Isolation and Structure Elucidation of a Novel Antimalarial Macrocyclic Polylactone, Menisporopsin A, from the Fungus Menisporopsis theobromae

Article abstract of DOI:10.1021/np0304870

An antimalarial macrocyclic polylactone, menisporopsin A (1), was isolated from a cell extract of the seed fungus Menisporopsis theobromae. The structure of 1 was elucidated on the basis of spectroscopic analysis and chemical transformations, with the absolute configuration established by application of the modified Mosher method and by using chiral HPLC. Menisporopsin A (1) possesses an unprecedented residue, 2,4-dihydroxy-6-(2,4-dihydroxy-n-pentyl)benzoic acid. This compound exhibited antimalarial activity, with an IC₅₀ value of 4.0 μg mL ^-1, and antimycobacterial activity (MIC value of 50 μg mL ^-1).

Full text of DOI:10.1021/np0304870

J . Nat. Prod. 2004, 67, 689-692
689
Isola tion a n d Str u ctu r e Elu cid a tion of a Novel An tim a la r ia l Ma cr ocyclic
P olyla cton e, Men isp or op sin A, fr om th e F u n gu s Men ispor opsis th eobr om a e
†
,‡
‡
‡
Maneekarn Chinworrungsee, Prasat Kittakoop,* Masahiko Isaka, Pacharee Maithip,
‡
†,‡
Sumalee Supothina, and Yodhathai Thebtaranonth
Department of Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand, and National Center for Genetic
Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Science Park,
1
13 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
Received November 25, 2003
An antimalarial macrocyclic polylactone, menisporopsin A (1), was isolated from a cell extract of the
seed fungus Menisporopsis theobromae. The structure of 1 was elucidated on the basis of spectroscopic
analysis and chemical transformations, with the absolute configuration established by application of the
modified Mosher method and by using chiral HPLC. Menisporopsin A (1) possesses an unprecedented
residue, 2,4-dihydroxy-6-(2,4-dihydroxy-n-pentyl)benzoic acid. This compound exhibited antimalarial
-
1
-1
activity, with an IC50 value of 4.0 µg mL , and antimycobacterial activity (MIC value of 50 µg mL ).
Ta ble 1. 1H (400 MHz) and 13C (100 MHz) NMR Spectral Data
As part of our continuing search for naturally occurring
biologically active compounds from Thai bioresources, we
have screened the biological activities of extracts from
plants and microorganisms. Routine biological activity
screening revealed that a crude extract of the chemically
unexplored seed fungus Menisporopsis theobromae BCC
1
(acetone-d ) of Menisporopsin A (1)
6
δC, multiplicitya
unit
δH, multiplicity, J in Hz
2
,4-Dihydroxy-6-(2-hydroxy-n-propyl)benzoic Acidb
171.0, s; 171.3, s
1
, 15
2, 16
3, 17
105.8, s; 105.5, s
165.9, s; 165.7, s
4
162 exhibited significant antimalarial activity. Chemical
4
5
6
7
8
, 18
, 19
, 20
, 21
, 22
102.3, d; 102.2, d 6.29, d, 2.2; 6.25, d, 2.0
162.6, s; 162.6, s
112.5, d; 111.6, d 6.37, d, 1.9; 6.33, d, 2.3
143.0, s; 143.0, s
investigation led to the isolation of a novel macrocyclic
polylactone, menisporopsin A (1), from a cell extract of M.
theobromae BCC 4162. We report herein the isolation,
structure elucidation, and biological activities of menisporop-
sin A (1), which possesses an unusual 2,4-dihydroxy-6-(2,4-
dihydroxy-n-pentyl)benzoic acid residue.
