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PHYTOTHERAPY RESEARCH, VOL. 11, 174–176 (1997)

SHORT COMMUNICATION

Antidepressant Effects of Ethanol Extract of Areca catechu in Rodents Ahsana Darw and Shagufta Khatoon Pharmacology Section HEJ Research Institute of Chemistry, University of Karachi, Karachi–75270, Pakistan

We report on the antidepressant activity in the ethanol extract of Areca catechu. Antidepressant activity was evaluated in rodents using the forced swimming and tail suspension tests. The ethanol extract (4–80 mg/kg) caused a significant reduction in the immobility time without effecting the spontaneous motor activity. Our findings suggest that the ethanol extract possesses antidepressant activities. © 1997 by John Wiley & Sons, Ltd. Phytother. Res. 11, 174–176, 1997 (No. of Figures: 0.

No. of Tables: 2.

No. of Refs: 12.)

Keywords: Areca catechu; antidepressant activity; tail suspension test; forced swim test.

INTRODUCTION

MATERIALS AND METHODS

Areca catechu (A. catechu) belongs to the family Palmaceae. This chewing nut is cultivated throughout tropical India (Satyavatia et al., 1976). Nuts contain alkaloids namely, arecoline, arecaine, arecaidine, guvacoline, guvacine and traces of choline. Tannins, gallic acid, gum, oily matter (Nadkarni, 1976) and a number of amino acids (Satyavatia et al., 1976) are among the constituents found in the nuts. In traditional medicine it is one of the constituents in nervine tonic (Medicinal Plants of Nepal, 1982) and possesses stimulant and astringent properties. The dry nut increases salivation, lowers prespiration, sweetens the breath and strengthens the gums (Nadkarni, 1976). There is no information regarding its antidepressant properties. Substantial efforts have been made to establish animal models for the screening of antidepressant drugs. Of these models, the forced swimming test (FST) developed by Porsolt et al., (1977a, 1977b, 1978) has gained considerable acceptance. A similar phenomenon of immobility has also been described in mice which are suspended by the tail (Steru et al., 1985). The duration of the immobility time in both the tests were reduced after pretreatment with a wide variety of antidepressant agents including tricyclics, monoamine oxidase inhibitors (MAOI) and atypical drugs. Stress-induced conditions have led to the isolation of two new acylsterylglucosides having antidepressant properties from the roots of Withania somnifera (Bhattacharya et al., 1987). In the present investigation the tail suspension test (TST), FST, locomotion test (Svensson and Thieme, 1969) and yohimbine potentiation test have been used to assess antidepressant properties in the ethanol extract of A. catechu (ACE).

Plant material and extraction procedure. One kg dried nuts of Areca catechu was used to obtain the ethanol extract (ACE) used in various pharmacological experiments.

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Correspondence to: A. Dar.

CCC 0951–418X/97/020174–03

© 1997 by John Wiley & Sons, Ltd.

Drugs. Clorgyline [N-methyl-N-propargyl-3 (2,4 dicholorophenoxy) propylamine HC1] and yohimbine hydrochloride (Sigma Chemical Co., USA) were dissolved in distilled water and ACE was suspended in 0.9% saline and administered as a clear solution or suspension. In the FST and TST tests described below animals (3–18 per dose) were given either saline or test compound (i.p.: 0.2 mL/20 g, mice or 0.5 mL/100 g, rats) 1 h prior to the experiment. Forced swim test. Male Wistar rats were treated either with saline or clorgyline (2.5, 5 and 10 mg/kg) or different doses of ACE and the duration of immobility time was measured as described earlier (Porsolt et al., 1978). Each animal was tested only once. Tail suspension test. Male NMRI mice were treated either with saline or clorgyline (4, 10, 13 and 16 mg/kg) or different doses of ACE and the duration of immobility time was measured as described earlier (Steru et al., 1985). Yohimbine potentiation test. Potentiation of yohimbine

lethality was tested using 13, 50, 100 and 200 mg/kg (10 animals/dose) of ACE, as described by Quinton (1963). Locomotion test. Five NMRI mice of either sex were treated 1 h before the test with saline. Animals were placed in an Opto-varimex Minor (Svensson and Thieme, 1969) 15 min prior to observation. Ten min locomotor counts were noted for a period of 1 h. The mean of six (10 min) readings was noted. The same animals were treated with 10, 20 and 30 mg/kg of ACE and the observations were made as above. The counts of control and treated groups were compared. Accepted 15 October 1996

