Fascioquinols A-F: Bioactive meroterpenes from a deep-water southern Australian marine sponge, Fasciospongia sp.

Article abstract of DOI:10.1016/j.tet.2011.02.015

Chemical investigation of a southern Australian deep-water marine sponge, Fasciospongia sp., returned the new meroterpene sulfate fascioquinol A (1) together with a series of acid mediated hydrolysis/cyclization products, fascioquinols B (2), C (3) and D

Full text of DOI:10.1016/j.tet.2011.02.015

Tetrahedron 67 (2011) 2591e2595
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Fascioquinols AeF: bioactive meroterpenes from a deep-water southern
Australian marine sponge, Fasciospongia sp.
*
Hua Zhang, Zeinab G. Khalil, Robert J. Capon
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
a r t i c l e i n f o
a b s t r a c t
Article history:
Chemical investigation of a southern Australian deep-water marine sponge, Fasciospongia sp., returned
the new meroterpene sulfate fascioquinol A (1) together with a series of acid mediated hydrolysis/cy-
clization products, fascioquinols B (2), C (3) and D (4), and strongylophorine-22 (5). Additional co-me-
tabolites include the new meroterpenes fascioquinol E (6) and fascioquinol F (8), together with the
known sponge metabolite geranylgeranyl 1,4-hydroquinone (7). Structures were assigned to 1e8 on the
basis of detailed spectroscopic analysis, chemical interconversion, mechanistic and biosynthetic con-
siderations, and literature comparisons. The known 1,4-hydroquinone 7 was identified as the dominant
cytotoxic principle in the Fasciospongia sp. extract, with selective inhibitory activity against gastric ad-
Received 3 November 2010
Received in revised form 19 January 2011
Accepted 7 February 2011
Available online 12 February 2011
Keywords:
Fascioquinol
Fasciospongia
Meroterpene
Cytotoxicity
Antibacterial
enocarcinoma (AGS, IC50
fascioquinols displayed little or no inhibitory activity towards human cell lines, 1 and 2 displayed
promising Gram-positive selective antibacterial activity towards Staphylococcus aureus (IC50 0.9e2.5 M)
and Bacillus subtilis (IC50 0.3e7.0 M).
8 mM) and neuroblastoma (SH-SY5Y, IC50 4 mM) cell lines. By contrast, while the
m
m
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
together with consideration of the biosynthetic and chemical re-
lationshipsbetweenthesemetabolites,andanassessmentofcytotoxic
and antibiotic properties.
During an investigation aimed at discovering new anticancer
agents from marine organisms we screened a collection of w2600
southern Australian and Antarctic marine invertebrates and algae for
cytotoxic properties against colon (HT-29), lung (A549), skin (MM96L
and SK-MEL-28), prostate (DU145), ovarian (JAM and C180-13S) and
breast(MDA-MB-231)humancancercell lines.This screeningstrategy
identified >120promisingcytotoxicextracts,withearlyinvestigations
leading to the discoveryof the terpenyl-taurine phorbasins,1 terpenyl-
pyrrolizidine bistellettazines,2 indolo-imidazole trachycladindoles3
and polyketide-phosphodiester franklinolides.4 This current report
describes our investigations into another extract from this priority list,
a deep-water Fasciospongia sp. (CMB-02028) collected during scien-
tific trawling operations (ꢀ100 m) off the southern coast of Australia.
Metabolites recovered from thisspecimen include a new meroterpene
sulfate fascioquinol A (1) together with a series of new acid mediated
hydrolysis/cyclizationproducts, fascioquinols B (2), C (3)andD(4), and
the known sponge metabolite strongylophorine-22 (5).5 Other bio-
synthetically related co-metabolites include the new meroterpenes
fascioquinol E (6) and fascioquinol F (8), together with the known
sponge metabolite geranylgeranyl 1,4-hydroquinone (7).6 What fol-
lows is an account of the isolation and structure elucidation of 1e8,
2. Results and discussion
A portion of the aqueous ethanol extract obtained from Fas-
ciospongia sp. (CMB-02028) was concentrated in vacuo and sub-
jected to sequential solvent partitioning and trituration, followed
by gel (Sephadex LH-20), normal (silica) and reverse phase (C8 and
C18) column chromatography, to yield 1e8.
