Pregnane glycosides from Hoodia gordonii

Article abstract of DOI:10.1016/j.phytochem.2009.02.006

Hoodia gordonii is a 'weight loss' herb, which has gained popularity in the western countries as an appetite suppressant dietary supplement. Phytochemical study of its aerial parts led to isolation of seven pregnane glycosides (hoodigosides W-Z, hoodistan

Full text of DOI:10.1016/j.phytochem.2009.02.006

Phytochemistry 70 (2009) 675–683
Contents lists available at ScienceDirect
Phytochemistry
journal homepage: www.elsevier.com/locate/phytochem
Pregnane glycosides from Hoodia gordonii
Yatin J. Shukla a, Rahul S. Pawar b, Yuanqing Ding b, Xing-Cong Li b, Daneel Ferreira a, Ikhlas A. Khan a,b,
*
a Department of Pharmacognosy, School of Pharmacy, University of Mississippi, MS 38677, USA
b National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, University of Mississippi, MS 38677, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Hoodia gordonii is a ‘weight loss’ herb, which has gained popularity in the western countries as an appe-
tite suppressant dietary supplement. Phytochemical study of its aerial parts led to isolation of seven preg-
nane glycosides (hoodigosides W–Z, hoodistanalosides A–B). Their structures were elucidated by
chemical degradation studies and spectroscopic methods, including 1D and 2D NMR and CD spectro-
scopic methods.
Received 25 September 2008
Received in revised form 11 February 2009
Available online 19 March 2009
Keywords:
Ó 2009 Elsevier Ltd. All rights reserved.
Hoodia gordonii
Asclepiadaceae
Pregnane
Hoodistanal
Dehydrohoodistanal
Hoodigogenin A
Isoramanone
Calogenin
1. Introduction
known compounds (3, 4, 10) (Schemes 2 and 3). These constituents
were identified as the glycosides of hoodigogenin A, isoramanone,
Hoodia gordonii (Asclepiadaceae) is a succulent plant, indige-
nous to the summer rainfall regions of the Kalahari Desert in South
Africa, Namibia, and Botswana. There are 13 reported species of the
Hoodia genus, which have been a part of African food for centuries
(Anonymous, 2007; Muller and Albers, 2002). Various uses of Hoo-
dia have also been reported in African folklore such as for treat-
ment of abdominal cramps, hemorrhoids, tuberculosis, diabetes,
and as an aphrodisiac (Folden, 2008, Rubin et al., 2002). However,
it has recently been known as an appetite suppressant (Anony-
mous, 2007; MacLean and Luo, 2004; Van Heerden et al., 1998,
2007).
In our previous phytochemical studies on H. gordonii, we have
reported the isolation and characterization of 11 new oxypregnane
glycosides (hoodigosides A–K) (Pawar et al., 2007b), and 10 new
calogenin glycosides (hoodigosides L–U) (Pawar et al., 2007a).
These compounds were used as markers for developing HPLC,
and LC–MS based methods for identification, and quality control
of H. gordonii plant materials, and dietary supplements (Avula
et al., 2006, 2007). Here we report the isolation, and characteriza-
tion of seven new pregnane glycosides (1, 2, 5–9), along with three
calogenin, and two novel chemotypes of aglycones, namely hood-
istanal, and dehydrohoodistanal (Scheme 1). The structures of the
isolates were identified by extensive spectroscopic and chemical
studies.
2. Results and discussion
The CHCl3 extract of the aerial parts of H. gordonii was fraction-
ated by multistep column chromatography to yield steroidal glyco-
sides 1–10.
Based on the 13C NMR spectrum and HRESIMS m/z 1045.5711
for a sodiated molecular ion, the molecular formula for compound
1 was determined as C54H86O18. The presence of four sugar moie-
ties was evident as its 1H NMR spectrum showed signals for four
anomeric protons at dH 4.72 (d, J = 7.2 Hz), 4.94 (d, J = 11.2 Hz),
5.12 (d, J = 9.6 Hz), and 5.26 (d, J = 9.2 Hz), and corresponding car-
bon resonances at dC 106.3, 100.8, 100.7, and 96.6, respectively.
Upon acid hydrolysis, compound 1 yielded aglycone 1a. Upon com-
parison of 13C NMR and HR-MS characteristics of 1a with the re-
ported data (Pawar et al., 2007b), the structure of 1a was
confirmed as 12-O-b-tigloyl-3b,14b-dihydroxypregn-5-en-20-one
(hoodigogenin A) (Scheme 1). The E configuration of the double
bond in tigloyl(2-methyl-2-butenoic acid) substitution at C-12
was identified by the small coupling constant (J = 6.0 Hz) of the
olefinic proton at C-3* (Table 1) (Pawar et al., 2007b). With the help
* Corresponding author. Address: National Center for Natural Products Research,
Research Institute of Pharmaceutical Sciences, University of Mississippi, MS 38677,
USA. Tel.: +1 662 915 7821; fax: +1 662 915 7989
E-mail addresses: yatin.shukla@gmail.com (Y.J. Shukla), ikhan@olemiss.edu (I.A.
Khan).
0031-9422/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.phytochem.2009.02.006

676
Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
O
O
O
OH
O
OH
H
OH
OH
OH
HO
HO
HO
Hoodigogenin A (1a)
Calogenin
Isoramanone (2a)
OH
H
OH
OH
H
H
H
H
H
H
HO
CHO
HO
HO
HO
HO
OH
CHO
Hoodistanal (8a)
Pregna-5,14-diene-3 β,20−diol
(5a)
Dehydrohoodistanal (9a)
Scheme 1. Structures of aglycones for compounds 1–9 from Hoodia gordonii.
of 2D NMR (HMBC and COSY) spectroscopic data, the sugar units
were identified as three 3-O-methyl-2,6-dideoxyhexopyranoses,
and one 3-O-methyl-6-deoxyhexopyranose. These sugars were
(1?4)-b-
pound 2 was named hoodigoside X.
