Aspernolides A and B, butenolides from a marine-derived fungus Aspergillus terreus

Article abstract of DOI:10.1016/j.phytochem.2008.10.017

Two aromatic butenolides, aspernolides A and B along with the known metabolites, butyrolactone I, terrein and physcion were isolated from the fermentation broth of a soft coral derived fungus Aspergillus terreus. The structures of these metabolites were a

Full text of DOI:10.1016/j.phytochem.2008.10.017

Phytochemistry 70 (2009) 128–132
Contents lists available at ScienceDirect
Phytochemistry
journal homepage: www.elsevier.com/locate/phytochem
Aspernolides A and B, butenolides from a marine-derived fungus Aspergillus terreus
*
Rajesh R. Parvatkar , Celina D’Souza, Ashootosh Tripathi, Chandrakant G. Naik
Bioorganic Chemistry Laboratory, National Institute of Oceanography, Council of Scientific and Industrial Research (CSIR), Dona Paula, Goa 403 004, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 May 2008
Received in revised form 21 October 2008
Available online 10 December 2008
Two aromatic butenolides, aspernolides A and B along with the known metabolites, butyrolactone I, ter-
rein and physcion were isolated from the fermentation broth of a soft coral derived fungus Aspergillus ter-
reus. The structures of these metabolites were assigned on the basis of detailed spectroscopic analysis.
The absolute stereochemistry of aspernolides A (1) and B (2) was established by their preparation from
the known butyrolactone I. Biogenetically aspernolides A and B must be derived from butyrolactone I, a
well known specific inhibitor of cyclin dependent kinase (cdk) from A. terreus. When tested, aspernolide A
exhibited mild cytotoxicity against cancer cell lines.
Keywords:
Aspergillus terreus
Marine natural products
Butenolides
Ó 2008 Elsevier Ltd. All rights reserved.
Butyrolactone I
Aspernolides
1. Introduction
1 has been described in the literature (Kiriyama et al., 1977) as a
reaction product in the structure elucidation of 3, neither its
Marine-derived microbes, fungi in particular have long been
recognized as potential source of structurally novel and biologi-
cally potent metabolites (Faulkner, 2000; Bugni and Ireland,
2003; Saleem et al., 2007). Fungi belonging to Aspergillus genera
are one of the major contributors to the secondary metabolites of
fungal origin. Aspergillus terreus is a ubiquitous fungus in our envi-
ronment and although Aspergillus sp. are normally considered ter-
restrial species, the genus is tolerant to high salt concentrations. In
recent years, we sought to draw marine microbial diversity into the
arena of drug discovery. The present investigation is an outcome of
such a study on the fungus A. terreus associated with a soft coral
Sinularia kavarattiensis.
Terrestrial isolates of A. terreus are well known for the produc-
tion of butenolides. Cytotoxic butyrolactones I–IV, biogenetically
derived from tyrosine (Rao et al., 2000; Kiriyama et al., 1977; Nitta
et al., 1983) and non prenylated-decarboxylated butenolides,
xenofuranones A (4) and B (5) (Morishima et al., 1994), biogeneti-
cally produced from phenyl alanine are known to be derived from
A. terreus. Xenofuranones A (4) and B (5) are also known as metab-
olites of bacterium Xenorhabdus szentitmaii (Brachmann et al.,
2006). There is a recent report on the identification of 3 and its sul-
fated derivatives (6 and 7) (Niu et al., 2008) from a strain A. terreus
(HKI0499).
NMR data is reported nor it is known to be a natural product.
Moreover this is the first report describing the isolation of 3 and
other related butenolides from marine-derived fungus.
2. Results and discussion
Fungus, A. terreus was isolated as an epiphyte from a soft coral
Sinularia kavarattiensis collected from the coast of Mandapam,
Tamil Nadu, India. This fungus was grown on potato dextrose broth
prepared in seawater. New secondary metabolites, aspernolides A
(1) and B (2) were identified from the chloroform and ethyl acetate
extracts of the culture broth respectively. These butenolides along
with their plausible biogenetic precursor 3 and the known metab-
olites physcion and terrein were purified using repeated silica gel
and Sephadex LH-20 gel filtration chromatography.