41.6, t; 41.2, t
3.10, dd, 7.0, 13.0 (H-8a) and 3.43,
dd, 7.4, 13.0 (H-8b); 2.85, m (H-22a)
and 3.57, dd, 7.7, 13.9 (H-22b)
5.24, m; 5.16, m
9
1
, 23
0, 24
72.4, d; 72.2, d
19.5, d; 19.4, d
A crude extract from mycelia of M. theobromae BCC 4162
was purified by repeated Sephadex LH-20 column chro-
1.23, d, 7.3; 1.21, d, 6.7
3-Hydroxybutyric Acidc
1, 25 169.8, s; 170.0, s
matography to furnish menisporopsin
A (1). The
1
1
1
1
ESITOFMS of menisporopsin A (1) gave an accurate mass
2, 26
3, 27
4, 28
40.9, t; 40.7, t
69.8, d; 69.3, d
19.7, d; 19.6, d
2.85, m; 2.86, m
5.54, m; 5.56, m
1.41, d, 6.2; 1.47, d, 5.6
-
of m/z 797.2670 [(M - H) , ∆ +1.3 mmu], establishing the
1
molecular formula of 1 as C40
trum (acetone-d
presence of three resorcylic acid derivatives (δ
five methyl groups (δ 1.21, 1.23, 1.41, 1.47, and 1.47), six
methine protons (five with ester linkages (δ 5.16-5.60)
and one attached to carbon bearing an oxygen atom at δ
H
46
O
17. The H NMR spec-
6
) of menisporopsin A (1) showed the
6.25-6.37),
2
,4-Dihydroxy-6-(2,4-dihydroxy-n-pentyl)benzoic Acid
H
2
3
31
32
33
3
3
3
9
0
171.2, s
104.7, s
166.3, s
102.0, d
162.9, s
113.9, d
144.8, s
45.6, t
H
H
6.25, d, 2.0
H
1
3
3
.95), and six methylenes (δ
spectrum of 1 revealed five carbonyl carbons (δ
H
1.97-3.57). The C NMR
169.8-
71.3), and its IR spectrum showed absorption peaks at
4
5
6
6.35, d, 2.1
C
1
1
2.60, dd, 9.7, 12.8 (H-36a)
-
1
715 and 1651 cm , confirming the presence of ester
3
.34, dd, 9.7, 13.0 (H-36b)
carbonyls. Methylation of menisporopsin A (1) with MeI/
CO in DMF afforded a hexa-O-methyl derivative 2,
indicating the existence of three pairs of hydroxyl groups
37
38
69.1, d
43.6, t
3.95, brt, 9.3
1.97, ddd, 4.3, 11.5, 11.5 (H-38a)
K
2
3
2
.13, ddd, 4.3, 11.2, 11.8 (H-38b)
1
3
39
71.7, d
19.6, d
5.57, m
1.47, d, 5.6
9.25, brs; 11.45 brs; 11.71 brs
on three resorcylic acid rings. Extensive analysis of C,
4
0
1
1
DEPT, H- H COSY, and HMQC spectral data of 1 allowed
OH
complete assignment of protons attached to their respective
a
1
1
Multiplicity was determined by analysis of the DEPT spectra.
carbons (Table 1). The H- H COSY and TOCSY spectra
of 1 established the connectivities from H-8 to H-10, from
H-12 to H-14, from H-22 to H-24, from H-26 to H-28, and
b,c
Protons and carbons may be exchangeable in the same acid unit.
two units of 3-hydroxybutyric acid, and a residue of 2,4-
dihydroxy-6-(2,4-dihydroxy-n-pentyl)benzoic acid. The link-
age between these organic acids in 1 was readily assigned
by HMBC spectral data which showed correlations of both
H-9 and H-12 to C-11; H-13 to C-15; both H-23 and H-26
to C-25; H-27 to C-29; and H-39 to C-1. Other key HMBC
correlations were observed from H-8 to C-2, C-6, C-7, and
C-10; H-22 to C-16, C-20, C-21, and C-24; and H-36 to C-30,
C-34, and C-35. On the basis of these spectral data, the
1
1
from H-36 along the chain to H-40. Analysis of the H- H
COSY, TOCSY, and HMBC spectral data suggested that
menisporopsin A (1) is a cyclic polylactone composed of two
units of 2,4-dihydroxy-6-(2-hydroxy-n-propyl)benzoic acid,
*
To whom correspondence should be addressed. Tel: +662-5646700, ext.
3
560. Fax: +662-5646707. E-mail: prasat@biotec.or.th.
†
Mahidol University.
National Center for Genetic Engineering and Biotechnology.
