Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica Bojer ex Hook.

Article abstract of DOI:10.1016/j.phytol.2015.03.006

Phytochemical study on the methanolic extract of Sansevieria cylindrica aerial parts lead to the isolation, characterization and structure elucidation of a new steroidal saponin, 1β-hydroxy-kryptogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside (1), a new homoisoflavanone, (3S)-3,7-dihydroxy-8-methoxy-3-(3′,4′-methylenedioxybenzyl) chroman-4-one (2) and the known saponin alliospiroside A (3). To the best of our knowledge, the genin 1β-hydroxy-kryptogenin is reported here for the first time. The structures of the new compounds were determined by UV, IR, EIMS, HRESIMS together with 1D (¹H and ¹³C) and 2D (HSQC and HMBC) NMR spectral analysis. The isolated compounds 1-3 were tested for their radical scavenging activity (DPPH). Compound 2 exhibited activity compared to that of ascorbic acid as a standard. The cytotoxicity of the isolated compounds and the standard doxorubicin was tested against the three human tumor cell lines HT116, MCF-7 and PC-3. The results showed that the isolated compounds were inactive.

Full text of DOI:10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
Phytochemistry Letters xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Phytochemistry Letters
journal homepage: www.elsevier.com/locate/phytol
1
2
3
Steroidal saponins and homoisoflavanone from the aerial parts of
Sansevieria cylindrica Bojer ex Hook.
a
b
c
4
5
Q1 Ataa Said , Elsayed Ali Aboutabl , Farouk Rasmy Melek ,
d
a,
Gehad Abdel Raheem Abdel Jaleel , Mona Raslan *
a
6
7
8
9
Pharmacognosy Department, National Research Centre, Dokki, 12622 Giza, Egypt
b
Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr-el-Aini Street, 11562 Cairo, Egypt
c
Chemistry of Natural Compounds Department, National Research Centre, Dokki, 12622 Giza, Egypt
d
Pharmacology Department, National Research Centre, Dokki, 12622 Giza, Egypt
A R T I C L E I N F O
A B S T R A C T
Article history:
Phytochemical study on the methanolic extract of Sansevieria cylindrica aerial parts lead to the isolation,
Received 28 November 2014
Received in revised form 23 February 2015
Accepted 6 March 2015
Available online xxx
characterization and structure elucidation of a new steroidal saponin, 1
b
-hydroxy-kryptogenin-1-O-
-arabinopyranoside (1), a new homoisoflavanone, (3S)-3,7-dihydroxy-
-methoxy-3-(3 ,4 -methylenedioxybenzyl) chroman-4-one (2) and the known saponin alliospiroside A
-hydroxy-kryptogenin is reported here for the first time.
The structures of the new compounds were determined by UV, IR, EIMS, HRESIMS together with 1D
a-
L
-rhamnopyranosyl-(1 ! 2)-
a-L
0
0
8
(3). To the best of our knowledge, the genin 1b
Keywords:
1
13
(
H and C) and 2D (HSQC and HMBC) NMR spectral analysis. The isolated compounds 1–3 were tested
Sansevieria cylindrica
Dracaenaceae
Steroidal saponin
Homoisoflavanone
Cytotoxicity
for their radical scavenging activity (DPPH). Compound 2 exhibited activity compared to that of ascorbic
acid as a standard. The cytotoxicity of the isolated compounds and the standard doxorubicin was tested
against the three human tumor cell lines HT116, MCF-7 and PC-3. The results showed that the isolated
compounds were inactive.
Antioxidant
ß 2015 Published by Elsevier B.V. on behalf of Phytochemical Society of Europe.