HRESI(ꢀ)MS analysisof fascioquinol A (1) revealed a highest mass
ion consistent with an anionic molecular formula (C26H37O5Sꢀ,
Dmmu 0.6) suggestive of eight double bond equivalents (DBE) (as-
suming an SII oxidation state). The NMR (methanol-d4) data for 1
(Table 1) revealed resonances consistent with a trisubstituted double
bond (dH 5.30, br s, H-12; dC 122.7, C-12; 137.0, C-13) bearing an
olefinic methyl (dH 1.44, br s, H3-25; dC 22.6, C-25), and a 1,2,4-tri-
substituted benzene (dH 6.66, d, 8.7 Hz, H-18; 6.91, dd, 8.7 and 2.7 Hz,
H-19; 7.14, d, 2.7 Hz, H-21; dC 132.2, C-16; 153.4, C-17; 116.0, C-18;
120.5, C-19; 146.6, C-20; 124.0, C-21). These observations accounted
for five DBE and suggested that 1 incorporated at least three addi-
tional rings.
Analysis of COSY NMR (methanol-d4) data for 1 (Table 1)
revealed structure subunits as indicated in Fig. 1, comprising (i) H2-
1 through H2-2 to H2-3, (ii) H-5 through H2-6 to H2-7, (iii) H-9
* Corresponding author. Tel.: þ61 7 3346 2979; fax: þ61 7 3346 2090; e-mail
address: r.capon@uq.edu.au (R.J. Capon).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.02.015

2592
H. Zhang et al. / Tetrahedron 67 (2011) 2591e2595
Fig. 1. Key 2D NMR correlations for 1.
through H2-11, H-12, H3-25, H-14 to H2-15 and (iv) H-18 through
H-19 to H-21. Consideration of the HMBC NMR (methanol-d4) data
for 1 revealed key correlations that defined (a) geminal dimethyls
(dH 0.89, s, H3-22; 0.85, s, H3-26; dC 34.1, C-22; 22.3, C-26) with
correlations to C-3, C-4 and C-5, (b) a tertiary methyl (dH 0.95, s, H3-
23; dC 16.4, C-23) with correlations to C-1, C-5, C-9 and C-10, and (c)
a tertiary methyl (dH 0.89, s, H3-24; dC 15.4, C-24) with correlations
to C-7, C-8, C-9 and C-14. The NMR (DMSO-d6) data for 1
(Supplementary data, Table S1) revealed an exchangeable phenol
resonance (dH 9.00, s) displaying a ROESY correlation to H-18 (dH
6.61, d, 8.6 Hz), consistent with a 17-OH moiety. The structure ar-
guments presented above accounted for all but the elements
of OSO3 and supported positioning of a sulfate moiety at C-20.
Taken with HMBC correlations from H2-15 to C-16, C-17 and C-21
(Table 1), the analysis presented above defined the planar structure
for 1 as indicated. Consideration of the ROESY NMR (methanol-d4)
Table 1
NMR data (methanol-d4, 600 MHz) for fascioquinol A (1)
No.
