Cucurbitane glycosides from Siraitia grosvenorii

Article abstract of DOI:10.1080/07328303.2011.583511

Systematic phytochemical studies of the extract of Luo Han Go (Siraitia grosvenorii) furnished six known cucurbitane glycosides, namely, mogrosides IVa, mogrosides V and VI, isomogroside V, 11-oxomogroside V, and siamenoside I. The structures of all the i

Full text of DOI:10.1080/07328303.2011.583511

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Cucurbitane Glycosides from Siraitia
grosvenorii
a
a
Venkata Sai Prakash Chaturvedula & Indra Prakash
a
The Coca-Cola Company, Organic Chemistry Department, Research
and Technology, One Coca-Cola Plaza, Atlanta, GA, 30313, USA
Published online: 27 Jun 2011.
To cite this article: Venkata Sai Prakash Chaturvedula & Indra Prakash (2011): Cucurbitane Glycosides
from Siraitia grosvenorii , Journal of Carbohydrate Chemistry, 30:1, 16-26
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Journal of Carbohydrate Chemistry, 30:16–26, 2011
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 0732-8303 print / 1532-2327 online
DOI: 10.1080/07328303.2011.583511
Cucurbitane Glycosides from
Siraitia grosvenorii
Venkata Sai Prakash Chaturvedula and Indra Prakash
The Coca-Cola Company, Organic Chemistry Department, Research and Technology,
One Coca-Cola Plaza, Atlanta, GA 30313, USA
Systematic phytochemical studies of the extract of Luo Han Go (Siraitia grosvenorii)
furnished six known cucurbitane glycosides, namely, mogrosides IVa, mogrosides V and
VI, isomogroside V, 11-oxomogroside V, and siamenoside I. The structures of all the
isolated compounds were characterized on the basis of extensive spectral and chemical
studies. Though the partial NMR spectral data has been reported for some of the iso-
1
13
lated compounds previously, the complete H and C NMR spectral assignments of all
the isolated compounds are reported herewith for the first time based on COSY, HSQC,
HMBC, and NOESY spectroscopic data.
Keywords Siraitia grosvenorii; Cucurbitaceae; Luo Han Go; Cucurbitane glycosides;
NMR; MS; Chemical studies
INTRODUCTION
The fruit of Siraitia grosvenorii (Swingle) Lu and Zhang (Momordica
grosvenorii; Cucurbitaceae) grow in Guangxi, People’s Republic of China, is
used as an expectorant as well as a natural sweetener in that country.[
1–3]
The
fruit, called Luo Han Guo, has been used for centuries in traditional Chinese
medicine for the treatment of dry cough, sore throat, and constipation.[ Luo
Han Guo is well known now throughout the world due to its intense sweet
taste and has been used as a noncaloric natural sweetener in some countries.
Early chemical investigation revealed that the sweet principles of Luo Han
4]
[
1–4]
Guo were triterpenoid glycosides.
lation of natural sweeteners,
In continuation of our study on the iso-
[
5,6]
we have investigated the aqueous alcoholic
extract of Luo Han Go extract that resulted in the isolation of six cucurbi-
tane glycosides. This paper describes the isolation and structure elucidation of
the known mogrosides, namely, mogroside IVa (1), mogrosides V and VI (2, 3),
isomogroside V (4), 11-oxomogroside V (5), and siamenoside I (6), based on the
Received January 30, 2011; accepted March 28, 2011.
Address correspondence to Venkata Sai Prakash Chaturvedula, The Coca-Cola Com-
pany, Organic Chemistry Department, Research and Technology, One Coca-Cola Plaza,
Atlanta, GA 30313, USA. E-mail: vchaturvedula@na.ko.com
1
6