1
1
0
1
1. Introduction
glycosides and ten new steroidal saponins were isolated from S. 26
trifasciata (Mimaki et al., 1996a,b, 1997). Sansevistatins 1 and 2 27
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Q3
Sansevieria belongs to family Dracaenaceae (Patil and Pai,
2011), is a genus of xerophytic perennial herbs growing in dry
tropical and subtropical parts of the world. The genus consists of
about 70 species with a distribution ranging from Africa through
Asia to Burma and the islands of the Indian Ocean (Takawira and
Nordal, 2003). Some species have an ethnopharmacological
background, in particular S. trifasciata which in tropical America
and South Africa, is used for the treatment of inflammatory
conditions and marketing as a crude drug for snakebite treatment
(Morton, 1981). Literature survey revealed that phytochemical
studies carried out on some Sansevieria species, led to the isolation
of several steroidal sapogenins and saponins. 25 S-ruscogenin and
new steroidal saponin with pregnane-type, were reported from S.
hyacinthoides (Gamboa-Angulo et al., 1996). Four new pregnane
isolated from the African S. ehrenbergii were shown to possess 28
anticancer activity against the P388 lymphocytic leukemia cell line 29
and a panel of human cancer cell lines. Sansevistatin 2 and other 30
saponins isolated from the same source, exhibited antifungal 31
activity against Candida albicans and Cryptococcus neoformans 32
(Pettit et al., 2005). From the leaves of S. cylindrica, a new steroidal 33
saponin was isolated and showed inhibition of the capillary 34
permeability activity (Da Silva Antunes et al., 2003).
35
Sansevieria cylindrica Bojer ex Hook. native to the subtropical 36
regions of the African continent, is cultivated in Egypt for 37
ornamental purposes. As a part of our interest in investigating 38
plants cultivated in Egypt, we describe in this report the isolation 39
and characterization of two steroidal saponins 1 and 3 including a 40
new one 1 together with one new homoisoflavonoid 2. The 41
structures ofthenew compoundsweredetermined bythecombined 42
use of EIMS, HRESIMS, UV and IR together with 1D and 2D NMR. The 43
isolated compounds were tested for their antioxidant activity and 44
*
Corresponding author. Tel.: +20 1143036424.
Q2
cytotoxicity against human cancer cell lines.
45
E-mail address: Azzam_mona@yahoo.com (M. Raslan).
http://dx.doi.org/10.1016/j.phytol.2015.03.006
874-3900/ß 2015 Published by Elsevier B.V. on behalf of Phytochemical Society of Europe.
1
Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
2
A. Said et al. / Phytochemistry Letters xxx (2015) xxx–xxx
+
4
6
2. Results and discussion
[M-H
2
O+H] at 707.4001 was also observed. IR spectrum of 1
57
58
59
60
61
62
63
64
65
66
67
68
69
ꢀ
1
displayed absorption bands at 3406 and 1047 cm , suggesting its
glycosidic nature, in addition to a characteristic strong absorption
4
4
7
8
2.1. Isolation, characterization and structure elucidation of
compounds
ꢀ
1
1
13
band at 1725 cm (C 55 O). The combined analysis of H and
NMR resonances of 1 in CD OD (Table 1), showed the presence of
four methyl groups [( 15.8/0.93) (3H, d, J = 6.8 Hz), 14.0/1.07
(3H, d, J = 6.8 Hz), 14.7/1.12 (3H, s) and 12.3/0.85 (3H, s)], two
carbonyl functions ( 219.2 and 215.6), an olefinic group [(
124.3/5.58) (d, J = 5.2 Hz) and 138.4] and a hydroxymethylene
group [ 66.8/3.43, 3.36], suggesting a steroidal moiety. The
glycosidic nature of 1 was confirmed by acid hydrolysis which
afforded sugar components identified as -arabinose and
rhamnose. The two anomeric proton resonances [ 99.6/4.31
C
3
49
50
51
52
53
54
55
56
The 70% aqueous methanolic extract of Sansevieria cylindrica
unflowering aerial parts was subjected to repeated column
chromatography to afford two new compounds 1 and 2 as well
as the known compound alliospiroside A 3 (Huang et al., 2013).
Compound 1 was isolated as colorless amorphous solid. It
C H
d /d
d
C
C H
d /d
d
C
C H
d /d
+
showed pseudo-molecular ion peaks [M+Na] at m/z 747.3926 and
+
[M+K] at m/z 763.3666 in the positive HRESIMS corresponding
L
L-
to the molecular formula C38
H
60
O
13. A prominent fragment ion
C H
d /d
Table 1
1
13
13
H and C-NMR data of compound 1, its acetate derivative 1a and selected C-NMR data of alliospiroside A 3.
