Cacalol derivatives from Roldana angulifolia

Article abstract of DOI:10.1021/np0604073

Four new modified eremophilanes, angulifolide (1) and angulifolins A-C (2-4), and two new triacetylglucosides (7 and 8) were isolated from Roldana angulifolia, together with several known compounds. The structures of the new compounds were elucidated by spectroscopic analysis and chemical reactions. The absolute configuration of compounds 2 and 3 was established by Mosher ester methodology. Cytotoxicity against selected human cancer cell lines was determined for the more abundant isolated metabolites.

Full text of DOI:10.1021/np0604073

1826
J. Nat. Prod. 2006, 69, 1826-1829
Cacalol Derivatives from Roldana angulifolia
Amira Arciniegas,† Ana-L. Pe´rez-Castorena,*,† Jose´ Luis Villasen˜or,‡ and Alfonso Romo de Vivar†
Instituto de Qu´ımica and Instituto de Biolog´ıa, UniVersidad Nacional Auto´noma de Me´xico, Circuito Exterior, Ciudad UniVersitaria,
Coyoaca´n 04510, D.F., Me´xico
ReceiVed August 15, 2006
Four new modified eremophilanes, angulifolide (1) and angulifolins A-C (2-4), and two new triacetylglucosides (7
and 8) were isolated from Roldana angulifolia, together with several known compounds. The structures of the new
compounds were elucidated by spectroscopic analysis and chemical reactions. The absolute configuration of compounds
2 and 3 was established by Mosher ester methodology. Cytotoxicity against selected human cancer cell lines was
determined for the more abundant isolated metabolites.
The genus Roldana (Asteraceae, Senecioneae), distributed from
southern Arizona to Panama, contains 48 species separated mainly
from the genera Senecio and Cacalia.1,2 Previous reports have
shown that sesquiterpenes with eremophilane or oplopane skeletons
are the most common secondary metabolites among the six species
of Roldana chemically studied so far.3-9 Roldana angulifolia (D.C.)
H. Rob. and Brettell has been examined for the first time in the
present investigation. In this paper, we report the isolation of four
new modified furanoeremophilanes, angulifolide (1) and angulifo-
lins A-C (2-4), and the known 13-acetoxy-14-oxocacalohastin
(5),7 13-hydroxy-14-oxocacalohastin (6),7 and maturin acetate.10 The
3′,4′,6′-triacetylglucoside derivative of (4S)-R-terpineol (7) and that
of 11-hydroxy-4(15)-eremophilene (8) are also new metabolites.
Structures of the new compounds were determined by spectroscopic
methods and chemical transformations. The known compounds
senecrassidiol,11 rutin,12 phaeophytin a,13 13-hydroxyphaeophytin
a,13 sucrose, and â-sitosterol glucoside were also isolated. The
cytotoxicity of compounds 1, 5, and 6 against selected cancer cell
lines was determined.
Angulifolide (1), a new modified furaneremophilane, showed the
molecular formula C18H16O6 by HRFABMS and exhibited evidence
from the IR spectrum of aliphatic ester and conjugated δ-lactone
groups at 1734 and 1715 cm-1, respectively. In the 1H NMR
spectrum (Table 1), a proton signal of a furan ring (H-12) appeared
at δ 7.72 (br t, J ) 1.0), coupled allylically to the C-13 methylene
hydrogens (δ 5.61 dd, J ) 13.5, 1.0 Hz and 5.55 dd J ) 13.5, 1.0
Hz). The absence of C-14 and C-15 methyl groups, characteristic
of a cacalol-type skeleton, was in agreement with the inclusion of
these carbon atoms in a δ-lactone function. This was confirmed
by the HMBC spectrum, which showed interaction between the
C-14 carbonyl group (δ 163.5) and H-15R (δ 4.56, dd, J ) 11.0,
5.0 Hz) and H-15â (δ 4.26, dd, J ) 12.5, 11.0 Hz). Signals at δ
6.90 (dd, J ) 9.5, 3.0 Hz) and 6.08 (ddd, J ) 9.5, 6.5, 3.0 Hz)
were assigned to the vinylic hydrogens at C-1 and C-2, according
NMR data were very similar (Table 1) and showed evidence of a
to the correlations observed in the COSY experiment. A methoxyl
furan group, an acetoxy attached to C-13, a methoxyl at C-9, and
group (δ 4.29) was attached to C-9 in agreement with the cross-
an aldehyde group at C-6 (δ 10.55). From COSY, HMBC, and
peaks between C-9 and CH3O in the HMBC spectrum. The same
FLOCK NMR experiments, the presence of a hydroxyl at C-1 and
experiment allowed placement of the acetoxy group (1H NMR: δ
an epoxy group between C-2 and C-3 was deduced for 2 and 3.