Aspernolide A (1) was obtained as white sticky solid. The
molecular formula C24H24O7 of 1 was determined by HRESITOFMS
which showed pseudomolecular ion peaks [M + Na]+ at 447.1433
(calcd. 447.1420 for C24H24O7Na) and [2M + Na]+ at 871.2959
(calcd. 871.2942 for C48H48O14Na). The IR spectrum showed the
presence of ester/lactone carbonyl at 1731 and 1738 cmꢀ1, phe-
nolic OHs were evident at 3330 cmꢀ1 and the presence of an
absorption at 1660 cmꢀ1 was suggestive of aromaticity in the
molecule.
This report focuses on the isolation and structure elucidation of
new butenolides, aspernolides A (1) and B (2) and other known
metabolites from culture medium of fungus A. terreus. Although,
The 1H NMR signals of the A2B2 system at dH 7.56, d, 2H,
J = 8.7 Hz and 6.86, d, 2H, J = 8.7 Hz revealed the presence of para
di-substituted benzene moiety. Two aromatic signals 6.53, s, 1H
and 6.47, s, 2H (two doublets merged into a singlet) were indica-
tive of the presence of additional unsymmetrical trisubstituted
benzene ring in the molecule. Its 13C NMR showed the presence
* Corresponding author. Tel.: +91 832 2450392.
E-mail addresses: parvatkar@gmail.com (R.R. Parvatkar), rparvatkar@nio.org
(R.R. Parvatkar).
0031-9422/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.phytochem.2008.10.017

R.R. Parvatkar et al. / Phytochemistry 70 (2009) 128–132
129
of 10 aromatic signals for two aromatic rings, two ester carbonyls
dc 169.3 s, and 169.6 s, olefenic carbon signals dc 137.2 s and 128.8
s, three sp3 CH2 s dc 22.1 t, 32.5 t and 38.6 t, a carbomethoxy dc 53.4
q and two oxygenated quaternaries dc 86.1 s and 74.2 s. The molec-
ular formula C24H24O7 requires 13 degrees of unsaturation. The
presence of two aromatic rings accounts for eight while two car-
bonyls and two olefenic carbons account for another three, which
makes a total of eleven degrees of unsaturation. Therefore 1 must
posses two aliphatic rings in addition to two aromatic rings.
A detailed comparison of the NMR data of 1 with that of buty-
rolactone I (3) (Rao et al., 2000), confirmed a common hydroxy-
phenylpyruvate dimer type of network in the molecule. The
significant difference observed in the NMR spectra of 1 as com-
pared to that of 3 was the absence of an olefinic proton signal dH
5.0, t, 1H, two olefinic carbon signals dc 121.0 d and 130.7 s and
the presence of three methylenes and two oxygenated sp3 quater-
naries compared to two methylenes and one oxygenated sp3 qua-
ternary in 3 in both 13C and DEPT NMR spectra. This data was
indicative of the presence of a dihydropyran ring fused to a trisub-
stituted benzene ring in place of the open prenyl chain present in 3.
HMBC was in good agreement with the structure 1 (Fig. 1). Key
HMBC correlations from H-200 to C-300 and C-700, from H-700 to
C-200, C-300 and C-400 and from H-800 to C-900 and C-1000 (1100) estab-
lished a dihydropyran ring fused through the C300–C400 bond of a
benzene ring. HMBC correlations from H-200 and H-600 to C-6 and
from H-6 to C-100, C-600, C-200, C-4, C-5 and C-3 were evidence of
the benzodihydropyranmethylene moiety linked to a lactone ring
at C-4. Furthermore HMBC correlation from H-20(60) to C-3 estab-
lished para di-substituted phenolic moiety at C-3. Out of two
carbonyls, C-5 and C-1, dc 169.6 was assigned to C-5 on the basis
of its HMBC correlation to the protons H-6 and H3–5OMe.
