Antimicrobiological activity of lignan: Effect of benzylic oxygen and stereochemistry of 2,3-dibenzyl-4-butanolide and 3,4-dibenzyltetrahydrofuran lignans on activity

Article abstract of DOI:10.1271/bbb.70168

The effect of oxidation degree at the benzylic position of 2,3-dibenzyl-4-butanolide and 3,4-dibenzyltetrahydrofuran lignans on the antimicrobiological activity was examined. The highest oxidation degree at the benzylic position of 2,3-dibenzyl-4-butanoli

Full text of DOI:10.1271/bbb.70168

Biosci. Biotechnol. Biochem., 71 (7), 1745–1751, 2007
Antimicrobiological Activity of Lignan: Effect of Benzylic Oxygen
and Stereochemistry of 2,3-Dibenzyl-4-butanolide
and 3,4-Dibenzyltetrahydrofuran Lignans on Activity
y
Koichi AKIYAMA,2 Masafumi MARUYAMA,1 Satoshi YAMAUCHI,1; Yuki NAKASHIMA,1
Tomofumi NAKATO,1 Ryosuke TAGO,1 Takuya SUGAHARA,1 Taro KISHIDA,1 and Yojiro KOBA
1
1Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
2Integrated Center for Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
Received March 22, 2007; Accepted April 12, 2007; Online Publication, July 7, 2007
[doi:10.1271/bbb.70168]
The effect of oxidation degree at the benzylic position
of 2,3-dibenzyl-4-butanolide and 3,4-dibenzyltetrahy-
drofuran lignans on the antimicrobiological activity
was examined. The highest oxidation degree at the
benzylic position of 2,3-dibenzyl-4-butanolide gave the
greatest activity, and 3,4-dibenzoyltetrahydrofuran
showed the highest antifungal activity. The relationship
between stereochemistry and activity was also examined.
Both enantiomers of cis-matairesinol were synthesized
for the first time, one of the cis-matairesinols showing
antibacterial activity.
synthesized stereochemically pure lignans to incorpo-
rate the actual biological activity contained as a
stereochemical mixture in the plant. The direction of
this research will help to elucidate the relationship
between the stereochemistry and biological activity of
lignans and discover new functions for this natural
resource.
This study focuses on the microbiological activity of
popular 2,3-dibenzyl-4-butanolide lignans and 3,4-di-
benzyltetrahydrofuran lignans. The stereoselective anti-
fungal7) and antibacterial8) activity of tetrasubstituted
tetrahydrofuran lignans has recently been reported. It
was found that the oxidation degree at the benzylic
position affected the antioxidant9,10) and cytotoxic ac-
tivity.11) It was therefore shown that the benzylic oxi-
dation degree was one of the important factors for bio-
logical activity in our previous study. The antifungal
activity of matairesinol (Mat 1) has been reported,12)
although the detailed structural factors containing the
stereochemistry for microbiological activity are un-
known. This report describes the effect of the stereo-
chemistry and degree of oxidation at the benzylic
positions of 2,3-dibenzyl-4-butanolide and 3,4-dibenzyl-
tetrahydrofuran lignans on the microbiological activity.
Compounds having different stereochemistry and
benzylic oxidation degree were synthesized. The com-
pounds apart from cis-matairesinols (Mat 9 and Mat 10)
have been previously synthesized,9,10) and Mat 9 and
Mat 10 were synthesized in this study by employing the
reported synthetic method.13) This is the first report on
the synthesis of cis-matairesinols and their biological
activity, and the result of this work will contribute to
more effective use of a natural resource.
