UV-Vis Spectroelectrochemistry of Oleuropein, Tyrosol, and p-Coumaric Acid Individually and in an Equimolar Combination. Differences in LC-ESI-MS2 Profiles of Oxidation Products and Their Neuroprotective Properties
Abstract
:1. Introduction
2. Materials and Methods
2.1. Chemicals and Reagents
2.2. Electrochemical Procedures
2.2.1. Square Wave Voltammetry (SWV) of Phenolic Compounds
2.2.2. Spectroelectrochemical Measurements
2.2.3. Linear Sweep Voltammetry (LSV)
2.2.4. Electrolysis
2.2.5. Electrolysis of Ole, Tyr, and p-Cou Individually
2.2.6. Simultaneous and Sequential Electrolysis of Ole, Tyr and p-Cou in Combination
2.3. HPLC-DAD-ESI-MS2 Process
2.4. HPLC-DAD-ESI-MS2 Analysis
2.5. Cell Culture and Cell Viability Assays
2.6. Cell Viability Assays
3. Results and Discussion
3.1. Square Wave Voltammetry (SWV) of the Three ArOH-EVOO Standards
3.2. Spectroelectrochemical Analysis of Three ArOH-EVOO Standards Individually and in the Mix Samples
3.3. The Remaining Content of the Molecules after Electrolysis Individually and in the Mix by LC-UV-ESI-MS2
3.4. Characterization of Products by LC-MS2 after the Electrochemical Oxidation of Ole
3.5. Characterization of Products by LC-MS2 after Electrochemical Oxidation of Tyr
3.6. Characterization of Products by LC-MS2 after Electrochemical Oxidation of p-Cou
3.7. Comparison of the Chemical Profiles between Mix and the Sequentially Electrolyzed Mix (Mix-seq)
3.8. Neuroprotective Effect of Oxidized Ole and Mix
4. Conclusions
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Compound Name | RT (min) | λmax (nm) | m/z | Ole 2 mM | Mix 2 mM | Mix-seq 2 mM | MS2 | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Ref | Ox | Ref | Ox | (Tyr + p-Cou) Ox + Ole | Ox | |||||||||
O1 | 3,4-Dihydroxyphenylglycol | 4.1 | 280 | 169 | traces | + | − | + | − | + | 151 (−18) | 123 (−46) | ||
O2 | 11-Methyl-oleoside | 22.0 | <240 | 403 | traces | + | traces | + | + | + | 223 (−180) | 179 (−224) | 359 (−CO2) | 161 (−242) |
O3 | unknown | 30.8 | 587 | + | + | + | + | + | + | 543 (−44) | 403 (−184) | |||
O4 | unknown | 32.4 | 288 | 573 | + | traces | traces | + | traces | - | 529 (−44) | 403 (−170) | 222 (−350) | |
O5 | 10- Hydroxy-oleuropein | 35.1 | 555 | + | + | + | + | + | + | 537 (−H2O) | 393 (162) | 403 (−152) | ||
O6 | Oleuropein + [EtOH] | 35.8 | 244/307 | 585 | + | + | + | + | + | + | 523 (−62) | 541 (−44) | 361 (−224) | 199 (−386) |
403 (−182) | ||||||||||||||
O7 | unknown | 37.0 | 255 | 615 | + | + | + | + | + | + | 423 (−191) | 455 (−160) | 273 (−344) | 551 (−64) |
O8 | unknown | 37.8 | 266/336 | 617 | traces | traces | - | + | + | + | 423 (−194) | 455 (−162) | 273 (−344) | 585 (−32) |
O9 | unknown | 38.0 | 266/337 | 431 | + | traces | + | + | + | + | 269 (−162) | |||
O10 | unknown | 38.3 | 267/344 | 567 | traces | + | traces | + | - | + | 373 (−194) | 403 (−164) | 223 (−344) | |