‡
1
0.1021/np0304870 CCC: $27.50
© 2004 American Chemical Society and American Society of Pharmacognosy
Published on Web 02/06/2004

6
90 J ournal of Natural Products, 2004, Vol. 67, No. 4
Notes
gross structure of menisporopsin A (1) could be established.
Complete NMR assignments of the protons and carbons of
1
are shown in Table 1. The presence of a 2,4-dihydroxy-
6
-(2,4-dihydroxy-n-pentyl)benzoic acid residue in this mac-
rocyclic polylactone makes menisporopsin A (1) structurally
unique. The relative stereochemistry of the 2,4-dihydroxy-
6
-(2,4-dihydroxy-n-pentyl)benzoic acid residue in men-
F igu r e 1. ∆δ values [δ(-) - δ(+)] for the MTPA esters (4a and 4b)
of 4.
isporopsin A (1) was assigned by analysis of the NOESY
spectrum, in which correlations between H-37/H-36â, H-37/
3 3
H-38â, H-37/H -40, H -40/H-38â, H-36R/H-38R, and H-38R/
ration at C-3 in 3-hydroxybutyric acid was determined to
be R by chiral HPLC analysis. Direct analysis of 3-hy-
droxybutyric acid with chiral HPLC provided poor informa-
tion of the acid identity due to its lack of chromophore. This
problem was resolved by forming its derivative with
Mosher reagent and generating diastereomers with aro-
matic chromophore. Mosher esters of (R)- and (S)-3-
hydroxybutyric acid could be readily distinguished by chiral
HPLC, and accordingly the acid in 1 was found to be (R)-
3
H-39R were observed, implying that H-37 and the H -40
methyl group are coplanar.
To establish the absolute stereochemistry of each indi-
vidual acid residue in 1, its methylated derivative (2) was
hydrolyzed in an aqueous solution of NaOH (1 M) and
purified by HPLC to yield 3,4-dihydro-6,8-dimethoxy-3-
methylisocoumarin (3) and 3,4-dihydro-6,8-dimethoxy-3-
(
2-hydroxypropyl)isocoumarin (4). Cyclization of 2,4-dihy-
droxy-6-(2-hydroxy-n-propyl)benzoic acid and 2,4-dihydroxy-
-(2,4-dihydroxy-n-pentyl)benzoic acid to their respective
3
-hydroxybutyric acid. The absolute configurations of all
6
six chiral centers in menisporopsin A (1) were finally
established as 9R, 13R, 23R, 27R, 37S, and 39R.
Menisporopsin A (1) exhibited antimalarial activity, with
corresponding lactones 3 and 4 took place spontaneously
during acidic workup.
-1
an IC50 value of 4.0 µg mL , and antimycobacterial activity
-
1
with a MIC value of 50 µg mL . Cytotoxicity of 1 against
the BC-1 (breast cancer) and KB (nasopharyngeal carci-
-
1
noma) cell lines was at IC50 values of 5.0 and 6.0 µg mL
,
respectively. However, menisporopsin A (1) was inactive
-
1
(
at 20 µg mL ) toward Candida albicans. Interestingly,
-
1
the methylated derivative 2 was inactive (at 20 µg mL
)
toward both the malarial parasite and the BC-1 and KB
cell lines. Compound 2 was also inactive against the
-
1
mycobacterium tested (at MIC 200 µg mL ). This implies
that the hydroxyl groups of menisporopsin A (1) might play
an important role in mediating these biological activities.
Naturally occurring macrocyclic polylactones are rare,
but they have been reported as fungal metabolites (Peni-
cillium verruculosum, Hypoxylon oceanicum, Periconia
2
-5
byssoides isolated from the sea hare, Aplysia kurodai).
Macrocyclic polylactones have been previously reported to
exhibit antibiotic and antifungal activities, as well as
inhibition of cell adhesion.2
-5
Exp er im en ta l Section
Gen er a l Exp er im en ta l P r oced u r es. IR spectra and opti-
cal rotations were measured on a Perkin-Elmer 2000 spec-
trometer and J asco DIP 370 polarimeter, respectively. UV
spectra were recorded on a Cary 1E UV-vis spectrophotom-
1
13
1
1
eter. H, C, H- H COSY, HMQC, HMBC, TOCSY, NOESY,
and DEPT spectra were recorded on a Bruker DRX 400 NMR
spectrometer, operating at 400 MHz for proton and 100 MHz
for carbon. The ESITOFMS were obtained from a Micromass
LCT mass spectrometer, and the lock mass calibration was
7
applied for the determination of the accurate masses.
