TY - JOUR
T1 - Application of gradient-enhanced nuclear Overhauser effect spectroscopy (GOESY) in the structure elucidation of plant secondary metabolites
AU - Sarker, Satyajit D.
AU - Latif, Zahid
AU - Nash, Robert J.
N1 - Sarker, S. D., Latif, Z., Nash, R. J. (2001). Application of gradient-enhanced nuclear Overhauser effect spectroscopy (GOESY) in the structure elucidation of plant secondary metabolites. Phytochemical Analysis, 12, 23-27.
Sponsorship: BBSRC
Phytochemical Analysis
Special Issue: Special Issue on Nuclear Magnetic Resonance Spectroscopy
PY - 2001
Y1 - 2001
N2 - Nuclear Overhauser effect (nOe) enhancement plays a
vital role in structure determination, especially conformational
analysis, by NMR (Neuhaus and Williamson,
1989). A number of one- and two-dimensional NMR
methods, notably, nOe-difference spectroscopy (Sanders
and Mersh, 1982), NOESY (States et al., 1982;
Bodenhausen et al., 1984; Neuhaus and Williamson,
1989) and ROESY (Bothner-By et al., 1984; Bax and
Davies, 1985; Neuhaus and Williamson, 1989) Hwang
and Shaka, 1992; Hwang et al., 1992) have routinely been
used to determine this effect. However, NOESY and
ROESY experiments can be quite time-consuming,
depending on mixing times (Braun et al., 1996), and in
nOe-difference experiments imperfect subtraction often
gives rise to a subtraction artefact which makes it difficult
to visualise the nOe enhancements (Stonehouse et al.,
1994). Therefore there has always been a pressing need
for a modified, reliable and quicker nOe experiment.
With the advent of gradient technology and subsequent
advancement in this field, the use of gradients to take
advantage of specific coherence selection in several
NMR experiments is now becoming more and more
popular (Hurd, 1990). As a result, a number of gradientenhanced
versions of many useful high-resolution oneand
multi-dimensional homonuclear and heteronuclear
NMR experiments have been developed (Hurd, 1990;
Hurd and John, 1991; Rinaldi and Keifer, 1994;
Bernassau and Nuzillard, 1994; Parella et al., 1995;
Mackin and Shaka, 1996; Wagner and Berger, 1996;
Uzawa and Koshino, 1996). The major advantages that result from gradient selection of coherence are the
elimination of the need for phase cycling and a reduction
in coherent t1 artefacts (Hurd and John, 1991).
Using this gradient technology a new method of
measuring transient nOe enhancements, which avoids the
need to compute difference spectra and thus gives spectra
containing no subtraction artefact, has recently been
developed and the acronym GOESY (gradient enhanced
nuclear Overhauser effect spectroscopy) has been
assigned for this experiment (Stonehouse et al., 1994;
Stott et al., 1995). Since its introduction, to our knowledge,
this method has never been applied to the structural
determination of plant secondary metabolites. However,
GOESY together with ROESY techniques have recently
been employed successfully to assign 1H NMR chemical
shifts for ampicillin (Tung et al., 2000).
We now report on the application of GOESY in the
structure determination of five compounds, namely
eucalyptin (1), arctigenin (2), 5-geranyloxy-7-methoxycoumarin
(3), 2,6-dihydroxy-4-methoxyisovalerophenone
(4) and N-feruloyltyramine (5), isolated from
plants, and we also evaluate the future of this experiment
as a routine method.
AB - Nuclear Overhauser effect (nOe) enhancement plays a
vital role in structure determination, especially conformational
analysis, by NMR (Neuhaus and Williamson,
1989). A number of one- and two-dimensional NMR
methods, notably, nOe-difference spectroscopy (Sanders
and Mersh, 1982), NOESY (States et al., 1982;
Bodenhausen et al., 1984; Neuhaus and Williamson,
1989) and ROESY (Bothner-By et al., 1984; Bax and
Davies, 1985; Neuhaus and Williamson, 1989) Hwang
and Shaka, 1992; Hwang et al., 1992) have routinely been
used to determine this effect. However, NOESY and
ROESY experiments can be quite time-consuming,
depending on mixing times (Braun et al., 1996), and in
nOe-difference experiments imperfect subtraction often
gives rise to a subtraction artefact which makes it difficult
to visualise the nOe enhancements (Stonehouse et al.,
1994). Therefore there has always been a pressing need
for a modified, reliable and quicker nOe experiment.
With the advent of gradient technology and subsequent
advancement in this field, the use of gradients to take
advantage of specific coherence selection in several
NMR experiments is now becoming more and more
popular (Hurd, 1990). As a result, a number of gradientenhanced
versions of many useful high-resolution oneand
multi-dimensional homonuclear and heteronuclear
NMR experiments have been developed (Hurd, 1990;
Hurd and John, 1991; Rinaldi and Keifer, 1994;
Bernassau and Nuzillard, 1994; Parella et al., 1995;
Mackin and Shaka, 1996; Wagner and Berger, 1996;
Uzawa and Koshino, 1996). The major advantages that result from gradient selection of coherence are the
elimination of the need for phase cycling and a reduction
in coherent t1 artefacts (Hurd and John, 1991).
Using this gradient technology a new method of
measuring transient nOe enhancements, which avoids the
need to compute difference spectra and thus gives spectra
containing no subtraction artefact, has recently been
developed and the acronym GOESY (gradient enhanced
nuclear Overhauser effect spectroscopy) has been
assigned for this experiment (Stonehouse et al., 1994;
Stott et al., 1995). Since its introduction, to our knowledge,
this method has never been applied to the structural
determination of plant secondary metabolites. However,
GOESY together with ROESY techniques have recently
been employed successfully to assign 1H NMR chemical
shifts for ampicillin (Tung et al., 2000).
We now report on the application of GOESY in the
structure determination of five compounds, namely
eucalyptin (1), arctigenin (2), 5-geranyloxy-7-methoxycoumarin
(3), 2,6-dihydroxy-4-methoxyisovalerophenone
(4) and N-feruloyltyramine (5), isolated from
plants, and we also evaluate the future of this experiment
as a routine method.
U2 - 10.1002/1099-1565(200101/02)12:1<23::AID-PCA551>3.0.CO;2-E
DO - 10.1002/1099-1565(200101/02)12:1<23::AID-PCA551>3.0.CO;2-E
M3 - Special issue
SN - 0958-0344
VL - 12
SP - 23
EP - 27
JO - Phytochemical Analysis
JF - Phytochemical Analysis
IS - 1
ER -