Key words: antimicrobiological activity; ꢀ-butyrolac-
tone lignan; tetrahydrofuran lignan
Lignans are one of the biggest group of natural
products and have many biological activities, including
antimicrobiological activity.1–3) Though many synthetic
studies on lignans have also been reported,4) there are
only a few about the relationship between the biological
activity and stereochemistry. Lignans are contained in
the usual plant food and many plant resources, but a
detailed study of the structure-activity relationship is
limited. Most of the reports about the structure-activity
relationship have been restricted isolated compounds
from the target plants. The reason for this is that the
reported biological activity of many lignans is not very
strong, despite strong activity not being required in such
cases as application to wall, paper material, and many
kinds of sheets. The biosynthesis of lignans as an
enantiomeric mixture has recently been reported.5,6)
These reports promoted us to make a stereochemical
study of biologically active lignans by employing the
organic synthetic method. Even if strong biological
activity has not been reported, a biological study using
synthesized stereochemically pure lignans is a new
approach to lignan research. Our work does not use
isolated lignans like many previous studies, but employs
Experimental
Melting point (mp) data are uncorrected. NMR data
were measured by a JNM-EX400 spectrometer using
y
To whom correspondence should be addressed. Fax: +81-89-977-4364; E-mail: syamauch@agr.ehime-u.ac.jp

1746
K. AKIYAMA et al.
TMS as standard (0 ppm), and optical rotation values
were evaluated with a Horiba SEPA-200 instrument.
The silica gel used was Wakogel C-300 (Wako, 200–
300 mesh). Numbering of the compounds follows
IUPAC nomenclatural rules.
C34H34O7, 554.2305. Found, 554.2303. (2S,3R,4R)-
20
Hydroxymethyl lactone 3, ½ꢁꢂ
¼ ꢀ20 (c 0.4, CHCl3).
D
Treatment of hydroxymethyl lactone 3 with NaOH and
HCl. A reaction solution of hydroxymethyl lactone 3
(50 mg, 78 mmol) in EtOH (0.6 ml) and 1 M aq. NaOH
solution (0.6 ml) was stirred at room temperature for
16 h before acidification with 6 M aq. HCl solution. The
mixture was extracted with CHCl3. The organic solution
was separated, washed with saturated aqueous NaHCO3
solution and brine, and dried (Na2SO4). Concentration
followed by silica gel column chromatography (EtOAc/
hexane = 2/3) gave benzyl alcohol lactone 2 (10 mg,
18 mmol, 23%) and hydroxymethyl lactone 3 (25 mg,
46 mmol, 59%).
Lio-1, Lio-3, Lio-5, Lio-7, Lio-8, Lio-10, Lio-11, Lio-
12, (ꢀ)-matairesinol (Mat-1), Mat-2, Mat-3, Mat-4,
Mat-7, and (+)-matairesinol (Mat-8). The synthetic
method and data were described in previous reports.9,10)
The optical purity was determined by the method
previously described.11)
(2R,3S)-2-(4-Benzyloxy-3-methoxybenzyl)-3-[(S)-(4-
benzyloxy-3-methoxyphenyl)(hydroxy)methyl]-4-butano-
lide (2) and (2R,3S,4S)-2-(4-benzyloxy-3-methoxybenz-
yl)-4-(4-benzyloxy-3-methoxyphenyl)-3-hydroxymethyl-
4-butanolide (3). A reaction solution of lactone 19) (1.05
g, 1.64 mmol) in EtOH (12 ml) and 1 M aq. NaOH so-
