The triterpenoid constituents of the leaves of Ficus nitida L. - Constituents of local plants, XXII


Elgamal, M.A.H.; El-Tawil, B.A.H.; Fayez, M.B.E.

Naturwissenschaften 62(10): 486

1975


The sterol mixture was shown to comprise two components as evidenced by TLC and GLC and by mass spectrometry; the latter revealing that each is a mono-unsaturated C29H50O compound-one containing a nuclear double bond not located in ring A and the other having its unsaturation in the side chain beyond C-23.

Lattice
parameters:
1.
Feldspar,
space
group
Cl
a
o
=
8.564(1)
;
b
°
=
13.274(1)
;
c
o
=
7.289(1)A
;
a=91.28(1);
/3=115.19(1);
7=90.78(1)°
2.
New
compound,
space
group
Fddd
a
°
=
15.4898(7);
b
°
=26.5558(13);
c
°
=
7.2823(5)A;
a
=90.0;
fl=90.0;
y
=90.0°
The
estimated
standard
errors
are
given
in
parenthesis
and
refer
to
the
last
decimal
place.
Thanks
are
due
to
the
Deutsche
Forschungsgemeinschaft
for
providing
equipment.
Received
July
31,
1975
1.
Laves,
F.:
Plenarvortrag
auf
der
51.
DMG-Jahrestagung,
Kiel
(1971)
The
Triterpenoid
Constituents
of
the
Leaves
of
Ficus
nitida
L.
Constituents
of
Local
Plants,
XXII
M.H.A.
Elgamal,
B.A.H.
El-Tawil
and
M.B.E.
Fayez
National
Research
Centre,
Dokki-Cairo,
Egypt
Fiats
nitida
L.
is
a
common
Egyptian
tree,
the
leaves
of
which
have
not
been
previously
investigated.
Examination
of
the
coumarin
fraction
led
to
the
isolation
of
angelicin
(in
0.004%
yield,
dry
weight
basis)
which
is
the
first
angular
furocoumarin
[1,
2]
to
be
encountered
in
Ficus
plants
(identity
established
by
m.p.
and
mixed
m.p.
(140-141
°C),
UV,
IR
and
MS
spec-
tra).
The
unsaponifiable
matter
was
fractionated
by
column
chromatography
to
give
three
distinct
triterpenoids
and
a
mix-
ture
of
sterols.
One
terpenoid
was
identified
as
friedelin
(0.06%
yield,
m.p.
262-264°C,
[a]p
-
3
L
7°,
oxime,
m.p.
290-293
°C,
2,4-dinitrophenyl
hydrazone,
m.p.
296-298
°C)
and
another
as
epifriedelanol
(0.08%
yield,
m.p.
and
mixed
m.p.
278-
282
°C,
[a]
D
+
32.9°,
acetate,
m.p.
288-291
°
C,
[a]p
+
39°).
The
third
component
was
a
new
triterpenoid
(I),
m.p.
250-
253
°C,
[a]
E
,
+
88.9°
for
which
the
name
"nitidol
"
is
proposed.
Its
composition
as
C0
30
H
50
0
was
evidenced
by
MS
(MW
426)
and
elemental
analysis.
The
oxygen
function,
as
an
easily
acylable
hydroxyl
group,
was
revealed
by
IR
of
I
and
its
acetate
(II,
C
3
41
52
02,
MS),
m.p.
216-221
°C,
[a]p
+63°.
I
was
easily
oxidized
to
afford
a
ketone
(III,
C301
-
1480,
MS),
m.p.
205-208
°C,
rah
:
,
+51°.
The
existence
of
3/3-hydroxyl
group
and
a
4,4-gem-dimethyl
system
was
supported
by
retro-
pinacolic
dehydration
reaction
which
excludes
a
friedelane
type
of
structure.
Nitidol
(I)
contains
one
ethenoid
bond
(low-
intensity
UV
at
203
nm)
which
could
readily
be
hydrogenated
to
give
a
dihydro
derivative
(IV),
m.p.
228-230
°C,
[a]p
+64°
(MW
428
for
C
30
H
52
0,
MS).
Inspection
of
the
IR
spectra
of
I-IV
in
the
1
392-1
355
cm
-1
and
1
330-1
245
cm
-1
regions
[3]
revealed
that
the
compound
does
not
belong
to
the
oleanaene
or
ursane
types
of
triterpenoids.
The
negative
TNM
reaction
and
the
IR
bands
near
1
650
and
890
cm
-1
together
with
the
observed
facility
of
saturation
are
all
in
favor
of
an
exocyclic
double
bond.
Moreover,
a
selenium
dioxide
oxi-
dation
of
II
affords
a
product
which
gives
a
strong
UV
peak
at
214
nm
attributable
to
an
a,
)
6-unsaturated
aldehyde
system
[4]
which
could
result
from
the
allyl
oxidation
of
an
isopro-
penyl
side
chain.
The
data
collected
so
far