2.10, 13C NMR: δ 170.7 s and 21.0 q) at C-13, since an interaction
The signals at δ 3.75 (ddd, J ) 4.5, 2.5, 1.0 Hz) and 3.54 (dd, J )
between its carbonyl group and H-13 was observed. A â-orientation
4.5, 2.5 Hz) in the spectrum of 2 and at δ 3.59 (ddd, J ) 3.9, 3.0,
was assigned to the C-15 methylene group on biogenetic grounds.14
0.9 Hz) and 3.47 (ddd, J ) 3.9, 3.0, 1.2 Hz) in that of 3 were
assigned to the hydrogen atoms geminal to the epoxide functions;
the respective carbon signals appeared at δ 53.5 and 55.8 for 2
and δ 51.8 and 55.0 for 3.
Angulifolins A (2) and B (3) showed the same molecular formula,
C18H18O7, established from their HRFABMS. The presence of
hydroxyl, aliphatic ester, and aromatic aldehyde groups was
1
observed in the IR spectra of both compounds. Their H and 13C
The absolute stereochemistry of C-1 in angulifolins A and B
was determined by treatment of 2 and 3 with (S)- and (R)-R-
* To whom correspondence should be addressed. Tel: (5255) 56-224412.
methoxy-R-(trifluoromethyl)phenylacetyl chloride [(S)- and (R)-
Fax: (5255) 56-162217. E-mail: alperezc@servidor.unam.mx.
† Instituto de Qu´ımica, contribution No. 2642.
‡ Instituto de Biolog´ıa.
MTPA-Cl] to produce their respective esters. Compound 2 afforded
2r and 2s derivatives with negative ∆δ ) [δ(S) - δ(R)] values for
10.1021/np0604073 CCC: $33.50
© 2006 American Chemical Society and American Society of Pharmacognosy
Published on Web 11/16/2006

Notes
Journal of Natural Products, 2006, Vol. 69, No. 12 1827
Table 1. 1H NMR Spectroscopic Data of Compounds 1-4, 7, and 8 (500 MHz, CDCl3)a
position
1
2
3b
4
7b,c
8c
1a
1b
2
6.90, dd, (9.5, 3.0)
5.40 d (2.5)
5.76 br d (2.4)
7.14 d (10.0)
1.50 dq (9.0, 5.5)
1.24 m
1.62 m
6.08 ddd (9.5,
6.5, 3.0)
3.75 ddd (4.5,
2.5, 1.0)
3.59 ddd (3.9,
3.0, 0.9)
6.23 ddd (10.0,
6.0, 1.0)
5.36 m
3a
3b
4
2.38 ddd (16.5,
7.0, 6.5)
1.96 dddd (16.5,
16.5, 3.0, 3.0)
3.42 dddd (16.5,
12.5, 7.0, 5.0)
3.54 dd (4.5, 2.5)
3.47 ddd (3.9,
3.0, 1.2)
4.16 dd (6.0, 1.5)
2.03 m
2.03 m
2.29 br d (12.5)
1.98 ddd (14.0,
12.5, 0.5)
4.56 qd (7.5, 2.5)
4.48 qd (6.9, 3.0)
4.19 qt (7.0, 1.5)
1.60 dddd (11.4,
11.4, 4.2, 2.1)
2.00 m
1.23 m
1.99 m
5a
5b
6a
6b
7
1.43 br d (12.5)
1.24 m
1.52 m
1.59 m
1.76 ddd (12.5,
5.0, 2.5)
1.64 s
1.23 s
8
9a
9b
10
12
13a
13b
14
1.16 q (12.5)
1.74 br d (12.0)
1.24 sd
1.18 s
7.72 br t (1.0)
5.61 dd (13.5, 1.0)
5.55 dd (13.5, 1.0)
7.78 br t (1.0)
5.39 dd (13.5, 1.0)
5.28 dd (13.5, 1.0)
10.55 s
7.79 br t (0.9)
5.39 dd (13.2, 0.9)
5.29 dd (13.2, 0.9)
10.55 s
7.77 br t (1.0)
5.43 dd (13.5, 1.0)
5.35 dd (13.5, 1.0)
10.59 s
1.22 sd
0.69 s
15a
15b
OCH3
Ac
4.56 dd (11.0, 5.0)
4.26 dd (11.0, 12.5)
4.29 s
1.22 d (7.5)
1.45 d (7.0)
1.16 d (7.0)
4.41 d (2.6)
4.69 d (2.6)
4.41 s
2.08 s
4.39 s
2.08 s
4.33 s
2.09 s
2.10 s
b
a Assignments are based on COSY, HSQC, and HMBC experiments. 300 MHz, assignments are based on COSY, HETCOR, and FLOCK
c
experiments. Glucose signals of 7: δ 4.55 (1H, d, J ) 7.5 Hz, H-1′), 3.53 (1H, brt, J ) 9.0 Hz, H-2′), 5.15 (1H, t, J ) 9.6 Hz, H-3′), 4.98 (1H,
t, J ) 9.6 Hz, H-4′), 3.66 (1H, ddd, J ) 2.7, 6.3, 9.9 Hz, H-5′), 4.20 (1H, dd, J ) 12.0, 6.3 Hz, H-6′a), 4.08 (1H, dd, J ) 12.0, 2.7 Hz, H6′b), 2.07