Cucurbitane Glycosides
1
7
Figure 1: Structures of the isolated cucurbitane glycosides 1–6.
extensive NMR and mass spectroscopic studies (Fig. 1). The complete assign-
1
13
ments of the H and C NMR values of the isolated compounds were made on
the basis of COSY, HSQC, HMBC, and NOESY spectral data.
RESULTS AND DISCUSSION
Purification of the commercial extract of Luo Han Guo obtained from S.
grosvenorii resulted in the isolation of six cucurbitane glycosides 1–6, which
were identified as mogrosides IVa, mogrosides V and VI, isomogroside V, 11-
oxomogroside V, and siamenoside I, respectively. The structures of all the
compounds were characterized from the detailed spectroscopic studies (COSY,
HSQC, HMBC, and NOESY) and in comparison of their spectral data with the
[
7–9]
reported values in the literature.
Compound 1 was obtained as a white powder. The molecular formula
was inferred as C54H92O24 from MS studies. The ESI-MS spectrum of this
compound was found at m/z 1123 to correspond to [M-H] quasi-molecular ion,
1
suggesting that the molecular weight of compound 1 is 1124. The H NMR
spectrum of 1 showed the presence of eight methyl signals at δ 0.90, 0.91, 1.08,
1.11, 1.34, 1.36, 1.49, and 1.55; eight methylene and seven methine groups
between δ 1.15 and 3.86 (including three secondary hydroxyl groups); and a
tertiary hydroxyl resonating at δ 72.9, characteristic of the aglycone moiety
C

V. S . P. Chaturvedula & I. Prakash
1
8
1
of the triterpenoid mogrol isolated earlier from S. grosvenorii. The H NMR
spectrum of 1 also showed the presence four anomeric protons as doublets at
δ 4.91, 4.93, 5.04, and 5.20, suggesting the presence of four hexose moieties,
which was supported by the fragment ions observed in the negative mode of
the ESI-MS/MS spectrum at m/z 961, 799, 637, and 475. Acid hydrolysis of 1
afforded a hexose unit that was identified and its configuration was confirmed
as D-glucose by preparing the corresponding thiocarbamoyl-thiazolidine car-
boxylate derivative with L-cysteine methyl ester and O-tolyl isothiocyanate,
and in comparison of its retention time with the standard sugars as described
[
10]
1
13
in the literature.
The H and C NMR values for all the protons and
carbons were assigned on the basis of COSY, HSQC, and HMBC correlations
and are given in Tables 1 through 4. The placement of the four sugar units in
1
was confirmed as 1 → 6 β-D-glucobiosyl substituents at both C-3 and C-24
positions on the basis of the key HMBC (H-6 of G-4 to C-1 of G-5 and H-6 of G-1
to C-1 of G-2) and NOESY (H-6 of G-4 to H-1 of G-5 and H-6 of G-1 to H-1 of
G-2) data, respectively. A close comparison of the NMR spectral data of 1 with
the reported literature values for mogroside IVa confirmed its structure.[
Compound 2 was also obtained as a white amorphous powder and its
molecular formula was inferred as C60H102O29 from the ESI-MS/MS spectrum.
A peak at m/z 1285 corresponding to [M-H] in the ESI-MS spectrum suggested
7,8]
1
that the molecular weight of compound 2 might be 1286. The H NMR spec-
trum of 2 showed the presence of eight methyls, eight methylenes, and seven
1
methines, identical to 1. The H NMR spectrum of 2 showed the presence five
anomeric protons, suggesting the presence of five hexose moieties, and acid
hydrolysis confirmed the sugar and its stereochemistry as D-glucose. The 1 →
6
linked β-D-glucobiosyl substituent at C-3 and 2,6-branched β-D-glucotriosyl
moiety at C-24 were identified on the basis of the NOESY data: H-6 of G-4 to
H-1 of G-5; H-6 of G-1 to H-1 of G-2 and H-2 of G-1 to H-1 of G-3 correlations,
1
13
respectively. The H and C NMR spectral data (Tables 1 through 4) were as-
signed based on the COSY, HSQC, and HMBC spectra and are consistent with
mogroside V, which confirmed the structure.[8]
Compound 3 was also obtained as a white amorphous powder. The ESI-MS
spectrum showed the molecular ion at m/z 1447 [M-H] corresponding to the
1
molecular formula C66H112O34. The H NMR spectrum of 3 for the aglycone
moiety showed peaks identical to 1 and 2. The ESI-MS/MS showed the pres-
ence of a total of six glucosyl moieties with fragment ions that appeared at m/z
1
285, 1123, 961, 799, 637, and 475, and this was supported by the presence of
1
six anomeric protons in its H NMR spectral data. Acid hydrolysis performed
as in 1 and 2 confirmed the sugar and its configuration as D-glucose The pres-
ence of a 2,6-branched β-D-glucotriosyl moiety at C-24 in 3 was supported by
comparison of its 13C NMR values with 2, and NOESY correlations (H-2 of G-
4
to H-1 of G-7 and H-6 of G-4 to H-1 of G-5) suggested the presence of an
additional 2,6-branched β-D-glucotriosyl substitution at C-3. Comparison of