D-cymaropyranosyl-(1?4)-b-D-cymaropyranoside. Com-
Based on positive HRESIMS data, compounds 3 and 4 had
molecular formulae C54H86O17 (m/z 1029.5761, [M+Na]+) and
C53H83O17 (m/z 1015.5592, [M+Na]+), respectively. The 13C NMR
spectra suggested that both of these compounds contained hoodig-
ogenin A as aglycone. Further 1D and 2D NMR spectroscopic anal-
yses facilitated establishment of the structures of 3 and 4 as
gordonoside F and gordonoside D, respectively, which were previ-
ously reported from H. gordonii by Innocenti et al. (Dall’Acqua and
Innocenti, 2007). The 1H and 13C NMR chemical shifts for 3 and 4
were consistent with the reported data.
identified as
D-cymarose, D-oleandrose, and D-thevetose via the
13
hydrolysis studies. The C NMR spectrum showed that C-10 of
the first cymarose unit resonated at dC 96.6, which is characteristic
for a cymarose attached to C-3 (Table 2). This was further sup-
ported by the HMBC correlation of H-10 (dH 5.26) with C-3 (dC
77.5). H-100 (dH 5.12) of the second cymarose moiety showed
long-range correlation with C-40 (dC 83.7), and the anomeric proton
of thevetose (dH 4.72) with C-400 (dC 83.5). Further, H-4000 of theve-
tose (dH/dC 3.54/82.7) showed HMBC correlation with C-10000 of ole-
androse (dC 100.8). Thus, the sugar chain at C-3 was established as
Compound 5 was obtained as white amorphous powder. Its
3-O-b-
b- -cymaropyranosyl-(1?4)-b-
structure of hoodigoside W (1) was established as 12-O-b-tigloyl-
14b-hydroxypregn-5-en-20-one-3-O-b- -oleandropyranosyl-(1?
4)-b- -thevetopyranosyl-(1?4)-b- -cymaropyranosyl-(1?4)-b-
cymaropyranoside.
D
-oleandropyranosyl-(1?4)-b-
D-thevetopyranosyl-(1?4)-
HRESIMS spectrum showed a quasi-molecular ion [M+Na]+ at m/z
D
D-cymaropyranoside. Hence the
823.4519 that corresponded to a molecular formula C41H68O15.
The 13C NMR spectrum displayed seven methyls, 20 methines, 10
methylenes, and four quaternary carbon atoms. The 1H NMR sig-
nals for three anomeric protons were observed at dH 4.82 (d,
J = 9.2 Hz), 4.87 (d, J = 7.6 Hz), and 4.94 (d, J = 7.6 Hz), with their
corresponding carbons at dC 98.3, 104.4 and 105.2, respectively.
The sugar moieties with anomeric protons at dH 4.82 and 4.87 were
identified as 3-O-methyl-2,6-dideoxyhexopyranose and 3-O-
methyl-6-deoxyhexopyranose, respectively, and the remaining
one as a hexopyranose. These sugars were identified as oleandro-
pyranose, thevetopyranose and glucopyranose by GC–MS of the
acid hydrolysate as well as by examination of 2D NMR (HMQC,
HMBC, COSY) data. The 1H NMR signals for the aglycone portion
of 5 suggested the presence of a D5 pregnane as evidenced by a
broad olefinic proton singlet at dH 5.54. The 13C NMR spectrum
indicated three oxygenated carbons at dC 77.9 (C-3), 84.3 (C-14),
and 79.3 (C-20). To determine the skeleton of the aglycone, 5
was hydrolyzed with 0.05 N HCl to yield compound 5a. The HRE-
SIMS data of 5a had an [M+H]+ ion at m/z 317.2481 that was con-
sistent with a molecular formula C21H32O2. Based on this molecular
formula, and detailed study of the NMR spectroscopic data, the
structure of 5a was determined as pregna-5,14-diene-3b,20-diol
(Scheme 1), which was reported in our previous studies on calog-
enin glycosides (Pawar et al., 2007a). It was evident that 5a was a
product of dehydration at C-14 under the hydrolytic acidic condi-
tions. Therefore, the aglycone in compound 5 was determined to
be calogenin [(20S)-pregn-5-en-3b,14b,20-triol].
D
D
D
D-
The molecular formula of compound 2, C42H68O14, was deduced
from the [M+Na]+ ion at m/z 819.4571. The 13C NMR data for 2 was
generally similar to that of 1 except that the signals for the tigloyl
moiety were absent. Upon acid hydrolysis, compound 2 produced
aglycone 2a (Scheme 1), which was identified as isoramanone
(Warashina and Noro, 1998). 1H NMR spectroscopic data of 2
established the presence of three sugars with their anomeric pro-
tons resonating at dH 4.25 (d, J = 7.6 Hz), 4.71 (d, J = 8.8 Hz), and
4.80 (d, J = 8.8 Hz). The corresponding carbons for these anomeric
protons resonated at dC 104.3, 99.6, and 95.9, respectively (Table
2). Analysis of the acid hydrolysate identified two of these sugars
as D-cymarose, and the third as D-thevetose. The anomeric proton
of the first cymarose moiety (H-10, dH 4.80) showed HMBC correla-
tion with C-3 (dC 78.0) indicating attachment of the sugar moiety at
C-3. Further, H-100 (dH 4.71) of the second cymarose moiety showed
a three-bond correlation to C-40 (dC 82.5), and H-1000 of the theve-
tose unit showed a correlation to C-400 (dC 82.3). The C-4000 of theve-
tose (dC 74.7) resonated upfield as compared to the corresponding
signal in compound 1, confirming that thevetose was the terminal
sugar moiety of the saccharide sequence in compound 2. Based on
these observations, the structure of compound 2 was elucidated as
12b, 14b-dihydroxypregn-5-en-20-one-3-O-b-D-thevetopyranosyl-

Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
677
O
OR2
OH
R1O
R2
R1
O
O
O
O
O
HO
O
Hoodigoside W (1)
O
O
O
O
OH
O
O
Cym
O
Ole
Cym
O
The
O
Hoodigoside X (2)
Gordonoside F (3)
HO
H
O
O
O
O
O
OH
O
O
O
O
O
O
O
O
O
O
O
O
HO
O
O
O
O
O
HO
Gordonoside D (4)
O
O
O
O
O
O
OH
Dig
OR2
H
OH
R1O
R2
R1
O
HO
HO
O
O
O
HO
HO
O
OH
O
Hoodigoside Y (5)
OH
Glc
The
Ole
O
HO
HO
HO
O
O
O
O
O
Hoodigoside V (6)
Hoodigoside Z (7)
O
O
OH
O
OH
O
HO
HO
HO
O
O
O
O
O
O
O
OH
OH
O
O
Scheme 2. Structures of compounds 1–7 (Cym: D-cymarose, The: D-thevetose, Ole: D-oleandrose, Dig: D-digitoxose, Glc: D-glucose).
Analysis of the acid hydrolysate of 5 confirmed the sugar moie-
ties as -oleandrose, -thevetose, and -glucose. Compound 5a
showed upfield chemical shifts at C-3 and C-20, as compared to
5. Based on these glycosylation shifts, compound 5 was considered
D
D
D

678
Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
21
OR2
OR2
20
18
12
17
H
H
11
9
13
19
10
16
1
4
H
H
14
2
15
H
OH
CHO
H
8
OH
5
3
7
R1O
R1O
CHO
6
OH
Hoodistanaloside A (8)
Hoodistanaloside B (9)
R2
R1
O
OH
O
O
O
HO
HO
O
O
O
O
OH
Glc
OH
Ole
The
OH
O
HO
HO
O
OH
10
Scheme 3. Structures of compounds 8–10 (The: D-thevetose, Ole: D-oleandrose, Glc: D-glucose).
