The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity.
(-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein of interest as a target for cancer and neuroprotection. Determination of the spectral properties of EGCG fluorescence in...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2013-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3838354?pdf=render |
| _version_ | 1818287093036613632 |
|---|---|
| author | Vladislav Snitsarev Michael N Young Ross M S Miller David P Rotella |
| author_facet | Vladislav Snitsarev Michael N Young Ross M S Miller David P Rotella |
| author_sort | Vladislav Snitsarev |
| collection | DOAJ |
| description | (-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein of interest as a target for cancer and neuroprotection. Determination of the spectral properties of EGCG fluorescence in environments similar to those of binding sites found in proteins provides an important tool to directly study protein-EGCG interactions. The goal of this study is to examine the spectral properties of EGCG fluorescence in an aqueous buffer (AB) at pH=7.0, acetonitrile (AN) (a polar aprotic solvent), dimethylsulfoxide (DMSO) (a polar aprotic solvent), and ethanol (EtOH) (a polar protic solvent). We demonstrate that EGCG is a highly fluorescent molecule when excited at approximately 275 nm with emission maxima between 350 and 400 nm depending on solvent. Another smaller excitation peak was found when EGCG is excited at approximately 235 nm with maximum emission between 340 and 400 nm. We found that the fluorescence intensity (FI) of EGCG in AB at pH=7.0 is significantly quenched, and that it is about 85 times higher in an aprotic solvent DMSO. The Stokes shifts of EGCG fluorescence were determined by solvent polarity. In addition, while the emission maxima of EGCG fluorescence in AB, DMSO, and EtOH follow the Lippert-Mataga equation, its fluorescence in AN points to non-specific solvent effects on EGCG fluorescence. We conclude that significant solvent-dependent changes in both fluorescence intensity and fluorescence emission shifts can be effectively used to distinguish EGCG in aqueous solutions from EGCG in environments of different polarity, and, thus, can be used to study specific EGCG binding to protein binding sites where the environment is often different from aqueous in terms of polarity. |
| first_indexed | 2024-12-13T01:35:00Z |
| format | Article |
| id | doaj.art-4145d762aa7146a995af3c6f5167b119 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-13T01:35:00Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-4145d762aa7146a995af3c6f5167b1192022-12-22T00:03:54ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01811e7983410.1371/journal.pone.0079834The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity.Vladislav SnitsarevMichael N YoungRoss M S MillerDavid P Rotella(-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein of interest as a target for cancer and neuroprotection. Determination of the spectral properties of EGCG fluorescence in environments similar to those of binding sites found in proteins provides an important tool to directly study protein-EGCG interactions. The goal of this study is to examine the spectral properties of EGCG fluorescence in an aqueous buffer (AB) at pH=7.0, acetonitrile (AN) (a polar aprotic solvent), dimethylsulfoxide (DMSO) (a polar aprotic solvent), and ethanol (EtOH) (a polar protic solvent). We demonstrate that EGCG is a highly fluorescent molecule when excited at approximately 275 nm with emission maxima between 350 and 400 nm depending on solvent. Another smaller excitation peak was found when EGCG is excited at approximately 235 nm with maximum emission between 340 and 400 nm. We found that the fluorescence intensity (FI) of EGCG in AB at pH=7.0 is significantly quenched, and that it is about 85 times higher in an aprotic solvent DMSO. The Stokes shifts of EGCG fluorescence were determined by solvent polarity. In addition, while the emission maxima of EGCG fluorescence in AB, DMSO, and EtOH follow the Lippert-Mataga equation, its fluorescence in AN points to non-specific solvent effects on EGCG fluorescence. We conclude that significant solvent-dependent changes in both fluorescence intensity and fluorescence emission shifts can be effectively used to distinguish EGCG in aqueous solutions from EGCG in environments of different polarity, and, thus, can be used to study specific EGCG binding to protein binding sites where the environment is often different from aqueous in terms of polarity.http://europepmc.org/articles/PMC3838354?pdf=render |
| spellingShingle | Vladislav Snitsarev Michael N Young Ross M S Miller David P Rotella The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. PLoS ONE |
| title | The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. |
| title_full | The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. |
| title_fullStr | The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. |
| title_full_unstemmed | The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. |
| title_short | The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity. |
| title_sort | spectral properties of epigallocatechin 3 o gallate egcg fluorescence in different solvents dependence on solvent polarity |
| url | http://europepmc.org/articles/PMC3838354?pdf=render |
| work_keys_str_mv | AT vladislavsnitsarev thespectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT michaelnyoung thespectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT rossmsmiller thespectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT davidprotella thespectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT vladislavsnitsarev spectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT michaelnyoung spectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT rossmsmiller spectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity AT davidprotella spectralpropertiesofepigallocatechin3ogallateegcgfluorescenceindifferentsolventsdependenceonsolventpolarity |