1
9

V. S . P. Chaturvedula & I. Prakash
2
0
1
Table 2: H NMR data (chemical shifts and coupling constants) for the glucosyl
a–c
5 5
units of compounds 1–6 in C D N
Proton
1
2
3e
4d
5
6
G-1
1
5.20 d (7.5) 5.21 d (7.6) 5.22 d (7.8) 5.19 d (7.6) 5.20 d (7.4) 5.19 d (7.6)
2
3.31 m
3.32 m
3.30 m
3.50 m
3.60 m,
3.61 m
3.58 m
3.34 m
3.52 m
3.62 m,
4.23 m
3.61 m
3.56 m
3.32 m
3.51 m
3.62 m,
4.20 m
3.61 m
3.57 m
3.33 m
3.50 m
3.61 m,
4.24 m
3.61 m
3.58 m
3.34 m
3.52 m
3.62 m,
4.24 m
3.61 m
3.56 m
3.32 m
3.52 m
3.60 m,
4.22 m
3
4
5
6
4
.24 m
G-2
1
4.91 d (7.4) 4.93 d (7.6) 4.92 d (7.5) 4.93 d (7.4) 4.90 d (7.6) 4.92 d (7.5)
2
3.21 m
3.34 m
3.30 m
3.25 m
3.62 m,
3.24 m
3.36 m
3.32 m
3.35 m
3.66 m,
3.84 m
3.21 m
3.35 m
3.30 m
3.24 m
3.66 m,
3.84 m
3.23 m
3.36 m
3.31 m
3.23 m
3.65 m,
3.84 m
3.22 m
3.34 m
3.30 m
3.25 m
3.66 m,
3.86 m
3.21 m
3.36 m
3.30 m
3.25 m
3.66 m,
3.85 m
3
4
5
6
3
.86 m
G-3
1
5.45 d (7.8) 5.42 d (7.6) 5.43 d (7.8) 5.42 d (7.7) 5.44 d (7.8)
2
3.22 m
3.36 m
3.28 m
3.24 m
3.62 m,
3.23 m
3.39 m
3.26 m
3.26 m
3.65 m,
3.89 m
3.24 m
3.38 m
3.25 m
3.25 m
3.65 m,
3.91 m
3.20 m
3.37 m
3.27 m
3.26 m
3.62 m,
3.91 m
3.22 m
3.38 m
3.28 m
3.24 m
3.65 m,
3.89 m
3
4
5
6
3
.91 m
G-4
1
5.04 d (7.6) 5.02 d (7.8) 5.02 d (7.6) 5.04 d (7.5) 5.02 d (7.6) 5.04 d (7.8)
2
3.52 m
3.37 m
3.28 m
3.42 m
3.82 dd
3.50 m
3.37 m
3.28 m
3.42 m
3.82 dd
3.51 m
3.37 m
3.28 m
3.42 m
3.82 dd
3.24 m
3.38 m
3.56 m
3.42 m
3.62 m,
3.52 m
3.37 m
3.28 m
3.42 m
3.82 dd
3.22 m
3.37 m
3.28 m
3.42 m
3.65 m,
3
4
5
6
(
12.0, 5.8), (12.0, 5.8), (12.0, 5.8), 3.86 m
(12.0, 5.8), 3.83 m
4.06 dd
4
.06 dd
4.06 dd
(12.0, 1.8)
4.06 dd
(12.0, 1.8)
(
12.0, 1.8)
(12.0, 1.8)
G-5
1
4.93 d (7.8) 4.89 d (7.6) 4.90 d (7.8)
4.91 d (7.7)
3.26 m
2
3.25 m
3.46 m
3.23 m
3.34 m
3.80 m,
3.27 m
3.44 m
3.24 m
3.36 m
3.80 m,
3.94 m
3.27 m
3.46 m
3.27 m
3.35 m
3.84 m,
3.92 m
3
3.43 m
4
3.25 m
5
3.32 m
6
3.82 m,
3.91 m
3
.91 m
a
Assignments were made on the basis of COSY, HSQC, and HMBC data.
Coupling constants are in Hz.
b
c
Chemical shift values are in δ (ppm).
d1
H NMR chemical shift values for G-6 in 4 (δ, ppm): H-1: 4.82 d (7.6); H-2: 3.21 m; H-3: 3.35 m;
H-4: 3.25 m; H-5: 3.32 m; H-6: 3.64 m, 3.84 m.
e1
H NMR chemical shift values for G-7 in 3 (δ, ppm): H-1: 4.91 d (7.7); H-2: 3.25 m; H-3: 3.46 m;
H-4: 3.53 m; H-5: 3.34 m; H-6: 3.82 m, 3.91 m.

