Anxiogenic properties of Ptychopetalum olacoides Benth. (Marapuama)

Abstract

Alcohol infusions of roots of Ptychopetalum olacoides Benth. (PO), known as Marapuama or Muirapuama, are used in the Brazilian Amazon as a 'nerve tonic'. Over the years PO has been found increasingly in phytoformulations and regarded as a stimulant, claimed to enhance physical and mental performances. This study determined that a P. olacoides ethanol extract (30, 100 and 300 mg/kg) decreased exploratory behaviour in the hole-board test, without interfering with locomotion or motor coordination (rota-rod test). The data are comparable to that obtained with pentylenetetrazol (40 mg/kg), suggesting an anxiogenic effect of P. olacoides.

Full text

Anxiogenic Properties of Ptychopetalum
olacoides Benth. (Marapuama)
A. L. da Silva,
1,2
S. Bardini,
2
D. S. Nunes
3
and E. Elisabetsky
1,2
*
1
Curso de Po´s Graduac¸a
˜oemCie
ˆncias Biolo´gicas-Bioquı´mica, Universidade Federaldo Rio Grande do Sul, Av. Ramiro Barcelos 2600,
90035-003, Porto Alegre, RS, Brazil
2
Laborato´rio de Etnofarmacologia, ICBS, Universidade Federal do Rio Grande do Sul, Av. Sarmento Leite 500/202, 90046-900, Porto
Alegre, RS, Brazil
3
Departamento de Quı´mica, Universidade Estadual de Ponta Grossa, Campus Uvaranas, Bloco M, 84030-310, Ponta Grossa, PR, Brazil
Alcohol infusions of roots of Ptychopetalum olacoides Benth. (PO), known as Marapuama or Muirapua-
ma, are used in the Brazilian Amazon as a ‘nerve tonic’. Over the years PO has been found increasingly
in phytoformulations and regarded as a stimulant, claimed to enhance physical and mental perfor-
mances. This study determined that a P. olacoides ethanol extract (30, 100 and 300mg/kg) decreased
exploratory behaviour in the hole-board test, without interfering with locomotion or motor coordination
(rota-rod test). The data are comparable to that obtained with pentylenetetrazol (40 mg/kg), suggesting
an anxiogenic effect of P. olacoides. Copyright #2002 John Wiley & Sons, Ltd.
Keywords: Ptychopetalum olacoides; Marapuama; Muirapuma; anxiogenic; hole-board; rota-rod.
Introduction
Ethnopharmacological studies indicate that Amazonian
‘caboclos’ (Amazonian native rural inhabitants) use an
alcohol infusion of the roots of Ptychopetalum olacoides
Benth. (PO) (Olacacea), known as Marapuama, as a
‘nerve tonic’, aphrodisiac, appetite modulator and as an
anti-tremor agent (Elisabetsky, 1987; Grenand et al.,
1987). The concept of a ‘nerve tonic’ has been discussed
in detail elsewhere (Elisabetsky et al., 1992); relevant to
this study is to mention that the use of a ‘nerve tonic’
includes recovery of cognitive and motor functions after
brain injuries (such as stroke), and cognition improve-
ment (including alertness and memory) in the elderly. P.
olacoides is currently present in herbal products in
several American and European countries (Table 1).
Although little is known about the chemistry or
pharmacology of this species (Paiva et al., 1998; Uber
Bucek et al., 1987), we previously reported that a PO
ethanol extract (POEE) potentiated yohimbine-induced
lethality, reversed reserpine-induced ptosis, and pre-
vented apomorphine-induced stereotypy in mice (Si-
queira et al., 1998). These data support the hypothesis of
a PO modulatory effect on brain functions, suggesting the
involvement of cateholaminergic transmission.
Considering the therapeutic claims of the marketed P.
olacoides formulations, the purpose of this paper was to
investigate the effects of P. olacoides ethanol extract in
the hole-board model (exploratory behaviour) and the
rota-rod test (motor coordination).
Material and Methods
Plant material. Roots of Ptychopetalum olacoides
Benth. (Olacaceae) were collected in the State of Para´,
Brazil, and identified by Nelson Rosa. Voucher speci-
mens were deposited at the herbarium of the Museu
Paraense Emilio Goeldi (MPEG 108.036). The collection
was authorized by CNPq and is in line with the Brazilian
policy regarding access to genetic resources.
Preparation of extract. Ptychopetalum olacoides etha-
nol extract (POEE) was prepared as detailed elsewhere
(Elisabetsky and Siqueira, 1998). Briefly, the dried roots
(2.5 kg) were peeled, ground and extracted with ethanol
(12 L), using a Soxhlet apparatus (40 h). The extract was
evaporated under reduced pressure resulting in the POEE
(150 g; 6% yield).
Animals. Experiments were performed with male adult
mice, CF1 strain, received from Fundac¸a
˜o Estadual de
Experimentac¸a
˜o e Produc¸a
˜o da Sau
´de (FEEPS) immedi-
ately after weaning (21 days). Animals were maintained
in our own animal facilities under a controlled environ-
ment (22°1°C, 12 h light/dark cycle, free access to
food [Nuvilab CR1] and water) up to 10 weeks old
(25–40 g). All procedures were carried out according
to institutional policies on experimental animal hand-
ling.
Drugs. Diazepam and propylene glycol (PPG) were
acquired from Sigma; dimethyl sulphoxide (DMSO)
from Delaware and pentylenetetrazol (PTZ) from Knoll
A.G-Ludwingshafen/Rheno. Diazepam (0.5 mg/kg) was
suspended in propylene glycol 10% (v/v). POEE (30, 100
and 300mg/kg) was dissolved in DMSO 20%(v/v). PTZ
was dissolved in saline.
PHYTOTHERAPY RESEARCH
Phytother. Res. 16, 223–226 (2002)
Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ptr.825
Copyright #2002 John Wiley & Sons, Ltd.
* Correspondence to: Dr E. Elisabetsky, CP 5072, 90041-970, Porto Alegre,
RS, Brazil.
E-mail: elisasky@vortex.ufrgs.br
Contract/grant sponsor: FAPERGS; Contract/grant number: 98/1610-3.
Contract/grant sponsor: CNPq.
Contract/grant sponsor: CAPES.
Received 7 January 2001
Accepted 11 January 2001

