Antistress, Adoptogenic Activity Of Aegle marmelos Fruit In Mice

Abstract

Ethanolic extract of unripe fruits of Aegle marmelos was tested for antistress, adoptogenic activity in mice using swim endurance test and cold restrain stress. The extract exhibited significant antistress, adoptogenic activity by improving the swim duration and reducing the elevated WBC, blood glucose and plasma cartisone. Acute toxicity studies revealed that LD₅₀ is more than a dose of 3 g/kg body weight

Introduction

An Adaptogen increases the power of resistance against physical, chemical or biological noxious agents; it has a normalizing influence on body. The mode of action of adoptogens is basically associated with the stress system Adoptogens increase the capacity of stress system to respond to external signals at the higher level of the equilibrium of activating and deactivating mediators of stress response. The plant Adoptogen is defined as “Smooth pro-stressors which reduce reactivity of host defense systems and decrease damaging effects of various stressors due to increased basal level of mediators involved in the stress response” (Panossian et al.,1999). A number of plants possess adoptogenic activity due to diverse classes of chemical compounds.

Various parts of Aegle marmelos, Correa, Family Rutaceae, commonly known as Bael, are used in Ayurveda, as well as in Unani medicine for the treatment of many diseases. Unripe fruit of the plant is prescribed in chronic diarrhoea and dysentery. Decoction of the root is useful in intermittent fever, hypochondriasis, melancholia and palpitation of the heart (Nadkarni, 1992). The plant possess antifungal activity (Rana et al., 1997), antibacterial activity(Ghosh and Playford, 2003), radioprotective effect(Jagetia et al., 2003) and anticancer activity(Lampronti et. al., 2003, Lambertini et. al., 2005,). The Bael leaves can be used as potential hypoglycemic agent (Kamalakkanan et.al, 2003). The present study was taken up to evaluate antistress, adoptogenic activity of ehanolic extract of unripe fruits of Aegle marmelos in mice.

Materials and Methods

Plant material Unripe fruits of Aegle marmelos were collected from Hillgreen pvt. Ltd, Bangalore, dried in shade, coarsely powdered, subjected to Soxhlet extraction, using ethanol (40%), at a temperature below 60°C for 24 hours. The extract was concentrated by distilling the solvent and air-dried.(11.7% w/w, reddish brown, solid ).

Animals Eight-week old Swiss albino mice of either sex, weighing 20-25 g, maintained on a 12 hour light/dark cycle, at a temperature of 25⁰C + 2⁰C, commercial pellet diet (Lipton India, Bangalore) and water ad libitum were used in study.

Acute toxicity The fruit extract was administered to group of mice in graded doses
upto 3g/kg body weight orally and observed for toxic signs and symptoms and mortality
for 48 hours.(Jayasekar et. al., 1997)

Experimental

Swim endurance test- The mice were given extract 50 and 100 mg/kg orally, using oral gague, for 7 days. The standard group was administered water-soluble powder of Ashwagandha (Natural remedies, Bangalore) 100 mg/kg orally. On the 8^th day, the animals were allowed to swim till exhausted in a propylene tank of dimension 37 X 37 X 30 cm, filled with water to a height of 25 cm. The end point was taken when the animals drowned and ‘Swimming time’ for each animal was noted. The mean swimming time for each group was calculated and the data was statistically analyzed. (Kumar et al., 1999)

Cold restraint stress- The mice were given extract 50 and 100 mg/kg orally, using oral gague, for 7 days. The standard group was administered water-soluble powder of Ashwagandha (Natural remedies, Bangalore) 100 mg/kg orally. On the 8^th day, animals were individually placed in plastic containers of capacity 350 ml. They were immobilized in their normal position, using adhesive tape. The containers were placed in a cold chamber maintained at 4 C for 2 hours. The blood was collected by heart-puncture method, in a heparinised tube and WBC count was done using Neubauer’s chamber, blood glucose was determined by Folin Wu method and plasma cortisol level was determined by photofluorimetric method (Varley et al., 1984).

Statistics All the values are expressed as mean ± SEM and data was analyzed using one-way ANOVA using Graphpad instat-3. The post-hock analysis was carried out by Dunnet’s multiple comparison test to estimate the significance of difference between various individual groups.

Result

Acute toxicity studies with extract revealed that LD₅₀ is more than
a dose of 3g/kg body weight.

As shown in table 1, the extract improves the swim duration and reduces the elevated WBC, blood glucose and plasma cartisol levels.

Discussion

Increased swimming endurance in mice, which is pretreated with adoptogens has been reported and the test system is used to evaluate the agents with adoptogenic properties (Banerjee and Izquierdo, 1982; Bhargava and Singh, 1981; Singh et al., 1991). Mice pretreated with ethanolic extract of Aegle marmelos show significant improvement in the swimming time.

Cold stress typically increases total leukocyte count, eosinophils and basophils (Sundaresan et al., 1990), Plant adoptogens are smooth prostressors which reduce the reactivity of host defense system and decrease the damaging effects of various stressors due to increased basal levels of mediators involved in the stress response (Panossian et al.,1999). Since the stress induced increased total WBC count is decreased by extract of Aegle marmelos the plant posses antistress, adoptogenic activity.

Estimation of plasma cortisol level is a valid and controlled way to study how people react to psychological and physical stressors in laboratory settings (Negrao et al., 2000). Cortisol is released in response to neural stimuli, caused by chronic stress. (Simmons, 1998). Increased plasma cortisol influences the mobilisation of stored fat and carbohydrate reserves (Tache and Selye, 1976), which in turn increases blood glucose level. The increased cortisol levels and increased blood glucose level are reversed by Anti-stress agents (Sen et al., 1992). The extract of Aegle marmelos reduced plasma cortisol level as well as blood glucose level, exhibiting antistress activity.

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Table 1 : Effect of ethanolic extract of Aegle marmelos on stress(Values
are Mean ± SEM)

Treatment	Swimmimg time(minutes)	TotalWBCcount (cells/cumm)	Blood glucose (mg/dl)	Plasma cortisol (mg/100ml)
Normal control	-	5620.00±80.63	86.24±3.86	13.04 ± 0.24
Stress control	419.81±10.55	7126.50±35.73*	137.50±4.43*	21.41±0.56*
A.marmelos 50mg/kg	499.08±21.62	6012.30±25.84	92.72±4.81	17.23±0.05
A.marmelos 100mg/kg	512.27±17.28	5562.60±43.83**	86.06±4.92**	15.16±0.75**
Ashwagandha100mg/kg	716.17±27.28	5679.20±62.98**	85.85±3.52**	13.97±0.38**
	F=45.011	241.48,	333.33	44.798,