2686 J. Agric. Food Chem., Vol. 45, No. 7, 1997
Chassagne et al.
roacetamide)] according to the method of Voirin et al. (1992).
Phenyl â-D-glucopyranoside (10 µg) was used as an internal
standard.
GC An a lysis. Varian Model 3300 gas chromatographs
equipped with split injector (1/10) and a flame ionization
detector were used.
Dea cetyla tion of P er a cetyla ted Glu cosid es. To per-
acetylated glucosides dissolved in 2 mL of methanol was added
0.1 mL of 0.3 M sodium methoxide in methanol at room
temperature. The mixture was stirred for 90 min at room
temperature, then neutralized by adding Zerolit 225 (H+ form)
resin, and filtered. The crude product was purified by column
chromatography on silica gel (Merck, 230-400 mesh) using
ethyl acetate/ethanol (3:1) as solvent.
For aglycons, two types of fused silica capillary columns
were employed: J &W Scientific (Folsom, CA) DB-Wax (a) and
DB-5MS (b) (30 m × 0.25 mm i.d., film thickness ) 0.25 µm).
The temperature programs were (a) 3 min isothermal at 60
°C and then increased at 2 °C/min to 220 °C and (b) 40 °C
increased to 200 °C at 2 °C/min. The flow rates (a and b) were
1.8 mL/min of H2 for the carrier gas, 30 mL/min N2 for the
makeup gas, and 30 mL/min of H2 and 300 mL/min of air for
the detector gases. The injector temperature (a and b) was
maintained at 250 °C and the detector temperature at 250 (a)
and 300 °C (b).
For trifluoroacetylated glycosides, a DB-5MS fused silica
capillary column was used (30 m × 0.25 mm i.d., film thickness
) 0.25 µm, J &W Scientific). The column temperature was
programmed at 3 °C/min from 125 to 220 °C, then increased
at 2 °C/min to 280 °C, and held at this temperature for 15
min. The flow rates for the carrier gas (H2), the makeup gas,
and detector gases were the same as those mentioned above.
The injector temperature was maintained at 280 °C and the
detector temperature at 300 °C.
GC/MS An a lysis of Tr iflu or oa cetyla ted Glycosid es.
Mass spectra were recorded by coupling a Hewlett-Packard
(HP) 5890 gas chromatograph equipped with a DB-5MS fused
silica capillary column (30 m × 0.25 mm i.d., film thickness )
0.25 µm) and an injector on column to a HP 5889A mass
spectrometer. The transfer line was heated at 290 °C, and
the injector temperature was programmed at 60 °C/min from
110 to 260 °C and then held at this temperature for 55 min.
The column temperature was programmed at 3 °C/min from
125 to 290 °C with helium as carrier gas at 1.1 mL/min. EI-
MS was performed at 70 eV and NCI-MS at 200 eV with
methane as reagent gas at 80 Pa, according to the procedure
described by Chassagne et al. (1995b).
â-D-Glucopyranoside of methyl salicylate (1c): 1H NMR of
(250 MHz, D2O) δ 3.64-3.84 (m, 4H, H-2′, H-3′, H-4′, H-5′),
3.90 (dd, J ) 12.4, 5.2 Hz, Ha-6′), 4.05 (s, 3H, H-8), 4.07 (dd,
J ) 12.4, 2.3 Hz, Hb-6′), 5.30 (d, J ) 7.7 Hz, H-1′), 7.36 (dd, J
) 7.8, 7.8 Hz, H-4), 7.46 (d, J ) 8.3, H-6), 7.76 (ddd, J ) 8.3,
7.8, 1.7 Hz, H-5), 7.95 (dd, J ) 7.8, 1.7 Hz, H-3).
Eugenyl â-D-glucopyranoside (2c): 1H NMR (250 MHz, D2O)
δ 3.24 (d, J ) 6.7 Hz, H-7), 3.48 (m, 4H, H-2′, H-3′, H-4′, H-5′),
3.64 (dd, J ) 12.4, 5.0 Hz, Ha-6′), 3.76 (s, 3H, H-10), 3.80 (dd,
J ) 12.4, 1.4 Hz, Hb-6′), 4.97 (m, H-9), 4.98 (d, J ) 7.7 Hz,
H-1′), 5.92 (m, H-8), 6.75 (dd, J ) 8.3, 1.6 Hz, H-5), 6.88 (d, J
) 1.6 Hz, H-3), 7.02 (d, J ) 8.3 Hz, H-6).