lution (12 ml) was stirred at room temperature for 16 h
before acidification with 6 M aq. HCl solution. The
mixture was extracted with CHCl3. The organic solution
was separated, washed with saturated aqueous NaHCO3
and brine, and dried (Na2SO4). Concentration followed
by silica gel column chromatography (EtOAc/hexane =
2/3) gave benzyl alcohol lactone 2 (0.17 g, 0.31 mmol,
19%) as colorless crystals, mp 161–163 ꢁC, and hydroxy-
(2R,3S)-2,3-Bis(4-hydroxy-3-methoxybenzyl)-4-buta-
nolide (Mat 9). A reaction mixture of benzyl ether 2
(0.15 g, 0.27 mmol) and 20% Pd(OH)2/C (0.3 g) in
EtOAc (20 ml) was stirred under H2 gas at ambient
temperature for 50 h before filtration. The filtrate was
concentrated, and then the residue was applied to silica
gel column chromatography (EtOAc/hexane = 1/1) to
give Mat 9 (81 mg, 0.23 mmol, 85%) as a colorless oil,
20
½ꢁꢂ
¼ ꢀ81 (c 0.6, CHCl3). NMR ꢂH (CDCl3): 2.31
D
(1H, dd, J 13.9, 12.5 Hz, 3-ArCHH), 2.64 (1H, m, 3-H),
2.77 (1H, dd, J 14.9, 10.5 Hz, 2-ArCHH), 2.94 (1H, dd,
J 13.9, 3.6 Hz, 3-ArCHH), 3.06 (1H, m, 2-H), 3.25 (1H,
dd, J 14.9, 4.9 Hz, 2-ArCHH), 3.84 (3H, s, OCH3), 3.90
(3H, s, OCH3), 4.00–4.07 (2H, m, 4-H2), 5.51 (1H, s,
ArOH), 5.56 (1H, s, ArOH), 6.49 (1H, s, ArH), 6.55 (1H,
d, J 8.0 Hz, ArH), 6.81–6.84 (3H, m, ArH), 6.90 (1H, d,
J 8.7 Hz, ArH). NMR ꢂC (CDCl3): 30.5, 32.6, 40.2, 45.5,
55.89, 55.94, 69.6, 111.1, 111.3, 114.5, 114.6, 120.9,
121.4, 130.3, 130.5, 144.3, 146.6, 146.7, 178.0. EIMS
m=z (%): 358 (Mþ, 98), 137 (100). HREIMS (Mþ):
Calcd. for C20H22O6, 358.1416. Found, 358.1416.
ꢃ99%ee (HPLC, DAICEL chiral column AD-H, de-
methyl lactone 3 (0.40 g, 0.72 mmol, 44%) as a color-
20
less oil. Benzyl alcohol lactone 2, ½ꢁꢂ
¼ ꢀ67 (c 1.3,
D
CHCl3). NMR ꢂH (CDCl3): 2.25 (1H, br. s, OH), 2.61
(1H, m, 3-H), 2.96 (1H, dd, J 14.2, 10.4 Hz, ArCHH),
3.01 (1H, m, 2-H), 3.35 (1H, dd, J 14.2, 2.1 Hz,
ArCHH), 3.82 (3H, s, OCH3), 3.87 (3H, s, OCH3), 4.01
(1H, dd, J 9.5, 6.5 Hz, 4-HH), 4.34 (1H, d, J 9.5 Hz, 4-
HH), 5.07 (1H, br. s, ArCHOH), 5.11 (2H, s, OCH2Ar),
5.13 (2H, s, OCH2Ar), 6.58 (1H, d, J 8.0 Hz, ArH),
6.75–6.77 (2H, m, ArH), 6.80–6.85 (3H, m, ArH), 7.26–
7.44 (10H, m, ArH). NMR ꢂC (CDCl3): 30.6, 43.1, 44.0,
56.0, 56.1, 66.4, 70.5, 71.0, 109.1, 112.3, 114.0, 114.3,
117.4, 120.1, 127.19, 127.24, 127.8, 127.9, 128.50,
128.53, 132.4, 135.0, 136.9, 137.1, 146.8, 147.5, 149.8,
178.3. EIMS m=z (%): 554 (Mþ, 98), 91 (100). HREIMS
tected at 280 nm, 1 ml minꢀ1, 20% EtOH in hexane, tR
20
44 min. Mat 10. ½ꢁꢂ
¼ þ81 (c 1.6, CHCl3), ꢃ99%ee,
D
tR 35 min.
(Mþ): calcd. for C34H34O7, 554.2305. Found, 554.2302.
Organisms. Bacillus subtilis subsp. subtiis NBRC
13719T, Pseudomonas fluorescens NBRC 14160T, and
Staphylococcus aureus subsp. aureus NBRC 14462
were purchased from the National Institute of Technol-
ogy and Evaluation (NITE), Biological Resource Center,
Japan. Escherichia coli JCM 1649, Listeria denitrificans
JCM 11481, Salmonella choleraesuis subsp. cholerae-
suis JCM 6977 and Yersinia intermedia JCM 7579 were
obtained from the Institute of Physical and Chemical
Research (RIKEN), Japan.