Table 1
1H and 13C NMR spectroscopic data for aglycone parts of 1, 2, and 5–9 in pyridine-d5 (values in parentheses denote J values in Hz).
1
2a
5–7
8
9
dH
dC
dH
dC
dH
dC
dH
dC
dH
dC
1
2
3
4
5
6
7
8
1.88, 2.32
1.63, 2.06
3.78 m
37.3
30.5
77.5
39.4
139.7
122.6
28.1
37.1
43.7
37.7
26.9
77.1
54.5
85.9
34.6
24.5
58..6
11. 0
19.7
217.1
32.3
1.02, 1.78
1.16, 1.88
3.30 m
36.9
29.7
78.0
38.6
138.9
122.1
28.9
35.6
43.4
37.3
27.4
73.2
55.1
85.5
34.5
24.4
56.8
8.4
1.13, 1.78
1.79, 2.10
3.80 m
37.9
30.3
77.9
39.6
139.9
123.2
28.2
37.7
46.8
37.7
20.1
41.1
47.8
84.3
33.7
21.8
57.6
15.6
19.9
79.3
22.1
1.86, 2.02
1.39, 1.89
4.12 m
27.2
29.9
74.6
43.3
84.9
205.3
63.5
46.9
47.0
46.1
21.1
42.1
49.7
83.9
32.7
23.5
57.1
16.4
19.5
78.0
22.1
1.24, 1.83
1.28, 2.16
4.25 m
36.7
30.1
78.3
33.2
176.1
191.4
138.1
53.1
55.5
47.0
22.1
43.8
48.9
83.1
31.9
21.9
57.5
17.1
15.2
78.1
23.7
2.31, 2.49
2.11, 2.28
2.33, 2.69
1.37, 1.60
1.47, 1.83
5.38 br s
2.53, 2.56
1.94
5.35 br s
1.11, 1.52
2.11
5.54 br s
1.96, 2.67
1.81
10.12 s
2.70 m
3.02
10.06 s
2.83 d (12.4)
1.81
9
1.36
1.16
1.26 m
1.73
10
11
12
13
14
15
16
17
18
19
20
21
1.58, 1.94
4.93 dd (4, 12)
1.29, 2.28
3.38
1.29, 1.74
1.27, 1.43
1.82, 2.04
2.11, 2.31
1.86, 2.53
1.45
1.91
1.78
1.88
3.55
0.86 s
0.93 s
1.72
1.71, 2.22
1.37, 1.52
1.68
1.43 s
1.19 s
2.25, 3.82
1.28
1.63
1.32 s
0.84 s
1.92, 1.98
3.21 m
0.92 s
1.77, 1.99
1.62 m
1.38 s
0.97 s
4.11 m
1.72 d (5.2)
1.30 s
19.4
218.5
33.1
4.12
1.43 d (8)
4.06
1.48 d (6.0)
2.25 s
2.20 s
12-O-tigloyl
1*
2*
167.9
129.6
138.2
14.7
3*
4*
5*
7.15 d (6)
1.74 d (6)
1.98 s
12.7
*
Atoms of tigloyl substituent at C-12.
Data recorded in CDCl3.
a
to be a bisdesmoside. The anomeric proton of oleandrosyl unit (H-
the anomeric proton of thevetose (H-100, dH 4.87) showed a three-
bond correlation with C-40 (dC 83.7). This established the sugar se-
10, dH 4.82) showed an HMBC correlation with C-3 (dC 77.9), while

Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
679
1.69 (d, J = 6.4 Hz), and 1.86 (s). Further, the 1H and 13C NMR sig-
nals of 6 were consistent with those of hoodigoside V (Pawar
et al., 2007a). Thus, the structure of compound 6 was determined
Table 2
1H, and 13C NMR spectroscopic data for sugar portions of 1 in pyridine-d5, and 2 in
CDCl3 (values in parentheses denote J values in Hz).
1
2
as hoodigoside V [calogenin-20-O-b-
D
-glucopyranosyl-3-O-b-(4-
O-tigloyl)- -thevetopyranosyl-(1?4)-b-
D
D-oleandropyranoside]. In
dH
dC
dH
dC
our previous study, hoodigoside V was reported as a product of
enzymatic hydrolysis. This is the first report of the natural occu-
rance of hoodigoside V.
Cym
Cym
10
5.26 br d (9.2)
1.01, 1.66
4.07
3.47
4.22
1.37 d (5.6)
3.62 s
Cym
5.12 br d (9.6)
1.91, 2.60
4.07
3.60
4.22
1.58 d (6)
3.62 s
The
4.72 d (7.2)
3.88
3.67
3.54
3.68
1.59 d (6)
3.88 s
Ole
4.94 d (11.2)
1.91, 2.60
3.49
3.51
3.62
1.58 d (6)
3.49 s
96.6
37.5
78.4
83.7
69.3
18.8
59.2
4.80 br d (8.8)
1.56, 2.11
3.75
3.20
3.83
1.25 d (6.4)
3.37 s
Cym
4.71 br d (8.8)
1.66, 2.11
3.78
3.71
3.87
1.23 d (6.4)
3.38 s
The
4.25 d (7.6)
3.43
3.06
3.43
3.41
95.9
20
35.4
77.1
82.5
68.5
18.4
57.9
30
The HRESIMS data of compound 7 gave an [M+Na]+ ion at m/z
1049.5655, which was 144 amu greater than that for hoodigoside
V (6). This suggested the presence of an additional 3-methoxy-
2,6-dideoxy sugar unit. From the 13C NMR spectroscopic data, the
aglycone moiety for compound 7 was identified as calogenin. Car-
bon chemical shifts for the tigloyl moiety were also present. HMBC
correlations provided information about sugar linkages, in which
the anomeric proton of the glucosyl unit (H-10000, dH 4.92) showed
a correlation with C-20 (dC 79.3), confirming glycosylation at C-
20. Further correlations between H-10 (dH 5.31) and C-3 (dC 77.8),
H-100 (dH 5.13) and C-40 (dC 84.9), H-1000 (dH 4.82) and C-40 (dC
84.0), and a three bond correlation between H-4000 (dH 5.15/dC
75.9) of thevetose with C-1* of the tigloyl moiety (dC 167.5) estab-
40
50
60
OMe
100
100.7
37.6
78.3
83.5
69.6
19.0
59.2
99.6
35.1
77.1
82.3
68.4
18.2
58.0
200
300
400
500
600
OMe
1000
106.3
75.0
85.8
82.7
71.8
18.9
60.7
104.3
74.4
85.9
74.7
71.7
17.9
60.8
2000
3000
lished the sugar linkage at C-3 as 3-O-b-(4-O-tigloyl)-
thevetopyranosyl-(1?4)-b- -cymaropyranosyl-(1?4)-b- -cymar-
opyranoside. Hence, the structure of hoodigoside Z (7) was
deduced as calogenin-20-O-b- -glucopyranosyl-3-O-b-(4-O-tig-
loyl)- -thevetopyranosyl-(1?4)-b- -cymaropyranosyl-(1?4)-b-
cymaropyranoside.