ANTIDEPRESSANT EFFECT OF A. CATECHU

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and 21% increase in the immobility time respectively, compared with that of the control. A.catechu extract significantly reduced the immobility time at 4–80 mg/kg (Table 2). However, at 100 mg/kg there was an 11% rise in the duration of immobility time compared with that of the control. To investigate the mechanism of the antidepressant activity of ACE, a yohimbine lethality potentiation test was performed. The mortality in the yohimbine treated mice was not potentiated in the presence of ACE and no dramatic change in the behaviour was observed. The locomotor activity in mice after treatment with ACE did not differ from the counts obtained with control animals (2997.5 ± 680.8).

Statistical analysis. The F-test was applied to the results to

evaluate the significance of the differences, followed by Duncan’s multiple range test (Milton and Tsokos, 1983).

RESULTS A. catechu extract was evaluated for its antidepressant activity in rodents using the following tests: TST, FST, locomotion test and potentiation of yohimbine induced sublethality. Saline and clorgyline were included as appropriate controls. Acute toxicity was also determined and the LD50 of ACE was found to be 600 mg/kg. In the FST clorgyline at 2.5, 5 and 10 mg/kg caused a 17%, 42%, and 68% reduction in the immobility time, respectively. Using the TST, clorgyline at 4, 10, 13 and 16 mg/kg caused a 18%, 32%, 63% and 92% reduction in the immobility time, respectively. Table 1 shows the ANOVA for immobility time using the FST. The reduction in the immobility time of rats treated with 10, 13, 50, 80 and 100 mg/kg of ACE were significantly different from each other. Table 1 also shows ANOVA for immobility time using TST. The reduction in the immobility time of mice treated with 4, 10, 13, 50, 80 and 100 mg/kg of ACE were also significantly different from each other. Table 2 represents the means (Duncan’s multiple range test), the shortest significance range (SSRp) values and also the percent change in immobility time compared with the control for both FST and TST. A. catechu extract lowered the immobility time (FST) significantly at 10, 13 and 50 mg/ kg. However, at 80 and 100 mg/kg of ACE there was a 16%

DISCUSSION Rodents under stress from which they cannot escape, become immobile after an initial period of struggling. This immobility signifies behavioural despair, resembling a state of mental depression (Porsolt et al., 1977a; 1977b). Clorgyline, in the present study caused a dose dependent reduction in the duration of immobility time using antidepressant screens (TST or FST) without having significant effects on the power of the movements. Similar results were obtained by previous investigators (Porsolt et al., 1977a; 1977b; 1978; Steru et al., 1985) indicating antidepressant properties of this drug. One of the important findings in our study is that the concentration of ACE plays an important role in eliciting antidepressant property which was evident between 4 to 80 mg/kg and there was a reversal in the behaviour of the animal at higher concentrations. Thus indicating that the ACE contains more than one active

Table 1. ANOVA for immobility time using forced swim and tail suspension test Sources of variation

Replication Treatment Error

d.f.

M.S.

FST

TST

FST

TST

2 5 10

2 6 12

78 9070.1 82.2

267.8 3405.6 75.2

F-Value FST TST

110.3a

45.3a

FST, forced swim test TST, tail suspension test. a Significance at 0.01 level of probability.

Table 2. Means of Duncan’s test, SSRp values and percent change in immobility time of forced swim and tail suspension tests Test

Mean

Control

4

10 13 (ACE mg/kg)

50

80

100 at 0.01

SSRp

170s

N.D.

