In vitro evaluation of antifungal properties of 8.O.4'-Neolignans

Article abstract of DOI:10.1021/np9605504

Eighteen racemic 8.O.4'-neolignans with six different substitution patterns in rings A and B, in their ketone and in their erythro and threo alcoholic forms, were evaluated for antifungal activity by the agar dilution method. Only the alcohols exhibited a broad spectrum of activities against Microsporum canis, Microsporum gypseum, Tricophyton mentagrophytes, Tricophyton rubrum, and Epidermophyton floccosum. (±)-erythro-3,4- (methylenedioxy)-7-hydroxy-1'-allyl-3',5'-dimethoxy-8.O.4'-neolignan (11) was the most active compound in the series, and E. floccosum was the most susceptible species.

Full text of DOI:10.1021/np9605504

© Copyright 1997 by the American Chemical Society and the American Society of Pharmacognosy
Volume 60, Number 7
J uly 1997
Full Papers
In Vitr o Eva lu a tion of An tifu n ga l P r op er ties of 8.O.4′-Neolign a n s
Susana Zacchino,* Gladis Rodr´ıguez, Germa´n Pezzenati, and Gabriela Orellana
Area Farmacognosia, Facultad de Ciencias Bioquı´micas y Farmace´uticas, Universidad Nacional de Rosario,
Suipacha 531, 2000 Rosario, Argentina
Ricardo Enriz
Ca´tedra de Quı´mica General II, Facultad de Quı´mica, Bioqu´ımica y Farmacia, Universidad Nacional de San Luis,
Chacabuco y Pedernera, 5700 San Luis, Argentina
Manuel Gonzalez Sierra
Instituto de Qu´ımica Orga´nica de Sı´ntesis (CONICET-UNR), Facultad de Ciencias Bioqu´ımicas y Farmace´uticas,
Suipacha 531, 2000 Rosario, Argentina
Received J uly 15, 1996X
Eighteen racemic 8.O.4′-neolignans with six different substitution patterns in rings A and B,
in their ketone and in their erythro and threo alcoholic forms, were evaluated for antifungal
activity by the agar dilution method. Only the alcohols exhibited a broad spectrum of activities
against Microsporum canis, Microsporum gypseum, Tricophyton mentagrophytes, Tricophyton
rubrum, and Epidermophyton floccosum. (()-erythro-3,4-(methylenedioxy)-7-hydroxy-1′-allyl-
3′,5′-dimethoxy-8.O.4′-neolignan (11) was the most active compound in the series, and E.
floccosum was the most susceptible species.
Drugs from Myristicaceae species have been used in
the Amazonian region as hallucinogens and arrow
poisons as well as for the healing of infected wounds.1
Chemical investigations of Amazonian Myristicaceae led
to the hypothesis that the alleged usefulness of plasters
made from leaves or bark resin in the treatment of skin
infections may be due to the fungistatic or fungitoxic
activity of neolignans.2 Within the great structural
variety of neolignans, the 8.O.4′-type represents a small
group, whose members have been isolated from plants
of the Myristicaceae.3 They were reported in Myristica
fragrans,4-7 Virola surinamensis,8 Virola carinata,9 and
Virola pavonis.10
tion of cercaria of Schistosoma mansoni,3 inhibition of
the growth of silkworm larvae,11 and antileukemic
activity in rats.12 Studies on the antifungal activity of
8.O.4′-neolignans have not been reported to date.
In the course of our screening program for biological
activities of this type of compound, we chose to carry
out systematic research into their fungistatic activity
and to establish whether the antifungal activity ob-
served in the Myristicaceae family can be ascribed to
8.O.4′-neolignans. To gain insight into structure-
activity relationships, we tested neutral racemic struc-
tures with six different substitution patterns on rings
A and B in their ketone (compounds 1-6) and in their
erythro and threo alcoholic forms (compounds 7-18).13
Amongst them, alcohols (but not ketones) have been
isolated from natural sources. Alcohols with two meth-
oxyls on ring B were isolated from M. fragrans3 only in
their erythro form (compounds 7, 9, and 11); those with
Regarding their reported biological activity, 8.O.4′-
neolignans showed strong activity against the penetra-
* To whom correspondence should be addressed. FAX: 54 41 254906.