C
1
3
1a
d
C
d
H
d
C
d
C
d
C
d
H
(CD
3
OD)
(CD
3
OD)
(C
5
D
5
N)
(C
5
D
5
N)
(CD
3
OD)
3
(CD OD)
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
83.2
37.1
69.4
41.3
3.42
83.6
37.2
67.7
43.6
139.4
125.0
31.4
32.1
49.8
42.6
23.5
37.4
41.3
51.2
38.9
213.2
66.3
15.4
14.8
43.5
12.9
217.9
37.2
27.4
35.9
67.2
17.1
83.4
37.2
83.3
36.9
70.1
41.4
136.5
125.9
30.9
31.9
49.6
41.9
23.4
38.8
41.9
51.4
37.9
215.0
66.2
12.4
14.7
43.3
13.7
219.0
39.0
26.5
31.8
69.0
15.8
3.60 (dd, 12.0, 4.0)
2.18, 1.70
3.77
68.0
2.22, 2.20
–
43.4
138.4
124.3
31.1
32.1
49.8
42.0
23.2
39.0
42.0
51.4
37.1
215.6
66.5
12.3
14.7
43.4
14.0
219.2
39.4
26.5
34.9
66.8
15.8
139.3
124.5
5.58 (brd, 5.2)
1.93, 1.59
1.54
1.43
50.2
42.7
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
–
2.68, 1.50
1.98, 1.60
–
1.62
2.12, 1.72
–
2.57 (d, 12.0)
0.85 (s)
1.12 (s)
2.70
1.07 (d, 6.8)
–
2.72, 1.70
1.75, 1.37
1.63
3.43, 3.36
0.93 (d, 6.8)
1
-O-sugars
Ara
0
1
99.6
74.3
74.7
67.7
66.8
4.31 (d, 6.8)
100.4
75.0
75.8
69.9
67.2
100.2
74.9
75.7
69.9
68.0
99.2
74.2
74.2
68.5
63.7
4.63 (d, 7.6)
0
2
3.72
3.86 (dd, 8.0,8.0)
5.10 (dd, 8.0,3.8)
5.03 (brs)
0
3
3.48
0
4
3.88
0
5
3.84, 3.54 (d, 12.0)
3.78 (d, 2.0)
3.59 (dd, 12.0,3.0)
Rha
0
1
100.2
70.9
70.7
72.7
68.3
17.1
5.31 (brs)
3.92
101.5
72.3
72.3
74.0
69.2
18.9
101.5
72.4
72.3
74.0
69.2
18.8
96.6
71.3
70.2
72.1
66.5
16.9
170.2
5.14 (brs)
0
2
5.26 (brs)
0
3
3.67
5.30 (dd, 8.0,3.0)
5.03 (dd, 9.0,9.0)
4.44 (dq, 9.0,6.0)
1.23 (d, 6.0)
0
4
3.40
0
5
4.12
0
6
1.28 (d, 6.9)
AC
2.00, 2.05, 2.05,
2.07, 2.11, 2.11, 2.16
170.4
170.5
170.6
170.7
171.2
172.0
Ara =
Rha =
a
-
L
-arabinosyl.
a-L-rhamnopyranosyl.
Overlapped signals are represented without designated multiplicity.
1
1
Values in parentheses represent H– H splitting.
Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
A. Said et al. / Phytochemistry Letters xxx (2015) xxx–xxx
3
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
9
9
9
9
9
9
9
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
(d, J = 6.8 Hz), 100.2/5.31 (brs)] indicated the presence of one
arabinose and one rhamnose units in the molecule. The structure of
the steroid moiety with 27 carbons was determined by the use of
1D and 2D (HSQC and HMBC) NMR analysis which allowed proton
and carbon assignments. The assigned carbon resonances due to
the steroid part of 1 were in agreement with the reported data of
kryptogenin (Agrawal et al., 1985) except the significant lowfield
structure (B o¨ hler and Tamm, 1967; Heller et al., 1976; Saitoh 136
et al., 1986). The basic skeleton of 3-hydroxy-3-benzyl-4- 137
chromanone was corroborated by the HMBC correlations (Fig. 2) 138
between H
2
-2 and C-3, H
2
-9 and C-2, H
2
-2 and C-4, H
2
-9 and C-4 139
) exhibited 140
6.74 (1H, 141
108.1), ( 142
0
1
and H -9 and C-1 . The H NMR spectrum of 2 (CDCl
2
3
resonances for three aromatic protons of the B-ring [(
d
H
0
0
brs, H-2 );
d
C
110.9), (
d
H
6.75 (1H, d, J = 8.5 Hz, H-5 );
d
C
d
H
0
position of C-1 resonance at
deshielded positions observed for C-2 (
and the shielded location of Me-19 (
d
C
83.2, as well as the relatively
6.63 (1H, d, J = 8.5 Hz, H-6 );
d
C
123.6)], characteristic of homo- 143
0
0
d
C
37.1) and C-10 (
14.7); indicating attach-
d
C
42.0)
isoflavonoids having 3 ,4 dioxygenation. The spectrum also 144
showed two proton singlets at 5.95 suggesting a methylene 145
dioxy group (OCH O). In the HSQC spectrum of 2 the OCH O group 146
was recognized at 100.9 and its location was confirmed by the 147
observed HMBC correlations between the methylene proton 148
resonances at 5.95 and the carbon resonances at 147.5 149
and 146.7 assignable to C-3 and C-4 , respectively. In the EIMS 150
spectrum of 2, the base peak at m/z 135 (C ) due to B-ring 151
d
C
d
H
ment of the disaccharide unit at C-1 position and recognizing
b
-
2
2
orientation of an oxygen function at this position (Mimaki et al.,
d
C
1996a,b). The presence of an axial oxymethine proton resonance
1
assigned to H-1 at
d
H
3.60 (dd, J = 12.0, 4.0 Hz) in the H NMR
d
H
d
C
0
0
spectrum of the acetate derivative 1a (Table 1), confirmed the
deduced stereochemistry at C-1. The HMBC correlations between
d
C
8 7 2
H O
the resonances due to C-19 (
the resonances of C-1 (
d
C
14.7) and H-1 (
d
d
H
3.42) and between
4.31) confirmed
tropylium fragment, lent further support to the structure of B-ring. 152
The oxygenation pattern of A ring in 2 was established by the 153
combined use of UV and NMR spectra. The absorption at 287 nm in 154
the UV spectrum of 2 experienced bathochromic shift upon 155
addition of sodium methoxide (6 nm) and sodium acetate (2 nm), 156
indicating the presence of a hydroxyl group at C-7 position. This UV 157
absorption remained unaffected upon addition of aluminum 158
chloride revealing that 2 was devoid of a hydroxyl function at 159
0
d
C
83.2) and H-1 (
H
glycosylation at C-1 position. Therefore, the steroid part of 1 was
assigned the structure of 1 -hydroxy kryptogenin. To the best of
b
our knowledge, this is the first reported occurrence of this genin.
1
The full structure of the disaccharide unit was defined by H NMR
spectrum of the heptaacetate derivative 1a. The spectrum showed
better resolution of the oxymethine and oxymethylene sugar
0
0
00
resonances and revealed that H-2 (
d
H
5.26, brs), H-3 (
d
H
5.30, dd,
C-5 position. This information together with the observation of 160
0
0
1
J = 8.0, 3.0 Hz) and H-4
(
d
H
5.03, dd, J = 9.0, 9.0 Hz) of the
further two doublets in the H NMR spectrum of 2 at
d
H
7.61 (1H, d, 161
110.4) 162
rhamnose unit, were linked to acetylated carbon atoms as
indicated by their lowfield positions; suggesting the terminal
position of this unit. The relatively highfield chemical shift of
J = 8.5 Hz;
d
C
123.9) and 6.75 (1H, d, J = 8.5 Hz;
d
C
demonstrated the presence of two o-coupled protons located at 163