s, 2.05 s, 2.03 s (3H each, Ac). Glucose signals of 8: δ 4.54 (1H, d, J ) 7.5 Hz, H-1′), 3.54 (1H, dd, J ) 9.0, 7.5 Hz, H-2′), 5.15 (1H, t, J ) 9.0
Hz, H-3′), 4,98 (1H, t, J ) 9.0 Hz, H-4′), 3,65 (1H, ddd, J ) 2.5, 6.0, 9.0 Hz, H-5′), 4.19 (1H, dd, J ) 12.0, 6.0 Hz, H-6′a), 4.07 (1H, dd, J ) 12.0,
d
2.5 Hz, H6′b), 2.07 s, 2.06 s, 2.03 s (3H each, Ac). Exchangeable signals.
H-2, H-3, and H-4 and positive differences for OCH3, CHO, H-12,
and H-13, indicating R absolute stereochemistry of C-1. The 3r
and 3s derivatives obtained from compound 3 showed positive ∆δ
) [δ(S) - δ(R)] values for H-2, H-3, and H-4 and negative
differences for OCH3, CHO, H-12, and H-13, supporting the S
absolute stereochemistry of C-1. Oxidation of 2 and 3 produced
the same keto derivative (9), indicating that they are epimers at
C-1. Compound 3 exhibited a low-field shift of H-1 (∆δ 0.36)
relative to that in compound 2 (Table 1), which could be explained
by the deshielding effect of the epoxide function. Furthermore, the
CD curve of 9 showed a negative Cotton effect, similar to that
observed for ∆1,3-ketosteroids with an R-oriented 4,5-oxirane ring.15
Consequently, the epoxide function should have an R-orientation
in both compounds. Therefore, the absolute stereochemistry of
compound 2 is 1R, 2R, 3S, 4R, and that of compound 3 is 1S, 2R,
3S, 4R.
three carbonyl groups in the 13C NMR spectrum (δ 170.6, 170.6,
and 169.7), supported the presence of three acetyl groups at C-3′,
C-4′, and C-6′. The remaining 10 carbons were assigned as part of
a cyclic monoterpene with three methyl groups and a double bond.
The singlet at δ 1.64 was attributed to the vinylic methyl at C-1,
in agreement with a FLOCK NMR experiment. The other two
methyl groups (δ 1.23 and 1.18) were placed at C-8, which appeared
as a singlet (δ 81.0) in the 13C NMR spectrum. The interaction
between the anomeric hydrogen and C-8, observed in the FLOCK
spectrum, allowed placement of the sugar moiety at this carbon.
Compound 7 by partial acid hydrolysis produced compound 10,
whose physical and spectroscopic features were identical to those
reported for (4S)-R-terpineol glucopyranoside.16
The IR spectrum of 8 exhibited bands attributable to ester and
1
alcohol groups, while the H NMR spectrum (Table 1) revealed
the presence of the triacetylglucopyranose moiety, already described
in 7. The 13C NMR spectrum (Table 2) contained 15 additional
signals indicating that the basic skeleton was that of a sesquiterpene.
The EIMS showed fragments of triacetylglucopyranose (m/z 305,
C12H17O9) and aglucon moieties (m/z 205, C15H25). Signals at δ
4.41 (d, J ) 2.6 Hz) and 4.69 (d, J ) 2.6 Hz) were attributed to
the exocyclic methylene group of C-15, while the attachment of
the triacetylglucopyranose moiety to C-11 was indicated by the
interaction in the HMBC spectrum between H-1′ (δ 4.54, d, J )
7.5 Hz) and C-11 (δ 80.9). The NOESY experiment showed cross-
peaks of CH3-14 with CH3-12, CH3-13, and H-10, suggesting a
cis-decalin configuration and â-orientation of the isopropyl portion
since on biogenetic grounds CH3-14 is â-oriented.