X Abstract published in Advance ACS Abstracts, April 1, 1997.
S0163-3864(96)00550-2 CCC: $14.00
© 1997 American Chemical Society and American Society of Pharmacognosy

660 J ournal of Natural Products, 1997, Vol. 60, No. 7
Zacchino et al.
only one methoxyl on ring B were found in M. fragrans
and Virola species having one, or both configurations:
erythro 13, in M. fragrans7 and threo alcohols 16 and
18 in V. surinamensis.8
able 4-allyl-2,6-dimethoxyphenol, moieties of molecule
11. All diphenylpropanoids and 1-[3,4-(methylenedi-
oxy)phenyl]-1-hydroxypropane were synthesized follow-
ing methods described previously.4,8,14-17 To the best
of our knowledge, threo compounds 10 and 12, erythro
15 and 17, and 1-[3,4-(methylenedioxy)phenyl]-1-hy-
droxypropane have not been reported previously in the
literature (see Experimental Section). In this study,
agar dilution assays were used to determine the mini-
mum inhibitory concentration (MIC) of compounds,
using a panel of human pathogenic fungi, yeasts as well
as dermatophytes.
Resu lts a n d Discu ssion
To carry out the antifungal evaluation, concentrations
of 8.O.4′-neolignans up to 250 µg/mL were incorporated
into growth media according to reported procedures.18
The agar dilution method showed that none of the
compounds tested was active against the yeasts Can-
dida albicans, Saccharomyces cerevisiae, or Cryptococ-
cus neoformans nor against the filamentous fungi
Aspergillus niger, Aspergillus fumigatus, or Aspergillus
flavus (results not shown). In contrast, different results
were obtained for the compounds of the series against
dermatophytes. These results are shown in Table 1.
All the tested dermatophytes were inhibited at 250
µg/mL and, most often at lower concentrations. The
most sensitive species was E. floccosum. Ketones were
drastically less active than alcohols. Only structures
10, 14, and 17 showed significant activity against all
the dermatophytes tested (MICs < 100 µg/mL). Alcohol
erythro-11, with a (methylenedioxy)phenyl as ring A,
showed the strongest antifungal activity with MIC ) 5
µg/mL against E. floccosum comparable to MICs of 0.3
and 15 µg/mL found for the control drugs amphotericin
B and ketoconazole.
Within the activity shown by alcohols against the
most sensitive fungus, the following conclusions can be
extracted: erythro-compounds were up to three times
more active than their threo-isomers (see structures 11
and 12, MICs ) 5 and 15 µg/mL, respectively). The
replacement of two OMe groups in structure 7 for a
methylenedioxy substituent (compound 11) enhanced
the activity eight times (MICs 40 vs. 5 µg/mL). The
addition of an extra OMe group in ring A (compounds
7-9), decreased activity 1.25 times (MICs 40 vs. 50 µg/
mL), and the suppression of a OMe in ring B (structures
7-13) increased fungistatic properties 2.67 times (MICs
40 vs. 15 µg/mL). In compounds with only one OMe in
ring B, the change of an allyl group for a trans-propenyl
substituent (compounds 13-15) decreased the activity
4.67 times (MICs 15 vs. 70 µg/mL), and an extra OMe
in ring A (compounds 15-17) increased the fungistatic
action 2.8 times (MICs 70 vs. 25 µg/mL).
Because dermatophytes are a group of fungi that
characteristically infect the superficial keratinized areas
of the body and because dermatophytoses are of par-
ticular concern in the tropics,19 it is interesting to note
that only dermatophytes (and not other types of fungi)
were affected by these alcohols, which were described
in the Myristicaceae family.