Aspernolide B (2) (Rf, 0.51), more polar than 1 (Rf, 0.81) was ob-
tained as a light brown syrup [a]D + 48.27 (c 0.29, MeOH). The IR
spectrum showed the presence of – OHs at 3330 cmꢀ1, ester/lac-
tone carbonyls overlapping peaks at 1732 and 1747 cmꢀ1 and
1610 and 1519 cmꢀ1 for aromatic rings. Although chemical shift
variations were present in the 1H and 13C NMR of 2, they were sim-
ilar to those of 1. Significant variations in the chemical shifts were
observed for the ring carrying the iso-pentyl chain wherein C-100,
C-300, C-700, C-800 C-1000 and C-1100 were considerably deshielded to
resonate at dc 128.1 (
D
d 4.6 ppm), 124.0 (
D
d 3.7 ppm), 24.2 (
D
d
2.1 ppm), 43.2 ( d 10.7 ppm), 28.4 (
D
D
d 1.8 ppm) and 28.5 (D
d
1.9 ppm) while C-500 and C-900 were considerably shielded to reso-
nate at dc 114.6 (Dd 2.0 ppm) and 70.8 (Dd 3.4 ppm) as compared
to 1, suggesting a change on the aromatic ring carrying iso-pentyl
chain. Compound 2 was well distinguished from ESI–MS spectrum
which showed pseudomolecular ions [M + H]+ at 443.1699 (calcd.
443.1706 for C24H27O8) and [M + Na]+ at 465.1516 (calcd.
465.1525 for C24H26O8Na) suggesting a molecular weight of 442
for the compound 2, which was 18 units more than that of 1. Based
on these observations it was evident that 2 has open chain hydrox-
ylated prenyl chain ortho to a phenolic –OH(C-400).
Based on the reported feeding experiments for establishing the
biosynthesis of xenofuranones A (4) and B (5) together with com-
pound 3 (Brachmann et al., 2006; Nitta et al., 1983) and isolation of
1 and 2 from A. terreus, it is apparent that the structures of 1 and 2
are an extension of the biosynthesis of 3, which is derived from
p-hydroxyphenylpyruvate. The enzyme-catalysed cyclization or
O
O
R1O
O
1
O
HO
O
O
O
3
O
5
4
3"
1'
8"
6
11"
10"
1"
6"
5'
O 9"
OR2
HO
4'
HO
1
3, R1 = R2= H (Butyrolactone I )
6, R1 = SO3H, R2= H
7, R1 = H, R2= SO3H
O
O
HO
O
O
OR
RO
O
O
OH
HO
2, R = H
8, R = Me
4, R = Me
5, R = H
O
O
HO
O
OMe
HO
O
Fig. 1. HMBC correlation for 1.

130
R.R. Parvatkar et al. / Phytochemistry 70 (2009) 128–132
O
HO
O
CO2H
O
O
2
OMe
O
HO
3
OH
H+,-OH, (H2O)
HO
O
HO
O
O
OMe
HO
O
O
OH
OMe
O
HO
1
OH
2
HO
Scheme 1. Biogenetic pathway of 1 and 2.
addition of water across the double bond of the prenyl chain of 3
results in the formation of 1 and 2, respectively (Scheme 1). The
last step in the biogenetic scheme was mimicked using mild acid
catalysis to confirm the structure of 1.
cell lines displayed weak cytotoxicity against H460, ACHN, Calu,
Panc1 and HCT116 cell lines (IC50 > 88, >103, >147, >130,
>121 lM, respectively).