Structures of the known compounds 13-acetoxy-14-oxocacalo-
hastin (5),7 maturin acetate,10 13-hydroxy-14-oxocacalohastin (6),7
senecrassidiol,11 rutin,12 phaeophytin a,13 and 13-hydroxyphaeo-
phytin a13 were determined by comparison of their physical
constants and spectroscopic features with those reported in the
literature. Sucrose and â-sitosterol glucoside were identified by
comparison with authentic samples.
1
The H and 13C NMR spectra of angulifolin C (4), C18H18O7,
presented the same pattern as those of compounds 2 and 3, with
differences in the signals assigned to ring A. Signals at δ 7.14 (d,
J ) 10.0 Hz) and 6.23 (ddd, J ) 10.0, 6.0, 1.0 Hz) were assigned
to the C-1 double bond, and the alcohol function was placed at
C-3 since the H-3 signal appeared at δ 4.16 (dd, J ) 6.0, 1.5 Hz)
coupled to H-2 and to H-4. Since the NOESY experiment did not
conclusively establish the stereochemistry of C-3, 4 was treated
with Mosher’s reagents, but only a dehydration product10 was
obtained.
The IR spectrum of compound 7 showed strong bands at 3593
and 1747 cm-1, characteristic of alcohol and carbonyl groups. The
presence of 22 carbon atoms deduced from the 13C NMR spectrum
was in agreement with the molecular formula C22H34O9 (HR-
FABMS). Five C-H (δ 97.1, 74.5, 72.4, 71.7, and 68.9) and one
CH2 (δ 62.7) signals suggested the presence of a sugar moiety
whose anomeric proton signal was observed at δ 4.55 (d, J ) 7.5
Hz). The downfield shift of H-3′, H-4′, and H-6′ together with the
evidence of three methyl signals at δ 2.07, 2.05, and 2.03, and

1828 Journal of Natural Products, 2006, Vol. 69, No. 12
Notes
Table 2. 13C NMR Spectroscopic Data of Compounds 1-4, 7,
and 8 (125 MHz, CDCl3)a
The acetone extract (16 g) was separated by column chromatography
eluting with hexane-acetone mixtures of increasing polarity. From the
hexane fractions, 350 mg of 5 was isolated. Fractions eluted with 9:1
and 4:1 mixtures (1.5 g), after a new purification with hexane-acetone
(9:1), afforded 250 mg of compound 6 and 180 mg of 1. Fractions
obtained with hexane-acetone (7:3 and 6:4) (800 mg) were further
separated over silica gel; elution with hexane-acetone (4:1) furnished
fractions A and B. Fraction A (450 mg) was purified by column
chromatography with hexane-acetone (4:1) to give 50 fractions.
Fractions 30-39 (95 mg) and 40-47 (120 mg) were each submitted
to preparative TLC (hexane-acetone, 7:3). Angulifolin B (3, yellow
oil, 52 mg) was obtained from fractions 30-39. Additionally 32 mg
of 3 and 58 mg of angulifolin C (4, yellow needles, mp 123-124 °C)
were isolated from fractions 40-47. Senecrassidiol11 (colorless oil, 15
mg) was isolated from fractions 48-50 (preparative TLC, CH2Cl2-
acetone, 8:2). Fraction B (100 mg) was subjected to preparative TLC
(hexane-acetone, 7:3) to yield angulifolin A (2, yellow oil, 40 mg).
The dried and ground aerial parts (1.1 kg) were extracted successively
with hexane, acetone, and methanol. The hexane extract (11.5 g) was
subjected to column chromatography eluted with hexane-acetone
gradient mixtures. Fractions eluted with hexane-acetone (4:1, 1.2 g)
were purified by column chromatography eluted with hexane-acetone
(4:1) followed by passage over a flash column, eluted with hexane-
acetone (9:1), to afford compound 7 (colorless needles, mp 90-91 °C,
28 mg) and compound 8 (white needles, mp 148-150 °C, 82 mg).
Fractions of the acetone extract (19 g), eluted with a hexane-acetone
(9:1) mixture, were purified by column chromatography eluted with
hexane-CH2Cl2 (9:1) to produce phaeophytin a (dark brown oil, 50
mg)13 and 13-hydroxyphaeophytin a (dark brown oil, 62 mg).13
From the methanolic extract (45 g) an insoluble portion (18 g) was
separated. The methanol-soluble portion was purified by passage over
a column eluted with an EtOAc-MeOH gradient system to afford
â-sitosterol glucoside (0.5 g) and sucrose (0.8 g). A sample (2 g) of
the methanol-insoluble fraction was purified through a Sephadex column
eluted with MeOH-H2O (1:1) to obtain rutin12 (78 mg).
