Table 3.
Average content of polyphenols and respective retention time (Rt) and wavelengths of maximum absorption in the visible region (λ max) in M. pulegium extracts (by elution order)†.
| Polyphenols | Rt (min) | UV (nm) | UV-DAD/VIS bands (nm) in 70% methanol |
Class | Mg·g−1 dry weight |
|---|---|---|---|---|---|
| p-Hydroxybenzoic acid | 13.46 | 280 | 227, 260sh, 295 | Hydroxybenzoic acid | 0.212 ± 0.004 |
| Chlorogenic acid | 17.95 | 320 | 242, 300sh, 327 | Hydroxycinnamic acid | 0.387 ± 0.004 |
| (+)-Catechin | 18.10 | 280 | 231, 280 | Flavan-3-ols | 0.212 ± 0.004 |
| Caffeic acid | 21.32 | 320 | 243, 296sh, 324 | Hydroxycinnamic acid | 0.230 ± 0.001 |
| Quercetin-3-O-rutinoside | 22.96 | 370 | 256, 266sh, 351 | Flavonol | 0.144 ± 0.003 |
| Quercetin-3-O-glucoside | 23.63 | 370 | 255, 266sh, 348 | Flavonol | 0.140 ± 0.002 |
| Neohesperidin | 24.84 | 280 | 283, 326 | Flavanone | 0.628 ± 0.001 |
| Luteolin-7-O-glucoside | 25.31 | 370 | 254, 266, 349 | Flavone | 0.201 ± 0.004 |
| Diosmin | 26.04 | 370 | 253, 268, 339 | Flavone | 0.623 ± 0.006 |
| Rosmarinic acid | 26.78 | 320 | 249, 299sh, 330 | Hydroxycinnamic acid | 0.287 ± 0.006 |
| Ferulic acid | 27.55 | 320 | 241, 296sh, 324 | Hydroxycinnamic acid | 0.277 ± 0.003 |
| Apigenin | 32.65 | 370 | 235, 267sh, 341 | Flavone | 0.323 ± 0.002 |
|
| |||||
| Total of hydroxybenzoic acids | 0.212 ± 0.004 | ||||
| Total of hydroxycinnamic acids | 1.181 ± 0.014 | ||||
| Total of flavan-3-ols | 0.212 ± 0.004 | ||||
| Total of flavonols | 0.284 ± 0.005 | ||||
| Total of flavones | 1.147 ± 0.012 | ||||
| Total of flavanones | 0.628 ± 0.001 | ||||
| Total polyphenols identified | 3.664 ± 0.040 | ||||
†Values expressed as mean ± standard deviation of three replicates.