20
(2S,3R)-3-[(R)]-Benzyl alcohol lactone 2, ½ꢁꢂ
¼ þ67
D
D
20
(c 0.7, CHCl3). Hydroxymethyl lactone 3, ½ꢁꢂ
¼ þ20
(c 1.6, CHCl3). NMR ꢂH (CDCl3): 0.99 (1H, t, J 5.4 Hz,
OH), 2.64 (1H, m, 3-H), 2.94 (1H, m, 2-H), 3.02 (1H,
dd, J 14.0, 5.5 Hz, ArCHH), 3.08 (1H, dd, J 14.0,
5.5 Hz, ArCHH), 3.16 (1H, m, CHHOH), 3.27 (1H, m,
CHHOH), 3.85 (3H, s, OCH3), 3.87 (3H, s, OCH3), 5.12
(2H, s, ArCH2O), 5.13 (2H, s, ArCH2O), 5.32 (1H, d, J
7.7 Hz, 4-H), 6.67–6.72 (2H, m, ArH), 6.76 (1H, s,
ArH), 6.80–6.87 (3H, m, ArH), 7.28–7.43 (10H, m,
ArH). NMR ꢂC (CDCl3): 34.9, 43.2, 45.8, 56.0, 56.1,
61.1, 71.0, 71.1, 80.7, 109.3, 112.8, 113.9, 114.2, 117.8,
121.3, 127.3, 127.8, 128.0, 128.5, 128.6, 128.8, 130.6,
136.7, 137.1, 147.2, 148.2, 149.8, 178.4. EIMS m=z (%):
554 (Mþ, 37), 91 (100). HREIMS (Mþ): Calcd. for
Antibiotic spectra of compounds. The ability of com-
pounds to inhibit the growth of a variety of Gram-
positive and Gram-negative bacterial strains was as-
sessed by the paper disc method, and the mini-
mum inhibitory concentration (MIC) was determined

Antimicrobiological Activity of Lignan
1747
O
O
O
H3CO
O
O
H3CO
BnO
O
H
BnO
HO
a
BnO
H
+
OCH3
OH
OPiv
H3CO
OBn
H3CO
OBn
H3CO
OBn
2
3
1
b
O
O
O
O
O
H3CO
H3CO
HO
H3CO
BnO
O
c
HO
2
OPiv
H3CO
H3CO
H3CO
OBn
OH
Mat 10
OH
Mat 9
Scheme 1. Synthesis of the cis-Matairesinols (Mat 9 and Mat 10).
a, (1) 1 M aq. NaOH, EtOH, r.t., 16 h; (2) 6 M aq. HCl (2, 19%; 3, 44%); b, (1) 1 M aq. NaOH, EtOH, r.t., 16 h; (2) 6 M aq. HCl (2, 23%; 3, 59%);
c, H2, 20% Pd(OH)2/C, EtOAc, r.t., 50 h (85% yield).
for those strains that showed sensitivity to the tested
compounds. The paper disc test used agar plates con-
taining ‘‘Nissui’’ nutrient broth (Nissui Pharmaceutical
Co.) A hundred microliter of an exponential culture of
each respective strain was made into molten agar con-
taining the nutrient broth. After the agar had solidified
a paper disc containing 15 ml of 50 mM of the tested
compound was put on to the agar plate. The plate was
incubated for 24 hr at 30 ꢁC (L. denitrificans and P. fluo-
rescens) or at 37 ꢁC (B. subtilis, S. aureus, E. coli,
S. choleraesuis and Y. intermedia), and the diameter of
any halo of inhibition around the paper disc was meas-
ured. The MIC value was determined from a two-fold
dilution series (from 50 mM to 1.56 mM) for any strain
that showed a halo of inhibition, the assays being
triplicated.
containing a test chemical was placed at the edge of the
colony. Growth inhibition was observed after culturing
at 28 ꢁC for 7–10 days. A further inhibition test was per-
formed with the active compounds. Each compound was
added to three aliquots each containing 3 ml of PDA at
50 ꢁC, mixed rapidly and poured into the PDA plates
(’50 mm dishes). Dimethyl sulfoxide only without a test
compound served as the control. After incubating at
28 ꢁC for 7–10 days, the area of the mycelial colony was
measured by a caliper, the assays being triplicated.