D-
4000
D
D
5000
6000
1.20 d (6.4)
3.59 s
D
OMe
D
D
D-
10000
20000
30000
40000
50000
60000
OMe
100.8
37.7
81.9
76.6
73.3
18.9
57.4
In HRESIMS, compound 8 gave an [M+Na]+ ion at m/z 937.4822,
indicating a molecular formula of C46H74O18. The FT-IR spectrum of
8 showed absorption bands at 3396, 1710, 1645, and 1071 cmꢀ1
indicating the presence of a hydroxy, an aldehyde, an olefin, and
an ester functionality. Upon a brief overview, the 1H and 13C
NMR spectroscopic data of 8 were similar to those of 6, suggestive
of a steroidal bisdesmoside. However, an aldehyde proton at dH
10.12, which corresponded to a carbonyl carbon at dC 205.3 instead
of the olefinic bond, and an additional oxygenated quaternary car-
bon (dC 84.9) were observed. This indicated a marked difference in
the nature of functional groups of these two compounds. Further,
analyses of the NMR spectra indicated the presence of nine meth-
yls, nine methylenes, 21 methines, and seven quaternary carbons.
Starting from the HMBC correlations of the angular methyl groups
(C-18 and C-19), the ring systems of the aglycone moiety of 8 were
established (Fig. 1). The H3-18 (dH 1.43 s) showed an HMBC corre-
lation with C-12 (dC 42.1), C-14 (dC 83.9), and C-17 (dC 57.1), which
were consistent with those observed in compound 6. However, the
correlations between H3-19 (dH 1.19 s) and C-5 (dC 84.9), C-10 (dC
46.1), C-9 (dC 47.0) and C-1 (dC 27.2) indicated presence of an
quence at C-3 to be 3-O-b-
D
-thevetopyranosyl-(1?4)-b-
D
-olean-
dropyranoside. Further, HMBC correlations between the anomeric
proton of the glucosyl unit (H-1000, dH 4.94) and C-20 (dC 79.3) con-
firmed attachment of glucose at C-20. Based on these observations,
the structure of compound 5 was established as the new bisdesmo-
side, calogenin-20-O-b-
syl-(1?4)-b- -oleandropyranoside. Compound
hoodigoside Y.
D
-glucopyranosyl-3-O-b-
D
-thevetopyrano-
D
5
was named
Compound 6 showed an [M+Na]+ ion at m/z 905.4919 that was
consistent with molecular formula C46H74O16. The 1H and 13C NMR
spectra of 6 were generally similar to those of 5, except for the
characteristic signals of a tigloyl moiety, a quartet at dH 7.04
(J = 7 Hz) for an olefinic proton, and two methyl signals at dH
OR2
H
H
OH
O
R1
O
H
R1
OH
H
O
9
8
O
HMBC
↔ROESY
Fig. 1. HMBC and ROESY correlations for compound 8 and key correlations for 9.

680
Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
B
A
3
0
0
0
-3
-10
400
-2
-6
200
250
300
λ / nm
350
400
200
250
350
λ3/0n0m
C
Fig. 2. (A) Experimental ECD spectrum for 8; (B) calculated ECD spectrum for 8a; and (C) optimized geometry of compound 8a.
Table 3
1H, and 13C NMR spectroscopic data for sugar portions of compounds 5–9 in pyridine-d5 (values in parentheses denote J values in Hz).
5
6
7
8
9
dH
dC
dH
dC
dH
dC
dH
dC
dH
dC
Ole
Ole
Cym
5.31 br d (9.6)
1.76, 2.33
Ole
Ole
10
4.82 br d (9.2)
1.77, 1.87
3.62
3.65
3.65
98.3
38.1
79.8
83.7
72.2
19.3
57.5
4.82 br d (9)
1.80, 1.83
3.61
3.67
4.18
98.3
38.2
79.8
84.3
72.2
19.3
57.7
97.2
37.5
78.3
83.7
69.3
18.8
59.1
4.71 br d (8.4)
1.74, 2.34
3.57
3.61
4.14
99.3
37.7
79.7
84.0
72.2
19.2
57.6
4.91 br d (6.4)
1.86,1.89
3.61
3.61
4.25
98.6
38.0
79.8
84.2
72.2
19.2
57.8
20
30
40
3.48
4.22
1.37 d (6.4)
3.56 s
50
60
1.79 d (5.8)
3.52 s
1.75 d (6)
3.54 s
1.70 d (6.8)
3.45 s
1.74 d (5.6)
3.55 s
OMe
The
4.87 d (7.6)
3.87
3.59
3.57
3.69
1.43 d (5.6)
3.87 s
The
4.96 d (8)
3.98
3.71
5.25 t (10)
3.74
Cym
5.26 br d (7.6)
1.76, 2.36
The
4.92 d (8.0)
3.90
3.65
5.19
3.69
1.34 d (5.6)
3.67 s
The
4.98 d (7.6)
4.04
3.65
5.15
3.70
1.36 d (6.0)
3.68 s
100
104.4
75.4
88.4
76.3
73.1
18.8
61.3
104.5
75.2
85.4
76.0
70.7
18.4
60.7
101.3
37.3
78.3
83.5
69.5
18.9
59.2
104.4
75.2
85.3
76.0
70.7
18.3
60.6
104.5
76.1
85.3
76.0
70.7
18.4
60.7
200
300
400
3.56
4.22
1.38 d (5.6)
3.62 s
500
600
1.36 d (6)
3.69 s
OMe
The
4.92 d (8)
4.22
3.68 m
5.22 t (9)
3.80
1.35 d (6.4)
1000
106.3
75.3
84.8
75.3
70.6
18.4
60.7
2000
3000
4000
5000
6000
OMe
3.70 s
Tigl
–
–
7.05 d (6.8)
1.68 d (7.6)
1.91 s
Tigl
–
–
7.03 d
1.68 d (6)
1.86 s
Glc
Tigl
–
–
7.04 d (7.2)
1.69 d (7.0)
1.89 s
Glc
Tigl
–
–
7.06 d (6.8)
1.70 d (6.4)
1.90 s
Glc
1*
2*
3*
4*
5*
167.5
129.2
138.4
14.6
167.5
129.1
138.4
14.7
167.5
129.2
138.3
14.6
167.5
129.2
138.4
14.6
12.6
12.7
12.6
12.6
Glc
Glc
10000
20000
30000
40000
50000
60000
4.94 d (7.6)
3.87
3.87
4.13
4.13
105.2
75.5
78.8
71.7
78.3
63.1
4.91 d (7)
3.94
3.94
3.74
4.15
105.3
75.5
78.9
71.8
78.3
63.1
4.91 d (6.8)
3.90
4.08
4.14
105.0
75.2
79.9
72.3
78.9
63.7
4.86 d (6.8)
3.90
4.08
4.14
105.0
75.1
79.6
71.8
78.8
63.1
4.91 d (6.4)
3.95
3.94
4.25
3.94
106.2
75.3
79.0
72.0
78.7
63.3
3.87
3.87
4.31 m, 4.49 d
(11.2)
4.34 m, 4.53 br d
(11.0)
4.32 dd (4.8, 11.6), 4.50
d (10.0)
4.32 dd (4.8, 11.6), 4.50
d (10.0)
4.40 m, 4.57 d
(10.8)
*
Atoms of tigloyl substituent on the terminal sugar moiety.

Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
681
oxygenated quaternary carbon at C-5. The aldehydic proton H-6
(dH 10.12) showed a two-bond correlation to C-7 (dC 63.5) that
indicated attachment of the aldehyde functionality at C-7. Based
on these observations, a preliminary structure for the aglycone
was contemplated as 3,5,14,20-tetrahydroxy-5(6?7)abeo-preg-
nan-7-al. Previously, orostanal, a related B ring abeo derivative of
cholesterol, was reported from a marine sponge Stelletta hivasaen-
sis, and the chemical shift values for rings A and B for compound 8
were comparable to those for orostanal (Miyamoto et al., 2001).
The relative configuration of the aglycone was determined by the
ROESY spectrum, in which correlations between H-7 (dH 2.70)
and methines H-8 (dH 3.02), and H-4b (dH 1.37) confirmed the b-
orientation of H-7. Further, interactions between methyl protons
H3-19 (dH 1.19)/H-8 (dH 3.02), and H-6 (dH 10.12)/H-9 (dH 1.73),
and sugar moieties of compound 9 were comparable to those of
compound 8. Hence, compound 9 was considered as a C-5
dehydrated product of 8. Based on this, the structure of hoodist-
analoside B (9), a new natural product, was deduced as 14b-hydro-
xy-5(6?7)-abeo-pregn-5-en-7-al-20-O-b-
D-glucopyranosyl-3-O-b-
(4-O-tigloyl)-D-thevetopyranosyl-(1?4)-b-D-oleandropyranoside.
Compound 10 showed an [M+H2O]+ ion in HRESIMS at 594.4703
corresponding to a molecular formula of C35H60O6. Comparison of
NMR spectroscopic data with reported information established
the structure of compound 10 as stigmast-5-en-3-O-b-D-glucopy-
ranoside (Kadowaki, 2003).
3. Concluding remarks
in turn indicated the
a-orientation of the aldehyde moiety. A
Previous phytochemical studies have shown that H. gordonii
contains an abundance of pregnane glycosides, which comprise
of hoodigogenin A, and calogenin as the aglycones (Dall’Acqua
and Innocenti, 2007; Pawar et al., 2007a, 2007b). Hoodigogenin A
is an unique pregnane derivative from Hoodia, due to the tigloyl es-
ter substitution at C-12. Although calogenin bisdesmosides have
been reported from other plants in Asclepiadaceae family (Al-
Yahya et al., 2000; Deepak et al., 1996; Siciliano et al., 2005; Sigler
et al., 2000; Srivastava et al., 2007; Trivedi et al., 1989), the tigloyl
functionality attached at the C-4 of terminal sugar is a distinctive
feature of calogenin glycosides from H. gordonii. The present com-
munication reports structures of two new hoodigogenin A glyco-
sides (1, 2), two new glycosides of calogenin (5, 7) and two
glycosides (8, and 9), which comprise of novel chemotypes of agly-
cones, namely hoodistanal (8a) and dehydrohoodistanal (9a). Nat-
ural occurrences of such 6-5-6-5 fused ring sterols, like compounds
8 and 9 are rare. There have been only two reports of abeo-sterols
from marine sponges (Miyamoto et al., 2001; Wei et al., 2007), and
one from a terrestrial plant (Lin et al., 1998). Hoodistanalosides A
and B are the first two naturally occurring glycosides, comprising
a 5(6?7)abeo-sterol aglycone.
ROESY correlation was also observed between H-20 (dH 4.12) and
H3-18 (dH 1.43) that confirmed the b-orientation of H-20, and thus
indicated the configuration at C-20 to be 20S.
Further the absolute configuration of the aglycone (8a) was
determined by comparison of its theoretically calculated electronic
circular dichroism (ECD) spectrum, and the experimental ECD of
the glycoside (8), assuming both the aglycone and the glycoside ex-
hibit similar ECD spectra. This assumption was based on the fact
that the sugar moieties in glycosides (e.g., flavanone or 3-hydrox-
yflavanone glycosides) (Gaffield, 1970) generally have little effect
on their overall experimental ECD spectra. The calculated results
showed that the negative Cotton effect (CE) at 293 nm attributable
to the aldehyde p?p
* transition in 8a, corresponds to the negative
CE at 300 nm in the experimental ECD spectrum of 8 in methanol.
Therefore, the aglycone possesses 5S, 7S, 8S, 20S absolute configu-
ration (Fig. 2). The major reason using the aglycone for theoretical
ECD calculation was to reduce the ‘size’ of the molecule and hence
conformational ‘‘freedom” in order to facilitate practical calcula-
tions with available computational methods. In addition, the agly-
cone of 8 is not readily accessible by chemical degradation due to
its acid-lability.