1
dC
41.4
dH (mult., J (Hz))
COSY
ROESY
HMBC (1He13C)
b
a
b
a
b
a
1.64e1.69A (m)
1
1
2
1
3
2
a
b
a
a
a
b
,
11
a
2, 3, 5, 10
23,
3
1, 4
1, 5, 26
2, 4, 22, 26
0.83e0.89B (m)
, 2
, 3
, 2
,
b
a
b
3
a
, 5, 9
2
3
19.8
43.3
1.60e1.66A (m)
23, 26
1.38e1.43C (m)
1.35e1.40C (m)
22, 26
22
1.19 (ddd, 14.0, 13.0, 4.1)
, 3
b
4
5
6
34.2
57.6
20.2
0.91 (dd, 12.0, 1.9)
6
5, 6
6
6
6
b
1
7
7, 22
15b, 6a, 6b, 24
5, 6
a
, 7
a
, 9
4, 6, 22, 23, 26
10
7, 8, 10
5, 9
b
a
b
a
1.40e1.45C (m)
a
, 7
, 7
a
b
b, 23, 26
1.56e1.61 (m)
2.03 (ddd, 12.8, 3.1, 3.1)
1.30 (ddd, 13.3, 12.8, 3.9)
b
a
a
, 7a
, 7a
, 6b
7
42.4
, 7
b
a
, 14
, 5, 14
, 12, 23, 24
6, 8, 14, 24
8
9
38.3
56.9
38.6
1.25 (dd, 10.1, 7.0)
11
1
a
1, 8, 10, 11, 14, 23, 24
12, 13
10
11
12
13
14
15
24.0
1.89e1.94 (2H, m)
5.30 (br s)
9, 12, 14, 25
11, 14, 25
1
b
122.7
137.0
56.2
11, 25
2.39 (br d, 9.7)
a 2.68 (dd, 15.3, 9.7)
b 2.53 (dd, 15.3, 2.4)
11, 12, 15a
14, 15b
15a
7
a
, 9, 21
21, 24, 25
, 21, 24
13, 16
13, 14, 16, 17, 21
8, 13, 14, 16, 17, 21
27.1
7
b
16
17
18
19
20
21
22
23
24
25
26
132.2
153.4
116.0
120.5
146.6
124.0
34.1
16.4
15.4
22.6
22.3
6.66 (d, 8.7)
6.91 (dd, 8.7, 2.7)
19
18, 21
16, 17, 20
17, 20, 21
7.14 (d, 2.7)
0.89 (s)
0.95 (s)
19
14, 15a, 15b
15, 17, 19, 20
3, 4, 5, 26
1, 5, 9, 10
7, 8, 9, 14
12, 13, 14
3, 4, 5, 22
3
2
7
a
b
b
, 3
b
, 6
, 11
, 15a, 15b, 23
a
, 6
b
b, 24, 26
0.89 (s)
, 11
b
1.44 (br s)
11, 12
12, 15a
, 3 , 6b, 23
0.85B (s)
2
b
b
AeDOverlapping resonances within the column.

H. Zhang et al. / Tetrahedron 67 (2011) 2591e2595
2593
data for 1 revealed key correlations that defined the complete
relative configuration. More specifically, ROESY correlations (Fig. 1)
HRESI(ꢀ)MS analysis of fascioquinol F (8) revealed a pseudo-mo-
lecular ion (MꢀH)ꢀ consistent with a molecular formula C26H36O2
established that H-5, H-9 and H-14 were positioned one (
while H3-26, H3-23, H3-24 and H2-15 were positioned on the op-
posite ( ) face of the fused tricyclic system. Thus the complete
a
) face,
(Dmmu ꢀ0.2), while the NMR (CDCl3) data (Supplementary data,
Table S8) disclosed resonances (dH 5.58, d, 9.8 Hz, H-10; 6.25, d,
9.8 Hz, H-20; 1.35, s, H3-170) suggestive of a chromene moiety. The
planar structure assigned to 8 was confirmed by spectroscopic com-
parison to the closely related marine brown alga metabolite dictyo-
chromenol8 and the sponge metabolite 2-(hexaprenylmethyl)-2-
methylchromenol.9 As the latter two natural products exhibited small
b
relative stereostructure for fascioquinol A (1) could be assigned as
indicated.
During HPLC fractionation of 1 it proved advantageous to em-
ploy an H2O/MeCN gradient, with a constant 0.01% TFA modifier to
enhance peak shape and improve resolution. The benefits of a TFA
modifier notwithstanding, during concentration in vacuo (freeze
drying) samples of 1 underwent acid mediated degradation to yield
3e5 (structure assignments detailed below). The proposition that
the cyclic ethers 3e5 were handling artifacts was further supported
by acid hydrolysis studies (see Experimental section), and the fact
that formation could be avoided by either neutralizing HPLC frac-
tions with sodium bicarbonate prior to concentration in vacuo, or
by avoiding HPLC in favour of gel chromatography (Sephadex LH-
20) in neutral solvent (MeOH).
but positive [
the near zero [
a
]D measurements (þ4andþ3.6(c1, CHCl3), respectively),
a]
D
22 þ 0.06 (c 0.58, CHCl3) value for 8 was taken as evi-
dence of a near racemic mixture. Literature reports of 8 are limited to
a single occurrence in a 1989 patent as a synthetic anti-ulcer agent,10
with the current report being the first account of 8 as a natural product.