Results and Discussion
Preparation of cis-matairesinols
(2R,3S)-cis-Matairesinol (Mat 9) and (2S,3R)-cis-
matairesinol (Mat 10) were synthesized by the method
shown in the Scheme 1. Lactone 19) was treated with an
aqueous NaOH solution, and then the reaction mixture
was acidified to give desired benzyl alcohol lactone 2
(19%) and hydroxymethyl lactone 3 (44%). Hydroxy-
methyl lactone 3 could be converted to benzyl alcohol
lactone 2. Finally, reduction of the benzyl alcohol and
hydrogenolysis of the benzyl ether of 2 by using
Pd(OH)2 gave Mat 9 in 85% yield. The other enan-
tiomer (Mat 10) was synthesized from the enantiomer of
1 by the same method. The optical purity of both Mat 9
and Mat 10 was determined to be more than 99% ee by
employing a chiral column.
Fungal strains and culture conditions. The phytopa-
thogenic fungi, Colletotrichum lagenarium and Bipola-
ris oryzae, had been isolated from a farm of Ehime
University and kindly presented by Dr. Ohguchi. Each
fungus was cultured on potato dextrose agar (PDA,
Sigma-Aldrich, Canada).
Antifungal assay. The paper disc method was adopted
for the first screening. Briefly, fungal mycelia were
spotted on the center of the PDA plate (’100 mm dishes)
and incubated at 28 ꢁC until the colony diameter became
4–5 cm. A disc paper soaked in dimethyl sulfoxide

1748
K. AKIYAMA et al.
Table 1. Antibacterial Activity of Lio 7, Lio 11, Mat 1, and Mat 8 (MIC mM)
ND, not detected at 50 mM.
Lio 7
Lio 11
Mat 1
Mat 8
Bacillus subtilis NBRC 13719T
Listeria denitrificans JCM 11481
Staphylococcus aureus subsp. aureus NBRC 14462
50.0
25.0
50.0
50.0
6.25
12.5
50.0
25.0
ND
ND
25.0
12.5
O
O
O
O
Ar
Ar
Ar
Ar
O
O
Ar
Ar
Ar
Mat 1
Ar
Lio 7
Lio 11
Mat 8
Ar = 4-hydroxy-3-methoxyphenyl
Antibacterial activity of the Mat and Lio compounds
None of the tested compounds showed activity against
gram-negative bacteria, but some showed activity
against gram-positive bacteria.
and 2,3-dibenzyl-4-butanolide lignan. In the case of
the tetrahydrofuran type, stereoselective activity was
only observed against B. subtilis. Both Lio 3 and Lio 10
showed the same level of activity against L. denitrifi-
cans, although there was no activity against S. aureus.
In the case of the 4-butanolide type, no stereoselective
activity was exhibited. Activity was observed against all
bacteria, the strongest being against L. denitrificans
(MIC, 3.12 mM). The antibacterial activity of both Mat 4
and Mat 7 was higher than that of a previously reported
virgatusin-related compound.8) Although Lio 10, Mat 4
and 7 showed the same level of activity against
S. subtilis, the 4-butanolide type had stronger activity
than that of the tetrahydrofuran type. The activity of
fully benzylic oxidized 2,3-dibenzyl-4-butanolide was
generally stronger than that of non-oxidized 2,3-dibenz-
yl-4-butanolide, although the activity of Mat 7 against
S. aureus was a little weaker than that of Mat 8. It could
be assumed that both the benzylic carbonyl groups were
important for the higher antibacterial activity of the 2,3-
dibenzyl-4-butanolide lignan, although this assump-
tion was not valid in the case of the 3,4-dibenzyltetra-
hydrofuran lignan. It seems that the activity of fully
benzylic oxidized 3,4-dibenzyltetrahydrofuran was a
little weaker than that of non-oxidized 3,4-dibenzylte-
trahydrofuran, although the activity of Lio 3 against
L. denitrificans was higher than that of Lio 7 and the
activity of Lio 10 against B. subtilis was higher than that
of Lio 11.