On heating with 1% aqueous sulphuric acid, 3 was converted to
1 as well as small amount of 2 (Scheme 2). Only 50% conversion
was observed. When the same reaction was carried out using 2%
conc. HCl in methanol, complete conversion of 3 was observed as
indicated by TLC (90:10, CHCl3/MeOH). On chromatographic sepa-
ration, 75% of 1 was obtained along with minor amounts of 2 and a
new product 8. Compound 8 displayed an extra methoxy signal dH
3.15, s, dC 49.0 q in its NMR spectra compared with 2. In the rest of
the NMR spectra it was seen that C-7”, C-8”, C-10” and C-1100 were
3. Conclusion
A. terreus is known to be a producer of the cholesterol lowering
agent lovastatin (mevinoline) (Alberts et al., 1980) and many
other important secondary metabolites such as terreineol (Mac-
edo et al., 2004), terreulactone A (Kim et al., 2002), terrein, terreic
acid and aspulvinones. The list of metabolites also includes buty-
rolactone I (3), a specific inhibitor of cdk1/cyclin B and cdk2/cy-
clin A (Fischer and Lane, 2000) as potent as roscovitine, a drug
currently undergoing phase IIb clinical evaluation.1 Compound 3
exhibits antiproliferative activity against colon and pancreatic car-
cinoma, human lung cancer (Nishio et al., 1996) and prostatic can-
cer (Suzuki et al., 1999). Computer aided molecular modeling using
automated docking methods and molecular dynamics simulations
studies (Brana et al., 2004) have proven the importance of the alke-
nyl (prenyl) side chain in the molecule and explains why these but-
enolides lacking the alkenyl side chain do not maintain antitumor
activity. After considering the potential of 3 as a cdk inhibitor it
can be suggested that these marine natural products 1 and 2 or
synthetically modified natural products such as 8, which retain
the alkenyl side chain, could be tested in future to explore as
potential cdk inhibitors.
shielded and observed at dc 23.2(
4.4), and 24.4( d 4.1) while only methoxylated quaternary carbon
C-900 was deshielded to 75.4 (
d 4.6) compared to 2. Pseudomolec-
Dd 1.0), 40.0 (Dd 3.2), 24.0 (Dd
D
D
ular ion peaks [M + H]+ at 457.1851 and [M + Na]+ at 479.1669 ob-
served in ESI–MS indicated molecular weight of 456 for the
compound. On the basis of these observations, the structure was
assigned as shown in 8. Compounds 2 and 8 are formed by Markov-
nikoff’s addition of water and methanol respectively, across the
double bond of the prenyl chain.
During the structure elucidation of 3, compound 1 has been re-
ported as the product of its reaction with ethanolic HCl (Kiriyama
et al., 1977). In the present investigation, the same reaction in
methanolic HCl yielded besides 1, two additional products 2 and
8. Co-metabolite 3 used in the above reaction was determined to
be 4R configured by comparison of specific rotation data
4. Experimental
[a]D + 84.32° with the previously reported result (Kiriyama et al.,
1977). The absolute configurations of 1 and 2, therefore could be
deduced to be also 4R based on the biosynthetic grounds and sim-
4.1. General experimental procedures
ilarity of the specific rotations [a]D + 88.73° for 1 and +48.27° for 2.
Sephadex LH-20 (Pharmacia) and silica gel (60–120 mesh,
Qualigens) were used for column chromatography. Culture med-
ia Czapek agar and potato dextrose broth were procured from
Himedia Ltd., Mumbai. Solvents of laboratory reagent grade used
for column chromatography were purchased from a local sup-
plier and were distilled prior to use. Petroleum ether of boiling
range 60–80 °C was used for column chromatography. Precoated
kiesegel 60 F254 TLC plates were used for analytical TLC. A mix-
ture of methanol and chloroform (10:90, v/v) was used as mobile
phase for TLC analysis. Compounds were visualized as intense
rose coloured spots on spraying with methanolic sulphuric acid
Further confirmation of the absolute stereochemistry of 1 and 2 re-
sults from the fact that the natural 1 and 2 and those obtained as
products of the acid-catalyzed reaction had identical spectral data
and specific rotations [a]D + 88.73° for 1 and +48.27° for 2. There-
fore, we conclude that the compounds 1 and 2 also have 4R-
configuration.
Butyrolactone I (3), a metabolite of A. terreus var. africans IFO
8355 discovered in 1977, seems to be a common metabolite of this
fungus (Kiriyama et al., 1977; Rao et al., 2000; Niu et al., 2008;
Schimmel and Parsons, 1999). To our best knowledge, this is the
first report of 3 and its derivatives from marine-derived fungus.
Aspernolides B (2) and C (3) were unstable and were converted
to 1 on long standing. Aspernolide C (1) when tested against five
1
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R.R. Parvatkar et al. / Phytochemistry 70 (2009) 128–132
131
O
O
HO
O
O
HO
O
+
O
H
+
+
2
8
O
H+
O
2% HCl/MeOH
O
3
O
HO
1
HO
H
Scheme 2. Conversion of butyrolactone I (3) to aspernolide A (1).