carbon
1
2
3b
4
7b,c
8c
1
2
3
4
121.4 d
125.3 d
23.9 t
65.1 d
53.5 d
55.8 d
62.5 d
51.8 t
55.0 d
122.8 d 134.2 s
125.7 d 120.3 d
41.1 t
22.4 t
36.8 t
68.1 d
36.6 d
27.0 t
43.7 d 151.1 s
31.9 d
30.2 d
30.3 d
5
6
7
8
137.0 s
119.1 s
127.9 s
146.4 s
144.3 s
111.2 s
118.2 s
138.9 s
147.9 s
122.0 s
130.5 s
145.1 s
121.9 s
116.6 s
138.9 s
147.7 s
121.7 s
131.1 s
144.6 d
121.0 s
116.6 s
147.4 d
58.6 t
140.6 s
122.4 s
129.0 s
145.3 s
145.2 s
118.7 s
117.1 s
147.6 d
58.9 t
189.8 d
19.6 q
60.9 s
170.6 s
20.9 q
23.8 t
30.8 t
23.3 q
81.0 s
24.8 q
22.5 q
35.9 s
41.8 t
48.4 d
23.4 t
9
24.8 t
10
11
12
13
14
15
OMe
Ac
49.8 s
80.9 s
25.6 qd
23.4 qd
16.3 q
105.3 t
146.9 d 147.2 d
59.6 t
163.5 s
70.9 t
60.9 q
170.7 s
21.0 q
58.6 t
189.9 d
21.4 qd
61.4 q
189.7 d
21.1 qd
60.9 q
170.6 s
170.6 s
20.9 qd
20.9 qd
a Assignments are based on DEPT, HSQC, and HMBC experiments.
b75 MHz, assignments are based on DEPT, HETCOR, and FLOCK
c
experiments. Glucose signals of 7: δ 97.1 (d, C-1′), 72.4 (d, C-2′),
74.5 (d, C-3′), 68.9 (d, C-4′), 71.7 (d, C-5′), 62.7 (t, C-6′), 170.6 s,
170.6 s, 169.7 s, 20.8 q, 20.7 q, 20.6 q (Ac signals). Glucose signals
of 8: δ 97.1 (d, C-1′), 72.4 (d, C-2′), 74.5 (d, C-3′), 68.9 (d, C-4′),
71.6 (d, C-5′), 62.6 (t, C-6′), 170.7 s, 170.6 s, 169.7 s, 20.8 q, 20.7 q,
d
20.6 q (Ac signals). Exchangeable signals.
Compounds 1, 5, and 6 were tested against central nervous
system (U-251), prostate (PC-3), leukemia (K562), colon (HCT-
15), breast (MCF-7), and lung (SKLU-1) human cancer cells
following the protocols established by the National Cancer Institute
(Bethesda, MD).17 However, none of these compounds were active
(IC50 > 10 µM for all cell lines).
25
Angulifolide (1): white needles (EtOAc); mp 223-224 °C; [R]D
-216.5 (c 0.23, CHCl3); UV (MeOH) λmax (log ꢀ) 262 (3.96), 295 (3.78)
nm; IR (CHCl3) νmax 1734, 1717 cm-1; 1H NMR data, see Table 1; 13
C
Experimental Section
NMR data, see Table 2; EIMS m/z 328 [M]+ (30), 285 (100), 267 (20);
HRFABMS m/z 329.1020 [M + H]+ (C18H17O6 requires 329.1025).
General Experimental Procedures. Melting points were determined
on a Fisher-Jones melting point apparatus and are uncorrected. Optical
rotations were determined on a Perkin-Elmer 343 polarimeter. UV and
IR spectra were recorded on a Shimadzu UV 160U and a Bruker Tensor
27 spectrometer, respectively. 1D and NMR spectra were obtained on
an Eclipse JEOL 300 MHz, Bruker Avance 300 MHz, or a Varian-
Unity Inova 500 MHz spectrometer with tetramethylsilane (TMS) as
internal standard. EIMS data were determined on a Bruker Daltonics
Analysis 3.2 mass spectrometer. FABMS were obtained on a JEOL
JMS-SX102A mass spectrometer operated with an acceleration voltage
of 10 kV, and samples were desorbed from a nitrobenzyl alcohol matrix
using 6 kV xenon atoms. HRFABMS were performed at 10 000
resolution using electric field scans and polyethylene glycol ions (Fluka
200 and 300) as the reference material. Column chromatography was
carried out under vacuum on silica gel G 60 (Merck, Darmstadt,
Germany). TLC was performed on Si gel 60 and preparative TLC on
Si gel GF254 (Merck), layer thickness 2.0 mm.