C-5 and C-6 positions. Furthermore, a three proton singlet located 164
0
1
arabinose H-2 at
d
H
3.86 (dd, J = 8.0, 8.0 Hz) clearly proved position
at
d
H
4.0 in the H NMR spectrum of 2, corresponding to aromatic 165
0
13
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
2 to be a glycosidic linkage site. The C NMR spectrum of 1
C
carbon resonance at d 61.4 in the HSQC, indicated the presence of 166
measured in C
structure of the disaccharide unit. The resonances at
5
D
5
N (Table 1) provided definitive evidence for the
101.5, 72.3,
sterically hindered methoxyl group. The methoxyl group was then 167
placed at the only available C-8 position. This conclusion was 168
confirmed by the HMBC correlation between the resonances of 169
d
C
72.3, 74.0, 69.2 and 18.9 assigned to a terminal rhamnose unit and
0
100.4, 75.0, 75.8, 69.9 and 67.2 attributed to a C-2 glycosylated
3 C
OCH protons and the oxygenated carbon at d 134.4 assigned to C- 170
arabinose, were very close to the corresponding data (C
reported for the co-existed metabolite alliospiroside A 3 (Huang
et al., 2013) and other steroidal saponins bearing identical 1 , 3
5 5
D N)
8. Further evidence for the oxygenation pattern of A ring was 171
1
3
allowed from the very similar C NMR data for A ring of 2 and the 172
corresponding values for other homoisoflavonoids bearing identi- 173
cal A ring oxygenation pattern (Chen and Yang, 2007). The HMBC 174
b
b
oxygenation pattern for A ring of the steroid moiety as well as
disaccharide unit at C-1 position (Mimaki et al., 1996a,b, 1997,
1999). The pyranose form of the two sugar units was derived from
correlations between the resonances of H-5 (
194.4), C-7 ( 156.0) and C-8a ( 154.5) and between H-6 (
6.75) and C-5 ( 123.9), C-8 ( 134.4) and C-4a (
d
H
7.61) and C-4 (
d
C
175
176
d
C
d
C
d
H
1
3
their C chemical shift values and the
a
-anomeric configuration of
d
C
d
C
d
C
113.0) 177
3
the arabinose unit was deduced from
JH1-H2 value (6.8 Hz). The
provided definitive evidence for A ring structure. The stereochem- 178
istry at C-3 was determined by comparison of its electronic circular 179
dichorism (ECD) spectrum with these of previously reported 180
broad singlet of the anomeric proton and the chemical shift values
of the resonances due to C-3 and C-5 as well as the presence of
three-bond strong HMBC correlations between the resonance of
the anomeric proton and those due to C-3 and C-5 of the rhamnose
homoisoflavonoids (Adinolfi et al., 1988). The negative
p*Cotton effect at 288 nm and the positive n- *Cotton effect at 182
318 nm indicated S configuration. Thus, the structure of compound 183
p
!
p*- 181
p
unit, indicated an
assigned the structure of 1
nopyranosyl-(1 ! 2)- -arabinopyranoside. This is the first
20 Q4 reported occurrence of 1 (Fig. 1).
a
-orientation. Therefore compound 1 was
0
0
b
-hydroxy-kryptogenin-1-O- -rham-
a
-
L
2 was concluded to be (3S)-3,7-dihydroxy-8-methoxy-3-(3 ,4 - 184
a
-L
methylenedioxybenzyl) chroman-4-one. This is the first reported 185
occurrence of 2.
186
187
188
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Compound 2 was isolated as yellow amorphous solid. It had the
molecular formula C18 as determined by the HRESIMS which
H
16
O
7
2.2. Evaluation of antioxidant and cytotoxic activities
+
exhibited a pseudo-molecular ion peak [M+1] at m/z 345.0969.
Compound 2 also showed in its EIMS a molecular ion peak at m/z
344. The IR spectrum exhibited absorption bands at 3443 and
2.2.1. Antioxidant
The isolated compounds 1, 2, 3 were tested for their radical 189
scavenging activityusing DPPH assaywithascorbic acid as standard. 190
ꢀ
1
1646 cm , indicating the presence of hydroxyl and conjugated
1
carbonyl groups. The H NMR spectrum of 2 displayed the typical
The IC50 values were 67.7, 35.2, 254
mg/ml, respectively. The IC50 191
splitting pattern of homoisoflavonoid (Table 2) with two pairs of
value of ascorbic acid was 33.3 g/ml. The results showed that 192
m
geminal coupled proton resonances at
d
H
4.41 and 4.14 (each a
compound 2 exhibited activity compared to that of ascorbic acid.