Cucurbitane Glycosides
2
1
Table 3: 13C NMR chemical shift values (δ, ppm) for the aglycone moieties of
a
5 5
compounds 1–6 in C D N
Carbon
1
2
3
4
5
6
1
2
3
4
5
6
7
8
9
27.5
29.9
87.9
42.7
144.9
118.8
25.0
43.9
40.5
37.1
77.0
41.4
47.8
50.1
34.9
28.9
51.3
17.5
26.7
37.2
19.7
34.2
29.9
92.4
72.9
26.3
21.9
28.0
27.2
19.5
27.5
29.9
87.9
42.8
144.7
118.8
25.0
44.0
40.6
37.2
77.8
41.5
47.9
50.2
34.9
29.0
51.5
17.6
26.7
36.8
19.8
33.6
30.0
92.5
73.0
25.0
21.9
28.0
27.3
19.5
27.4
29.9
87.8
42.6
144.7
118.8
25.0
43.9
40.6
37.1
77.7
41.4
47.9
50.1
34.9
29.0
51.6
17.6
26.6
36.8
19.8
33.6
29.8
92.5
73.0
25.0
21.8
28.0
27.2
19.5
27.5
29.8
88.3
42.8
144.5
118.9
25.0
44.0
40.5
37.2
77.5
41.6
47.9
50.1
35.0
29.0
51.5
17.6
26.7
36.8
19.8
33.6
29.9
92.5
73.0
26.5
21.9
28.1
27.5
19.5
22.6
29.7
87.2
42.4
141.7
118.8
24.5
44.4
49.3
36.3
213.9
49.2
49.4
50.1
35.0
28.3
50.4
17.5
20.8
36.6
19.2
33.4
29.8
92.6
72.9
25.0
27.5
28.6
26.2
18.7
27.5
29.9
88.4
42.8
144.7
118.8
25.0
44.0
40.5
37.2
77.8
41.6
47.9
50.2
34.9
29.0
51.5
17.6
26.8
36.7
19.8
33.6
29.9
92.5
73.0
25.0
21.9
28.0
27.5
19.5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
aAssignments were made on the basis of COSY, HSQC, and HMBC data.
the H and 13C NMR values (Tables 1 through 4) of 3 with the literature val-
1
ues confirmed the structure as mogroside VI.
Compound 4 was found to be a similar white amorphous powder and its
molecular formula was inferred as C60H102O29 from the ESI-MS spectrum (i.e.,
m/z at 1285 corresponding to [M-H]), suggesting that its molecular weight is
1286. This compound was found to be similar to compound 2 in its structure
by having five D-glucosyl moieties, which were identified on the basis of the
hydrolysis study and its identical chemical shifts for the aglycone moiety in its
1
H NMR spectral data. Based on the NOESY correlations of 4, it was found
that three glucosyl units are present at C-24 as 2,6-branched β-D-glucotriosyl
moiety (H-6 of G-1 to H-1 of G-2; H-2 of G-1 to H-1 of G-3) similar to 2, whereas
the additional two glucosyl units at C-3 were attached as 1 → 4 linked β-D-
glucobiosyl substituent on the basis of NOESY correlations H-4 of G-4 to H-1
of G-6 and confirmed its structure as isomogroside V.[
9]