In an attempt to explain the mechanism for the acid mediated
transformations noted above we propose (Fig. 2) that following
hydrolysis of the sulfate 1 to the phenol 2, cyclization of 2 to 3e5
proceeds via initial protonation of D12,13 to yield a C-13 tertiary
carbocation. This intermediate carbocation then undergoes either
(i) pro R facial SN1 addition by the adjacent 17-OH to yield 4, or (ii)
pro S facial SN1 addition to yield 5, or (iii) stereocontrolled intra-
HRESI(ꢀ)MS analysis of fascioquinol B (2) revealed a pseudo-
molecular ion (MꢀH)ꢀ attributed to a molecular formula (C26H38O2,
D
mmu ꢀ0.5) consistent with a desulfated analogue of 1. Supportive
molecular 1,2-hydride transfer (across the
tertiary carbocation which in turn undergoes SN1 addition by the
adjacent 17-OH from the less sterically hindered face. This latter
stereocontrolled 1,2-hydride transfer and facial attack suggest
a face) to yield a C-14
of such a structure assignment, the 1H NMR (methanol-d4) data for
2 (Supplementary data, Table S2) was almost identical to that for 1,
with the significant exception being an w0.5 ppm shielding of
resonances for H-19 and H-21, which now flanked a phenol rather
than a sulfate functionality. Likewise, diagnostic 13C NMR chemical
shift differences between 1 and 2 (C-17 DdC ꢀ4.4, C-19 DdC ꢀ6.9, C-
20 DdCþ4.6, C-21 DdC ꢀ6.9) could be attributed to hydrolysis of the
C-20 sulfate moiety to a phenol.
a
a
assignment of the C-13/C-14 relative configuration to fascioquinol C
(3) as indicated. Furthermore, given the proposed mechanistic
relationship to 5, a sponge metabolite of known absolute configu-
ration,5 we propose that 1e4 belong to the same antipodal series.
The natural product meroterpenes 1 and 6e8 were assessed in
cytotoxicity and cell proliferation assays against human gastric (AGS)
HRESI(ꢁ)MS analysis of the acid degradation products 3e5
revealed pseudo-molecular ions consistent with molecular for-
mulae (C26H38O2,
D
mmu ꢀ0.6, ꢀ1.1 and 0.6, respectively) isomeric
with 2. Detailed analysis of the NMR (methanol-d4) data for 3e5
(Supplementary data, Tables S3eS5) revealed a loss of the D12,13
moiety with concomitant ring closure to yield cyclic ethers. For
example, analysis of the NMR data for fascioquinol C (3) revealed
diagnostic resonances for a secondary aliphatic H3-25 methyl
(dH 0.68, d, 6.5 Hz), a quaternary oxygenated C-14 (dC 96.2), and an
isolated H2-15 benzylic spin system (dH 2.73, d, 16.6 Hz, Hb-15; 3.19,
d, 16.6 Hz, Ha-15), with strong ROESY correlations observed be-
tween Hb-15 and H3-25, and between Ha-15 and H3-24dconsistent
with the five member cyclic ether as indicated (with the C-13 and
C-14 relative stereochemistry assigned on mechanistic grounds as
indicated below). Similar analysis of the NMR data for 4 and 5
confirmed retention of H-14 (4 dH 1.26, d, 8.2 Hz; 5 dH 1.61, m), and
the appearance of quaternary oxygenated C-13 (4 dC 75.3; 5 dC 76.8)
and tertiary aliphatic H3-25 methyl (4 dH 1.11, s; 5 dH 1.15, s) reso-
nances, consistent with the C-13 epimeric six member cyclic ethers
as indicated. On reviewing the scientific literature 5 proved to be
identical in all respects, including absolute configuration, with the
known marine sponge metabolite strongylophorine-22 first
reported in 2003 by Miyaoka et al. from an Okinawan specimen of
Petrosia (Strongylophora) corticata.5 Based on this comparison, fas-
cioquinol D (4) was assigned as the C-13 epimer as indicated.