Table 1 shows the antibacterial activity of the com-
pounds bearing two secondary benzylic positions. These
compounds are not oxidized at two benzylic positions.
In a comparison of the stereochemistry of tetrahydro-
furan lignan (Lio 7 and Lio 11), one enantiomer (Lio
11) showed stronger activity than that of Lio 7, except
against B. subtilis. Both enantiomers Lio 7 and Lio 11
showed the same level of activity against B. subtilis. In
the case of 2,3-dibenzyl-4-butanolide lignan (matairesi-
nols Mat 1 and Mat 8), one of the enantiomers (Mat 1)
showed stronger activity against B. subtilis, and the
other enantiomer (Mat 8) displayed stronger activity
against S. aureus. Both enantiomers (Mat 1 and Mat 8)
showed the same level of activity against L. denitrifi-
cans. In a comparison of the tetrahydrofuran ring with
the 4-butanolide ring having the same stereochemistry,
Lio 7 and Mat 1 showed almost the same level of
activity. Lio 7 showed stronger activity than that of Mat
1 against S. aureus. A grater difference in activity was
observed between tetrahydrofuran Lio 11 and 4-buta-
nolide Mat 8 than between Lio 7 and Mat 1. All though
the activity level against S. aureus was similar, Lio 11
showed stronger activity than that of Mat 8 against the
other bacteria. It could be assumed that the 3,4-
dibenzyltetrahydrofuran lignan had stronger antibacte-
rial activity than that of the corresponding 2,3-dibenzyl-
4-butanolide lignan in the absence of benzylic oxygen.
Table 1 shows that one of the enantiomers of 3,4-
dibenzyltetrahydrofuran lignan (Lio 11) had the stron-
gest activity against L. denitrificans (MIC 6.25 mM).
Different levels of activity were observed between
enantiomers.
Table 3 shows the antibacterial activity of 3,4-dibenz-
yltetrahydrofuran bearing two hydroxy groups at both
benzylic positions (Lio 1), bearing one hydroxy group at
one benzylic position (Lio 5), and one carbonyl group at
one benzylic position (Lio 8 and Lio 12), and of 2,3-
dibenzyl-4-butanolide bearing one carbonyl group at one
benzylic position (Mat 2 and Mat 3). It seems that the
activities of these compounds were weaker than those of
the corresponding non-benzylic oxidized compounds
Table 2 shows the antibacterial activity of fully
benzylic oxidized 3,4-dibenzyltetrahydrofuran lignan

Antimicrobiological Activity of Lignan
1749
Table 2. Antibacterial Activity of Lio 3, Lio 10, Mat 4, and Mat 7 (MIC mM)
ND, not detected at 50 mM.
Lio 3
Lio 10
Mat 4
Mat 7
Bacillus subtilis NBRC 13719T
Listeria denitrificans JCM 11481
Staphylococcus aureus subsp. aureus NBRC 14462
ND
12.5
ND
12.5
12.5
ND
12.5
3.12
25.0
12.5
3.12
25.0
O
O
O
O
O
O
O
O
Ar
Ar
Ar
O
Ar
O
O
O
O
O
Ar
Lio 10
Ar
Lio 3
Ar
Mat 4
Ar
Mat 7
Ar = 4-hydroxy-3-methoxyphenyl
Table 3. Antibacterial Activity of Lio 1, Lio 5, Lio 8, Lio 12, Mat 2, and Mat 3 (MIC mM)
ND, not detected at 50 mM.