Additionally, we evaluated the minimal requirements
to produce the biological response by studying the
phenylpropanoid molecules 1-[3,4-(methylenedioxy)-
phenyl]-1-hydroxypropane and the commercially avail-
Concerning the reported antifungal properties of the
Myristicaceae family, it is very difficult at this point to
attribute activity only to the presence of 8.O.4′-neolig-
nans. Their moderate activity coupled with the fact that

Antifungal Neolignans
J ournal of Natural Products, 1997, Vol. 60, No. 7 661
Ta ble 1. MIC Values (µg/mL) for Antifungal Activities of
8.O.4′-Neolignans against Dermatophytes
ATCC 9029. Strains were grown on Saboureaud
chloramphenicol agar slants for 48 h at 30 °C. Cell
suspensions in sterile distilled H2O were adjusted to
give a final concentration of 106 viable yeast cells/mL.
Dermatophytes: M. canis C 112, T. rubrum C 113, E.
floccosum C 114, and M. gypseum C 115 are clinical
isolates and were kindly provided by CEREMIC, Centro
de Referencia Micolo´gica, Facultad de Ciencias Bio-
qu´ımicas y Farmace´uticas, Suipacha 531-(2000)-Rosario,
Argentina. T. mentagrophytes was ATCC 9972. Organ-
isms were maintained on slopes of Saboureaud dextrose
agar (SDA, Oxoid) and subcultured every 15 days to
prevent pleomorphic transformations. Spore suspen-
sions were obtained according to reported procedures20
and adjusted to 106 spores with colony forming ability
per milliliter.
dermatophytes
compd
a
b
c
d
e
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
250
250
>250
250
>250
>250
150
40
50
60
20
80
250
20
50
50
60
>250
>250
250
250
250
>250
50
150
150
80
>250
>250
>250
>250
>250
>250
150
150
50
50
100
>250
>250
>250
250
>250
>250
80
>250
>250
>250
250
>250
>250
40
40
25
25
60
50
60
50
40
>250
5
200
20
15
15
25
70
100
25
50
>250
>250
250
20
20
60
50
40
150
An tifu n gal Assays. The fungistatic activity of 8.O.4′-
neolignans was evaluated with the agar dilution method
by using Saboureaud-chloramphenicol agar for both
yeast and dermatophyte species. The assays were
carried out in 96-well microtiter plates. Stock solutions
of 8.O.4′-neolignans in DMSO were diluted to give serial
twofold dilutions that were added to each medium,
resulting in concentrations ranging from 0.10 to 250 µg/
mL. The final concentration of DMSO in the assay did
not exceed 2%. Using a micropipette, an inoculum of 5
µL of the yeast cell or spore suspensions was added to
each Saboureaud-chloramphenicol agar well. The an-
tifungal agents ketoconazole (J anssen Pharmaceutica)
and amphotericin B (Sigma Chemical Co.) were included
in the assay as positive controls. Drug-free solution was
also used as blank control. The plates were incubated
24, 48, or 72 h at 30 °C (according to the control fungus
growth) up to 15 days for dermatophyte strains. MIC
was defined as the lowest 8.O.4′-neolignan concentration
showing no visible fungal growth after incubation time.
>250
>250
>250
60
80
50
>250
>250
>250
125
a
b
d
M. canis. M. gypseum. c T. mentagrophytes. T. rubrum. e E.
floccosum.
they are minor components of the Myristicaceae species,
suggest them to be contributors but not the main agents
responsible for the alleged antifungal properties of the
family. On the other hand, it is not possible to attribute
the activity observed in Amazonian Myristicaceae to
compound 11, inasmuch as its presence was described
only in Myristica fragrans and not in native Amazonian
trees.
To gain insight into structural requirements for
activity of compound 11, we tested the phenylpropanoids
synthetic (()-1-[3,4-(methylenedioxy)phenyl]-1-hydroxy-
propane and commercially available 4-allyl-2,6-dimeth-
oxyphenol (Sigma Chemical Co.), moieties corresponding
to rings A and B, respectively, against E. floccosum.