V. S . P. Chaturvedula & I. Prakash
2
2
Table 4: 13C NMR chemical shift values (δ, ppm) for the glucosyl units of
a
5 5
compounds 1–6 in C D N
Carbon
1
2
3c
4b
5
6
G-1
1
102.3
75.7
78.2
71.4
76.3
70.0
104.2
81.2
78.4
71.4
76.3
70.0
104.3
81.2
78.4
71.4
76.3
70.0
104.2
81.3
78.5
71.6
76.5
70.2
104.2
81.2
78.4
71.4
76.3
70.0
104.2
81.2
78.4
71.4
76.3
70.0
2
3
4
5
6
G-2
1
106.4
75.8
78.0
72.5
78.2
63.7
106.2
75.8
78.0
72.5
78.2
63.8
106.4
75.8
78.0
72.5
78.2
63.7
106.1
75.7
78.0
72.5
78.1
63.6
106.1
75.8
78.0
72.5
78.2
63.7
106.2
75.8
78.0
72.5
78.2
63.8
2
3
4
5
6
G-3
1
105.3
75.7
77.7
71.5
78.1
62.6
105.3
75.7
77.7
71.5
78.1
62.8
105.4
75.8
77.8
71.5
78.2
62.6
105.3
75.7
77.7
71.5
78.1
62.8
105.3
75.7
77.7
71.5
78.1
62.6
2
3
4
5
6
G-4
1
107.5
75.3
78.8
71.7
77.4
69.9
107.5
75.3
78.8
71.7
77.4
69.9
107.4
81.6
79.1
72.1
77.4
69.9
107.4
75.5
76.6
80.9
77.8
62.1
107.5
75.3
78.8
71.7
77.4
69.9
107.8
75.7
77.7
71.5
78.1
62.8
2
3
4
5
6
G-5
1
105.9
75.3
78.2
71.7
78.2
62.8
105.9
75.3
78.2
71.7
78.2
62.7
105.9
75.3
78.2
71.7
78.2
62.7
105.9
75.3
78.2
71.7
78.2
62.8
2
3
4
5
6
a
Assignments were made on the basis of COSY, HSQC, and HMBC data.
C NMR chemical shift values for G-6 in 4 (δ, ppm): C-1: 105.3; C-2: 75.3; C-3: 78.2; C-4: 71.6;
b13
C-5: 78.3; C-6: 62.8.
c13
C NMR chemical shift values for G-7 in 3 (δ, ppm): C-1: 105.3; C-2: 75.3; C-3: 78.2; C-4: 71.7;
C-5: 78.2; C-6: 62.8.
Compound 5 was obtained as a white amorphous powder and its molecular
formula was inferred as C60H100O29 from the ESI-MS studies, which showed a
peak at m/z 1283 corresponding to [M-H], suggesting that the molecular weight
1
of compound 5 could be m/z 1284. The H NMR spectrum of 5 showed the pres-
ence of five anomeric protons, suggesting the presence of five hexose moieties,
and acid hydrolysis confirmed the sugar and its configuration as D-glucose.