Comparison of the optical rotation ([R]29
-91.95°,
D
F u n ga l Ma ter ia l. The seed fungus M. theobromae BCC
162 was collected from Khao Yai National Park, Thailand,
c 0.217, MeOH) and its NMR spectral data with those in
the literature2 indicated that compound 3 is (3R)-3,4-
dihydro-6,8-dimethoxy-3-methylisocoumarin. The absolute
configuration of 4 was addressed by the formation of
Mosher esters.6 Both the (R)- and (S)-methoxytrifluoro-
methylphenyl acetate (MTPA) esters of 4 (compounds 4a
4
-5
and identified by S. Somrithipol. The culture was deposited
at the BIOTEC Culture Collection, Bangkok, Thailand (reg-
istration no. BCC 4162). The fungus was grown in a potato
dextrose broth and incubated for 7 days at 25 °C, then
transferred into 250 mL of peptone yeast glucose medium
(PYGM). The culture was subsequently incubated (at 25 °C)
for 19 days and harvested for further study.
Extr a ction a n d Isola tion . The culture (5 L) of M. theo-
bromae BCC 4162 was filtered to separate cells and broth.
Mycelia were macerated in MeOH for 2 days at room temper-
1
and 4b) were separately prepared and subjected to H NMR
analysis. The ∆δ values [δ(-) - δ(+)] are shown in Figure 1,
indicating that the absolute configuration at C-2′ of 4 is
represented as R; hence the R configuration was estab-
lished at C-39 in menisporopsin A (1). As mentioned earlier,
H-37 and the H -40 methyl group in 1 are in the same
3
plane; therefore the absolute stereochemistry at C-37 may
2
ature, and the extract was concentrated and then H O (100
mL) was added. The mixture was washed with hexane (300
mL × 2). The aqueous solution was then extracted twice with
an equal volume of EtOAc. The EtOAc layers were combined
be assigned with the S configuration. The absolute configu-

Notes
J ournal of Natural Products, 2004, Vol. 67, No. 4 691
1
and evaporated to dryness, yielding 1.2 g of a crude extract.
The crude EtOAc extract was fractionated using a Sephadex
LH-20 column (eluted with MeOH) to provide 15 fractions
(MeOH) λmax (log ꢀ) 216 (4.6), 268 (4.4), 301 (4.1) nm; H NMR
(CDCl
3
) δ 6.43 (1H, d, J ) 2.2 Hz, H-5), 6.33 (1H, d, J ) 2.1
H
Hz, H-7), 4.58 (1H, m, H-3), 4.16 (1H, m, H-2′), 3.94 (3H, s,
OMe), 3.88 (3H, s, OMe), 2.98 (1H, dd, J ) 11.3, 16.0 Hz, H-4a),
2.86 (1H, dd, J ) 2.9, 16.1 Hz, H-4b), 2.07 (1H, m, H-1′a), 1.80
(1H, m, H-1′b), 1.29 (3H, d, J ) 6.2 Hz, H-3′); ESITOFMS m/z
(
A-O), each with a volume of 100 mL. Fractions M and N were
combined and further rechromatographed on Sephadex
LH-20 (eluted with MeOH) to furnish menisporopsin A (1)
+
+
(173.5 mg).
18 5
289.1061 [M + Na] , calcd for [C14H O + Na] 289.1052.
Bioa ssa ys. Antimalarial activity was evaluated against the
parasite Plasmodium falciparum (K1, multidrug-resistant
P r ep a r a tion of MTP A Ester Der iva tives of 4. A reaction
mixture consisting of 4 (ca. 1.3 mg), pyridine (300 µL), and
(R)-(-)-R-methoxy-R-trifluoromethylphenylacetyl chloride (40
µL) was left standing at room temperature for 6 h. The mixture
was dried under vacuum, then dissolved in 5 mL of EtOAc
strain), which was cultured continuously according to the
8
method of Trager and J ensen. Quantitative assessment of
antimalarial activity in vitro was determined by means of the
microculture radioisotope technique based upon the method
2
and subsequently washed with H O. The EtOAc layer was
9
described by Desjardins et al. The inhibitory concentration
dried, yielding the (S)-(-)-MTPA ester of 4 (ca. 1.6 mg).