Because neither of them showed antifungal activity up
to 50 µg/mL, both rings A and B appear to be a
necessary structural requirement to produce the biologi-
cal response, strongly suggesting a synergistic action
between them. We believe that our results may be
helpful in identifying and understanding the minimal
structural requirements for antifungal action of 8.O.4′-
neolignans and in providing guidance in the design of
new compounds that exhibit strong activity against
dermatophytes.
Test Com p ou n d s. Ketones 1-6 and alcohols 7-9,
11, 13, 14, 16, and 18 were synthesized in accordance
1
with our previous work.3,16,21,22 Their H- and 13C-NMR,
IR, and MS spectra were identical with the reported
data.
th r eo-3,4,5-Tr im et h oxy-7-h yd r oxy-1′-a llyl-3′,5′-
dim eth oxy-8.O.4′-n eolign an (10). A solution of NaBH4
(114 mg; 3 mmol) in dry 2-propanol (10 mL) was added
to a stirred solution of 15-crown-5 ether (720 mg; 3,6
mmol) in dry 2-propanol (5 mL). After 6 h, a solution
of ketone 2 (416 mg, 1 mmol) in dry MeOH (5 mL) was
added, and the mixture was stirred for 4 h at room
temperature.Then H2O and a few drops of HOAc were
added, and the mixture was extracted with Et2O (4 ×
10 mL). The combined Et2O extracts were washed with
a saturated aqueous solution of NaHCO3 and H2O, dried
(Na2SO4), decanted, and evaporated, affording a (9:1)
mixture of threo (10) and erythro (9). Pure colorless oil
10 (292 mg, 78% yield) was obtained by preparative TLC
on Si gel G F254 using hexane-EtOAc (80:20); IR νmax
Exp er im en ta l Section
Gen er a l Exp er im en ta l P r oced u r es. The 1H-NMR
spectra were recorded at either 80.13 or 200.15 MHz;
13C-NMR spectra, at 20.15 or 50.3 MHz in the Fourier
transform mode and in CDCl3 solutions. Carbon chemi-
cal shifts are expressed in the δ scale using CDCl3 as a
reference signal at 76.9 ppm; J values are given in
Hertz. Preparative TLC was done on Si gel F254 with
visualization under UV (254 and 365 nm). IR spectra
were measured with a Bruker IFS 25 spectrophotom-
eter. MS were measured at 70 eV for electron impact
(EIMS).
Micr oor ga n ism s a n d Med ia . The following micro-
organisms used for the fungistatic evaluation were
purchased from American Type Culture Collection
(Rockville, MD): C. albicans ATCC 10231, S. cerevisiae
ATCC 9763, C. neoformans ATCC 32264, A. flavus
ATCC 9170, A. fumigatus ATCC 26934, and A. niger
(film) 3479, 2938, 1591, 1460, 1234, 1126, 1020 cm-1
;
1H NMR (CDCl3) δ 1.21 (3H, d, J ) 6.0 Hz, H-9), 3.35
(2H, br d, H-7′), 3.81, 3.84, 3.87 (15H, s, 5 × OMe), 4.00
(1H, dq, H-8), 4.6 (1H, d, J ) 8.0 Hz, H-7), 5.07 (1H, m,
H-9′), 5.95 (1H, m, H-8′), 6.44, 6.57 (4H, s, ArH); 13C
NMR (CDCl3) δ 17.55 (q, C-9), 40.35 (t, C-7′), 55.82,
55.95 (q, C-3, C-5, C-3′, and C-5′, OMe), 60.64 (q, C-4,
OMe), 79.23 (d, C-7), 86.21 (d, C-8), 104.12 (d, C-2 and
C-6), 105.28 (d, C-2′ and C-6′), 118.04 (t, C-9′), 135.04

662 J ournal of Natural Products, 1997, Vol. 60, No. 7
Zacchino et al.