The anomeric region of the 1H NMR spectrum of 8 showed three
doublets at dH 4.71 (J = 10.2 Hz), 4.92 (J = 8.0 Hz), and 4.88
(J = 7.6 Hz) corresponding to carbons at dC 99.3, 104.4 and 105.0,
respectively. Based on the 2D NMR spectroscopic data, and the
hydrolysis studies, the sugar moiety with the anomeric proton at
4. Experimental
4.1. General experimental procedures
NMR spectra were recorded on a Varian AS400 NMR spectro-
scope at 400 MHz (1H) and 100 MHz (13C). Proton and carbon
chemical shift values are relative to internal standard TMS and
were acquired in C5D5N and CDCl3. High-resolution mass spectra
(positive) were acquired using electro-spray ionization (ESI)
source, on an Agilent Series 1100 SL spectrometer. Optical rota-
tions were measured on the Autopol IV polarimeter and specific
rotations are expressed as deg.10.gꢀ1.cm2. The ECD spectrum of
compound 8 was recorded on Jasco J-715 CD spectropolarimeter,
in MeOH at 0.5, 1 and 2 mg/mL. TLC analyses were carried out on
silica gel 60 F254 plates (Merck, Germany) using CHCl3/MeOH/
H2O (90:10:0.5, 90:12:1) and C-18 reversed phase silica TLC plates
(Analtech, USA) with MeOH/H2O (70:30, 75:25). Compounds were
visualized by spraying with anisaldehde-H2SO4 followed by heat-
ing at 105 °C for 1–2 min Column chromatography (CC) was
dH 4.71 was recognized as
D
-oleandrose, the one with the anomeric
-glucose.
proton at dH 4.92 as -thevetose, and the third sugar as
D
D
The chemical shift values for the sugar protons and carbons were
consistent with those of compound 6 (see Table 3). HMBC correla-
tions facilitated determination of the sugar linkages. The HMBC
correlations of H-1000 of glucose (dH 4.88) to C-20 (dC 78.0) con-
firmed attachment of glucose at C-20. Further, the correlations of
H-10 of oleandrose (dH 4.71) with C-3 (dC 74.6), H-100 of thevetose
(dH 4.92) with C-40 (dC 84.0) and H-400 of thevetose (dC 75.9) with
dC 167.5 indicated the presence of the sugar chain at C-3 as
b-(4-O-tigloyl)-
Thus, the structure of 8 was elucidated as a novel abeo-sterol
glycoside, ,14b-dihydroxy-5(6?7)abeo-pregnan-7 -al-20-O-b-
-glucopyranosyl-3-O-b-(4-O-tigloyl)- -thevetopyranosyl-(1?4)-
-oleandropyranoside, and was named hoodistanaloside A.
The HRESIMS for compound 9 showed a sodiated molecular ion
D-thevetopyranosyl-(1?4)-b-D-oleandropyranoside.
5a
a
D
D
b-D
carried out on silica gel (JT Baker, 40–60
phy) and reversed phase C18 silica gel (Polarbond, JT Baker). Sugars
were identified by GC–MS of their alditol acetates. -thevetose and
-glucose were obtained from Sigma–Aldrich (USA).
lm for flash chromatogra-
at m/z 919.4671, which was 18 amu less than that of 8, indicating
loss of a water molecule. The molecular formula of C46H73O17 was
further corroborated by the 13C NMR spectrum that indicated the
presence of an additional pair of olefinic carbon atoms at dC
176.1 and 138.1. Compared to compound 8, the aldehydic carbon
was shifted upfield at dC 191.4 (Table 1) in compound 9. This, along
with the other important HMBC correlations (Fig. 1), defined the
D
D
4.2. Plant material
Powdered whole aerial parts of H. gordonii were purchased from
Psychoactive Herbs Ltd. (www.psychoactiveherbs.com) in
September 2005. The plant material was authenticated by compar-
double bond at
chemical shift values for other atoms of the aglycone part (9a),
D
5–7, and the aldehyde functionality at C-7. The

682
Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
ing with an authentic sample of H. gordonii provided by the Mis-
souri Botanical Garden, Missouri, USA. Chemical authentication
was done by comparing the HPLC fingerprint of the methanol ex-
tract of the purchased material with that of the authentic sample
of H. gordonii. A voucher specimen (voucher no. 2799) has been
deposited in the repository of National Center for Natural Product
Research.
troscopic data, see Tables 1 and 3; HRESIMS m/z 1049.5655 (calcd
for C53H86O19Na, [M+Na]+ m/z 1049.5583).
4.3.6. Hoodistanaloside A (8)
White amorphous powder; ½a D25
ꢀ22.7 (c 0.3, MeOH); IR (NaCl)
ꢂ
m
max 3368, 2932, 1710, 1690, 1059 cmꢀ1; for 1H NMR and 13C NMR
spectroscopic data, see Tables 1 and 3; HRESIMS m/z 937.4822
(calcd for C46H74O18Na, [M+Na]+ m/z 937.4815).
4.3. Extraction and isolation
4.3.7. Hoodistanaloside B (9)
White amorphous powder; ½a D25
ꢀ27.3 (c 0.2, MeOH); IR (NaCl)
ꢂ
m
max 3445, 2940, 1714, 1687, 1057 cmꢀ1; for 1H NMR and 13C NMR
Coarsely powdered H. gordonii material (4.75 kg) was extracted
by percolation with CHCl3 (4 ꢁ 4 L). The extracts were combined
and concentrated to obtain a thick mass (402.1 g). The latter was
dissolved in MeOH/H2O (95:5) and partitioned with hexanes. The
polar fraction (136 gm) was subjected to VLC on silica gel
(1500 gm) by eluting with gradients of CHCl3/MeOH/H2O from
100:4:0.5 (3 L), up to 90:12:0.5 (by increasing MeOH and reducing
CHCl3, each by 1% increments), to generate eight sub-fractions
(fr.1–fr.8).
Upon storing overnight at room temperature, a white precipi-
tate was formed in sub-fraction 8. This precipitate was washed
with hexanes and acetone to obtain compound 10 (71 mg). Upon
chromatographic separation on an RP-18 column with MeOH/
H2O (7:3), as eluant sub-fraction 2 afforded compound 2 (52 mg).
Sub-fraction 4 was subjected to multiple reversed phase column
chromatography separations, using MeOH/H2O (7:3) to obtain
compounds 1 (75 mg), 3 (8 mg), and 4 (206 mg). Sub-fraction 6
was subjected to silica gel CC with linear gradients of CHCl3/MeOH
(99:1) to isolate the major compound 6 (1.3 gm), CHCl3/MeOH
(97:3) to obtain compound 8 (38 mg), and CHCl3/MeOH (95:5) to
yield compound 9 (5.5 mg). Sub-fraction 8 was subjected to re-
versed phase (C-18) CC using MeOH/H2O (6:4), followed by re-
peated purification on silica gel column using an isocratic solvent
system of CHCl3/MeOH/H2O (90:8:0.5) that yielded compounds 5
(41 mg) and 7 (26 mg).
spectroscopic data, see Tables 1 and 3; HRESIMS m/z 919.4663
(calcd for C46H72O17Na, [M+Na]+ m/z 919.4661).