(95:5, v/v) followed by heating at 120 °C. UV and IR spectra were
recorded on Shimadzu UV-2401 PC and Shimadzu FTIR-8201 PC
spectrometers. Optical rotations were measured on optical polar-
imeter ADP220 (Bellingham & Stanley Ltd.). NMR (1H, 13C, DEPT,
HSQC and HMBC) data were obtained on Bruker Avance 300 and
Bruker Avance 500 spectrometer with TMS as internal standard.
EI-MS and HRESITOFMS were recorded on Shimadzu 2010 and
QSTARXL MS/MS, Applied Biosystems, Switzerland.
purified on a silica gel column using gradient elution with
MeOH–CHCl3 (0:100–20:80) to afford 3 (32.0 mg; Rf, 0.64) and
another nearly pure compound which was purified over Sepha-
dex LH-20 using MeOH–CHCl3–Pet. ether (40:40:20) to yield 1
(26.3 mg; Rf, 0.81).
4.3.1. Aspernolide A (1)
White sticky solid; ½a D28
ꢂ
þ 88:73ꢃ (c 0.58, CHCl3); UV (MeOH)
kmax nm : 303, 240; IR (NaCl) mmax cmꢀ1 3340, 3024, 2970, 2935,
1737, 1732, 1610, 1519, 1498, 1436, 1386, 1261, 1182, 1122,
1068, 1037, 948, 839, 754; For NMR data see Table 1; HRESITOFMS
[M + Na]+ m/z 447.1433 (calcd. 447.1420 for C24H24O7Na),
[2M + Na]+ m/z 871.2959 (calcd. 871.2942 for C48H48O14Na); EIMS
m/z(%): M+ 424(2.7), 380(37.8), 348(35.1), 320(6.8), 293(13.5),
265(8.1), 237(10.8), 218(5.4), 205(6.8) 189(6.8), 175(100),
157(8.1), 145(10.8), 131(16.2), 119(13.5), 107(5.4), 91(24.3),
77(3.5), 69(12.1), 44(37.8).
4.2. Fungal isolation, identification and cultivation
Soft coral Sinularia kavarattiensis was collected by scuba diving
at a depth of 8–10 m from the coast of Mandapam, Tamil Nadu,
India in May 2004. After washing the soft coral with sterile sea
water, fungus A. terreus was isolated as an epiphyte using Czapek
agar containing (g/l) NaNO3 (2.0), MgSO4ꢁ7H2O (5.0) FeSO4ꢁ7H2O
(0.1), KH2PO4 (1.0), KCl (0.5), agar (3.0) sucrose (30.0) at pH 5.5
prepared in seawater supplemented with penicillin benzyl sodium
salt (0.02) to avoid any bacterial growth. After 6–7 days sand
brown, velvety colonies were observed. The strain was identified
as A. terreus from the morphological features of conidiophores
by Dr. Sanjay K. Singh, mycologist, Agharkar Research Institute,
Pune, India. A voucher specimen of the fungus is deposited at Na-
tional Institute of Oceanography, Dona Paula, Goa, India. Stock
cultures of the fungus, maintained at ꢀ20 °C preserved with 20%
glycerol was used to inoculate 500 ml of seed medium in an
Erlenmeyer flask (4 L) containing 24 g/l of potato dextrose broth
in seawater. It was then cultured at 27 2 °C on a rotary shaker
at 200 rpm. The flask was incubated for 72 h and used as a first
stage inoculum. The same medium (1 L) was made in 10 Erlenma-
yer flasks (4 L) and inoculated with 5% of first stage inoculum. The
flasks were incubated for 21 days at 27 2 °C on a rotary shaker at
200 rpm for 10 h/day.