Preparation of the (R)-(+)-MTPA ester of 4 from (S)-(+)-R-
methoxy-R-trifluoromethylphenylacetyl chloride was also con-
ducted in the same manner as that of the (S)-(-)-MTPA ester
(
IC50) represents the concentration that causes 50% reduction
3
in parasite growth as indicated by the in vitro uptake of [ H]-
hypoxanthine by P. falciparum. An IC50 value of 1 ng mL
-
1
was observed for the standard compound, artemisinin, in the
same test system. The cytotoxicity of compound 1 was deter-
mined, employing the colorimetric method as described by
derivative. The S-(-)-MTPA ester (4a ) was obtained as a
1
colorless oil: H NMR (CDCl
3
) δ
H
7.53 (2H, m, aromatic
protons of MTPA), 7.43 (3H, m, aromatic protons of MTPA),
6.44 (1H, s, H-5), 6.25 (1H, s, H-7), 5.43 (1H, m, H-2′), 4.22
(1H, m, H-3), 3.94 (3H, s, OMe), 3.89 (3H, s, OMe), 3.59 (3H,
s, OMe of MTPA), 2.73 (2H, m, H-4), 2.24 (1H, m, H-1′a), 1.92
(1H, m, H-1′b), 1.46 (3H, d, J ) 6.3 Hz, H-3′); ESITOFMS m/z
1
0
Skehan and co-workers. The reference substance, ellipticine,
exhibited activities toward BC-1 (breast cancer) and KB
(
nasopharyngeal carcinoma) cell lines (both with an IC50 of 0.3
-1
µg mL ). The antimycobacterial activity was assessed against
Mycobacterium tuberculosis H37Ra using the Microplate
Alamar Blue Assay (MABA). The standard drugs, isoniazid
and kanamycin sulfate, used as reference compounds for the
antimycobacterial assay showed minimum inhibitory concen-
+
+
483.1636 [M + H] , calcd for [C24
H
25
O
7
F
3
+ H] 483.1630. The
1
1
1
R-(+)-MTPA ester (4b) was obtained as a colorless oil:
H
NMR (CDCl
3
H
) δ 7.53 (2H, m, aromatic protons of MTPA), 7.43
(3H, m, aromatic protons of MTPA), 6.44 (1H, s, H-5), 6.29
(1H, s, H-7), 5.43 (1H, m, H-2′), 4.40 (1H, m, H-3), 3.95 (3H, s,
OMe), 3.89 (3H, s, OMe), 3.51 (3H, s, OMe of MTPA), 2.84 (2H,
m, H-4), 2.33 (1H, m, H-1′a), 1.96 (1H, m, H-1′b), 1.38 (3H, d,
-
1
trations (MIC) of 0.040-0.090 and 2.0-5.0 µg mL , respec-
tively.
Men isp or op sin A (1): amorphous solid; [R]29
-42.37° (c
.236, MeOH); UV (MeOH) λmax (log ꢀ) 216 (4.8), 264 (4.3), 304
4.2) nm; IR (KBr) νmax 3392, 2985, 2938, 1715, 1651, 1621,
D
+
0
(
J ) 6.2 Hz, H-3′); ESITOFMS m/z 483.1627 [M + H] , calcd
+
for [C24
H
25
O
7
F
3
+ H] 483.1630.
-
1
1
456, 1384, 1353, 1315, 1262, 1197, 1173, 1108, 1053 cm
;
P r ep a r a tion of MTP A Ester Der iva tives of Au th en tic
(R)- a n d (S)-3-Hyd r oxybu tyr ic Acid . A reaction mixture
consisting of (S)- or (R)-3-hydroxybutyric acid (1 mg), pyridine
(300 µL), and (S)-(+)-R-methoxy-R-trifluoromethylphenylacetyl
chloride (40 µL) was left standing at room temperature for 6
h. The mixture was dried under vacuum, then dissolved in 5
1
13
H and C NMR, see Table 1; ESITOFMS m/z 797.2670
-
-
[
M - H] , calcd for [C40
Meth yla tion of Men isp or op sin A (1). To a solution of
menisporopsin A (1) (30.0 mg) in DMF (1 mL) were added
CO (100 mg) and MeI (0.3 mL), and the mixture was left
46
H O17 - H] 797.2657.
