Table 1.
Identification and online ABTS-scavenging activities of the principal peaks in olive extracts.
| Peak | TR | λmax (nm) | Identification | ABTS | [M − H]− | Extract | References |
|---|---|---|---|---|---|---|---|
| 1 | 3.6 | 231, 278 | Unknown | Yes | 191 | OLE | |
| 2 | 5.1 | 231, 279 | Unknown | Yes | 487 | OLE | |
| 3 | 6.1 | 283 | Hydroxytyrosol glucoside | Yes | 315 | OLE, HTE | [42] |
| 4 | 6.8 | 231, 275 | Hydroxytyrosol (3) | Yes | 153 | OLE, OFE, HTE, OLP | [42] |
| 5 | 7.4 | 232, 333 | Caffeic acid glucoside | Yes | 339 | OLE | [43] |
| 6 | 8.2 | 277 | Tyrosol (2) | No | ND | OLP | [44] |
| 7 | 8.3 | 229, 278 | Oleuropein aglycone-1 | Yes | 377 | OLE, HTE, OLP | [42] |
| 8 | 8.5 | 233 | Elenolic acid (5) | No | 241 | OLE | [45] |
| 9 | 9.1 | 237 | Elenolic acid glucoside | No | 403 | HTE | [46] |
| 10 | 11.3 | 282, 333 | Verbascoside (6) | Yes | 623 | OLE, OFE OLP, HTE | [47] |
| 11 | 12.3 | 254, 267s, 340 | Luteolin-7-O-glucoside | Yes | 447 | OLE, OFE, HTE | [47] |
| 12 | 13.0 | 278 | Unknown “secoiridoid” | No | 581 | OLE | |
| 13 | 14.0 | 278 | Unknown “secoiridoid” | Yes | 577 | OLE, OFE | |
| 14 | 14.5 | 265, 325, 359 | Flavonoid glycoside | Yes | 447 | OLE | |
| 15 | 14.8 | 266, 341 | Flavonoid glycoside | Yes | 461 | OLE | |
| 16 | 15.1 | 260 | Unknown | No | ND | OFE | |
| 17 | 15.4 | 237, 280 | Oleuropein (4) | Yes | 539 | OFE, OLE | [42] |
| 18 | 16.0 | 232 | Non-phenolic secoiridoid | No | 285 | OLP | |
| 19 | 16.42 | 234 | Oleuroside | Yes | 539 | OFE, OLE | [47] |
| 20 | 19.1 | 287, 290 | Oleuropein aglycone-2 | Yes | 377 | HTE | [42] |
| 21 | 21.2 | 234, 280 | Unknown | No | 415 | OLE |
TR: retention time in minutes; λmax: wavelength(s) of maximum absorption in the UV-Vis spectrum; ND: not detected in MS; s: shoulder; OLE: olive leaf extract; OFE: olive fruit extract; HTE: Hydroxytyrosol Extreme; OLP: Olivenol Plus.