25
Angulifolin A (2): yellow oil; [R]D +114.4 (c 0.18, CHCl3); UV
(MeOH) λmax (log ꢀ) 207 (4.02), 240 (4.06), 304 (3.83) nm; IR (CHCl3)
1
νmax 3423, 1741, 1679 cm-1; H NMR data, see Table 1; 13C NMR
data, see Table 2; EIMS m/z 346 [M]+ (12), 302 (30), 257 (100);
HRFABMS m/z 347.1134 [M + H]+ (C18H19O7 requires 347.1131).
25
Angulifolin B (3): yellow oil; [R]D +61.8 (c 0.22, CHCl3); UV
(MeOH) λmax (log ꢀ) 208 (4.02), 240 (4.06), 305 (3.85) nm; IR (CHCl3)
1
νmax 3422, 1740, 1678 cm-1; H NMR data, see Table 1; 13C NMR
data, see Table 2; EIMS m/z 346 [M]+ (20), 302 (30), 257 (100);
HRFABMS m/z 347.1125 [M + H]+ (C18H19O7 requires 347.1131).
Angulifolin C (4): yellow pale needles (EtOAc); mp 123-124 °C;
25
[R]D -74.0 (c 0.25, CHCl3); UV (MeOH) λmax (log ꢀ) 205 (3.95),
275 (4.05), 301 (3.78) nm; IR (CHCl3) νmax 3591, 1741, 1681 cm-1
;
1H NMR data, see Table 1; 13C NMR data, see Table 2; EIMS m/z 330
[M]+ (35), 312 (45), 269 (55), 253 (100); HRFABMS m/z 330.1112
[M]+ (C18H18O6 requires 330.1107).
(4S)-R-Terpineol 8-O-â-D-(3′-O,4′-O,6′-O-triacetyl)glucopyrano-
25
Plant Material. Roldana angulifolia (D.C.) H. Rob. and Bretell was
collected near Nevado de Toluca (Toluca-Sultepec Rd., km 3), Me´xico
State, Me´xico, in November 2002. A voucher specimen (MEXU
1045506) has been deposited at the Herbario del Instituto de Biolog´ıa,
Universidad Nacional Auto´noma de Me´xico.
side (7): white needles (EtOAc); mp 90-91 °C; [R]D -3.0 (c 0.20,
1
CHCl3); IR (CHCl3) νmax 3593, 1747 cm-1; H NMR data, see Table
1; 13C NMR data, see Table 2; FABMS m/z 443 [M + H]+ (10), 399
(40), 289 (100); HRFABMS m/z 443.2303 [M + H]+ (C22H35O9 requires
443.2281).
Extraction and Isolation. Dried and ground roots (680 g) were
extracted successively with hexane and acetone at room temperature.
The hexane extract (16 g) was separated by column chromatography
eluted with a hexane-acetone gradient mixture system. Fractions eluted
with hexane afforded 3.7 g of 13-acetoxy-14-oxocacalohastin (5)7 as a
yellow pale oil. Fractions eluted with hexane-acetone (19:1, 550 mg)
after further column separation eluted with hexane-acetone (19:1)
afforded maturine acetate (35 mg, mp 80-82 °C).10 Fractions eluted
with hexane-acetone (4:1, 980 mg), after purification by column
chromatography eluted with hexane-acetone (9:1), yielded angulifolide
(1, 51 mg, mp 223-224 °C) and mixture A (230 mg). Mixture A was
separated by preparative TLC (benzene-acetone, 49:1, × 3) to give
55 mg of 13-hydroxy-14-oxocacalohastin (6)7and 110 mg of 1.
11-Hydroxy-7HR,10Hâ-eremophil-4(15)-ene 11-O-â-D-(3′-O,4′-
O,6′-O-triacetyl)glucopyranoside (8): white needles (EtOAc); mp
25
148-150 °C; [R]D +20.0 (c 0.20, CHCl3); IR (CHCl3) νmax 3465,
1
1748 cm-1; H NMR data, see Table 1; 13C NMR data, see Table 2;
EIMS m/z 305 [C12H17O9]+ (2), 289 [C12H17O8]+ (40), 229 [C10H13O6]+
(25), 205 [C15H25]+ (45), 169 [C8H9O4]+ (75), 109 [C10H13O6]+ (60),
161 [C12H17]+ (20), 204 [C15H24]+ (100).