Syn th esis of â-Ru tin osid e. 1,2,3,4-Tetra-O-acetyl-6-O-
(2′,3′,4′-tri-O-acetyl-R-L-rhamnopyranosyl)-â-D-glucopyrano-
side (1 mmol) and 0.2 mL of acetic anhydride were stirred at
-4 °C in 10 mL of chloroform, and then 1.8 mL of hydrobromic
acid (33% in acetic acid) was added dropwise. After stirring
under N2 for 3 h, the mixture was poured into 15 mL of ice-
cold water, then dried with Na2SO4, and concentrated under
vacuum at 35 °C. The crude heptaacetyl R-bromorutinoside
was used in the next step without further purification.
Synthesis and deacetylation of 3b were performed as described
for 1b and 2b.
2,3,4-Tetra-O-acetyl-6-O-(2′,3′,4′-tri-O-acetyl-R-L-rhamnopy-
ranosyl)-â-D-glucopyranoside of methyl salicylate (3b): 1H
NMR (250 MHz, CDCl3) δ 1.12 (d, J ) 6.3 Hz, H-6′′), 1.94-
2.02 (6s, each CH3CO), 3.52 (m, 1H, H-5′), 3.58 (dd, J ) 11.5,
7.2 Hz, Ha-6′), 3.68 (dd, J ) 11.5, 2.3 Hz, Hb-6′), 3.78 (s, 3H,
H-8), 3.82 (m, 1H, H-5′′), 4.68 (s, 1H, H-1′′), 4.98 (m, 2H, J )
8.7, 7.7 Hz, H-2′, H-4′), 5.04 (d, J ) 7.7 Hz, H-1′), 5.17-5.32
(m, 4H, H-3′, H-2′′, H-3′′, H-4′′), 7.04 (dd, J ) 7.8, 7.8 Hz, H-4),
7.06 (d, J ) 7.8 Hz, H-6), 7.48 (ddd, J ) 7.8, 7.8, 1.7 Hz, H-5),
7.67 (dd, J ) 7.8, 1.7 Hz, H-3).
6-O-R-L-Rhamnopyranosyl-â-D-glucopyranoside of methyl
salicylate (3c): 1H NMR (250 MHz, D2O) δ 1.15 (d, J ) 6.2
Hz, H-6′′), 3.37 (t, J ) 9.6 Hz, H-4′′), 3.50 (t, J ) 9.1 Hz, H-5′),
3.60 (t, J ) 8.9 Hz, H-3′), 3.64 (m, 2H, H-2′, H-4′), 3.70 (m,
2H, Ha-6′, H-5′′), 3.75 (dd, J ) 9.7, 3.4 Hz, H-3′′), 3.87 (m, 1H,
H-2′′), 3.89 (s, 3H, H-8), 3.99 (d, J ) 9.8 Hz, Hb-6′), 4.74 (d, J
) 1.3 Hz, H-1′′), 5.15 (d, J ) 7.3 Hz, H-1′), 7.20 (dd, J ) 7.8,
7.8 Hz, H-4), 7.28 (d, J ) 8.4 Hz, H-6), 7.64 (ddd, J ) 8.4, 7.8,
1.6 Hz, H-5), 7.78 (dd, J ) 7.8, 1.6 Hz, H-3).
NMR An a lysis. NMR spectra were recorded with a Bruker
1
250 MHz spectrometer (250 MHz for H NMR and 62.89 MHz
for 13C NMR) in chloroform-d1 for acetylated glycosides and
water-d2 for glycosides (internal standard, tetramethylsilane).
Syn th esis of 2,3,4,6-Tetr a -O-a cetyl-â-D-glu cop yr a n o-
sid es. Glucosides (1b, 2b) were synthesized under the
experimental conditions described by Baumes et al. (1989).
