Chirality in Biology
599
Essential oils have been used in folk
medicine, and it is a common belief
that odors can influence mood, alertness,
and sexual arousal (witness the appeal of
aromatherapy). Some work concerns the
effects of chiral fragrances on the hu-
man autonomic nervous system. In one
study, inhalation of (
+
)-limonene (odor
is orange) gave increased systolic blood
pressure, subjective alertness, and rest-
lessness; inhalation of (
)-limonene (odor
is turpentine) increased systolic blood
pressure without influencing psycholog-
ical parameters. Similar responses were
obtained with carvone enantiomers. The
effects were complex and both pharma-
cological and psychological mechanisms
were probably involved.
In studies of linalool enantiomers, differ-
ences in perception and responses elicited
by a sensory test and forehead surface
potential wave measurements were mea-
sured. (
R
)-(
)-linalool, administered after
hearing environmental sounds, gave a
favorable impression, and there was a
tendency for the beta wave to decrease.
With (
S
)-(
+
)-linalool, there was an un-
favorable impression and the beta wave
increased. Different and complex results
were obtained following mental work.
These preliminary results showed that
the responses to the two enantiomers de-
pended
,inadd
i
t
ion
,ontasksass
ignedto
the subjects.
Enantio-MDGC-MS has been used in
some human metabolic studies. Methyl-
citric acid, MCA, occurs in body fluids
of individuals with propionic acidemia,
methylmalonic aciduria, or holocarboxy-
lase deFciency. MCA has two chiral cen-
ters; of the four possible stereoisomers,
only the (2
S
,3
R
)and(2
S
,3
S
) diastereoiso-
mers were detected in patients and con-
trols, in proportions varying from about
30 to 70%. The differences may be due to
physiological effects on the citrate synthase
enzyme forming MCA from oxaloacetate
and propionyl-CoA.
3.3
Insect Pheromones
±or chiral insect pheromones, the nature
of the chirality generally has a profound
effect on the observed physiological re-
sponse. Thus, with the female spider sex
pheromone, 3-hydroxybutyric acid, only
the (3
R
) structure is functional. All of the
following situations have been observed:
1. As just noted, activity is present in only
one enantiomer, the other being in-
different (e.g. (
+
)-exobrevicomin, pine
sawfly pheromone) or inhibitory (e.g.
(
+
)-disparlure, (
S
)-
cis
-verbenol).
2. All stereoisomers are active (e.g. gran-
disol, seudenol).
3. Different
species
may
differentiate
enantiomers,
for
example,
(
S
)-(
+
)-
ipsdienol
used
by
Ips
paraconfusus
and
the
R
enantiomer
by
I.
cal-
ligraphus
.
A
more
complex
situa-
tion occurs with scarab beetles. ±or
Anomala
osakana
,
the
female
pro-
duces
the
male
attractant,
(
S
,
Z
)-5-
(1-decenyl)oxacyclopentan-2-one. How-
ever, in
Popillia japonica
the (
R
) enan-
tiomer is attractive to males. These
activities are inhibited by the respec-
tive enantiomers. In Feld tests with
A. osakana
,ca
t
che
so
fma
le
sint
rap
s
baited with the (
S
) enantiomer were
completely inhibited by as little as 5% of
the (
R
) form. The reciprocal behavioral
agonist–antagonist situation provides
a species-speciFc chemical signal with
the use of a single chiral structure. In-
terestingly, these two beetles share a
common habitat in Japan.
previous page 1273 Encyclopedia of Molecular Cell Biology and Molecular Medicine read online next page 1275 Encyclopedia of Molecular Cell Biology and Molecular Medicine read online Home Toggle text on/off