4.3.2. Aspernolide B (2)
Light brown syrup; ½a D28
ꢂ
þ 48:27ꢃ (c 0.29, MeOH); UV (MeOH)
kmax nm : 303, 240; IR (NaCl) mmax cmꢀ1 3380, 3024, 2975, 2933,
1745, 1610, 1519, 1442, 1386, 1182, 1070, 1037, 838, 762; For
1H and 13C NMR spectroscopic data see Table 2; HRESITOFMS:
[M + H]+ m/z 443.1699 (calcd. 443.1706 for C24H27O8), [M + Na]+
m/z 465.1516 (calcd. 465.1525 for C24H26O8Na); EIMS m/z(%):
[M–CO2]+ 398(13), 380(70), 348(100), 333(18), 320(15), 293(40),
205(26), 249(10), 237(23), 218(17), 205(25), 188(16), 175(77),
145(13), 131(41), 119(23), 107(15), 91(35), 77(17), 69(20),
59(33), 43(23), 41(11).
Table 1
NMR spectroscopic data of aspernolide A (1) (500 MHz, CDCl3).
Carbon No.
dC, mult.
dH, mult., J(Hz)
HMBC
4.3. Extraction and isolation of metabolites
1
2
3
4
169.3 s
137.2 s
128.8 s
86.1 s
Twenty-one days old fermentation broth (10 L) was separated
from fungal mat and concentrated to a volume of 1 L under re-
duced pressure. The broth was extracted first with chloroform
(200 ml X 4) followed by ethyl acetate (200 ml X 4). The chloro-
form and ethyl acetate layers were separately concentrated un-
der reduced pressure to yield chloroform extract (470 mg) and
ethyl acetate extract (430 mg). The ethyl acetate extract was
chromatographed over Sephadex LH-20 using MeOH–CHCl3
(1:1) to yield pure crystalline compound, terrein (92 mg) (Dunn
et al., 1975) and a fraction containing an intense rose coloured
spot. This fraction was flash chromatographed over silica gel
using gradient elution of MeOH–CHCl3 (5:95–20:80) to yield 2
(7.2 mg; Rf, 0.51). The chloroform extract was repeatedly chro-
matographed over Sephadex LH-20 using MeOH–CHCl3 (1:1)
and 100% MeOH, which yielded a pure yellow coloured com-
pound, physcion (17 mg) (Bachmann et al., 1979). Other fractions
giving two prominent rose coloured spots on TLC were further
5
6
10
169.6 s
38.6 t
3.39, d (15.0), 3.59, d, (15.0)
C4, C100, C600, C3, C200, C5
122.2 s
129.5 d
115.9 d
156.4 s
123.5 s
131.4 d
120.3 s
152.9 s
116.6 d
129.0 d
22.1 t
20(60)
30(50)
40
7.56, d (8.7)
6.86, d (8.7)
C40, C3
C10, C40
100
200
6.53, s
C700, C6, C600, C400
300
400
500
6.47, s
6.47, s
2.53 m
1.66, t (6.5)
C100, C300
C6, C200, C400
C800, C900, C200, C300, C400
C300, C7”, C9”, C1000(1100)
600
700
800
32.5 t
74.2 s
26.6 q
53.4 q
900
1000(1100)
5-OMe
1.21, s
3.72, s
C700, C800, C900
C5

132
R.R. Parvatkar et al. / Phytochemistry 70 (2009) 128–132
Table 2
We are grateful to Dr. (Mrs.) Solimabi Wahidulla, senior scientist,
National Institute of Oceanography and Prof. S.K. Paknikar, Retd.
Prof., Department of Chemistry, Goa University for critically
reviewing the manuscript. We also thank Dr. P.D. Mishra, Dr.
Asha Almeida and Dr. Pari Koteppa, Nicholas Piramal Research
Center, Mumbai for carrying out biological screening and
500 MHz NMR facility.
1H and 13C NMR spectroscopic data of compounds 2 and 3 (300 MHz, CDCl3+ 2drops
CD3OD).
Carbon
No.