193
doublet, J = 11.2 Hz, H-2) and 2.94 and 2.91 (each a doublet,
d
H
J = 10.5 Hz, H-9) (B o¨ hler and Tamm, 1967). The observation of
resonances due to 12 aromatic carbons, a flavones carbonyl
2.2.2. Cytotoxicity
194
The cytotoxicity of the isolates 1–3 was performed against the 195
three human tumor cell lines HCT116, MCF-7 and PC-3, using 196
doxorubicin as a standard drug. The IC50 values were 38, 318 and 197
carbon at
72.6 (C-3) and methylene carbon at
2 (Table 2), confirmed the eucomol type homoisoflavonoid
C C
d 194.4 (C-4), an oxygenated quaternary carbon at d
13
C
d 40.9 (C-9) in the C NMR of
90
mM against HCT116 cell line, 153, 131 and 69 mM against 198
Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
4
A. Said et al. / Phytochemistry Letters xxx (2015) xxx–xxx
Fig. 1. Chemical structures of compound 1 and 2.
199
200
201
202
MCF-7 cell line, 175, 366 and 99
respectively. The IC50 values of doxorubicin were 10, 6 and 4
against the used cell lines, respectively. The results showed that
the isolated compounds were inactive.
m
M against PC-3 cell line,
3. Experimental
203
204
mM
3.1. General
Optical rotations were measured in MeOH or CHCl
3
with Kruss
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
Table 2
1
13
polarimeter P8000. FT-IR was measured on FT-IR/FT Roman
spectrometer. Circular dichroism was performed on Jasco J-805
spectrometer. UV measurements were obtained using UV-Visible
Jasco V-670 spectrophotometer. EI-MS and HRESI-MS data were
measured using Jeol JMS-Ax500 spectrometer and Bruker micro-
TOF-QII MS (Amherst, MA), respectively. NMR spectra were
3
H and C-NMR data of compound 2 in CDCl .
1
3
1
Position
C
H
2
3
4
72.7
72.6
4.41 (d, 11.2), 4.14 (d, 11.2)
–
194.4
113.0
123.9
110.4
156.0
134.4
154.5
40.9
–
4
5
6
7
8
8
9
1
2
3
4
5
6
a
–
7.61 (d, 8.5)
measured using Bruker High Performance Digital FT-NMR
Spectrometer Avance III operating at 400 MHz for
1
6.75 (d, 8.5)
H and
–
13
1
00 MHz for C nuclei. Polyamide 6S (50–160
GmbH, Germany), Silica gel 60 (Merck) and Sephadex LH-20
Pharmacia, Uppsala, Sweden) were used for column chromatog-
m) (Fluka Chemie
–
a
–
(
2.94 (d, 10.5), 2.91 (d, 10.5)
0
0
0
0
0
0
128.0
110.9
147.5
146.7
108.1
123.6
100.9
61.4
–
raphy. Silica gel aluminum sheets G 60 (F254-Merck) were used for
TLC. TLC plates were observed under UV (254 and 366 nm) then
6.74 (brs)
–
2 4
visualized by heating after spraying with vanillin-H SO .
–
6.75 (d, 8.5)
6.63 (d, 8.5)
5.95 (s)
4.00 (s)
3.2. Plant material
220
2
OCH O
8
-OMe
The unflowering aerial parts of Sansevieria cylindrica fam.
Dracaenaceae were collected from Orman botanical garden, Giza,
221
222
1
1
Values in parentheses represent H– H splitting.
Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
A. Said et al. / Phytochemistry Letters xxx (2015) xxx–xxx
5
Fig. 2. Key HMBC correlation of compound 2.
+
2
2
2
2
2
2
2
23
24
25
26
27
28
29
Egypt in June 2009, kindly authenticated by Dr. Mohammed El-
Gebaly, Department of Botany, National Research Centre and
confirmed by Dr. Abd El-Magali, Flora & Phytotaxonomy Research
– Horticultural Research Institute, Agricultural Research Centre,
Ministry of Agriculture. A voucher specimen is deposited in the
Herbarium, Pharmacognosy Department, Faculty of Pharmacy,
Cairo University (2014-12).
