Vol. 21, No. 5, 2010
Porto et al.
783
in oils from caraway seeds (Carum carvi; 50-70% presence)
and from dill seeds (Anethum graveolens; 40-60%), though
of about 50 mL each were obtained. Fractions 2 and 3
(100% n-hexane) afforded limonene (15 mg). Fraction
5 (98:2) afforded dihydrocarvone (12 mg), and fractions
6 and 7 (95:5) afforded carvone (35 mg). The identity of
the isolated was established by co-injection (GC) with
standards available in our laboratories.
10-12
it is not always pure.
(R)-(-)-carvone is the principal
constituent in spearmint oil (Mentha spicata) and some
1
3
oils, such as gingergrass oil, contain racemic carvone.
S)-(+)-carvone is usually obtained from caraway seeds,
(
while (R)-(-)-carvone is obtained from spearmint oil.
Biosynthetically, (R)-(-)-carvone is formed by
cyclization of geranyl pyrophosphate to (-)-limonene,
hydroxylation to (-)-trans-carveol and dehydrogenation to
The oils were analyzed by GC and GC-MS. GC analyses
were performed using aVarian CP-3800 gas chromatograph
with a data handling system, FID detector and SE-54
fused-silica column (25 m x 0.25 mm i.d., film thickness
0.25 mm). Operation conditions were as follow: injector
14
15
(-)-carvone. According Croteau et al. this transformation
o
requiresfourenzymaticsteps, includinggeranyldiphosphate
synthase (prenyltransfer), limonene synthase (cyclization),
cytochrome P450 limonene hydroxylase (oxygenation) and
carveol dehydrogenase (redox transformation). On the other
hand, (1R, 4R)-trans-(+)-dihydrocarvone might be derived
from (R)-(-)-carvone, in which the C=C bond is reduced
and detector temperatures, 220 and 280 C, respectively;
o
carrier gas, H ; oven temperature program from 50 C to
2
o
o
-1
250 C at 4 C min . GC-MS analyses were performed using
a VARIAN model 3800 Saturn system operating in the EI
mode at 70 eV equipped with CP-SIL cross-linked capillary
columns (25 m x 0.25 mm i.d., film thickness 0.25 mm). The
identity of the oil components was established from their
GC retention times and comparison of their MS spectra with
16
enantioselectively to dihydrocarvone.
3
Experimental
those reported in the literature, and by computer matching
with the Wiley 5 mass spectra library, and as well as by
co-injection with standards available in our laboratories
whenever possible.
Plant material
Native Poiretia latifolia was collected in the town of São
Pedro do Sul, RS, Brazil (29º 37’ 14” S, 54º 10’ 44’’ W).
Cultivated P. latifolia was obtained from the botanical
garden of the University of Santa Maria, RS, Brazil (29°
Chiral monoterpene constituents (a-pinene, limonene,
trans-dyhidrocarvone and carvone) of P. latifolia oils were
identified by peak enrichment by enantioselective capillary
GCwithtwofusedcapillarycolumns,25m×0.25mm,coated
with the new phase heptakis (3-O-pentafluoropropionyl-
4
2’39” S, 53° 41’32”W). Leaves and flowers of native and
cultivated P. latifolia were collected in the flowering stage
November-December 2005) from the same population,
17
2,6-di-O-pentyl)-b-cyclodextrin and octakis(3-O-butiryl-
1
8
(
2,6-di-O-pentyl)-g-CD (Lipodex- E), each diluted with
polysiloxane OV-1701.Varian CP-3800 gas chromatograph
was used for the analyses; all runs were performed with the
respectively, and identified by a single author (T. C. D.).
Voucher specimens (SMDB 952-954) have been deposited
at the Herbarium of the Federal University of Santa Maria.
o
temperature program 35 °C for 15 min, and from 35 C to
o
o
-1
1
80 C at 3 C min .
Chemical analysis
Dihydrocarvones
Fresh native (sampleA, 100 g) and cultivated (sample B,
1
00 g) leaves from nine and seven individuals, respectively,
and fresh native flowers from four individuals (sample C,
0 g) from P. latifolia were subjected to hydrodistillation
Dihydrocarvones were prepared from (R)-(-)-carvone
1
9-20
and (S)-(+)-carvone as described previously,
as a 1:4.5
1
mixture (65-80 %) of C-1 epimers (cis-1,4 and trans-1,4,
for 4 h using a modified Clevenger-type apparatus, and
followed by extraction with diethyl ether. After solvent
removal, crude oil yields were 0.60%, 0.55% and 0.10%
respectively).
Antimicrobial bioassay
20
-1
20
(
m/m) for samples A {d : 0.89 g mL ; h = 1.4701; [a]
25
20
-1
20
=
-32.4(c0.08, CHCl )}, B{d :0.91gmL ;h =1.5502;
The MICs of samples A and B and limonene, carvone,
andtrans-dihydrocarvone,weredeterminedon96-wellculture
plates by a micro dilution method using a microorganism
suspension at a density of 10 CFU mL with Casein Soy
Broth incubated for 24 h at 37 C for bacteria, and Sabouraud
D
3
2
5
20
-1
[a] = -30.2 (c 0.10, CHCl )} and C {d : 0.85g. mL ;
D
3
2
0
h = 1.4821), respectively. Part of the resulting oil
Sample A, 100 mg) was further subjected to column
5
-1
(
o
chromatography on silica gel (10 g, 230-400 mesh), eluting
with hexane and increasing concentrations of diethyl
ether (100%, 98:2, 95:5, 90:10 and 80:20). Ten fractions
o
Broth incubated for 72 h at 25 C for yeasts. The cultures
that did not present growth were used to inoculate plates of
Porto, Carla