O11 | unknown | 38.3 | 461 | + | + | + | + | + | + | 299 (−162) | 446 (−15) | 307 (−154) | ||
O12 | Oleuropein | 38.4 | 278 | 539 | + | + | + | + | + | + | 377 (−162) | 307 (−232) | 275 (−264) | |
O13 | unknown | 38.6 | - | 553 | + | + | traces | + | + | + | 403 (−150) | 223 (−330) | 179 (−374) | |
O14 | Oleuropein diglucoside | 38.6 | 309 | 701 | + | + | + | + | + | + | 377 (−324) | 307 (394) | 275 (−426) | |
O15 | Ole dimer | 39.5 | 1077 | traces | + | traces | + | traces | - | 673 (−404) | 813 (−264) | 539 (−538) | ||
O16 | Ole quinone dimer derivative | 39.8 | 263/420 | 1091 | − | + | − | + | traces | + | 687 (−404) | 403 (−688) | 525 (−56) | |
O17 | Oleuropein quinone | 39.9 | 295 | 537 | traces | + | traces | traces | traces | + | − | |||
O18a | Oxidized lucidumoside C | 40.3 | 259/434 | 581 | − | + | − | + | + | + | 535 (-46) | 403 (−178) | ||
O19 | Oxidized Ole trimer | 40.3 | 1647 | − | + | − | traces | − | + | 685 (−962) | 1109 (−538) | |||
O20 | Lucidumoside C | 40.6 | 255/350 | 583 | − | + | − | − | + | + | 537 (−46) | |||
O18b | Oxidized lucidumoside C | 41.0 | <240/412 | 581 | − | + | + | traces | + | + | ||||
O21 | Ole trimer derivative | 41.2 | 280 | 1619 | − | + | − | + | + | + | 1575 (−CO2) | 1557 (−CO2, −H2O) | 1019 | |
O22 | Iso Ole trimer derivative | 41.6 | 280 | 1619 | − | + | − | + | + | + | 1575 | 1557 | 1019 | |
O23 | Iso Ole dimer | 41.7 | 1077 | + | - | + | - | traces | − | 813 (−264) | 673 (−404) | 539 (−538) | ||
O24 | Ole trimer derivative | 42.6 | 281 | 1629 | − | + | − | + | + | + | 1019 | 1045 | 1585 | 1091 |
O25 | Ole trimer derivative | 43.6 | 285 | 1601 | traces | + | − | + | traces | + | 1197 | 793 |
Compound Name | RT (min) | λmax (nm) | m/z | Tyr 2mM | Mix 2mM | Mix-seq 2mM | MS2 | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Ref | Ox | Ref | Ox | (Tyr + p-Cou) Ox + Ole | Ox | ||||||||
T1 | unknown | 10.4 | − | 1794 | − | + | − | − | − | − | |||
T2 | unknown | 12.9 | 280 | 1820 | − | + | − | − | − | − | 1761 (−59) | ||
T3 | Tyrosol | 14.6 | 275 | 502 | + | + | + | + | + | + | 365 (−Tyr) | 228 (−Tyr dim) | |
402 | + | + | + | + | + | + | 265 (−Tyr) | ||||||
273 | + | + | + | + | + | + | |||||||
T4 | unknown | 17.8 | 285 | 1499 | − | + | − | − | − | − | 1449 (−50) | 1414 (−85) | 1240 (−259) |
T5 | Tyrosol dimer | 34.0 | 280 | 273 | − | + | − | traces | + | + | 243 (−CH2O) | 255 (−H2O) | |
T6 | Tyrosol trimer | 38.1 | nd | 409 | − | + | − | traces | + | + | 391 (−H2O) | 341 (−68) | 273 (−Tyr ox) |
T7 | Tyrosol tetramer | 39.4 | 275–280 | 545 | − | + | − | − | traces | − | 409 (−Tyr ox) | ||
T8 | Tyrosol trimer | 40.0 | 409 | + | − | − | − | − | 271 (−neutral Tyr) | 341 (−68) | 136 (−Tyr dim) |
Compound Name | RT (min) | λmax (nm) | m/z | p-Cou 2mM | Mix 2mM | Mix-seq 2mM | MS2 | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Ref | Ox | Ref | Ox | (Tyr + p-Cou) Ox + Ole | Ox | |||||||
