4-Hydroxydigitolutein, a new anthraquinone from callus tissue of Digitalis lanata
1609
the same structural type as that contained in Verbenaceae, Bignoniaceae and Rubiaceae.
Some anthraquinones such as 1-methoxy-3-methylanthraquinone,” 1-methoxy-2-methyl-
( o r
and
(or
are found in the leaves of Digitalis species until now and belong to this type except
the latter two compounds. So the biosynthesis of anthraquinones in digitalis callus tissue is
of much interest in comparison with that in
and Polygonaceae
EXPERIMENTAL
were determined in a
apparatus and uncorrected. The NMR spectra were run in a
a Hitachi H-60NMR spectrometer. The mass spectra were taken on a JMS-OIS double-focusing
mass spectrometer with direct inlet system.
Tissue Culture of D. lanata
Seed of D.
was aseptically germinated and seedling were transferred onto White’s basal medium
containing 2.4-dichloroohenoxyacetic acid 1
1965. The callus tissue-was subcultured
yeast extract
3 weeks. A part ‘of this callus tissue was transferred onto
ppm and sucrose
and sucrose
in
Murashige and Skoog’s basal medium containing 3-indolylacetic acid 1 ppm, kinetin
in July 1967. This callus tissue has been subcultured.
3
Isolation of Anthraquinone Pigments from Callus Tissue
The callus tissue 224 was homogenized with cold acetone 300 ml, refluxed for 3 hr and filtered. This
process was repeated 3 times, and the filtrate evaporated. The concentrated aqueous solution was extracted
with benzene, and the benzene solution was shaken with
and 5
Each
basic solution after acidification was re-extracted with benzene, and the separate benzene solutions after
drying
evaporated to dryness. The fractions obtained were designated A, B, C respectively and
that from the original benzene D.
The mixed fraction of C and D was eluted with benzene using a deactivated silica gel column* (12 g) to
give two main bands (each fraction; 10 ml). The first gave a crystalline compound
which was recrystallized
after the same treatment: both com-
from
to give red needles and the second gave yellow needles
pounds were found in very small traces.
Fraction B (82.6 mg) on deactivated silica gel column* (40
and eluted with benzene (each fraction;
respectively. Fractions 15-19
100 ml) gave traces of red and brown pigments,
and
containing
The
was acetylated by usual method and rechromatographed to give the pure diacetate of
pigment
(2.1 mg) was obtained from fraction Nos.
as yellow needles, m.p. 218-219”. Fraction Nos.
35-37 gave trace of yellow pigment.
Properties of 4-Hydroxydigitolutein
Orange needles (from
m.p.
(requires 284068)
413
284.063,
(sh)
244
460
(sh) (log
(sh)
250
275
296
(OH), 1667 (non-chelated
1618
438
(chelated C===O), 1593 (double bond)
mass spectrum, m/e; 284
269
267 (M+
OH,
-2 x
266 (M+
255 (M+ CHO,
241
m.p.
CO,
diacetate. Light yellow needles (from
(requires
368
1776, 1270, 1186 (ester), 1678
284 (M+ 2 x
mass spectrum,
368.084, i.r.
326 (M+
other peaks gave similar ones to
* Silica gel Kanto Kagaku was stirred with
N oxalic acid, filtered and dried at 100” for 1 hr.
S. K. P AVANARAM, P. H OF ER, H.
and K. MEYER, Helv. Chim.
46, 1377 (1963).
S.
E.
E.
E.
and H. WAGNER , Phytochem. (1969).
and M. H. ZENK, Tetrahedron Letters 861 (1968).
and M. H. ZE NK, Tetrahedron Letters 1395 (1968).
and M. H. ZE NK, Chem.
210 (1969).