Lio 1
Lio 5
Lio 8
Lio 12
Mat 2
Mat 3
Bacillus subtilis NBRC 13719T
Listeria denitrificans JCM 11481
Staphylococcus aureus subsp. aureus NBRC 14462
ND
ND
ND
ND
ND
ND
ND
50.0
ND
ND
ND
ND
ND
50.0
50.0
ND
ND
25.0
O
O
O
H
OH
H
O
O
HO
Ar
O
O
H
H
H
Ar
Ar
Ar
Ar
Ar
O
O
O
O
O
HO
H
Ar
Ar
Ar
Ar
Ar
Ar
Lio 1
Lio 5
Lio 8
Lio 12
Mat 2
Mat 3
Ar = 4-hydroxy-3-methoxyphenyl
Table 4. Antibacterial Activity of Mat 9 and Mat 10 (MIC mM)
ND, not detected at 50 mM.
and fully benzylic oxidized compounds. Mat 3 showed
same level of activity as that of Mat 4 against only
S. aureus, although the activity of Mat 2 against
S. aureus was less. This fact shows the grater impor-
tance of one of the benzylic carbonyl groups on the ꢃ-
position. A comparison of the activity of Mat 4, Mat 2,
and Mat 3 revealed that both the benzylic carbonyl
groups were important for the activity against other
bacteria. Stereoselectivity was observed between Lio 8
and Lio 12. Lio 8 showed activity against L. denitrifi-
cans, but Lio 12 did not have activity. It is interesting
that the non-benzylic oxidized and fully benzylic
oxidized compounds showed higher antibacterial activ-
ity.
Mat 9 Mat 10
Bacillus subtilis NBRC 13719T
Listeria denitrificans JCM 11481
ND
25
ND
ND
ND
Staphylococcus aureus subsp. aureus NBRC 14462 ND
O
O
O
Ar
Ar
O
Ar
Ar
Table 4 shows the activity of the cis-matairesinols
(Mat 9 and Mat 10). There was no antibacterial activity
shown by Mat 10. The activity of Mat 9 was weaker
than that of Mat 1, although Mat 9 kept the same level
Mat 10
Mat 9
Ar = 4-hydroxy-3-methoxyphenyl

1750
K. AKIYAMA et al.
Table 5. Growth Inhibition against Colletotrichum lagenarium
antibacterial effect, both enantiomers Mat 4 and Mat
7 showed activity, although only one enantiomer (Mat
4) showed antifungal activity (Table 5). It could be
assumed that the presence of carbonyl groups at the two
benzylic positions increased the both the antifungal and
antibacterial activity. The antifungal activity of Mat 4
was weaker than that of previously reported (ꢀ)-
virgatusin.7) Although Mat 4 did not show activity
against B. oryzae, some Lio compounds did show
activity (Table 6). In particular, Lio 3, which is a fully
benzylic oxidized 3,4-dibenzyltetrahydrofuran lignan,
showed the highest activity. This fact means that two
benzylic carbonyl groups at the two benzylic positions
of 3,4-dibenzyltetrahydrofuran lignan were important
for higher antifungal activity. It could be said that this
activity was also enantioselective because the activity of
Lio 10 was weaker than that of Lio 3. It was shown that
the tetrahydrofuran ring was more important for anti-
fungal activity than the 4-butanolide ring in this
research.
Mat 4
Colletotrichum lagenarium
100 mM (1.00 mM final concentration)
25 mM (0.25 mM final concentration)
71:6 ꢄ 4:67%
93:9 ꢄ 1:27%
O
O
O
Ar
O
Ar
Mat 4
Ar = 4-hydroxy-3-methoxyphenyl
of activity against L. denitrificans as that of Mat 1.
These facts mean that the absolute configuration of the
ꢁ-position of Mat 1 was more important for antibacte-
rial activity than the absolute configuration of the ꢃ-
position. In a comparison of Mat 8, Mat 9, and Mat 10,
conversion of the ꢃ-absolute configuration of Mat 8
removed the activity, while the transformation of the ꢁ-
absolute configuration of Mat 8 retained the activity.
These facts mean that the absolute configuration of the
ꢃ-position of Mat 8 was more important than that of the
ꢁ-position. The antibacterial activity of one of the cis-
matairesinols was discovered for the first time.