Hole-board. The hole-board apparatus (Ugo Basile,
Italy) consisted of a grey Perspex panel (40 40 
40 cm, 2.2 cm thick) with 16 equidistant holes (3 cm in
diameter) in the floor. Photocells below the surface of the
holes provided measures of the number of head-dips. The
board was positioned 15cm above the table and divided
(with black water-resistant marker) in 9 squares of
10 10cm. The method was adapted from Takeda et
al. (1998). Mice were transported to the dimly lit
laboratory at least 1 h prior to testing. Each animal was
individually placed in the centre of the board (facing
away from the observer) and the following parameters
were noted for 5 min: the latency to the first head-dip,
measured using a stopwatch; the number of rearings and
spontaneous movements (number of squares crossed
with all four paws). The animals were divided into eight
groups (15–30 animals) and treatments (saline, PPG,
DMSO, diazepam, POEE and PTZ) administered in-
traperitoneally (i.p, 10 mL/kg) 30 min prior to the
testing.
Rota-rod. The rota-rod apparatus (Ugo Basile, Italy)
consisted of a rotating bar which is suitably machined to
provide grip. Six flanges divide the bar, enabling five
mice to be at the treadmill simultaneously. Latency to fall
from the bar is automatically recorded in seconds. The
method was adapted from Dalmmeier and Carlini (1981).
Mice were initially selected for their ability to remain in
the rota-rod (18 rpm) for at least two of three consecutive
90 s trials. On the test day (24 h after selection), the
latency to fall from the rota-rod (one trial of 60 s) was
determined 30 and 60 min after treatments.
Statistical analysis. The results are expressed as mean
SEM, and were analysed by ANOVA followed by
Student–Newman–Keuls test.
Results
The POEE (30,100 and 300 mg/kg) significantly reduced
the number of head-dips, as did PTZ (40 mg/kg) (Fig.
1A). POEE increased the latency to the first head-dip at
100 and 300 mg/kg (Fig. 1B), while reducing locomotion
only at 300 mg/kg (Fig. 1C). POEE significantly reduced
the number of rearings at 100 and 300 mg/kg (Fig. 1D).
Diazepam 0.5 mg/kg increased the number of head-dips
(Fig. 1A) and locomotion (Fig. 1C).
There were no deficits nor differences in the rota-rod
performance with any POEE doses, nor with DMSO
compared with saline (data not shown).
Discussion
Anxiety, a symptom accompanying various central
nervous system disorders and a disorder by itself, is
characterized in humans by a tense and physically
Table 1. Some herbal products containing Ptychopetalum olacoides
Product Description of Contents Country Reference
X-Action Pack or Ptychopetalum olacoides (Muira puama) USA http://www.herbs-are-us.net
Men X Action Pausinystalia yohimbe (yohimbe bark) /xaction.html
Arginine
Damiana leaves
Oat straw leaves concentrate
Saw palmetto berries
Touch®re HIS Ptychopetalum olacoides (Potency Wood) USA http://www.naturesvitamins.com
Juniperis brasiliensis (Catuaba) Canada /his®re.html
Turnera aphrodisiaca (Damiana)
Smilax papyracea (salsaparilla)
Urtica dioica (Nettle Root)
Doctor's Choice Essential vitamins and minerals USA http://www.enzy.com/products
for Men Zingiber of®cinale (Ginger Root extract) /individual/eprod004.html
Camellia sinensis (Green Tea Extract)
Ptychopetalum olacoides (Muira puama extract)
Serenoa repens (Saw Palmeto extract)
Panax Ginseng (Korean Ginseng Root Extract)
Masculex Vitamin E USA http://www.enzy.com/products
Ptychopetalum olacoides (Muira puama extract) /individual/eprod149.html
Turnera diffusa (Mexican Damiana leaves extract)
Serenoa repens (Saw Palmeto extract)
Cola nitida (Cola Nut extract)
Panax Ginseng (Korean Ginseng Root Extract)
Ginkgo biloba Extract
Potency Wood Ptychopetalum olacoides (Muira puama extract) USA http://www.rain-tree.com/muiraprod.html
Marapuanatus Ptychopetalum olacoides (Marapuama extract) Brazil http://www.pronatus.com.br
/productos_capsulados.htm
Guaracola Paullinia cupana Brazil http://www.pharmaciacordeiro.com.br/
Sterculia acuminata
Anemopaegma mirandum
Ptychopetalum olacoides
224 A. L. DA SILVA ET AL.
Copyright #2002 John Wiley & Sons, Ltd. Phytother. Res. 16, 223–226 (2002)