4.4. Acid hydrolysis of glycosides
A mixture of compounds 1, 3, and 4 (50 mg) was hydrolyzed
with 0.05 N HCl in 50% 1,4-dioxane at 90 °C for 2 h. The resulting
mixture was partitioned with CHCl3. The CHCl3 layer was dried
and subjected to CC on silica gel by eluting with gradients of CHCl3
and MeOH to obtain aglycone 1a (13 mg). Similarly, compound 2
(10 mg) and compound 5 (10 mg) were hydrolyzed using the same
protocol to obtain aglycones 2a (1 mg) and 5a (1.8 mg), respec-
tively (Scheme 1). 2a and 5a were purified from the reation mix-
ture by preparative TLC using CHCl3:MeOH (95:5). Structures of
aglycones 1a, 2a, and 5a were established by NMR spectroscopy.
4.5. Sugar analysis
Each compound (ca. 1 mg) was hydrolyzed as described above,
and the polar fraction obtained after partitioning with CHCl3 was
used for sugar analyses. Alditol acetates of sugars were prepared
(Sawardekar et al., 1965). Thus, the sugar portion was dissolved
in water and reduced with NaBH4 at room temperature for 3 h,
and the reaction mixture was neutralized with AcOH. To the dried
material, equal amounts of pyridine and Ac2O were added and
heated at 95 °C for 1 h. After cooling, H2O was added and alditol
acetates were extracted with CHCl3, which were subjected to
4.3.1. Hoodigoside W (1)
White amorphous powder; ½a D25
ꢂ
+3.3 (c 0.3, MeOH); IR (NaCl)
mmax 3392, 2933, 1713, 1648, 1067 cmꢀ1; for 1H NMR and 13C
NMR spectroscopic data, see Tables 1 and 2; HRESIMS m/z
1045.5711 (calcd for C54H86O18Na, [M+Na]+ m/z 1045.5706).
GC–MS analysis (column, JW DB-5, 30 m ꢁ 0.25 mm, 0.25
lm; car-
rier gas He; injection temp. 280 °C, detection temperature 280 °C,
column temperature; 150 °C (1 min), 10 °C/min to 250 °C, reten-
tion times: tR cymaritol acetate 5.34 min, tR oleandritol acetate
5.65 min, tR thevititol acetate 7.63 min, tR glucitol acetate
10.48 min). Glucose (1.7 mg), thevetose (2.3 mg), cymarose
(5.6 mg) and oleandrose (2.7 mg) were obtained from hydrolysis
of subfraction 4 (300 mg) by using the method described in Section
4.4. The absolute configurations of thevetose and glucose were
determined via GC–MS as described before (Hara et al., 1987; Pa-
war et al., 2007b). Retention times of acetylated thiazolidine deriv-
atives of glucose (tR 23.44 min) and thevetose (tR 16.29 min) were
compared with those of the acetylated thiazolidine derivatives
4.3.2. Hoodigoside X (2)
White amorphous powder; ½a D25
ꢀ20.0 (c 0.3, MeOH); IR (NaCl)
ꢂ
m
max 3398, 2930, 1713, 1646, 1071 cmꢀ1; for 1H NMR and 13C NMR
spectroscopic data, see Tables 1 and 2; HRESIMS m/z 819.4571
(calcd for C42H68O14Na, [M+Na]+ m/z 819.4501).
4.3.3. Hoodigoside Y (5)
White amorphous powder; ½a D25
ꢀ16.7 (c 0.25, MeOH); IR (NaCl)
ꢂ
max 3395, 2932, 1711, 1646, 1076 cmꢀ1; for 1H NMR and 13C NMR
synthesized from standard sugars (tR
D-glucose 23.4 min, tR L-glu-
m
cose 25.38 min, tR -thevetose 16.33 min). Both cymarose and ole-
D
spectroscopic data, see Tables 1 and 3; HRESIMS m/z 823.4519
(calcd for C41H68O15Na, [M+Na]+ m/z 823.4450).
androse were considered to be in D-form based on their specific
rotations (
D
-cymarose ½a 2D5
ꢂ
+55.55 (c 0.9, H2O); and D-oleandrose
½
a 2D5
ꢂ
ꢀ15.90 (c 0.7, H2O)).
4.3.4. Hoodigoside V (6)
White amorphous powder; ½a D25
ꢀ12.0 (c 0.23, MeOH); IR (NaCl)
ꢂ
4.6. Electronic circular dichroism calculations
m
max 3393, 2932, 1711, 1650, 1060 cmꢀ1; for 1H NMR and 13C NMR
spectroscopic data, see Tables 1 and 3; HRESIMS m/z 905.4882
For theoretical ECD calculations for compound 8a, ground state
geometries have been optimized at B3LYP/6-31G* level in gas
phase, vibrational harmonic frequencies have been calculated to
verify the minimum time dependent density functional theory
(TDDFT), and have been performed at B3LYP-SCRF/6-31G*//
B3LYP/6-31G* level with ‘‘COnductor-like continuum Solvent MOd-
(calcd for C58H94O25Na, [M+Na]+ m/z 905.4869).
4.3.5. Hoodigoside Z (7)
White amorphous powder; ½a D25
ꢀ22.4 (c 0.25, MeOH); IR (NaCl)
ꢂ
m
max 3389, 2934, 1710, 1068 cmꢀ1; for 1H NMR and 13C NMR spec-

Y.J. Shukla et al. / Phytochemistry 70 (2009) 675–683
683
Determination of aglycone chirality in flavanone glycosides. Tetrahedron 26,
4093–4108.
Hara, S., Okabe, H., Mihashi, K., 1987. Gas–liquid chromatographic separations of
aldose enantiomers as trimethylsilyl ethers of methyl-2-(polyhydroxyalkyl)-
thiazolidine-4(R)-carboxylate. Chem. Pharm. Bull. 35, 501–506.
Kadowaki, E., 2003. Z. Naturforsch. Sect. C 58, 441–445.
Klamt, A., Schurmann, G., 1993. COSMO – a new approach to dielectric screening in
solvents with explicit expressions for the screening energy and its gradient. J.
Chem. Soc., Perkin Trans. 2, 799–805.
Lin, W.-H., Fang, J.-M., Cheng, Y.-S., 1998. Diterpenoids and steroids from Taiwania
cryptomerioides. Phytochemistry 48, 1391–1397.
MacLean, D.B., Luo, L.-G., 2004. Increased ATP content/production in the
hypothalamus may be a signal for energy-sensing of satiety: studies of the
anorectic mechanism of a plant steroidal glycoside. Brain Res. 1020, 1–11.