Summary
This experiment compared the microbiological activ-
ity of 2,3-dibenzyl-4-butanolide, oxidized 2,3-dibenzyl-
4-butanolide, 3,4-dibenzyltetrahydrofuran, and oxidized
3,4-dibenzyltetrahydrofuran. The relationship between
the stereochemistry and activity was also examined.
Although the results of this experiment were compli-
cated, the two fully benzylic oxidized matairesinols
(Mat 4 and Mat 7) showed the strongest antibacterial
activity. One enantiomer of the fully benzylic oxidized
matairesinol (Mat 4) and one enantiomer of the fully
benzylic oxidized 3,4-dibenzyltetrahydrofuran (Lio 3)
showed antifungal activity. It was found that two benz-
ylic carbonyl groups were important for higher anti-
microbiological activity. Both the enantiomers of cis-
matairesinols (Mat 9 and Mat 10) were synthesized for
the first time in this project, and the antibacterial activity
of Mat 9 was determined for the first time. The im-
portance of the stereochemistry of matairesinol for anti-
bacterial activity was elucidated by a comparison of the
activity of the four stereoisomers.
Antifungal activity of the Mat and Lio compounds
Some of Mat and Lio compounds showed antifungal
activity against C. lagenarium or B. oryzae (Tables 5
and 6). The activity of the other compounds was not
apparent at 100 mM. It was shown that only Mat 4 had
antifungal activity against C. lagenarium among the 4-
butanolide and tetrahydrofuran compounds. It is note-
worthy that only fully oxidized matairesinol bearing two
carbonyl groups at the benzylic position (Mat 4) showed
activity against C. lagenarium. In the case of the
Table 6. Growth Inhibition against Bipolaris oryzae at 25 mM (final concentration was 0.25 mM)
Lio 3
67:6 ꢄ 3:58%
Lio 8
93:6 ꢄ 6:55%
Lio 10
90:7 ꢄ 5:69%
Lio 11
95:7 ꢄ 6:61%
Lio 12
95:4 ꢄ 4:78%
Mat 1
Mat 7
Bipolaris oryzae
95:1 ꢄ 9:26%
92:5 ꢄ 5:59%
O
O
O
O
O
O
O
O
Ar
Ar
O
O
Ar
O
Ar
O
Ar
Ar
Ar
O
O
O
O
O
Ar
Ar
Mat 1
Ar
Ar
Lio 8
Ar
Lio 10
Ar
Lio 12
Ar = 4-hydroxy-3-methoxyphenyl
Ar
Lio 3
Lio 11
Mat 7

Antimicrobiological Activity of Lignan
1751
7) Akiyama, K., Yamauchi, S., Nakato, T., Maruyama, M.,
Sugahara, T., and Kishida, T., Antifungal activity of
tetra-substituted tetrahydrofuran lignan, (ꢀ)-virgatusin,
and its structure-activity relationship. Biosci. Biotechnol.
Biochem., 71, 1028–1035 (2007).
8) Maruyama, M., Yamauchi, S., Akiyama, K., Sugahara,
T., Kishida, T., and Koba, Y., Antibacterial activity of a
virgatusin-related compound. Biosci. Biotechnol. Bio-
chem., 71, 677–680 (2007).
9) Yamauchi, S., Hayashi, Y., Nakashima, Y., Kirikihira,
T., Yamada, K., and Masuda, T., Effect of benzylic
oxygen on the antioxidant activity of phenolic lignans.
J. Nat. Prod., 68, 1459–1470 (2005).
Acknowledgments
This project was performed under grant from 06
feasibility test related to corporation for innovative
technology and advanced research in evolutional area
by Toyo Industrial Creative Center. We measured the
400 MHz NMR data at INCS of Ehime University. Our
thanks to the president of Ehime University for
supporting this project. We are also grateful to
Marutomo Co. for financial support.
10) Yamauchi, S., Sugahara, T., Nakashima, Y., Okada, A.,
Akiyama, K., Kishida, T., Maruyama, M., and Masuda,
T., Radical and superoxide scavenging activity of
matairesinol and oxidized matairesinol. Biosci. Biotech-
nol. Biochem., 70, 1934–1940 (2006).
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