256
Communications to the Editor
Chem. Pharm. Bull. 53(2) 256—257 (2005)
Vol. 53, No. 2
0.05% KCl, and 0.001% FeSO4·7H2O in distilled water H2O
(pH 7). After full growth of the microorganism, herbertene-
diol (5, 121 mg) was added to the medium and then the
microorganism was shake-cultivated for a further 19 d at
30 °C. After filtration, metabolites from liquid–liquid extrac-
tion using EtOAc were separated on silica gel column chro-
matography to yield a mixture of mastigophorenes A and B
together with the substrate.7)
Penicillium sclerotiorum Catalyzes the
Conversion of Herbertenediol into
Its Dimers: Mastigophorenes A and B
Liva HARINANTENAINA,a Yoshiaki NOMA,b and
Yoshinori ASAKAWA*,a
a Faculty of Pharmaceutical Sciences, Tokushima Bunri University;
Yamashiro-cho, Tokushima 770–8514, Japan: and b Faculty of
Human Life Sciences, Tokushima Bunri University; Yamashiro-cho,
Tokushima 770–8514, Japan.
Compounds 18) and 28) (3.3% yield) were isolated as a
mixture (ratio 3 : 1). Positive EI-MS exhibited a molecular
ion peak at m/z 466, corresponding to the molecular formula
C30H42O4 as identified by HR-EI-MS. Inspection of the NMR
spectral data revealed that the mixture contained herbertene-
Received September 6, 2004; accepted November 18, 2004
1
type compounds. The H-NMR spectrum displayed two sets
Herbertenediol was subjected to biotransformation by Peni-
cillium sclerotiorum. Spectral data analysis of the converted
metabolites revealed that the neurotrophic active compounds,
mastigophorenes A and B, dimeric to the substrate were
formed.
of signals due to four quaternary methyl groups (d 1.93,
1.47, 1.21, and 0.79 and d 1.92, 1.45, 1.20, and 0.79), to-
gether with an aromatic proton at d 6.85 (s), signals of two
hydroxyl groups at d 5.57 (s) and d 4.72 (s), and a multiplet
at d 2.66. The 13C-NMR data showed signals similar to those
of herbertenediol in which the signal the aromatic methine at
dC 113.4 was replaced with a quaternary aromatic carbon (dC
117.1) and almost every carbon signal split by 0.07 to
0.25 ppm (see Experimental). The above data coupled with
the molecular formula indicated that compounds 1 and 2
might be symmetrical dimeric compounds. One set of the
1H- and 13C-NMR signals were identical to those of
mastigophorene A, whereas the other set was very similar to
its B isomer. Both compounds were previously isolated from
a sample of Mastigophora diclados collected from Borneo.2)
It is interesting to note that the ratio 3 : 1 of 1 and 2 after iso-
lation was converted to 1 : 1 when the sample was kept at
0 °C for 3 d.
Liverworts are a rich source of dimeric compounds
biosynthetically originating from their monomer by aryl–aryl
bond formation.6) These compounds are mastigophorenes
(1—4), aquaticenol, and the antitumoral, antibacterial, and
antimycotic active compounds, isoplagiochins.6) Horseradish
peroxidase is a well-known enzyme catalyzing oxidative cou-
pling to synthesize dimeric compounds from the monomer.9)
The presence of the aryl–aryl bond formation-catalyzing
enzyme in P. sclerotiorum could open up a new horizon in
the biosynthesis of these metabolites as well as the synthesis
of new and biologically active dimeric compounds. A similar
enzyme could be present in the M. diclados sample from
Borneo and this may be a difference between the sample
Key words Penicillium sclerotiorum; biotransformation; mastigophorene;
dimerization
Mastigophorenes A—D (1—4) are dimeric herbertene-
type sesquiterpenoids found only in the liverwort
Mastigophora diclados (BRID.) NEES. They have usually been
isolated with their precursor herbertenediol (5).1,2) Our recent
investigation of a liverwort sample collected from Madagas-
car, however, did not show any trace of mastigophorenes A
and B but revealed the presence of 3—5.3) The remarkable
neurotrophic activity of mastigophorenes A, B, and D has at-
tracted considerable attention from synthetic chemists.2) The
synthesis of these compounds was started by Bringmann and
coworkers4) who used biomimetic oxidative dimerization of
the protected monomeric precursor and atropoenantioselec-
tive synthesis via lactone methodology. Fukuyama et al.5)
used the same method to obtain a large amount of sample for
biological evaluation. Even though no experimental evidence
has been reported, it was obvious that the biosynthesis of
1 and 2 was from the oxidative phenolic coupling of (ꢀ)-her-
bertenediol.2,6) To obtain structurally interesting and biologi-
cally active compounds and to evaluate the mechanism of
introducing an oxygen functional group at a nonactivated
carbon atom in organic compounds, biotransformation of
secondary metabolites is a topic of systematic investigations
in our laboratory. Carbon–carbon bond formation from the
biotransformation of organic compounds is not common.
Moreover, biotransformation using microorganism could
give information on the enzymes involved in sesquiterpene
biosynthesis. The present communication deals with the bio-
conversion of herbertenediol (5) into 1 and 2 by Penicillium
sclerotiorum.
Results and Discussion
The Penicillium genus is fungi commonly growing as
green or blue mold on decaying food and is used in making
cheese and as a source of penicillin. P. sclerotiorum, was
used for the first time in our laboratory for the biotransfor-
mation of organic compounds. After being identified, the
microorganism was statically cultivated at 30 °C for 2 d in
200 ml of a medium (Czapek) containing 1.5% sucrose, 1.5%
glucose, 0.5% polypeptone, 0.1% K2HPO4, 0.05% MgSO4,
Fig. 1
∗ To whom correspondence should be addressed. e-mail: asakawa@ph.bunri-u.ac.jp
© 2005 Pharmaceutical Society of Japan
Harinantenaina, Liva