(s, C-4′), 135.79 (s, C-4), 136.22 (s, C-1′), 136.87 (d, C-8′),
137.34 (s, C-1), 152.47 (s, C-3′ and C-5′), 152.91 (s, C-3
and C-5); EIMS m/ z [M]+ (19), 225 (7), 224 (28), 221-
(6), 197 (5), 195 (46), 194 (100), 193 (43).
H-7′), 6.62 (2H, s, H-2 and H-6), 6.89 (3H, m, H-3′, H-5′,
and H-6′); 13C NMR (CDCl3) δ 13.3 (q, C-9), 16.3 (q, C-9′),
55.5 (q, C-3′, OMe), 55.9 (q, C-3 and C-5, OMe), 60.5 (q,
C-4, OMe), 73.3 (d, C-7), 82.4 (d, C-8), 104.2 (d, C-2 and
C-6), 109.1 (d, C-2′), 118.5 (d, C-5′), 118.7 (d, C-6′), 124.6
(d, C-8′), 130.2 (d, C-7′), 133.3 (s, C-1′), 135.5 (s, C-4),
146.4 (s, C-4′), 150.5 (s, C-3′), 152.9 (d, C-3 and C-5);
EIMS m/ z [M]+ (4.39), 225 (14.65), 224 (53.64), 197
(100), 164 (99), 135 (37).
th r eo-3,4-(Met h ylen ed ioxy)-7-h yd r oxy-1′-a llyl-
3′,5′-d im et h oxy-8.O.4′-n eolign a n (12). The same
procedure as described for alcohol 10 was followed
starting with ketone 3 (368 mg, 1 mmol), NaBH4 (114
mg, 3 mmol), and 15-crown-5 ether (0.69 mL, 3.6
mmol). A 8:2 mixture of crude threo-12 and erythro-11
was obtained. Preparative TLC on Si gel afforded pure
12 (187 mg, 73% yield), as a colorless oil; IR νmax (film)
3480, 2936, 1589, 1502, 1247, 1126, 1038 cm-1; 1H NMR
(CDCl3) δ 1.17 (3H, d, J ) 6.4 Hz, H-9), 3.35 (2H, br d,
J ) 6.8 Hz, H-8′), 3.87 (6H, s, 2 × OMe), 3.94 (1H, m,
H-8), 4.60 (1H, d, J ) 8.4 Hz, H-7), 4.99 (1H, m, H-9′),
5.15 (1H, m, H-9′), 5.91 (2H, s, OCH2O), 6.00 (1H, m,
H-8′), 6.44 (2H, s, H-2′ and H-6′), 6.73-6.87 (3H, m, H-2,
H-5, and H-6); 13C NMR (CDCl3) δ 13.30 (q, C-9), 40.34
(t, C-7′), 55.77 (q, C-3′ and C-5′, OMe), 78.77 (d, C-7),
86.21 (d, C-8), 100.34 (t, OCH2O) 105.26 (d, C-2′ and
C-6′), 107.37 (d, C-2), 107.79 (d, C-5), 115.98 (d, C-9′),
120.86 (d, C-6), 134,60 (s, C-4′), 134,90 (s, C-1), 135,74
(s, C-1′), 136.92 (d, C-8′), 146.94 (s, C-3), 147.42 (s, C-4),
152.50 (s, C-3′ and C-5′); EIMS m/ z [M]+ (11, 221 (9),
194 (100), 193 (36), 179 (9), 163 (9), 91 (13), 65 (12).
