Analgesic and Anti-inflammatory Properties of Plantago australis

Trabajos originales
Acta Farm. Bonaerense 21 (2): 89-92 (2002)
Recibido el 23 de octubre de 2001
Aceptado el 7 de diciembre de 2001
Analgesic and Anti-inflammatory Properties
of Plantago australis Hydroalcoholic Extract
Nayana Schuch PALMEIRO, Cybele ESTEVES ALMEIDA*, Paulo César GHEDINI,
Letícia Silveira GOULART & Bernardo BALDISSEROTTO
Department of Physiology, Federal University of Santa Maria, Faixa de Camobi, Km 09,
CEP 97105-900 - Santa Maria, Rio Grande do Sul, Brasil
SUMMARY. The hydroalcoholic extracts of leaves, roots, and fruits of Plantago australis Lam. (Plantaginaceae) were investigated regarding their possible anti-inflammatory and analgesic properties. Carrageenan-induced rat hind paw edema was significantly inhibited (P<0.05) by oral administration of these
extracts. All studied extracts also reduced the total number of writhes induced by acetic acid. The results
indicated that the hydroalcoholic extracts of leaves, roots, and fruits of P. australis are endowed with antiinflammatory and analgesic activities.
RESUMEN. “Propiedades analgésicas y antiinflamatorias del extracto hidroalcohólico de Plantago australis”.
Fueron investigados los extractos hidroalcohólicos de hojas, raíces y frutos de Plantago australis Lam. (Plantaginaceae) para determinar sus posibles propiedades antiinflamatorias y analgésicas. La inducción del edema de
pata por carragenina fue significantemente inhibida (P<0,05) por la administración oral de estos extractos. También hubo una reducción en el número total de contorsiones inducidas por el ácido acético con todas las partes de
la planta estudiadas. Los resultados indican que los extractos hidroalcohólico de hojas, raíces y frutos de P. australis estarían dotados de actividad antiinflamatória y analgésica.
INTRODUCTION
Plantago australis Lam. is a perennial plant
that belongs to the Plantaginaceae family. This
plant is known as tansagem, transagem or tranchagem in Southern Brazil and it is used in folk
medicine as laxative, diuretic, anti-inflammatory,
anti-bacterial, cicatrizing, and other medicinal
treatments 1.
Several species of the genus Plantago (P. minor L., P. lanceolata L., P. major L.) are used to
treat pain and inflammation, in diseases as rheumatism, fever, gastric ulcers, and hemorrhoids 2-4.
The pharmacological activity of some of these
species was determined by scientific studies, as
the anti-inflammatory action of P. major 5. However, studies on pharmacological activities of
P. australis are scarce, and therefore the present
study aimed to investigate analgesic and anti-in-
flammatory properties of the hydroalcoholic extract (HAE) of P. australis leaves, roots, and
fruits on the carrageenan-induced paw edema in
rats and acetic acid induced writhing test in mice.
MATERIAL AND METHODS
P. australis was collected in Santa Maria, Rio
Grande do Sul state, Southern Brazil. A voucher
specimen is deposited in the herbarium of the
Department of Biology of the Universidade Federal de Santa Maria under number 6369. The
leaves, roots, and fruits were maintained in a
ventilated oven (40 °C) for drying and stabilization. The material was then pulverized in a Willye mill. The HAE of leaves, roots and fruits was
prepared at ethanol 70%, respectively. The obtained of each plant portion was lyophilized and
stored at -12 °C. The yield of this process was
KEY WORDS: Analgesic, Anti-inflammatory, Plantago australis.
PALABRAS CLAVE: Analgésico, Antiinflamatório, Plantago australis.
*
Author to whom correspondence should be addressed.
ISSN 0326-2383
89
Palmeiro, N.S., C. Esteves Almeida, P.C. Ghedini, L.S. Goulart & B. Baldisserotto
18.74 % for leaves, 17.08% for roots, and 10.48%
for fruits.
Antiedematogenic Activity
The method of carrageenan-induced paw
edema in rats to evaluate the anti-inflammatory
activity described by Winter et al. 6 was used.
Male rats were treated orally with the vehicle
(water), HAE of leaves, roots, and fruits (250,
500, and 1000 mg/kg) or indomethacin (10
mg/kg) 60 min before injection of 0.05 mL of
1% carrageenan into the rat hind paw plantar
surface. The measurements of foot volume were
taken before carrageenan injection and in every
hour for 4 h. The inhibition of the inflammation
was calculated by measuring the volume difference between the control and the tested paw.
Acetic Acid Induced Writhing Test
Adult mice (25-35 g) were treated with either
the vehicle (water) or HAE of leaves, roots, and
fruits (60, 125, and 250 mg/kg) v.o., 60 min
prior to i.p. injection of 1.2% acetic acid (0.1
mL/10g body weight). Indomethacin (10 mg/kg,
v.o.) treated animals were used for positive control. The number of writhes was counted for 30
min 7,8.
Statistical Analysis
Data were expressed as mean ± S.E.M. and
the different treatments were compared by
analysis of variance and the post-hoc Duncan’s
multiple range test, with the aid of the statistical
software SPSS (version 1986). The minimum significance level was set at P < 0.05. Differences
between two means were detected using the
Student’s t test.