Miyamoto, T., Kodama, K., Aramaki, Y., Higuchi, R., Soest, R.V., 2001. Orostanal, a
novel abeo-sterol inducing apoptosis in leukemia cell from a marine sponge,
Stelletta hiwasaensis. Tetrahedron Lett. 42, 6349–6351.
el” (COSMO) (Ding et al., 2007; Klamt and Schurmann, 1993; Pecul
et al., 2005; Sinnecker et al., 2006). All computations were carried
out at 298 K by using the Gaussian03 program package. The calcu-
lated rotatory strengths R in dipole length form (Rlen) were simu-
lated into an ECD curve by using the Gaussian function:
A
X
1
1
½ꢀðEꢀ
DEi=2
r
Þꢂ2
pffiffiffiffiffiffiffiffiffi
D
2 ðEÞ ¼
DEiRie
2:297 ꢁ 10ꢀ39
2
pr
i
where
r
is the width of the band at 1/e height and
D
Ei and Ri are the
excitation energies and rotatory strengths for transition i, respec-
tively = 0.10 eV was used.
r
Acknowledgements
Muller, B., Albers, F., 2002. Illustrated Handbook of Succulent Plants. Springer. pp.
142–146.
Pawar, R., Shukla, Y.J., Khan, I.A., 2007a. New calogenin glycosides from Hoodia
gordonii. Steroids 72, 881–891.
Pawar, R.S., Shukla, Y.J., Khan, S.I., Avula, B., Khan, I.A., 2007b. New oxypregnane
glycosides from appetite suppressant herbal supplement Hoodia gordonii.
Steroids 72, 524–534.
Pecul, M., Marchesan, D., Ruud, K., Coriani, S., 2005. Polarizable continuum model
study of solvent effects on electronic circular dichroism parameters. J. Chem.
Phys. 122, 024106.
Rubin, I.D., Cawthorne, M.A., Bindra, J.S., 2002. Extracts, compounds and
pharmaceutical compositions having anti-diabetic activity and their use.
European Patent, EP 2001-305172, 1166792, 26 pp.
Sawardekar, J.S., Sloneker, J.H., Jeanes, A., 1965. Quantitative determination of
monosaccharides as their alditol acetates by gas liquid chromatography. Anal.
Chem. 37, 1602–1604.
Siciliano, T., Bader, A., De Tommasi, N., Morelli, I., Braca, A., 2005. Sulfated pregnane
glycosides from Periploca graeca. J. Nat. Prod. 68, 1164–1168.
Sigler, P., Saksena, R., Deepak, D., Khare, A., 2000. C-21 steroidal glycosides from
Hemidesmus indicus. Phytochemistry 54, 983–987.
Sinnecker, S., Rajendran, A., Klamt, A., Diedenhofen, M., Nisse, F., 2006. Calculation
of solvent shifts on electronic G-tensors with the conductor-like screening
model (COSMO) and its self-consistent generalization to real solvents (direct
COSMO–RS). J. Phys. Chem. A 110, 2235–2245.
Part of the research was funded by ‘‘Botanical Dietary Supple-
ments: Science-Base for Authentication” of the US Food and Drug
Administration Grant No. FD-U-002071-07. The authors would like
to thank Missouri Botanical Garden, USA for authentic plant mate-
rial and Dr. V. Joshi for plant identification. The authors also thank
Dr. B. Avula for assistance in acquiring the mass data. Y.J.S. is
thankful to NCNPR for graduate research assistantship.
References
Al-Yahya, M.A.-A., Abdel-Sattar, E., Guittet, E., 2000. Pregnane glycosides from
Caralluma russeliana. J. Nat. Prod. 63, 1451–1453.
Anonymous, 2007. Bogus raw material tarnishes Hoodia’s equity, but committed
report strong sales. Nutr. Bus. J. 12, 12–14.
Avula, B., Wang, Y.-H., Pawar, R.S., Shukla, Y.J., Schaneberg, B., Khan, I.A., 2006.
Determination of the appetite suppressant P57 in Hoodia gordonii plant extracts
and dietary supplements by liquid chromatography/electrospray ionization
mass spectrometry (LC–MSD–TOF) and LC–UV methods. J. AOAC Int. 89, 606–
611.
Avula, B., Wang, Y.H., Pawar, R.S., Shukla, Y.J., Khan, I.A., 2007. Chemical
fingerprinting of Hoodia species and related genera: chemical analysis of
oxypregnane glycosides using high-performance liquid chromatography with
UV detection in Hoodia gordonii. J. AOAC Int. 90, 1526–1531.
Dall’Acqua, S., Innocenti, G., 2007. Steroidal glycosides from Hoodia gordonii.
Steroids 72, 559–568.
Deepak, D., Srivastava, S., Khare, A., 1996. Pregnane glycosides from Hemidesmus
indicus. Phytochemistry 44, 145–151.
Ding, Y., Li, X.-C., Ferreira, D., 2007. Theoretical calculation of electronic circular
dichroism of the rotationally restricted 3,800-biflavonoid morelloflavone. J. Org.
Chem. 72, 9010–9017.
Srivastava, S., Khare, N.K., Khare, A., 2007. Three pregnane glycosides from
Pergularia pallida. Nat. Prod. Commun. 2, 27–33.
Trivedi, R., Khare, A., Khare, M.P., 1989. A pregnane ester oligoglycoside from
Oxystelma esculentum. Phytochemistry 28, 1211–1213.
Van Heerden, F.R., Vleggaar, R., Horak, R.M., Learmonth, R.A., Maharaj, V. and
Whittal, R.D., 1998. Steroidal glycosides, methods for their production and
preparation, pharmaceutical compositions containing them, and their use as
appetite suppressants. International Patent, WO 98-GB1100, 9846243, 162 pp.
Van Heerden, F.R., Marthinus, H.R., Maharaj, V.J., Vleggaar, R., Senabe, J.V., Gunning,
P.J., 2007. An appetite suppressant from Hoodia species. Phytochemistry 68,
2545–2553.
Folden, W., 2008. Information document on trade in Hoodia gordonii and other
Warashina, T., Noro, T., 1998. Steroidal glycosides from the roots of Metaplaxis
japonica M. Part II. Chem. Pharm. Bull. 46, 1752–1757.
Hoodia species.
S
A
National Biodiversity Institute. Available from:
<www.plantzafrica.com/frames/plantsfram.htm>, accessed 03.03.09.
Gaffield, W., 1970. Circular dichroism, optical rotatory dispersion, and absolute
configuration of flavanones, 3-hydroxyflavanones, and their glycosides.
Wei, X., Rodriguez, A.D., Wang, Y., Franzblau, S.G., 2007. Novel ring B abeo-sterol as
growth inhibitors of Mycobacterium tuberculosis isolated from a Caribbean Sea
sponge, Svenzea zeai. Tetrahedron Lett. 48, 8851–8854.