1-[3,4-(Met h ylen ed ioxy)p h en yl]-1-h yd r oxyp r o-
p a n e. The same procedure as for reduction of ketone
5 was used with 1-[3,4-(methylendioxy)phenyl]-1-oxo-
propane (103 mg, 0.58 mmol), synthesized through
Grignard reaction from piperonylnitrile (Aldrich Chemi-
cal Co.),23 LiAlH4 (228 mg, 6 mmol), and dry Et2O (10
mL). After purification through preparative TLC (hex-
ane-EtOAc 80:20), pure 19 (90 mg, 0.50 mmol) was
obtained as a colorless oil; IR νmax 3520, 2940, 1630,
1540, 1500, 1470, 1450, 1055, 950 cm-1 1H NMR
;
(CDCl3) δ 0.89 (3H, t, J ) 8.0 Hz, H-9), 1.77 (2 H, m,
H-8), 4.50 (1H, t, J ) 6.0 Hz, H-7), 5.95 (2H, O-CH2-O),
6.77-6.86 (2H, ArH); 13C NMR (CDCl3) δ 10.05 (q, C-9),
31.71 (t, C-8), 75.80 (d, C-7), 100.84 (t, O-CH2-O), 106.29
(d, C-2), 107.86 (d, C-5), 119.30 (d, C-6), 138.54 (s, C-1),
146.75 (s, C-3), 147.63 (s, C-4); EIMS m/ z [M]+ (51),
151 (100), 93 (95), 65 (83), 57 (14), 41(12).
er yth r o-3,4-Dim eth oxy-7-h ydr oxy-1′(E)-pr open yl-
3′-m eth oxy-8.O.4′-n eolign a n (15). An Et2O solution
of ketone 5 (428 mg, 1.2 mmol) was gradually added to
a stirred suspension of LiAlH4 (456 mg, 12 mmol) in
dry Et2O (36 mL). After addition was complete, the
mixture was refluxed for 24 h. Excess LiAlH4 was
carefully destroyed by addition of EtOAc-ice and was
finally diluted with H2O (60 mL), acidified, (10% HCl),
and extracted with Et2O (3 × 60 mL). The combined
Et2O extracts were washed with 1 N aqueous NaOH and
H2O, dried (Na2SO4), followed by concentration affording
a crude oil, which on purification by preparative TLC
(hexane-EtOAc 80:20), yielded pure 15 (385 mg, 1.08
mmol); IR νmax (film) 3500, 2970, 1610, 1525, 1390, 1270,
Ack n ow led gm en t. We thank UNR (Universidad
Nacional de Rosario) for financial support, Dr. Oreste
Mascaretti (IQUIOS-CONICET-UNR) for helpful com-
ments on the manuscript, and Drs. Clara Lo´pez and
Alfredo Borghi (CEREMIC, UNR) for providing cultures
of dermatophytes and for their valuable assistance in
the mycological work.
Refer en ces a n d Notes
(1) Schultes, E.; Holmstedt, B. Lloydia 1971, 34, 61-78.
(2) Gottlieb, O. J . Ethnopharmacol. 1979, 1, 309-323.
(3) Herrera Braga, A.; Zacchino, S.; Badano, H.; Gonza´lez Sierra,
M.; Ru´veda, E. Phytochemistry 1984, 23, 2025-2028.
(4) Forrest, J .; Heacock, R.; Forrest, T. J . Chem. Soc., Perkin Trans.
I 1974, 205-209.
(5) Hattori, M.; Hada, S.; Shu,Y.; Kakiuchi, N.; Namba, T. Chem.
Pharm. Bull. 1987, 35, 668-674.
1
1150, 1050 cm-1; H NMR (CDCl3) δ 1.17 (3H, d, J )
(6) Isogai, A.; Murakoshi, S.; Suzuki, A.; Tamura, S. Agric. Biol.
Chem. 1973, 37, 1479-1486.
6.0 Hz, H-9), 1.88 (3H, d, J ) 5.2 Hz, H-9′), 3.89, 3.91,
3.92 (9 H, s, 3 × OMe), 4.37 (1H, m, H-8), 4.86 (1H, d,
J ) 3.2 Hz, H-7), 5.70-6.23 (1H, m, H-8′), 6.39 (1H, d,
J ) 18.0 Hz, H-7′), 6.84-7.0 (6H, m, ArH); 13C NMR
(CDCl3) δ 13.29 (q, C-9), 16.29 (q, C-9′), 55.67, 55.74 (q,
C-3 and C-4, OMe), 73.31 (d, C-7), 82.40 (d, C-8), 109.10
(t, C-2′), 109.23 (t, C-5), 110.60 (t, C-2), 118.27 (t, C-5′),
118.86 (t, C-6′), 119.81 (t, C-6), 124.92 (d, C-8′), 130.30
(d, C-7′), 132.29 (s, C-1′), 133.58 (s, C-1), 145.44 (s, C-4),
147.99 (s, C-3), 148.87 (s, C-4′), 151.37 (s, C-3′); EIMS
m/ z [M]+ (2) 195 (10), 194 (15), 167 (78), 165 (73), 164
(100), 149 (10), 139 (40), 121 (28), 91 (19), 77 (30).