RESULTS
Effect of the HAE of P. australis on the Rat
Paw Edema Induced by Carrageenan
Rats treated with HAE of leaves at the dose
of 250 mg/kg inhibited the edema in 29.91%
(0.89 ± 0.07 mL) and 21.80 % (1.14 ± 0.07 mL)
after 180 min and 240 min when compared with
the control group. The doses of 500 and 1000
mg/kg of the HAE of leaves inhibited the edema
after 120 min in 41.92% (0.42 ± 0.06 mL) and
20.46% (0.58 ± 0.05 mL), after 180 min in
31.74% (0.87 ± 0.05 mL) and 26.52% (0.94 ± 0.04
mL), and after 240 min in 24.53% (1.10 ± 0.05
mL) and 21.66% (1.15 ± 0.03 mL), respectively,
when compared with the control group (Figure
1 A).
Pretreatment with HAE of roots at dose of
90
EDEMA (% of Control)
A
B
C
TIME (minutes)
Figure 1. Effect of oral treatment with the hydroalcoholic extract (HAE) of leaves (A), roots (B) and fruits
(C) of P. australis Lam. (▲: 250, x: 500 and *: 1000
mg/kg) and vehicle (◆) or indomethacin (■) on the
rat paw edema induced by 0.05 mL of carrageenan
1%. Symbols and vertical lines are means ± SEM
(n=6) of the volume difference between the paws injected with the phlogistic agent and the contralateral
paws injected with saline.
* significantly different from control (P < 0.05).
500 mg/kg inhibited the edema after 120 min in
42.46% (0.42 ± 0.07 mL), after 180 min in
29.02% (0.90 ± 0.09 mL), and after 240 min in
19.07% (1.18 ± 0.10 mL), when compared with
the control group. No significant difference with
relation to control was detected at the doses of
250 and 1000 mg/kg (Figure 1 B).
Administration of HAE of fruits at dose of
250 mg/kg inhibited the edema after 120 min in
27.16% (0.53 ± 0.07 mL), 180 min in 34.88%
acta farmacéutica bonaerense - vol. 21 n° 2 - año 2002
NUMBER OF WRITHINGS
A
and 250 mg/kg) reduced the writhes by 50.12%
(38.4 ± 5.26) and 56,88% (33.2 ± 3.36). No significant difference was detected to the dose of 60
mg/kg (72.6 ± 7.31) (Figure 2 B). Previous administration with HAE of fruits (60, 125 and 250
mg/kg) reduced the writhes by 28.58% (55 ±
5.16), 45.46% (42 ± 4.40) and 44.42% (42.8 ±
4.09), respectively (Figure 2 C). Indomethacin
pretreatment reduced the number of writhes to
52.17% of control.
B
C
Figure 2. Number of writhes (in 30 min) induced by
intraperitoneal injection of acetic acid in mice pretreated orally with the vehicle (C), the HAE of P. australis leaves (A), roots (B), and fruits (C) at doses of 60,
125, and 250 mg/kg or indomethacin (Ind). Vertical
bars are means ± SEM (n=6)
* significantly different from control (P < 0.05)
(0.83 ± 0.09 mL), and after 240 min in 19.82%
(1.17 ± 0.05 mL) when compared with the control group. The dose of 500 mg/kg inhibited the
edema after 180 min in 26.20% (0.94 ± 0.09 mL),
and after 240 min in 18.50% (1.19 ± 0.07 mL).
The dose of 1000 mg/kg did not change significantly the edema with relation to control (Figure
1 C).
Effect on the Acetic Acid Induced Writhing
in Mice
Mice injected with 0.1 mL/10g of 1.2% acetic
acid i.p. presented 77 ± 4.49 writhes (n=6) in 30
min. Previous treatment with HAE of leaves (60,
125 and 250 mg/kg) reduced the number of
writhes by 27.46% (55.85 ± 2.73), 48.70% (39.5 ±
2.18) and 48.71% (39.5 ± 5.27), respectively (Figure 2 A). Treatment with HAE of roots (125
DISCUSSION
An analgesic and anti-inflammatory effect
was reported for Plantago species 5,9. Latin
American folk medicine refers also to the antiinflammatory activity of Plantago australis, but
no studies validating its use were reported. Although people utilize the aqueous infusion, this
study has assessed the pharmacological effects
of the HAE prepared with the leaves, roots, and
fruits separately, aiming to obtain the major presence of the active compounds.
Oral treatment of rats with the HAE of leaves, roots, and fruits inhibited the paw edema
induced by carrageeenan in a non-dependent
manner. The same was observed on the anti-inflammatory effect of the aqueous extract of leaves of Sida cordifolia L.10
The mechanism involved on the genesis of
the carrageeenan-induced edema may cause the
release of prostaglandins and kinins, among other substances 11. Pretreatment of mice with the
HAE of leaves, roots, and fruits of P. australis
inhibited writhing induced by acetic acid. When
this acid is administrated i.p. it induces the release of prostaglandins and sympathetic system
mediators 12. Writhing induced by chemical
substances is due to sensitization of nociceptors
by prostaglandins. This test is useful for evaluating mild analgesic non-steroidal anti-inflammatory compounds 13.
The anti-edematogenic and analgesic mechanisms of the HAE of P. australis may also be related to prostaglandin synthesis inhibition, as
described for the anti-inflammatory mechanism
of indomethacin 14.
Although this study suggests the existence of
a common mechanism for the analgesia and inflammation inhibition by the HAE of P. australis, higher doses were needed for a significant
anti-inflammatory effect. Additional studies with
other experimental models must be done to verify why the pain inhibition occurred with minor
dosis when compared with those used in edema
inhibition.
91
Palmeiro, N.S., C. Esteves Almeida, P.C. Ghedini, L.S. Goulart & B. Baldisserotto
CONCLUSIONS
The results indicated that the HAE of leaves,
roots, and fruits of P. australis shows anti-inflammatory and analgesic actions. Consequently,
a detailed study of this plant in order to determine its active compounds and their mechanism
of action certainly will produce interesting results.
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