129

86

80

198

206

8.77

N.D.

24↓

49↓

53↓

16↑

21↑

98

75

47

54

113

134

19↓

38↓

61↓

55↓

7↓

11↑

FST Percent change Mean

121s

7.60

TST Percent change

FST, forced swim test. TST, tail suspension test. s, second. Percent change, ↓/↑, Decrease/increase in the immobility time compared with the control. ACE, ethanol extract of A.catechu. SSRp, shortest significant range. N.D., not done.

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A. DAR AND S. KHATOON

constituent and activity directed fractionation is needed to separate the two components. The observations with the TST were largely consistent with those obtained with the FST; however, one important pharmacological difference was that the TST appeared to be more sensitive than FST. This was evident at the 10 mg/kg concentration of the ACE where the percent reduction in the immobility time was 1.5 times greater in the TST compared with the FST. The present findings also show that rodents when treated with ACE exhibited a marked reduction in immobility time which does not correlate with the spontaneous activity, further confirming the antidepressant action of ACE. Thus the report in the literature that A.catechu possesses stim-

ulant activity is an underestimation and overlooks other cryptic properties, such as an antidepressant activity which is evident only between 4–80 mg/kg concentrations. Yohimbine (a2-adrenoreceptor antagonist) lethality in mice was unable to detect the antidepressant activity in the ACE which was identifiable by the immobility screens (Malick, 1981), thereby, suggesting that possibly the ACE is not interfering with the re-uptake of noradrenaline. It may be suggested that FST and TST are the most suitable for screening of antidepressant actions of the natural products. In conclusion, the A.catechu extract appears to have dual activities which are concentration dependent. One of the activities i.e. antidepressant action is clearly reflected as a reduction in the immobility time in rodents.

REFERENCES

Bhattacharya, S. K., Goel, R. K., Kaur, R., and Ghosal, S. (1987). Anti-stress activity of sitoindosides VII and VIII, New acylsterylglucosides from Withania somnifera. Phytother Res. 1, 32–37. Malick, J. B. (1981). Yohimbine potentiation as predictor of antidepressant action. In, Neurochemical, Behavioural and Clinical Perspectives, ed. by S. J. Enna, J. B. Malick and E. Richelson. pp. 141–155. Raven Press, New York. Ministry of Forest and Soil Conservation, Department of Medicinal Plants (1982). Medicinal Plants of Nepal, p. 113. His Majestys Govt. of Nepal, Thapathali, Kathmandu, Nepal. Milton, J. S., and Tsokos (1983). Statistical Methods in the Biological and Health Sciences, International student edition, McGraw-Hill, London. Nadkarni, K. M. (1976). Indian Materia Medica, vol. 1, pp. 130–133. Popular Prakashan, Bombay. Porsolt, R. D., Anton, G., Blavet, N., and Jalfre, M. (1978). Behavioural despair in rats: A new model sensitive to antidepressant treatments. Eur. J. Pharmacol. 47, 379–391.

Porsolt, R. D., Bertin, A., and Jalfre, M. (1977b). Behavioural despair in mice: A primary screening test for antidepressants. Arch. Int. Pharmacodyn. 229, 327–336. Porsolt, R. D., Pichon, M.Le, and Jalfre, M. (1977a). Depression: a new animal model sensitive to antidepressant treatments. Nature 266, 730–732. Quinton, R. M. (1963). The increase in the toxicity of yohimbine induced by imipramine and other drugs in mice. Br. J. Pharmacol. 21, 51–66. Satyavatia, G. V., Raina, M. K., and Sharma, M. (1976). Medicinal Plants of the India, pp. 82–85. Indian Council of Medical Research, New Delhi. Steru, L., Chermat, R., Thierry, B., and Simon, P. (1985). The tail suspension test: A new method for screening antidepressants in mice. Psychopharmacology 85, 367–370. Svensson, T. H., and Thieme, G. (1969). An investigation of a new instrument to measure motor activity of small animals. Psychopharmacologia 14, 157–163.