HRESI(ꢀ)MS analysis of fascioquinol E (6) revealed a highest
mass ion isomeric with 1, whereas the NMR (methanol-d4) data
(Supplementary data, Table S6a) disclosed a simplified E,E,E-ger-
anylgeranyl side chain. Consistent with this interpretation, acid
mediated hydrolysis of 6 yielded the known sponge metabolite
geranylgeranyl 1,4-hydroquinone (7).6 Comparison of NMR shifts
between 6 and 7 (as discussed above for 1 and 2) permitted structure
assignment of the meroterpene sulfate fascioquinol E (6) as in-
dicated. Literature reports on 6 are limited to a single occurrence in
a 1989 patent as a synthetic reversetranscriptase inhibitor,7 with the
current report being the first account of 6 as a natural product.
Fig. 2. Biosynthetic and acid mediated relationships of 1e8.

2594
H. Zhang et al. / Tetrahedron 67 (2011) 2591e2595
and colourectal (HT-29) adenocarcinoma, neuroblastoma (SH-SY5Y)
and human foreskin fibroblast (HFF-1) cell lines. These assays dem-
onstrated that while the fascioquinols A (1), E (6) and F (8) were in-
with a constant 0.02% TFA) to yield a pure sample of fascioquinol
A (1), which underwent conversion to a mixture of 3e5 (6.1 mg)
during concentration in vacuo (freeze drying). Similarly, a pure
sample of fascioquinol E (6) underwent conversion to geranylger-
anyl 1,4-hydroquinone 7 (4.0 mg).
A third portion of the CH2Cl2 solubles (17 mg) was fractionated
using the same HPLC method as described above for the second
portion, however, eluted samples of fascioquinol A (1) and fas-
cioquinol E (6) were neutralized to pH w7 by the addition of sodium
bicarbonate and back extraction into CHCl3 prior to concentration in
vacuo. This process returned 1 (5.5 mg) and 6 (4.3 mg).
A fourth portion of the CH2Cl2 solubles (382 mg) was fraction-
ated by a Sephadex LH-20 column (90ꢃ2.2 cm, MeOH) to return six
mixed fractions (F1eF6) and two pure compounds, fascioquinol
A (1, 143.8 mg) and fascioquinol E (6, 30.4 mg). Fraction F5 (65 mg)
was subjected to normal phase isocratic silica gel column chro-
matography (28ꢃ2.2 cm, 6:1 n-hexane/acetone) to return ger-
anylgeranyl 1,4-hydroquinone (7, 37.4 mg) and a mixture that was
further separated by HPLC (Zorbax StableBond C18 semi-pre-
parative column, gradient elution at 4 mL/min 20% H2O/MeCN to
100% MeCN over 15 min) to yield fascioquinol F (8, 5.8 mg).
The yields of natural products in the Fasciospongia sp. extract,
based on an estimated total weight to weight % from the crude
aqueous EtOH extract are; fascioquinol A (1, 9.5%), fascioquinol E (6,
2.0%), geranylgeranyl 1,4-hydroquinone (7, 2.5%) and fascioquinol
F (8, 0.4%).
active (IC50 >30
selectively cytotoxic to gastric adenocarcinoma (AGS, IC50
neuroblastoma (SH-SY5Y, IC50 M) cell lines. The complete set of
mM), the geranylgeranyl 1,4-hydroquinone 7 was
8
mM) and
4
m
meroterpenes 1e8 was alsotested in antimicrobial assays against two
Gram-positive (Staphylococcus aureus and Bacillus subtilis) and two
Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacte-
ria, and a fungus (Candida albicans). These assays (Table 2 and
Supplementary data) confirmed that fascioquinols A (1) and B (2)
displayed promising Gram-positive selective antibacterial properties
towards S. aureus (IC50 0.9e2.5 mM) and B. subtilis (IC50 0.3e7.0 mM).
Table 2
Antibacterial screening data (IC50 mM) for 1e8
No.
S. aureusa
S. aureusb
B. subtilisc
B. subtilisd
1
2
3
4
5
6
7
8
2.4
1.0
5.4
25
7.8
4.1
8.0
13
2.5
0.95
5.6
>30
9.5
5.1
10
16
0.85
0.30
1.4
2.3
2.8
3.1
>30
>30
1.8
7.0
1.7
16
1.6
5.4
23
>30
Bacterial strains are
a
ATCC 25923.
ATCC 9144.
ATCC 6051.