2,3,4,6-Tetra-O-acetyl-R-D-glucopyranoside bromide (1.95
mmol) and freshly prepared Ag2CO3 (6.5 mmol) were added
under stirring to volatile compounds (3 mmol) and 1 g of
drierite in 20 mL of anhydrous pyridine. The mixture was
stirred in the dark for 48 h at room temperature and then
filtered under vacuum. The filtrate was concentrated under
vacuum at 50 °C and then dissolved in 50 mL of toluene and
concentrated again to eliminate pyridine traces. The crude
product was dissolved in 100 mL of diethyl ether, and washed
with ice-cold water, and dried with Na2SO4. After filtration
and concentration, the final crude product was purified by
column chromatography on silica gel (230-400 mesh, Merck)
using diethyl ether/petroleum ether (8:2) as solvent.
2,3,4,6-Tetra-O-acetyl-â-D-glucopyranoside of methyl salicyl-
ate (1b): 1H NMR (250 MHz, CDCl3) δ 1.95, 1.97, 1.99, 2.02
(each CH3CO), 3.87 (s, 3H, H-8), 3.90 (ddd, J ) 9.7, 5.1, 2.5
Hz, H-5′), 4.19 (dd, J ) 12.3, 2.5 Hz, Hb-6′), 4.31 (dd, J ) 12.3,
5.1 Hz, Ha-6′), 5.12 (d, J ) 7.6 Hz, H-1′), 5.20 (m, H-4′), 5.24-
5.34 (m, H-2′), 5.37 (dd, J ) 9.0, 8.1 Hz, H-3′), 7.14 (dd, J )
8.0, 7.2 Hz, H-4), 7.15 (d, J ) 8.0 Hz, H-6), 7.47 (ddd, J ) 8.0,
7.2, 1.7 Hz, H-5), 7.78 (dd, J ) 8.0, 1.7 Hz, H-3).
RESULTS AND DISCUSSION
Glycosidic extracts from juice or peel of fruits of P.
edulis were purified by selective retention on Amberlite
XAD-2 resin (Gu¨nata et al., 1985). After elution with
methanol, the glycosidic fractions were hydrolyzed with
hemicellulase REG-2 and almond glucosidase mixture
as indicated by Chassagne et al. (1995a) to release the
aglycons from passion fruit aroma precursors. GC/MS
of the liberated volatile compounds revealed the occur-
rence of eugenol and methyl salicylate by comparison
of linear retention index and MS data using authentic
compounds. Eugenol was very abundant in juice (920
µg/g) and peel (1700 µg/kg), whereas methyl salicylate
was abundant in only juice (760 µg/kg). However, there
is no information on the sugar moiety of these glyco-
sidically bound phenolic compounds. Thus, these phe-
nolic glycosides have been characterized by means of
GC and GC/MS analyses of their trifluoroacetylated
derivatives (Voirin et al., 1992). The GC of TFA
derivatives of passion fruit juice and peel glycosides
showed many peaks, as illustrated in Figure 1 for the
purple passion fruit peel extract; most of them were
Eugenyl 2,3,4,6-Tetra-O-acetyl-â-D-glucopyranoside (2b): 1H
NMR (250 MHz, CDCl3) δ 1.96-2.01 (4 s, CH3CO), 3.27 (d,
2H, J ) 6.6 Hz, H-7), 3.67 (ddd, J ) 10.0, 5.0, 2.5 Hz, H-5′),
3.74 (s, 3H, H-10), 4.09 (dd, J ) 12.2, 5.0 Hz, Ha-6′), 4.22 (dd,
J ) 12.2, 2.5 Hz, Hb-6′), 4.85 (d, J ) 7.7 Hz, H-1′), 4.96-513
(m, 3H, H-2′, H-3′, H-4′), 5.21 (m, 2H, H-9), 5.87 (m, J ) 16.5,
11.0, 6.6 Hz, H-8), 6.63 (dd, J ) 8.0, 2.6 Hz, H-5), 6.65 (m,
H-3), 6.97 (d, J ) 8.0 Hz, H-6).