C1 | p-coumaric acid | 28.9 | 308 | 163 | + | + | + | + | + | + | 119 (−CO2) | |
C2 | iso-p-coumaric acid (m- or o-) | 31.8 | 295 | 163 | + | + | + | traces | + | + | 126 (−37) | 119 (−CO2) |
C3 | unknown | 35.1 | − | 497 | + | + | − | − | − | − | ||
C4 | p-coumaric acid dimer | 38.8 | 305 | 325 | − | + | − | − | traces | traces | 281 (−CO2) | 237 (−2CO2) |
C5 | p-coumaric acid dimer | 40.0 | 305 | 325 | − | + | − | − | traces | traces | 281 (−CO2) | |
C6 | unknown | 48.9 | − | 271 | + | + | − | − | + | − | 213 (−58) | |
C7 | decarboxylated p-coumaric acid dimer | 41.8 | 300/316 | 281 | − | + | − | + | + | + | 237 (−CO2) | |
C8 | decarboxylated p-coumaric acid dimer | 42.3 | 292/330 | 281 | − | + | + | + | + | + |
Compound Name | RT (min) | λmax (nm) | m/z | Mix 2mM | Mix-seq 2mM | MS2 | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Ref | Ox | (Tyr + p-Cou) Ox + Ole | Ox | |||||||||
M1 | Oxidized (Tyr - p-Cou) dimer | 34.9 | 299 | − | + | + | + | 255 (−CO2) | 135 (−164) | |||
M2 | Oxidized (Tyr - p-Cou) dimer | 37.4 | 299 | − | + | + | + | 255 (−CO2) | 135 (−164) | |||
M3 | Oxidized (Tyr - Ole) dimer | 37.9 | 675 | − | + | − | − | |||||
M4 | unknown | 43.3 | 245/284 | 1195 | + | + | + | + | 655 (−Ole) | 791 (−11-methyl--oleoside) | 1033 (−glu) | 963 |
1163 (−O2) | 657 (−Ole Ox) | 403 | 539 | |||||||||
M5 | unknown | 43.4 | 245/284 | 1195 | + | + | + | + | ||||
M6 | unknown | 43.8 | 245/284 | 1195 | + | + | + | + | ||||
M7 | unknown | 48.3 | 305 | 325 | − | + | + | + | 281 (−CO2) |
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Lambert de Malezieu, M.; Ferron, S.; Sauvager, A.; Courtel, P.; Ramassamy, C.; Tomasi, S.; Abasq, M.-L. UV-Vis Spectroelectrochemistry of Oleuropein, Tyrosol, and p-Coumaric Acid Individually and in an Equimolar Combination. Differences in LC-ESI-MS2 Profiles of Oxidation Products and Their Neuroprotective Properties. Biomolecules 2019, 9, 802. https://doi.org/10.3390/biom9120802
Lambert de Malezieu M, Ferron S, Sauvager A, Courtel P, Ramassamy C, Tomasi S, Abasq M-L. UV-Vis Spectroelectrochemistry of Oleuropein, Tyrosol, and p-Coumaric Acid Individually and in an Equimolar Combination. Differences in LC-ESI-MS2 Profiles of Oxidation Products and Their Neuroprotective Properties. Biomolecules. 2019; 9(12):802. https://doi.org/10.3390/biom9120802
Chicago/Turabian StyleLambert de Malezieu, Morgane, Solenn Ferron, Aurélie Sauvager, Patricia Courtel, Charles Ramassamy, Sophie Tomasi, and Marie-Laurence Abasq. 2019. "UV-Vis Spectroelectrochemistry of Oleuropein, Tyrosol, and p-Coumaric Acid Individually and in an Equimolar Combination. Differences in LC-ESI-MS2 Profiles of Oxidation Products and Their Neuroprotective Properties" Biomolecules 9, no. 12: 802. https://doi.org/10.3390/biom9120802