(7) Hada, S.; Hattori, M.; Tezuka, Y.; Kikiuchi, T.; Namba, T.
Phytochemistry 1988, 27, 563-568.
(8) Barata, L.; Baker, P.; Gottlieb, O.; Ru´veda, E. Phytochemistry
1978, 17, 783-786.
(9) Cavalcante, S.; Yoshida, M.; Gottlieb, O. Phytochemistry 1985,
24, 1051-1055.
(10) Ferri, P.; Barata, L. Phytochemistry 1992, 31, 1375-1377.
(11) Isogai, A.; Murakoshi, S.;. Suzuki, A.; Tamura, S. Agric. Biol.
Chem. 1973, 37, 889-895.
(12) De Oliveira, M.; Sampaio, R. Cienc. Cult. (Sao Paulo) 1980, 32,
104-108.
(13) For the assignment of relative configurations of alcohols, the
appreciable differences in 1H- and 13C-chemical shifts between
the erythro and threo forms was used. See refs 3-7, 9.
(14) Wallis, A. Aust. J . Chem. 1973, 26, 585-594.
(15) Sarkanem, K.; Wallis, A. J . Chem. Soc., Perkin Trans. 1 1973,
1869-1877.
er yth r o-3,4,5-Tr im et h oxy-7-h yd r oxy-1′(E)-p r op -
en yl-3′-m eth oxy-8.O.4′-n eolign a n (17). The same
procedure as for reduction of ketone 5 was used with
ketone 6 (106 mg, 0.3 mmol), LiAlH4 (114 mg, 3 mmol),
and dry Et2O (10 mL). After purification through
preparative TLC (hexane-EtOAc 80:20), pure 17 (101
mg, 0.26 mmol) was obtained as a colorless oil; IR νmax
(film) 3500, 2920, 1601, 1470, 1420, 1330, 1265, 1140,
1040 cm-1; 1H NMR (CDCl3) δ 1.17 (3H, d, J ) 6.0 Hz,
H-9), 1.88 (3H, d, J ) 5.5 Hz, H-9′), 3.82, 3.85, 3.90 (12H,
4 × OMe), 4.35 (1H, m, H-8), 4.85 (1H, d, J ) 3.0 Hz,
H-7), 6.12-6.25 (1H, m, H-8′), 6.39 (1H, d, J ) 16.0 Hz,
(16) Fonseca, S.; Nielsen, L.; Ru´veda, E. Phytochemistry 1979, 18,
1703-1706.
(17) Zacchino, S.; Badano, H. J . Nat. Prod., 1985, 48, 830-832.
(18) Rahalison, L.; Hamburger, M.; Monod, M.; Fenk, E.; Hostett-
mann, K. Planta Med. 1994, 60, 41-44.
(19) Ca´ceres, A.; Lo´pez, B.; Giron, M.; Logeman H. J . Ethnophar-
macol. 1991, 31, 263-276.
(20) Wright, L.; Scott, E.; Gorman, S. J . Antimicrob. Chemother. 1983,
12, 317-327.
(21) Zacchino, S.; Badano, H. J . Nat. Prod. 1988, 51, 1261-1265.
(22) Zacchino, S.; Badano, H. J . Nat. Prod. 1991, 54, 155-160.
(23) Cannone, P.; Foscolos, G.; Limay, G. Tetrahedron Lett. 1980, 21,
155-158.
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