K
2
3
stirring at room temperature for 20 h. After the usual aqueous
workup, a crude reaction mixture (32.9 mg) was subjected to
Sephadex LH-20 column chromatography (eluted with MeOH)
2
mL of EtOAc and subsequently washed with H O. The EtOAc
layer was dried, yielding the corresponding MTPA ester of (R)-
or (S)-3-hydroxybutyric acid. Each individual product was
analyzed by HPLC on a chiral column (ChiraDex, Merck),
using H O-MeOH (60:40) as eluent. The standard MTPA ester
2
derivatives of (R)- and (S)-3-hydroxybutyric acid had retention
times of 5.0 and 6.4 min, respectively.
Deter m in a tion of th e Ster eoch em istr y of th e 3-Hy-
d r oxybu tyr ic Acid Resid u e in 1. Menisporopsin A (1) (15.2
mg) was dissolved in an aqueous solution of NaOH (1 M) and
stirred overnight at room temperature. After neutralization
with a dilute HCl solution, the reaction mixture was dried
under vacuum. The mixture was dissolved in dry pyridine (0.5
mL), and (S)-(+)-R-methoxy-R-trifluoromethylphenylacetyl chlo-
ride (40 µL) was added. The mixture was left standing at room
temperature for 6 h and dried under vacuum. The reaction
2
9
to obtain the methylated derivative 2 (20.2 mg): [R]
D
-94.11°
1
(
c 0.136, MeOH); H NMR (CDCl
3
) δ
H
6.43 (1H, d, J ) 1.9 Hz,
H-32), 6.38 (1H, brs, H-20), 6.38 (1H, brs, H-34), 6.34 (1H, brs,
H-6), 6.34 (1H, brs, H-18), 6.29 (1H, d, J ) 1.8 Hz, H-4), 5.50
(1H, m, H-13), 5.39 (1H, m, H-39), 5.17 (1H, m, H-9), 5.17 (1H,
m, H-23), 4.65 (1H, m, H-37), 4.12 (1H, m, H-27), 3.55-3.92
18H, s, 6 × OMe), 3.03 (1H, dd, J ) 2.9, 16.0 Hz, H-36a),
.88-2.97 (3H, m, H-8a, H-22a, H-36b), 2.67-2.77 (3H, m,
H-8b, H-12a, H-22b), 2.50 (1H, dd, J ) 6.6, 15.6 Hz, H-12b),
(
2
2
1
1
1
1
+
.43 (1H, dd, J ) 3.7, 16.1 Hz, H-26a), 2.38 (1H, dd, J ) 3.7,
6.0 Hz, H-26b), 2.35 (1H, m, H-38a), 1.97 (1H, m, H-38b),
.43 (3H, d, J ) 6.2 Hz, H-40), 1.33 (3H, d, J ) 6.3 Hz, H-14),
.23 (3H, d, J ) 6.7 Hz, H-10), 1.23 (3H, d, J ) 6.7 Hz, H-24),
.16 (3H, d, J ) 6.8 Hz, H-28); ESITOFMS m/z 906.3618 [M
mixture was washed with H
then subjected to HPLC analysis with a chiral column (Chira-
Dex, Merck), using H O-MeOH (60:40) as eluent. Co-injection
of the sample with a standard derivative of (R)-3-hydroxybu-
tyric acid (t 5.0 min) or (S)-3-hydroxybutyric acid (t 6.4 min)
2
O (equal volume, 6 times) and
+
+
Na] , calcd for [C46
58
H O17 + Na] 906.3650.
Hyd r olysis of 2. The methylated derivative (2) (9.4 mg)
2
was dissolved in an aqueous solution of NaOH (1 M) and
stirred overnight at room temperature. After workup with
dilute HCl solution, the reaction mixture was purified with
R
R
readily indicated the presence of (R)-3-hydroxybutyric acid in
the hydrolysate of menisporopsin A (1).