747.3932), 707.4001 [MꢀH
2
O+H] (calcd for
C
38
H
59
O
12 270
1
13
707.4007); H NMR (400 MHz, CD
see Table 1.
3
OD) and C NMR (100 MHz) 271
272
0
0
3.3.2. (3S)-3,7-dihydroxy-8-methoxy-3-(3 ,4 -
273
274
methylenedioxybenzyl) chroman-4-one (2)
2
0
Yellow amorphous solid; [
log
(5)sh., 339 (5.1) nm, (AlCl
HCl) 235 (4.9), 287 (5), 365 (5.1) nm, (NaOAc) 257 (4.9), 289 (5) nm, 278
339 (5.1) nm, (NaOAc/H BO ) 288(5) nm; ECD: [ 288-11 074, 279
max (cm ): 3443, 2924, 1646,1501, 1455, 1384, 280
a
]
D
+16.62 (c 0.1, CH
2
Cl
2
); UV
l
max 275
(
e
): (MeOH) 235 (4.9), 287 (4.9) nm, (NaOMe) 257 (4.9), 293 276
) 235 (4.9), 287 (5), 364 (5.1) nm, (AlCl 277
2
30
3.3. Extraction and isolation
3
3
/
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
The air-dried powdered unflowering aerial parts (1 kg) of S.
cylindrica were extracted by maceration with 70% aqueous
methanol until exhaustion. The combined methanolic extract
was evaporated under vacuum to dryness. The dark brown residue
(350 g) was applied on a chromatographic column packed with
3
3
Q]
ꢀ
1
[Q]318 + 7 669; IR
n
+
1034; EIMS m/z: 344 (M ), 209, 152, 149, 135, 105, 95, 77; HRESIMS 281
(positive ion mode) m/z: 345.0969 [M+H] (calcd for C18
+
H
17
O
7
282
1
13
345.0974); H NMR (400 MHz, CDCl
CDCl ) see Table 2.
3
) and C NMR (100 MHz, 283
284
polyamide gel (1 kg) and eluted with gradient solvent system H
MeOH (1:0–0:1) then MeOH–CH Cl (7:3) to give 109 fractions
(1 L) each. Fractions were detected by silica TLC using two different
solvent systems MeOH-CH CL (2:8) and EtOAc-n-hexane (4:6).
The TLC was visualized by spraying with vanillin-H SO reagent
and heating at 100 8C. Similar fractions were pooled to give 12
main fractions. Fraction 4 (10 g) eluted with H O-MeOH (9:1) was
chromatographed on silica gel CC (300 g) eluted with gradient
CH Cl –EtOAc (9:1–1:9) to give 104 fractions 50 ml each. Fractions
(48–64) eluted with CH Cl –EtOAc (88:12) were combined (2 g)
and rechromatographed on silica gel CC (10 g) eluted with
n-C 14–CH Cl –MeOH–isoPrOH (8:1:2:2) to afford 30 fractions
10 ml each. The material from fractions (11–20) that showed one
major spot on silica gel TLC (CH Cl –MeOH, 8:2) was purified using
sephadex LH-20 CC (10 g) using MeOH–CH Cl (8:2) to afford
compound 1 (25 mg). Fraction 8 (27 g) eluted from the main
column with H O–MeOH (7:3), was subjected to silica gel CC
2
O–
3
2
2
3.4. Acid hydrolysis of compound 1
285
2
2
2
4
Compound 1 (2 mg) in 1.5 N HCl (2 ml) was heated at 100 8C for 286
4 h. The solvent was evaporated and the residue was dissolved in 287
2
2 2 2
H O then extracted four times with CH Cl . The remaining aqueous 288
layer was repeatedly evaporated to dryness with MeOH until 289
neutral, and the sugars were then analyzed by paper chromatog- 290
2
2
2
2
3 2
raphy (n-BuOH–CH COOH–H O, 4:1:5, upper layer) by comparison 291
against authentic samples. The chromatogram was visualized by 292
spraying with aniline hydrogen phthalate reagent and heating 293
at 110 8C till the color of the spots appeared.
-arabinose were detected.