Cucurbitane Glycosides
2
3
The 1 → 6 linked β-D-glucobiosyl substituent at C-3 and 2,6-branched β-D-
1
3
glucotriosyl moiety at C-24 were identified on the basis of its comparative
C
1
13
NMR values with 2. A close comparison of the H and C NMR chemical shift
values of 2 and 5 together with the ESI-MS data, which has a 2 amu difference,
suggested the presence of a carbonyl group in 5 at the C-11 position in place of
an oxymethine proton in 2. This was further supported by the presence of the
peak observed in its 1 C NMR spectrum at δ 213.9, suggesting its structure as
3
1
1-oxomogroside V, consistent with literature.[7,8]
Compound 6 was also obtained as a white powder. The molecular formula
was inferred as C54H92O24 from MS studies, identical to 1 with four glucosyl
units, which were identified as D-glucose on the basis of acid hydrolysis. A
close comparison of the 13C NMR values of 6 with 2–5 suggested the presence
of three glucosyl units at the C-24 position as 2,6-branched β-D-glucotriosyl
moiety with the additional glucosyl unit at the C-3 position, which suggested
1
13
its structure as siamenoside I. The H and C NMR data (Tables 1 through
4
) assigned based on COSY, HSQC, and HMBC spectra were consistent to the
[
8]
reported literature values.
EXPERIMENTAL
General Methods
NMR spectra were acquired on a Varian Unity Plus 600 MHz instrument
using standard pulse sequences at ambient temperature. Chemical shifts are
given in δ (ppm), and coupling constants are reported in Hz. MS and MS/MS
data were generated with a Waters Premier Quadrupole Time-of-Flight (Q-
Tof) mass spectrometer equipped with an electrospray ionization source oper-
ated in the positive-ion mode and ThermoFisher Discovery OrbiTrap in the
Positive Mode Electrospray. Samples were diluted with water:acetonitrile (1:1)
containing 0.1% formic acid and introduced via infusion using the onboard sy-
ringe pump at ∼10 uL/min. Low-pressure chromatography was performed on a
Biotage Flash system using a C-18 cartridge (40+ M, 35–70 µm). TLC was per-
formed on Baker Si-C18F plates with mobile phase H2O-MeOH (35:65). Identi-
fication of the spots on the TLC plate was carried out by spraying 10% H2SO4
◦
in EtOH and heating the plate at about 80 C. Analytical HPLC for sugar anal-
ysis was carried out with a Waters 600E multisolvent delivery system using a
Phenomenex Luna C18 nonchiral (150 × 4.6 mm, 5 µm) column.
Materials
The Luo Han Guo commercial extract was purchased from Chengdu Biopu-
rify Phytochemicals, China. A voucher specimen is deposited at The Coca Cola
Company, No. VSPC-3166-99.

V. S . P. Chaturvedula & I. Prakash
2
4
Isolation and Purification
The Luo Han Guo extract (50 g) was purified on a C-18 column using a
Biotage flash chromatography system (solvent system: gradient from 20% to
80% MeOH-water, 60 mL/min, detection at UV 210 nm). Fractions 21–27 (3.2
g) were combined and further subjected to repeated flash chromatography pu-
rification with gradient from 30% to 60% MeOH-water, 30 mL/min, afforded
mogroside IVa (1, 130 mg), mogroside VI (3, 145 mg), iso-mogroside V (4,
120 mg), 11-oxo-mogroside V (5, 160 mg), and siamenoside I (6, 125 mg). Frac-
tions 28–38 (32 g) were combined and further subjected by flash chromatog-
raphy purification two times (solvent system: 50% MeOH-water, 20 mL/min,
detection: UV 210 nm) yielded the major sweet principle, mogroside V (2,
11.2 g). The TLC of the crude extract and the isolated compounds is shown in
Figure 2.
Figure 2: TLC of the crude extract (A) and isolated compounds 1–6 (B–G).