Esterification of Compound 2. Compound 2 (5 mg) in anhydrous
pyridine (100 mg) was treated with (S)- or (R)-R-methoxy-R-(trifluo-
romethyl)phenylacetyl chloride [(S) or (R)-MTPA-Cl] (10.5 mg each)
and stirred at room temperature for 4 h to afford the O-(R)- or O-(S)-
MTPA ester derivatives: 2r (3.2 mg) and 2s (3.5 mg). Selected ∆δ
values [δ(S) - δ(R)]: H-2 ) -0.143, H-3 ) -0.05, H-4 ) -0.031,

Notes
Journal of Natural Products, 2006, Vol. 69, No. 12 1829
OCH3 ) +0.316, H-12 ) +0.054, H-13a ) +0.024, H-13b ) 0.026,
CHO ) +0.011. Compound 2r: 1H NMR (CDCl3, 300 MHz) δ 6.725
(1H, d, J ) 3.3 Hz, H-1), 3.887 (1H, dd, J ) 3.3, 4.2 Hz, H-2), 3.585
(1H, dd, J ) 2.1,4.2 Hz, H-3), 4.670 (1H, qd, J ) 7.2, 2.1 Hz, H-4),
7.746 (1H, s, H-12), 5.363 (1H, d, J ) 13.2 Hz, H-13a), 5.259 (1H, d,
J ) 13.2 Hz, H-13b), 10.509 (1H, s, H-14), 1.225 (3H, s, J ) 7.2 Hz,
H-15), 3.969 (3H, s, OCH3), 2.068 (H, s, AcO), 3.660 (3H, OCH3),
7.40-7.75 (5H, aromatic H). Compound 2s: 1H NMR (CDCl3, 300
MHz) δ 6.823 (1H, d, J ) 3.3 Hz, H-1), 3.744 (1H, dd, J ) 3.3, 4.2
Hz, H-2), 3.535 (1H, dd, J ) 2.1, 4.2 Hz, H-3), 4.639 (1H, qd, J )
7.2, 2.1 Hz, H-4), 7.800 (1H, s, H-12), 5.387 (1H, d, J ) 13.2 Hz,
H-13a), 5.285 (1H, d, J ) 13.2 Hz, H-13b), 10.520 (1H, s, H-14),
1.226 (3H, s, J ) 7.2 Hz, H-15), 4.275 (3H, s, OCH3), 2.080 (3H, s,
AcO), 3.490 (3H, OCH3), 7.38-7.67 (5H, aromatic H).
J ) 13.5 Hz, H-13a), 5.27 (1H, d, J ) 13.3 Hz, H-13b), 10.55 (1H, s,
H-14), 1.33 (3H, d, J ) 6.9 Hz, H-15), 2.10 (H, s, AcO), 4.38 (3H,
OCH3).
Acknowledgment. We are indebted to H. R´ıos, A. Pen˜a, E. Huerta,
N. Zavala, R. Patin˜o, B. Quiroz, L. Velasco, J. Pe´rez, C. Ma´rquez, M.
T. Ram´ırez Apan, E. R´ıos, and G. Salcedo for technical assistance.
Supporting Information Available: 1H NMR spectra of anguli-
folide (1), angulifolins A-C (2-4), and triacetylglucosides (7 and 8)
are available free of charge via the Internet at http://pubs.acs.org.
References and Notes
(1) Robinson, H.; Brettell, R. D. Phytologia 1974, 27, 402-429.
(2) Fuston, A. A Revision of the Genus Roldana. Ph.D. Thesis, Kansas
State University, Manhattan, KS, 1999.
Esterification of Compound 3. O-(R)- and O-(S)-MTPA ester
derivatives 3r and 3s were obtained by the same method as described
for compound 2. Selected ∆δ values [δ(S) - δ(R)]: H-2 ) +0.031,
H-3 ) +0.083, H-4 ) +0.06, OCH3 ) -0.088, H-12 ) -0.028, H-13a
) -0.014, H-13b ) -0.007, CHO ) +0.002. Compound 3r: 1H
NMR (CDCl3, 300 MHz) δ 7.040 (1H, d, J ) 3.3 Hz, H-1), 3.673
(1H, dd, J ) 3.9, 3.3 Hz, H-2), 3.381 (1H, dd, J ) 2.4, 3.9 Hz, H-3),
4.463 (1H, qd, J ) 7.2, 2.4 Hz, H-4), 7.820 (1H, s, H-12), 5.387 (1H,
d, J ) 12.9 Hz, H-13a), 5.270 (1H, d, J ) 12.9 Hz, H-13b), 10.511
(1H, s, H-14), 1.162 (3H, s, J ) 7.2 Hz, H-15), 4.379 (3H, s, OCH3),
2.077 (3H, s, AcO), 3.555 (3H, OCH3), 7.33-7.59 (5H, aromatic H).