6
H
2
2
L-Rhamnose and 294
2
2
L
295
2
2
3.5. Acetylation of 1
296
2
(300 g) eluted with gradient n-hexane-EtOAc (9:1–1:9) followed
by MeOH to give 87 fractions 50 ml each. Fractions 6–8 (40 mg)
eluted with n-hexane-EtOAc (7:3) exhibiting one major spot on
Compound 1 (10 mg) was acetylated with acetic anhydride 297
(2 ml) in pyridine (2 ml) and the crude acetate was purified by 298
sephadex LH-20 CC using MeOH to yield the corresponding 299
silica gel TLC (CH
2
Cl
2
–MeOH, 97:3), were purified using silica gel
peracetate 1a (7 mg).
300
CC (10 g) eluted with n-hexane–EtOAc (7:3) to afford compound 2
(15 mg). Fraction 83 (42 mg) eluted with MeOH was rechromato-
3.6. Antioxidant activity
301
graphed on silica gel CC (10 g) eluted with CH
afford 15 fraction 10 ml each. The material from fractions 2 and 3
(20 mg) exhibiting one major spot on silica TLC (CH Cl –MeOH,
8:2), were combined and purified using sephadex LH-20 CC eluted
with MeOH–CH Cl (8:2) to afford compound 3 (11 mg).
2 2
Cl –MeOH (95:5) to
ꢀ1
A stock solution (1 mg ml ) of each test compound was 302
prepared in methanol. Sample concentrations of 20, 50, 100, 150, 303
2
2
200 and 250
mg/ml were prepared in methanol. The free radical 304
2
2
scavenging activity of compounds (1–3) was evaluated according 305
to the method described by Braca et al. (2001). Test sample (0.1 ml) 306
was added to 3 ml of a 0.004% methanol solution of DPPH (1,1- 307
diphenyl-2-picrylhydrazyl). Absorbance at 517 nm was deter- 308
mined after 30 min, and the percentage inhibition activity was 309
264
265
266
267
268
269
3.3.1. 1
b
-hydroxy-kryptogenin-1-O-
a
-
L
-rhamnopyranosyl-(1 ! 2)-
a
-L-arabinopyranoside (1)
2
0
Colorless amorphous solid; [
a
]
D
ꢀ6.97 (c 0.1,MeOH); IR (KBr)
ꢀ1
n
max (cm ): 3406, 2929, 1725, 1646, 1452, 1375, 1257, 1047;
calculated from [(A
0
ꢀ A
1
)/A
0
] ꢁ 100, where A
0
is the absorbance of 310
+
HRESIMS (positive ion mode) m/z: 763.3666 [M+K] (calcd for
the control, and A
1
is the absorbance of the test sample or standard 311
312
+
C
38
H
60
O
13K 763.3671), 747.3926 [M+Na] (calcd for C38
H
60
O
13Na
(ascorbic acid).
Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006

G Model
PHYTOL 906 1–6
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345
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361
362
363
364
365
366
367
368
369
370
371
372
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375
376
377
378
379
380
381
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13
3.7. Cytotoxicity assay
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314
315
316
317
318
319
320
321
322
323
The cytotoxicity of isolated compounds, 1, 2 and 3 were tested
against HCT116 (Colon Cancer), MCF-7 (Breast Cancer) and PC-3
(prostate Cancer) cell lines using SulphoRhodamine-B (SRB)
method as previously described by Skehan et al. (1990), with
doxrubcine as a standard drug. The cells were obtained from
American Type Culture Collection (ATTC) (University Boulevard,
Manassas, Virginia, USA). The absorbance at 490 nm (reference
wavelength) was measured with an ELISA microplate reader. The
IC50 values were calculated using sigmoidal concentration–
response curve fitting models (SigmaPlot software).
3
24 Q5 Uncited reference
3
25
26
Haraguchi et al. (1994).
3
Acknowledgements
3
3
3
27 Q6
28
29
The authors wish to acknowledge the National Research Centre
for financial support. Mass spectral data were obtained at the
University of Massachusetts Mass Spectrometry Centre.
3
30
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Please cite this article in press as: Said, A., et al., Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica
Bojer ex Hook.. Phytochem. Lett. (2015), http://dx.doi.org/10.1016/j.phytol.2015.03.006