exhaustive alertness (Treit, 1985). Other animal species
display a variety of defensive reactions in response to
predators, some understood as animal correlates of
anxiety states (Rodgers et al., 1995). Rodents demon-
strate anxiety, fear and curiosity when placed in a new
environment, and an overall assessment of behaviour can
be determined by observing freezing, grooming (fear) or
rearing, head-dips (curiosity) and the number of faecal
pellets (stress) (File, 1987a; Kennedy, 1978; Dalvi and
Rodgers, 1999).
The so-called hole-board model has become increas-
ingly the most frequently used test to detect and evaluate
the anxiolytic/anxiogenic properties of drugs (File and
Wardill, 1975; Durcan and Lister, 1988; Moreira et al.,
1996; Takeda et al., 1998). The present study demon-
strated that the P. olacoides ethanol extract reduced the
number of head-dips and rearings, and increased the
latency to the first head-dip; these behaviour alterations
are compatible with the profile of anxiogenic drugs
(Moreira et al., 1996; Takeda et al., 1998). Accordingly,
pentylenetetrazol, a known anxiogenic agent, reduced the
number of head-dips.
A decrease in locomotion was observed only with the
highest POEE dose studied, and the extract did not induce
motor deficits in the rota-rod.
Changes in emotional states of animals are associated
with benzodiazepine and non-benzodiazepine associated
mechanisms. Yohimbine, an a
2
-adrenergic antagonist,
causes anxiety in humans, and in animal models (File,
1987b). Buspirona, a 5-HT
1A
agonist, and ritanserine, a
5-HT
2
antagonist, possess anxiolytic proprieties in the
human as well as animal models. Adrenocorticotrophic
hormone (ACTH) has anxiogenic effects in the social
interaction test, being antagonized by chlordiazepoxide
(File, 1987b).
In this study, diazepam (0.5 mg/kg) increased the
number of head-dips and locomotion, without interfering
with rearing. Takeda et al. (1998) reported that diazepam
increases head-dipping behaviour at doses similar to those
used in this study, but did not observe modifications in
locomotion or rearings. Nevertheless, several studies
reported that diazepam increased locomotor activity in
the open field (Bhattacharya and Mitra, 1991; Wieland et
al., 1991; Ramanathan et al., 1998). Moreover, increases in
the number of squares crossed in the open field and in head-
dips in the hole-board were obtained with desmethyldia-
zepam and chlordesmethyldiazepam (De Angelis et al.,
1982). Our results indicate that a non-sedative but
anxiolytic dose of diazepam facilitates exploratory beha-
viour, expressed in increased head-dips and locomotion.
The present results add to previously reported data
obtained with POEE (Elisabetsky and Siqueira, 1998)
indicating a central stimulant profile. An anxiogenic
effect is in line with traditional therapeutic claims for
Ptychopetalum olacoides, since moderate anxiogenesis is
associated with alertness and increased physical and
Figure 1. Effects of Ptychopetalum olacoides ethanol extract (POEE) in the hole-board test. Number of head-dips (A), latency for
the ®rst head-dip (B), number of squares crossed (C) and number of rearings (D). PTZ, pentylenetetrazol; PPG, Propylene glycol
10%; DZP, diazepam 0.5 mg/kg; DMSO, Dimethyl sulphoxide 20%. Each column represents the mean SEM. ANOVA * = p<0.05
and ** p<0.01 compared with saline.
ANXIOGENIC PROPERTIES OF PTYCHOPETALUM OLACOIDES 225
Copyright #2002 John Wiley & Sons, Ltd. Phytother. Res. 16, 223–226 (2002)

psychological endurance (Jaffe, 1990). Further studies
are necessary to complete the psychopharmacological
profile of PO and unveil the mechanism(s) that underlie
the central effects of POEE.
Acknowledgements
This study was supported by FAPERGS (grant 98/1610.3), CNPq (EE)
and CAPES (ALS). Authors wish to thank Patricia Shanley for her
crucial assistance in collecting plant material.
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