4
W. ZHANG ET AL.
1
, except for the signals due to the upfield chemical shifts of C-3 (δ 79.1), which suggests
C
C-3 without sugar unit. And the sugar linkages were determined from the HMBC spectrum.
The long-range couplings observed between the proton signal at δ 6.24 (glc-H-1′) and the
H
carbon signal at δ 177.0 (C-28) of the aglycone moiety, and the anomeric proton signals at
C
δH 5.02 (xyl-H-1″″), 4.81 (glc-H-1″), 5.58 (glc-H-1″‴), and 5.36 (glc-H-1‴) showed correlations
with the carbon signals at δ 79.8 (glc-C-2′), 90.1 (glc-C-3′), 89.3 (glc-C-3″), and 69.8 (glc-C-6″)
C
of the inner sugar, respectively, confirm the glycosylation at C-28 of the aglycone with a
{
[glc-(1 → 6)-glc-(1 → 3)]-glc-(1 → 3)}-[xyl-(1 → 2)]-glc moiety. Therefore, the structure of 2
was established as [β-D-xylopyranosyl-(1 → 2)]-{[β-D-glucopyranosyl- (1 → 3)]-[β-D-glu-
copyranosyl-(1 → 6)]-β-D-glucopyranosyl-(1 → 3)}28-O-β-D-glucopyranosyl oleanolic acid
ester and named congmujingnoside C. (Figure 1)
Compound 3, which was isolated as a white acicular crystal. In the positive-ion HRFABMS
analysis revealed the molecular formula of 3 to be C H O . By the acid hydrolysis of 3,
5
4
88 23
1
13
D-glucose were identified by TLC analysis. The H and C NMR spectra of 3 were very similar
to those of 2, apart from the lack of signals of a β-D-xylopyranosyl. In contrast, long-range
couplings were observed from a proton signal at δ 6.32 (glc-H-1′) to the carbon signal at
H
δ 176.9 (C-28), δ 5.33 (glc-H-1″″) to δ 80.1 (glc-C-2′), δ 4.83 (glc-H-1″) to δ 89.8 (glc-C-3′),
C
H
C
H
C
and δ 5.57 (glc-H-1‴) to δ 89.1 (glc-C-3″) in the HMBC spectrum of 3, which suggests gly-
H
C
cosylation at C-28 with a{ [glc (1 → 3)]-glc-(1 → 3)]}-[glc(1 → 2)]-glc moiety. This result agrees
with the above observations and suggests that compound 3 is [β-D-glucopyrano-
syl-(1 → 2)]-{[β-D-glucopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 3)}28-O-β-D-
glucopyranosyl oleanolic acid ester and named congmujingnoside D. (Figure 1).
Compound 4 was obtained as an amorphous powder. The HRESIMS showed a deproto-
+
nated molecular ion peak at m/z 1097.5500 [M + Na] , indicating the molecular formula to
1
13
be C H O . The H and C NMR spectroscopic data (Table S2) were closely related to those
53
86 22
of 3 except for one D-glucose in 3 was replaced by D-xylose in 4. The sugar moieties and
1
3
linkages were the same as 3 on the basis of the similar C NMR and HMBC correlations,
1
1
which were further confirmed by HSQC and H– H COSY experiments. All of the correlations
showed that compound 4 was an oleanolic acid glycoside at C-28 with a {[glc (1 → 3)]-glc-
(
1 → 3)]}-[xyl-(1 → 2)]-glc moiety. Therefore, the structure of 4 was established as [β-D-xy-
lopyranosyl-(1 → 2)]-{[β-D-glucopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 3)}28-O-β-D-
glucopyranosyl oleanolic acid ester and named congmujingnoside E. (Figure 1).
2
0
Compound 5 was obtained as an amorphous white powder with [α]D −26.3 (c 0.1,
MeOH). It was determined to have the molecular formula of C H O on the basis of the
5
9
96 26
1
3
+
C NMR data and HRESIMS spectrum at m/z 1243.6085 [M + Na] (Calcd for C H O Na,
243.6088). An examination of the H and C NMR data (Table S3) showed the structure
5
9
96 23
1
13
1
of 5 to be similar to that of 1 except for one D-glucose in 1 was replaced by D-quinovose
in 5. Through detailed analysis of the 2D NMR spectra, the spin systems for the sugars
were assigned. In the HMBC spectrum, proton signal at δ 5.47 (glc-H-1′) had correlation
H
with the carbon signal at δ 89.2 (C-3) of the aglycone moiety, and the anomeric proton
C
signals at δ 5.02 (xyl-H-1″″), 4.81 (glc-H-1″), and 6.20 (qui-H-1‴) showed correlations with
H
the carbon signals at δ 79.2 (glc-C-2′), 83.7 (glc-C-3′) and 69.9 (glc-C-6″), respectively, of
C
the inner sugar. In addition an anomeric proton signal at δ 6.25 (glc-H-1″‴) showed corre-
C
lation with the carbon signal at δ 177.0 (C-28), which suggests glycosylation at C-3 of
C
aglycone with a [glc (1 → 3)-qui (1 → 6)]-[xyl (1 → 2)]-glc moiety glycosylation and at C-28
with a glucose. Therefore, taking together with the NOE spectrum, the structure of 5 was