ATCC 6633.
b
22
3.4.1. Fascioquinol A (1). Off-white solid; [
a]
þ24.6 (c 1.00,
D
c
MeOH); UV (MeOH) lmax (log e
) 219 (sh) (3.95), 281 (3.44) nm; 1H
d
and 13C NMR (600 MHz, methanol-d4) Table 1 (600 MHz, DMSO-d6)
Table S1; ESI (ꢀ)MS m/z 461 Mꢀ; HRESI(ꢀ)MS m/z 461.2361 Mꢀ
(calcd for C26H37O5S, 461.2367).
3. Experimental section
3.1. General experimental procedures
22
3.4.2. Fascioquinol B (2). White solid; [
UV (MeOH) lmax (log
a]
þ39.6 (c 0.22, MeOH);
D
e
) 220 (sh) (3.94), 296 (3.70) nm; 1H and 13
C
See Supplementary data.
NMR (600 MHz, methanol-d4) Table S2 (see Supplementary data);
ESI(ꢁ)MS m/z 383 [MþH]þ, 381 [MꢀH]ꢀ; HRESI(ꢀ)MS m/z
381.2794 [MꢀH]ꢀ (calcd for C26H37O2, 381.2799).
3.2. Animal materials (collection and taxonomy)
See Supplementary data.
22
3.4.3. Fascioquinol C (3). White solid; [
UV (MeOH) lmax (log
a
]
ꢀ13.0 (c 0.20, CHCl3);
D
e
) 219 (sh) (3.67), 230 (3.59), 306 (3.43) nm;
1H and 13C NMR (600 MHz, CDCl3) Table S3 (see Supplementary
data); ESI(ꢁ)MS m/z 383 [MþH]þ, 381 [MꢀH]ꢀ; HRESI(ꢀ)MS m/z
381.2793 [MꢀH]ꢀ (calcd for C26H37O2, 381.2799).
3.3. Bioassays
See Supplementary data.
22
3.4. Extraction and isolation
3.4.4. Fascioquinol D (4). White solid; [
UV (MeOH) lmax (log
a]
þ13.4 (c 0.40, CHCl3);
D
e
) 220 (sh) (3.79), 230 (sh) (3.65), 298 (3.48)
A portion (200 mL) of the aqueous EtOH extract of the Fas-
ciospongia sp. was decanted and concentrated in vacuo to return
a black solid (2.24 g), which was subsequently partitioned into
n-BuOH (672 mg) and H2O (1.5 g) soluble fractions. Bioassay estab-
lished that cytotoxic agents were concentrated in the n-BuOHsoluble
partition, which was subsequently defatted by sequential trituration
to yield n-hexane (87 mg) and CH2Cl2 (565 mg) soluble fractions.
A portion of the CH2Cl2 soluble material (133 mg) was frac-
tionated on an Alltech C18 SPE cartridge (10% stepwise gradient
elution from 50% H2O/MeCN to 100% MeCN with a constant 0.1%
TFA) to return six fractions (F1eF6), which were concentrated in
vacuo at 40 ꢂC. A portion (32/72 mg) of F2 was resolved by HPLC
(Zorbax Eclipse C8 semi-preparative column, gradient elution at
4 mL/min 30% H2O/MeOH to 10% H2O/MeOH with 10% isocratic
MeCN over 20 min) to yield strongylophorine-22 (5, 6.4 mg), fas-
cioquinol D (4, 4.1 mg) and fascioquinol C (3, 2.1 mg).
nm; 1H and 13C NMR (600 MHz, CDCl3) Table S4 (see Supplementary
data); ESI(ꢁ)MS m/z 383 [MþH]þ, 381 [MꢀH]ꢀ; HRESI(ꢀ)MS m/z
381.2788 [MꢀH]ꢀ (calcd for C26H37O2, 381.2799).
22
3.4.5. Strongylophorine-22 (5). White solid; [
a
]
ꢀ44.7 (c 0.64,
D
CHCl3); UV (MeOH) lmax (log e) 221 (sh) (3.76), 230 (sh) (3.67), 298
(3.52) nm; ESI(ꢁ)MS m/z 383 [MþH]þ, 381 [MꢀH]ꢀ; 1H and 13C
NMR (600 MHz, CDCl3) Table S5 (see Supplementary data); HRESI
(þ)MS m/z 787.5642 [2MþNa]þ (calcd for C52H76NaO4, 787.5636).
