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Table 2 1H NMR, 13C NMR characteristic signals and LC-MS/MS data of identified metabolites in C. caudatus extracts

From: Variation in the metabolites and α-glucosidase inhibitory activity of Cosmos caudatus at different growth stages

Metabolite NMR Chemical shift (ppm) Molecular ion (M-H)+ MS/MS fragments
δH, mult (J in Hz) δC
Quercetin 5.24, d (2)    
5.28, d (7.8)
6.24, d (2)
6.28, d (2)
6.44, d (2)
7.02, d (8.5)
7.36, d (2)
7.28, dd (8, 2)
7.56, dd (8, 2)
Quercetin 3-O-arabinofuranoside 6.28, d (2)   435.0780 303.0469, 181.0580, 153.9813
7.02, d (8.5)
7.36, d (2)
7.56, dd (8, 2)
5.28, d (7.8) 111.37
Quercetin 3-O- rhamnoside 6.28, d (2)   449.0954 303.0460, 181.0855, 153.0940
7.02, d (8.5)
7.36, d (2)
7.56, dd (8, 2)
5.18, d (7.8) 95.72
0.90, d (1.1) 19.51
Quercetin 3-O- glucoside 7.02, d (8.5)   465.0898 303.0466, 153.3540
7.36, d (2)
7.56, dd (8, 2)
5.18, d (7.8) 95.43
Quercetin 3-O-xyloside 6.28, d (2)   435.0801 303.0451, 181.6037, 153.8779
7.02, d (8.5)
7.36, d (2)
7.56, dd (8, 2)
5.07, d (8.) 104.71
Rutin 6.28, d (2)   611.1366 465.0893, 303.0466
7.02, d (8.5)
7.36, d (2)
7.56, dd (8, 2)
4.99, d (7.5) 105.01
3.78, d (1.5) 65.20
4.39, d (1.5) 101.93
0.92, d (6.6) 19.06
Chlorogenic acid 3.52, dd (10, 4)    
Fatty acid 1.32, m    
Acetic acid 1.92, s    
Catechin 2.56, dd (16, 7.5)