HPLC on a C18 reversed-phase column, eluted with H O-
2
MeCN (50:50), yielding (3R)-3,4-dihydro-6,8-dimethoxy-3-me-
thylisocoumarin (3) (2.3 mg) and (3S,2R)-3,4-dihydro-6,8-
dimethoxy-3-(2-hydroxypropyl)isocoumarin (4) (1.3 mg).
Ack n ow led gm en t. We thank the Biodiversity Research
and Training Program (BRT) for financial support via the
Bioresources Utilization Program (BUP). Financial support
from The Thailand Research Fund (TRF) to P.K. is gratefully
acknowledged. Y.T. thanks BIOTEC for a Senior Research
Fellowship Award. M.C. acknowledges the Thailand Graduate
Institute of Science and Technology (TGIST) for a student
grant.
(
3R )-3,4-D ih y d r o -6,8-d im e t h o x y -3-m e t h y lis o c o u -
2
9
m a r in (3): [R]
log ꢀ) 216 (4.4), 267 (4.2), 301 (3.9) nm; H NMR (CDCl
.43 (1H, d, J ) 2.3 Hz, H-5), 6.32 (1H, d, J ) 2.0 Hz, H-7),
.53 (1H, m, H-3), 3.94 (3H, s, OMe), 3.88 (3H, s, OMe), 2.90
D
-91.95° (c 0.217, MeOH); UV (MeOH) λmax
1
(
6
4
3
) δ
H
(
1H, dd, J ) 11.0, 16.0 Hz, H-4a), 2.81 (1H, dd, J ) 3.3, 16.0
Hz, H-4b), 1.48 (3H, d, J ) 6.4 Hz, Me-3); ESITOFMS m/z
2
1
13
1
1
Su p p or tin g In for m a tion Ava ila ble: The H, C, H- H COSY,
HMQC, and HMBC NMR spectra (acetone-d ) of menisporopsin A (1).
+
+
45.0806 [M + Na] , calcd for [C12
14 4
H O + Na] 245.0790.
6
(
3S,2R)-3,4-Dih yd r o-6,8-d im eth oxy-3-(2-h yd r oxyp r op y-
This material is available free of charge via the Internet at http://
pubs.acs.org.
2
8
l)isocou m a r in (4): [R]
D
3
-97.39° (c 0.0575, CHCl ); UV

6
92 J ournal of Natural Products, 2004, Vol. 67, No. 4
Notes
Refer en ces a n d Notes
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6
835.
(
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2
002, 65, 1346-1348. (b) Arthan, D.; Svasti, J .; Kittakoop, P.;
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tochemistry 2002, 59, 459-463. (c) Sawadjoon, S.; Kittakoop, P.;
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charoen, M.; Thebtaranonth, Y. Bioorg. Med. Chem. Lett. 2003, 13,
(8) Trager, W.; J ensen, J . B. Science 1976, 193, 673-675.
(9) Desjardins, R. E.; Canfield, C. J .; Haynes, J . D.; Chulay, J . D.
Antimicrob. Agents Chemother. 1979, 16, 710-718.
(10) Skehan, P.; Storeng, R.; Scudiero, D.; Monks, A.; McMahon, J .; Vistica,
D.; Warren, J . T.; Bokesch, H.; Kenney, S.; Boyd, M. R. J . Natl. Cancer
Inst. 1990, 82, 1107-1112.
1
253-1255. (f) Thongtan, J .; Kittakoop, P.; Ruangrungsi, N.; Saen-
boonrueng, J .; Thebtaranonth, Y. J . Nat. Prod. 2003, 66, 868-870.
(
(
2) Ito, M.; Tsuchida, Y.; Mizoue, K.; Hanada, K. J . Antibiot. 1992, 45,
(11) Collins, L.; Franzblau, S. G. Antimicrob. Agents Chemother. 1997,
41, 1004-1009.
1
566-1572.
3) Breinholt, J .; J ensen, G. W.; Nielsen, R. I.; Olsen, C. E.; Frisvad, J .
C. J . Antibiot. 1993, 46, 1101-1108.
NP0304870