Table 1.
Identification of phenolic compounds and flavonoids by HPLC–MS in the OLE. For each compound, the ultraviolet–visible absorption spectrum (UV–VIS), [M-H]− and fragment ions are shown.
| TR (min) | Molecule | UV–VIS (nm) | [M-H]− (m/z) | Product ions (m/z) |
|---|---|---|---|---|
| 14.1 | 3,4-DHBA (protocatechuic acid) | 225/260/294 | 153.0 | |
| 14.8 | Loganic accid | 230 | 375.0 | 213.0 |
| 15.6 | 3,4-DHPE (hydroxytyrosol) | 227/280 | 153.1 (305.2)* | 123.2 |
| 18.0 | 3,4-DHPE-glucoside | 228/278 | 315.0 | 153.1 |
| 20.6 | DM-EA glucoside (isomer 1) | 233 |
389.1 (779.2)* |
227.0, 183.0 |
| 34.0 | DM-EA glucoside (isomer 2) | 236 | 389.2 | 345.1 |
| 37.9 | EA glucoside (isomer 1) | 240 | 403.0 | 241.1, 139.1 |
| 40.6 | EA glucoside (isomer 2) | 240 | 403.0 (807.3)* | 100.9 |
| 50.4 | EA glucoside (isomer 3) | 238 |
403.1 (807.1)* |
|
| 56.6 | EA glucoside (isomer 4) + hydroxyloganin | 246/247/323 |
403.1 405.1 (811.0)* |
240.9 |
| 62.7 | EA (isomer 1) | 239 | 241.0 | 165.1, 139.1, 127.1, 121.1, 111.2, 101.0 |
| 64.5 | quercetin-3-O-rutinoside | 258/304sh/358 | 609.0 | 301.1 |
| 66.0 | quercetin-3-O-glucoside | 242/299sh/333 | 436.0 | 301.0 |
| 66.7 | EA (isomer 2) | 240 | 241.0 | |
| 70.2 | Verbascoside + luteolin-O-hexoside |
239/288sh/334 228/267sh/341 |
623.1 447.1 (895.2)* |
477.0 |
| 72.6 | 3,4-DHPE-DHEA-glucoside + 3,4-DHPE-DA-EDA (oleacein) | 230/277 |
543.0 (1087.4)* 319.0 |
513.0 275.1, 241.1, 139.2 |
| 78.1 | Apigenin-7-O-rutinoside | 257/333 | 577.0 | |
| 85.2 | Diosmin + luteolin-O-hexoside | 270/332 |
607.0 447.1 |
461.1 285.0 |
| 86.7 | 3,4-DHPE-EA-glucoside (oleuropein) | 280 | 539.1 | 377.0 |
| 91.8 | 3,4-DHPE-EA-glucoside (oleuropein,isomer 2) | 282 | 539.2 | 403.1, 377.0 |
| 95.9 | 3,4-DHPE-EA-glucoside (oleuropein,isomer 3) | 281 | 539.9 | 403.1, 377.1, 345.0, 307.0, 275.0 |
| 97.0 | Luteolin | 227/267/350 | 285.0 | |
| 98.9 | 4-HPE-EA-glucoside (ligustroside) | 281 | 523.2 | 509.0, 361.0 |
| 112.9 | Apigenin | 232/287sh/314 | 269.0 | |
| 115.6 | 3,4-DHPE-EA (isomer 1) | 281 | 377.1 | 307.1, 241.0 |
| 118.1 | 3,4-DHPE-EA (isomer 2) | 282 | 377.0 | 345.1, 307.0, 275.0, 149.1, 139.1 |
| 119.9 | 3,4-DHPE-EA (isomer 3) | 282 | 377.1 | 275.1, 240.9, 139.1 |
| 122.6 | 3,4-DHPE-EA (isomer 4) | 281 | 377.1 | 307.0, 275.0, 241.2, 138.9 |
3,4-DHBA = 3,4-dihydroxybenzoic acid; 3,4-DHPE = 3,4-dihydroxyphenylethanol (hydroxytyrosol); 4-HPE = 4-hydroxyphenylethanol (tyrosol); DM = demethyl; EA = elenolic acid; DHEA = dihydro elenolic acid; DA-EDA = deacetoxy elenolic acid dialdehyde form; * double ion.