Compound 3s: 1H NMR (CDCl3, 300 MHz) δ 7.044 (1H, d, J ) 3.0
Hz, H-1), 3.704 (1H, dd, J ) 3.0, 4.2 Hz, H-2), 3.464 (1H, dd, J )
3.0, 4.2, Hz, H-3), 4.530 (1H, qd, J ) 7.2, 3.0 Hz, H-4), 7.792 (1H, s,
H-12), 5.373 (1H, d, J ) 13.2 Hz, H-13a), 5.263 (1H, d, J ) 13.2 Hz,
H-13b), 10.509 (1H, s, H-14), 1.329 (3H, s, J ) 7.2 Hz, H-15), 4.291
(3H, s, OCH3), 2.074 (3H, s, AcO), 3.580 (3H, OCH3), 7.35-7.63 (5H,
aromatic H).
(3) Bohlmann, F.; Zdero, C. Phytochemistry 1978, 17, 565-566.
(4) Joseph-Nathan, P.; Villago´mez, J. R.; Roma´n, L. U.; Herna´ndez, J.
D. Phytochemistry 1990, 29, 977-979.
(5) Delgado, G.; Garc´ıa, P. E.; Roldan, E. I.; Bye, R.; Linares, E. Nat.
Prod. Lett. 1996, 8, 145-150.
(6) Pe´rez-Castorena, A. L.; Arciniegas, A.; Ramirez-Apan, M. T.;
Villasen˜or, J. L.; Romo de Vivar, A. Planta Med. 2002, 68, 645-
647.
(7) Burgen˜o-Tapia, E.; Joseph-Nathan, P. Magn. Reson. Chem. 2003,
41, 386-390.
(8) Arciniegas, A.; Pe´rez-Castorena, A. L.; Villasen˜or, J. L.; Romo de
Vivar, A. Biochem. Syst. Ecol. 2004, 32, 615-618.
(9) Pe´rez-Castorena, A. L.; Arciniegas, A.; Herna´ndez, M. L.; De la Rosa,
I.; Contreras, J. L.; Romo de Vivar, A. Z. Naturforsch. 2005, 60b,
1088-1092.
(10) Pe´rez-Castorena, A. L.; Arciniegas, A.; Villasen˜or, J. L.; Romo de
Vivar, A. ReV. Soc. Qu´ım. Me´x. 2004, 48, 21-23.
(11) Bohlmann, F.; Ziesche, J. Phytochemistry 1981, 20, 469-472.
(12) Wenkert, E.; Gottlieb, H. Phytochemistry 1977, 16, 1811-1816.
(13) Matsuo, A.; Ono, K.; Hamasaki, K.; Nozaki, H. Phytochemistry 1996,
42, 427-430.
(14) Richards, J.; Hendrickson J. Biosynthesis of Terpenes, Steroids and
Acetogenins; W. A. Benjamin Inc.: New York, 1964; Vol. 8, pp
225-237.
(15) Snatzke, G. In Optical Rotatory Dispersion and Circular Dichroism
in Organic Chemistry; Snatzke, G., Ed.; Heyden & Son Ltd.: London,
1965; Vol. 13, p 215.
Acid Hydrolysis of Compound 7. Compound 7 (50 mg) was
refluxed for 2 h with 10% HCl. The reaction mixture was extracted
with EtOAc and purified by column chromatography. Elution with
25
hexane-acetone (19:1) furnished 12 mg of 10, [R]D -42.0 (c 0.60,
MeOH).16
Oxidation of Angulifolins A and B (2 and 3). Compounds 2 and
3 (5 mg each) were oxidized with Jones reagent in acetone (1 mL) at
0 °C. Reaction mixtures were purified by preparative TLC (hexane-
acetone, 8:2) to obtain 3.0 and 3.3 mg, respectively, of the keto
derivative 9 as a yellow oil: [R]D25 -21.0 (c 0.10, MeOH); UV (MeOH)
λmax (log ꢀ) 267 (4.87), 235 (4.86), 2.07 (4.06) nm; IR (CHCl3) νmax
1740, 1683, 1699 cm-1; CD [θ]214 -9452.7, [θ]270 +12861.9, [θ]336
(16) Kikuzaki, H.; Sato, A.; Mayahara, Y.; Nakatani, N. J. Nat. Prod.
2000, 63, 749-752.
(17) Monks, A.; Scudiero, D.; Skehan, P.; Shoemaker, R.; Paul, K.;
Vistica, D.; Hose, C.; Langley, J.; Cronise, P.; Vaigro-Wolff, A.;
Gray-Goodrich, M.; Campbell, H.; Mayo, J.; Boyd, M. J. Natl.
Cancer Inst. 1991, 38, 757-766.
1
-8186.4; H NMR (CDCl3, 300 MHz) δ 3.81 (2H, m, H-2 and H-3),
4.73 (1H, qd, J ) 6.9, 2.2 Hz, H-4), 7.91 (1H, s, H-12), 5.40 (1H, d,
NP0604073