Aspernolide B (2)
dC, mult.
dH, mult., J
(Hz)
Aspernolide C (3)
dC, mult.
dH, mult., J
(Hz)
1
2
3
4
169.2 s
137.9 s
128.3 s
85.6 s
169.3 s
137.9 s
128.2 s
85.7 s
5
6
10
20(60)
30(50)
40
100
200
300
400
500
600
170.1 s
38.3 t
170.1 s
38.4 t
121.8 s
References
3.46, s
3.43, s
121.6 s
129.1 d
115.6 d
157.5 s
128.1 s
131.7 d
124.0 s
153.2 s
114.6 d
128.6 d
Alberts, A.W., Chen, J., Kuron, G., Hunt, V., Huff, J., Hoffman, C., Rothrock, J., Lopez,
M., Joshua, H., Harris, E., Patchett, A., Monaghan, R., Currie, S., Stapley, E., Albers-
Schonberg, G., Hensens, O., Hirshfield, J., Hoogsteen, K., Liesch, J., Springer, J.,
1980. Mevinolin: a highly potent competitive inhibitor of hydroxymethyl-
glutaryl-coenzyme A reductase and a cholesterol-lowering agent. Proc. Natl.
Acad. Sci. USA 77, 3957–3961.
Bachmann, M., Luethy, J., Schlatter, C., 1979. Toxicity and mutagenicity of molds of
the Aspergillus glaucus group. Identification of physcion and three related
anthraquinones as main toxic constituents from Aspergillus chevalieri. J. Agric.
Food Chem. 27 (6), 1342–1347.
Brachmann, A.O., Forst, S., Furgani, G.M., Fodor, A., Bode, H.B., 2006. Xenofuranones
A and B: phenylpyruvate dimers from Xenorhabdus szentirmaii. J. Natl. Prod. 69,
1830–1832.
Brana, M.F., Garcia, M.L., Lopez, B., Pascual-Teresa, B., Ramos, A., Pozuelo, J.M.,
Dominguez, M.T., 2004. Synthesis and biological evaluation of analogues of
butyrolactone I and molecular model of its interaction with CDK2. Org. Biomol.
Chem. 2, 1864–1871.
7.55, d (8.7) 129.2 d
6.87, d (8.7) 115.0 d
157.5 s
128.1 s
6.41, d (1.8) 131.8 d
124.0 s
7.54, d (8.7)
6.85, d (8.7)
6.40, d (1.8)
153.4 s
6.52, d (8.7) 114.4 d
6.49, d (8.1)
6.54, dd
(8.1, 1.8)
2.35, m
6.55, dd
(8.7, 1.8)
2.37, m
128.9 d
700
24.2 t
43.2 t
70.8 s
28.4 q
28.5 q
–
23.2 t
40.0 t
75.4 s
24.0 q
24.4 q
49.0 q
53.3 q
800
1.53, t (7.8)
1.54, t (7.8)
900
1000
1100
1200
5-OMe
1.20, s
1.19, s
1.12, s
1.12, s
3.15, s
3.74, s
Bugni, T.S., Ireland, C.M., 2003. Marine-derived fungi: a chemically and biologically
diverse group of microorganisms. Natl. Prod. Rep. 21, 143–163.
Dunn, A.W., Ian, D.E., Johnstone, A.W., 1975. Terrein and other metabolites of Phoma
species. Phytochemistry 14, 2081–2082.
53.5 q
3.76, s
Faulkner, D.J., 2000. Marine natural products. Natl. Prod. Rep. 17, 7–55.
Fischer, P.M., Lane, D.P., 2000. Inhibitors of cyclin-dependent kinases as anti-cancer
therapeutics. Current Med. Chem. 7, 1213–1245.
Kim, W., Cho, K., Lee, C., Yoo, I.D., 2002. Terreulactone A, a novel meroterpenoid
with anti-acetylcholinesterase activity from Aspergillus terreus. Tetrahedron
Lett. 43 (17), 3197–3198.
Kiriyama, N., Nitta, K., Sakaguchi, Y., Tagushi, Y., Yamamoto, Y., 1977. Studies on the
metabolic products of Aspergillus terreus. III. Metabolites of the strain IFO 8835.
Chem. Pharm. Bull. (Tokyo) 25 (10), 2593–2601.