indicate
that
I
has
a
pentacyclic
triterpenoid
skeleton
carrying
a
hydroxyl
group,
most
proba-
bly
at
C-3,
and
an
isopropenyl
side
chain.
The
mass
spectra
of
I-IV
show
fragmentation
data
which
are
reconcilable
with
this
assumption.
Apart
from
M+
and
the
usual
simple-group
expulsions,
all
spectra
exhibited
losses
of
43
(C
3
H
7
)
mass
units
with
the
resulting
fragment
being
markedly
more
abundant
in
IV
than
I-III.
This
type
of
expulsion
is
common
in
lupang
series
[5]
and
presumably
involves
hydrogen-ion
transfer.
The
base-peak
ion,
presumably
resulting
from
the
fission
across
ring
C,
showing
at
m/e
189
(I-III)
and
m/e
191
(IV),
comprises
the
"
right-hand
"
side
portion
of
the
molecule.
A
characteristic
cleavage
due
to
loss
of
69
(C
5
H
9
)
mass
units
is
observed
in
the
spectra
of
I
and
II.
The
fragmentation
patterns
of
nitidol
(I)
and
its
derivatives
(II-IV)
appear
to
be
typical
of
those
expected
[6]
from
the
lupane
and
hopane
types.
Further
study
to
establish
its
structure
is
in
progress.
The
sterol
mixture
was
shown
to
comprise
two
components
as
evidenced
by
TLC
and
GLC
and
by
mass
spectrometry;
the
latter
revealing
that
each
is
a
mono-unsaturated
C2
9115
00
compound—one
containing
a
nuclear
double
bond
not
located
in
ring
A
and
the
other
having
its
unsaturation
in
the
side
chain
beyond
C-23.
Received
June
13,
1975
1.
Abu-Mustafa,
E.A.,
El-Tawil,
B.A.H.,
Fayez,
M.B.E.:
Phyto-
chemistry
3,
701
(1964)
2.
Athnasios,
A.K.,
et
al.:
J.
Chem.
Soc.
1962,
4253
3.
Snatzke,
G.,
Lampert,
F.,
Tschesche,
R.:
Tetrahedron
18,
1417
(1962)
4.
Djerassi,
C.,
et
al.:
J.
Am.
Chem.
Soc.
77,
5330
(1955)
5.
Galbraith,
M.N.,
et
al.:
Aust.
J.
Chem.
18,
226
(1965)
6.
Budzikiewicz,
H.,
Djerassi,
C.,
Williams,
D.H.:
Structure
Eluci-
dation
of
Natural
Products
by
Mass
Spectrometry,
Vol.
2,
p.
136.
San
Francisco:
Holden-Day
1964
The
Role
of
Phytoalexin
as
the
Inhibitor
of
Infection
Establishment
in
Plant
Disease
H.
Oku,
T.
Shiraishi,
and
S.
Ouchi
Laboratory
of
Plant
Pathology,
Faculty
of
Agriculture,
Okayama
University,
Tsushima,
Okayama
700,
Japan
Despite
many
investigations,
the
exact
role
of
phytoalexin
in
the
mechanism
of
resistance
in
plant
disease
or
in
deter-
minating
host-parasite
specificity
remains
undetermined.
Dis-
cussions
on
this
point
have
been
based
mainly
on
the
antifungal
activity
of
phytoalexins
in
relation
to
their
concentration
accu-
mulating
in
infected
plant
tissues.
In
this
communication
the
authors
present
evidence
that
the
role
of
phytoalexin
in
host-parasite
specificity
should
not
be
considered
only
with
regard
to
its
antifungal
activity,
but
also
as
to
how
it
prevents
the
infectivity
of
an
invading
parasite.
In
a
previous
paper
[1]
the
authors
reported
that
pisatin,
a
phytoalexin
of
the
pea
plant
Pisum
sativum
L.,
was
produced
at
a
high
level
in
its
leaves
when
they
were
infected
with
Erysiphe
pisi
DC.,
a
typical
obligate
parasite;
this
pathogen
was
characterized
both
by
its
delayed
induction
(48
h
after
inoculation)
of
pisatin
and
by
its
high
tolerance
(ED
50
for
conidial
germination
was
530
ppm)
to
pisatin,
in
contrast
to
a
nonpathogen,
E.
graminis
DC.
f.
sp.
hordei
Marchal
(15
h
and
40
ppm,
respectively).
If
one
assumes
that
the
parasitic
ability
of
E.
pisi
on
the
pea
plant
is
solely
responsible
for
its
tolerance
to
pisatin,
it
should
not
be
necessary
to
inhibit
the
pisatin
induction
in
the
early
stage
of
infection.
Therefore,
486
Naturwissenschaften
62
(1975)
©
by
Springer-Verlag
1975