 1.7 (m)

HF, CF

Valine

0.98 (d, J = 6.5 Hz), 2.24 (m)

HF, CF

α-Glucose

5.16 (d, J = 3.5 Hz)

EF, MF

β-Glucose

4.62 (d, J = 9.5 Hz)

EF, MF

Fructose

4.16 (d, J = 6.5 Hz)

EF, MF

Oleanolic acid

0.70 (s), 0.74 (s), 0.81 (s), 0.87 (s), 0.95 (s), 1.10 (s)

HF, CF

Quercetin derivatives

6.36 (s), 6.93 (d, J = 9.5 Hz), 7.66 (dd, J = 2.3, 9.5 Hz), 7.71 (d, J = 2.0 Hz)

EF, MF

Kaempferol derivatives

6.05 (d, J = 1.5 Hz), 6.41 (d, J = 2.0 Hz), 6.85 (d, J = 8.0 Hz), 7.71 (d, J = 8.6 Hz)

EF, MF

Myricetin derivatives

6.26 (d, J = 2.3 Hz), 6.38 (s), 6.90 (d, J = 2.0 Hz)

EF, MF

Apigenin derivatives

6.55 (s), 6.93 (d, J = 8.0 Hz), 7.92 (d, J = 7.5 Hz)

EF, MF

Catechin

2.03 (dd, J = 16.6 Hz), 2.25 (dd, J = 15, 3.5 Hz), 3.79 (m), 5.88 (d, J = 2 Hz), 6.58 (d, J = 2 Hz), 6.69 (d, J = 8.9 Hz)

EF, MF

Gallic acid

6.84 (s)

EF, MF

3,4-O-dimetgylgallic acid

3.78 (s), 6.84 (s)

EF, MF

Caffeic acid

6.86 (s)

EF, MF

  1. HF hexane fraction; CF chloroform fraction; EF ethyl acetate fraction; MF methanol fraction