Cucurbitane Glycosides
2
5
General Procedure for Acid Hydrolysis and Determination
of Sugar Configuration
Each glycoside 1–6 (500 µg) was hydrolyzed with 0.5 M HCl (0.5 mL) for
1.5 h. After cooling, the mixture was passed through an Amberlite IRA400
column and the eluate was lyophilized. The residue was dissolved in pyridine
◦
(
0.25 mL) and heated with L-cysteine methyl ester HCl (2.5 mg) at 60 C for
1
.5 h, and then O-tolyl isothiocyanate (12.5 uL) was added to the mixture and
◦
heated at 60 C for an additional 1.5 h. The reaction mixture was analyzed by
HPLC: column Phenomenex Luna C18, 150 × 4.6 mm (5 u); 25% acetonitrile-
0.2% TFA water, 1 mL/min; UV detection at 250 nm. The sugar was identified
as D-glucose in each experiment (tR, 12.15 to 12.28 min) [authentic samples,
D-glucose (tR, 12.35) and L-glucose (tR, 11.12 min)].
CONCLUSIONS
This is the first report of the isolation of 4 along with the other five mogrosides
from S. grosvenorii. Though all the isolated compounds are reported in the
literature, the detailed NMR characterization has not been studied on the ma-
jority of the isolated compounds. Also, the NMR data for 4 has been reported
[
9]
in CD3OD earlier, which did not correlate well with our reported values, es-
pecially in the high field region corresponding to the methyl singlets at C-26
to C-29. The possible reason could be the solvent used to run the NMR spec-
trum, since we have acquired the data in CD5N5. This is a compilation of the
1
13
H and C NMR spectral data for all the six compounds in CD5N5 based on
the extensive two-dimensional NMR spectroscopic data and chemical studies.
ACKNOWLEDGMENT
The authors gratefully acknowledge Mani Upreti for technical assistance.
REFERENCES
1
.
Takemoto, T.; Arihara, S.; Nakajima, T.; Okuhira, M. Studies on the constituents
of Fructus momordicae. I. Yakugaku Zasshi 1983, 103, 1151–1154.
2
.
Takemoto, T.; Arihara, S.; Nakajima, T.; Okuhira, M. Studies on the constituents
of Fructus momordicae. II. Yakugaku Zasshi 1983, 103, 1155–1166.
3
.
Takemoto, T.; Arihara, S.; Nakajima, T.; Okuhira, M. Studies on the constituents
of Fructus momordicae. III. Yakugaku Zasshi 1983, 103, 1167–1173.
4. Yasushi, A.S.; Yuji, M.; Hiroshi, I.; Masaki, S.; Yoshihisa, N. Triterpene glycosides
of Siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glu-
cose level after a single oral administration of maltose in rats. J. Agric. Food Chem.
2
005, 53, 2941–2946.

V. S . P. Chaturvedula & I. Prakash
2
6
5
.
Venkata, S.P.C.; Joshua, R.; Dennis, M.; Ulla, M.; Indra, P. Two minor diterpene
glycosides from the leaves of Stevia rebaudiana. Nat. Prod. Commun. 2011, 6, 175–178.
6
. Venkata, S.P.C.; John, F.C.; Joshua, R.; Dennis, M.; Ulla, M.; Grant, E.D.; Indra,
P. Minor diterpenoid glycosides from the leaves of Stevia rebaudiana. Phytochemistry
Lett. 2011, in press.
7
. Mothiko, U.; Toshihiro, A.; Harukuni, T.; Masakazu, T.; Teruo, M.; Norihiro, B.;
Yumiko, K.; Jun-Ichi, H.; Hoyoku, N. Inhibitory effects of cucurbitane glycosides and
other triterpenoids from the fruit of Momordica grosvenori on Epstein-Barr virus early
antigen induced by tumor promoter 12-O-tetradecanoylphorbol-13-acetate. J. Agric.
Food Chem. 2002, 50, 6710–6715.
8
. Ryoji, K.; Rui-Lin, N.; Kenji, N.; Kazuhiro, O.; Jun, Z.; Guo-Da, T.; Osamu, T. Sweet
cucurbitane glycosides from fruits of Siraitia siamensis (chi-zi-luo-han-guo), a Chinese
folk medicine. Agric. Biol. Chem. 1989, 53, 3347–3349.
9
.
Zhonghua, J.; Xiaogen, Y. A minor, sweet cucurbitane glycoside from Siraitia
grosvenorii. Nat. Prod. Commun. 2009, 4, 769–772.
1
0. Tanaka, T.; Nakashima, T.; Ueda, T.; Tomii, K.; Kouno, I. Facile discrimination of
aldose enantiomers by reversed-phase HPLC. Chem. Pharm. Bull. 2007, 55, 899–901.