3.4.6. Fascioquinol E (6). Off-white solid; UV (MeOH) lmax (log e)
281 (3.45) nm; 1H and 13C NMR (600 MHz, methanol-d4) Table S6a
(see Supplementary data); 1H and 13C NMR (600 MHz, DMSO-d6)
Table S6b (see Supplementary data); ESI(ꢀ)MS m/z 461 ꢀ; HRESI(ꢀ)
MS m/z 461.2363 Mꢀ (calcd for C26H37O5S, 461.2367).
A second portion of the CH2Cl2 solubles (21 mg) was subjected
to an HPLC (Zorbax Eclipse C8 semi-preparative column, gradient
elution at 4 mL/min 50% H2O/MeCN to 100% MeCN over 20 min
3.4.7. Geranylgeranyl 1,4-hydroquinone (7). Pale yellow oil; UV
(MeOH) lmax (log
CDCl3) Table S7 (see Supplementary data), compares favourably
e
) 294 (3.66) nm; 1H and 13C NMR (600 MHz,

H. Zhang et al. / Tetrahedron 67 (2011) 2591e2595
2595
with literature data; ESI(ꢁ)MS m/z 383 [MþH]þ, 381 [MꢀH]ꢀ;
HRESI(ꢀ)MS m/z 381.2801 (calcd for C26H37O2, 381.2799).
Victoria) for sponge taxonomy, C. Cuevas and colleagues (Pharma-
Mar) for preliminary in vitro anticancer screening, M.M. Conte (UQ)
for in house in vitro cytotoxicity and cell proliferation screening,
and A.M. Piggott (UQ) for the acquisition of HRESIMS data. This
work was funded partially by the Australian Research Council, with
additional support from PharmaMar (Madrid, Spain).
3.4.8. Fascioquinol F (8). Paleyellow oil; [
a]
22 þ 0.06 (c 0.58, CHCl3);
D
UV (MeOH) lmax (log
e
) 230 (sh) (4.31), 264 (3.67), 331 (3.60) nm; 1H
and 13C NMR (600 MHz, CDCl3) Table S8 (see Supplementary data);
ESI(ꢁ)MS m/z 381 [MþH]þ, 403 [MþNa]þ, 379 [MꢀH]ꢀ; HRESI(ꢀ)
MS m/z 379.2641 (calcd for C26H35O2, 379.2643).
Supplementary data
3.5. Preparative acid hydrolysis of fascioquinol A (1)
These data include general experimental procedures, animal
materials (collection and taxonomy), preliminary cytotoxic screening
results on crude n-BuOH partition, MTT cytotoxicity and cell pro-
liferation, and antimicrobial assays for pure compounds, tabulated
NMR data and 1H NMR spectra for all compounds 1e8. Supplemen-
tary data associated with this article can be found in the online ver-
sion, at doi:10.1016/j.tet.2011.02.015. These data include MOL files
and InChiKeys of the most important compounds described in this
article.
A sealed solution of 1 (6.5 mg) in MeOH (650 mL) and TFA (20 mL)
was stirred at 40 ꢂC overnight. HPLC fractionation of the reaction
mixture (Zorbax Eclipse C8 semi-preparative column, gradient
elution at 4 mL/min, 35% H2O/MeCN to 100% MeCN over 15 min)
yielded fascioquinol B (2, 2.4 mg, 47%).
3.6. Analytical acid hydrolysis/cyclization study of
fascioquinol A (1)
Three sealed solutions of 1 (1.0 mg) in 20:1,10:1 and 5:1 ratios of
MeOH/TFA (200 m
L) were stirred at 40 ꢂC overnight. HPLC analysis
References and notes
(Zorbax Eclipse C8 analytical column, gradient elution at 1.0 mL/
min 30% H2O/MeCN to 100% MeCN with a constant 0.01% TFA over
15 min) detected only the desulfated analogue 2 in all the three
reaction mixtures. Two sealed solutions of 1 (1.0 mg) in 1:1 MeOH/
TFA (200 mL) and 1:1:2 MeCN/H2O/TFA (200 mL) were stirred at
room temperature overnight. HPLC analysis (as above) detected
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We thank CSIRO Marine Research and the crew of the RV
Franklin for assistance in sponge collection, L. Goudie (Museum