4.3.3. Butyrolactone I (3)
White powder;
½
a 2D8:8
ꢂ
þ 84:32ꢃ (c 0.617, MeOH); and
½
a 2D8:8
ꢂ
þ 87:56ꢃ (c 0.617, CHCl3); 1H NMR and 13C NMR data were
in agreement with the literature (Rao et al., 2000); HRESITOFMS:
[M + H]+ m/z 424.1516 (calcd. 424.1522 for C24H25O7).
Macedo Jr., C.F., Porto, A.L.M., Marsaioli, A.J., 2004. Terreinol – a novel metabolite
from Aspergillus terreus: structure and 13C labeling. Tetrahedron Lett. 45 (1), 53–
55.
Morishima, H., Fujita, K., Nakano, M., Atsumi, S., Ookubo, M., Kitagawa, M.,
Matsumoto, H., Okunyama, A., Okabe, T., Suda, H., Nishimura, S., 1994. Jpn.
Kokai Tokkyo Koho.
Nishio, K., Ishida, A., Arioka, H., Kurokawa, H., Fukuoka, K., Nomoto, T., Fukumoto, H.,
Yokote, H., Saijo, N., 1996. Antitumor effects of butyrolactone I, a selective cdc2
kinase inhibitor, on human lung cancer cell lines. Anticancer Res. 16, 3387–
3395.
Nitta, K., Fujita, N., Yoshimura, T., Arai, K., Yamamoto, U., 1983. Metabolic products
of Aspergillus terreus. IX. Biosynthesis of butyrolactone derivatives isolated from
strain IFO 8835 and 4100. Chem. Pharm. Bull. (Tokyo) 31 (5), 1528–
1533.
Niu, X., Dahse, H., Menzel, K., Lozach, O., Walther, G., Meijer, L., Grabley, S., Sattler, I.,
2008. Butyrolactone I derivatives from Aspergillus terreus carrying an unusual
sulfate moiety. J. Natl. Prod. 71, 689–692.
Rao, K.V., Sadhukhan, A.K., Veerender, M., Mohan, E.V.S., Dhanvantri, S.D.,
Sitaramkumar, S., Babu, M.J., Vyas, K., Reddy, O.G., 2000. Butyrolactones from
Aspergillus terreus. Chem. Pharm. Bull. (Tokyo) 48 (4), 559–562.
Saleem, M., Ali, M.S., Hussain, S., Jabbar, A., Ashraf, M., Lee, Y.S., 2007. Marine natural
products of fungal origin. Natl. Prod. Rep. 24, 1142–1152.
4.3.4. Aspernolide C (8)
Light brown syrup; for 1H and 13C NMR spectroscopic data see
Table 2; HRESITOFMS: [M + H]+ m/z 457.1851 (calcd. 457.1862
for C25H29O8) and [M + Na]+ m/z 479.1669 (calcd. 479.1682 for
C25H28O8Na).
4.4. Conversion of butyrolactone I (3) to aspernolides A (1), B (2) and C
(8)
Butyrolactone I (3), (76.9 mg) was dissolved in MeOH (10 ml)
containing conc. HCl (0.2 ml). The mixture was stirred at rt approx-
imately for 2 h. or until complete conversion of 3 as indicated by
TLC. The solvent was removed under vacuum and the resulting res-
idue was separated on a flash Si-gel column using gradient elution
of MeOH–CHCl3 (0:100–20:80) to yield in order of increasing
polarity 1 (58.6 mg, 75%), 8 (8.8 mg, 10.4%) and 2 (6.9 mg, 8.3%).
Schimmel, T.G., Parsons, S.J., 1999. High purity, high yield procedure for
butyrolactone I production from Aspergillus terreus. Biotechnol. Techniques 13,
379–384.
Acknowledgement
Suzuki, M., Hosaka, Y., Matsushima, H., Goto, T., Kitamura, T., Kawabe, K., 1999.
Butyrolactone I induces cyclin B1 and causes G2/M arrest and skipping of
mitosis in human prostate cell lines. Cancer Lett. 138, 121–130.
We sincerely acknowledge the Ministry of Earth Sciences
(MoES), New Delhi for funding the project. Authors RRP and
CDs are grateful to University Grant Commission (UGC), New
Delhi and MoES, for research fellowship and project assistantship.