Experimental Study of Analgesic Activity of Cajanus cajan Linn Leaves in Mice

R. S. Ghodake*, U.S. Chikhali, A.D. Shinde, S. B. Patil and N. S. Naikwade

Department of Pharmacology, Appasaheb Birnale College of Pharmacy, South Shivaji Nagar, Sangli 416416

ABSTRACT:

Cajanus cajan L (fabaceae) is an important indigenous plant with a lot of traditional importance. The analgesic potency of aqueous extract of the leaves of Cajanus cajan L was investigated using animal model using writhing methods, formalin induced methods. Result showed that aq. extract of Cajanus cajan L increased pain threshold in mice using writhing methods, formalin induced methods. It is concluded that the aqueous extract of Cajanus cajan L can demonstrate strong analgesic potency comparable in a times and dose dependant manner to a non steroidal anti-inflammatory drugs. The result tends to suggest that the extracts of Cajanus cajan L leaves posses analgesic activity.

KEYWORDS: Cajanus cajan L, analgesic activity, Writhing methods, formalin induced methods.

INTRODUCTION:

Pain is defined as one of the uncomfortable and uneasiness feeling associated with defense mechanism of the body. Cajanus cajan Linn which is synonymous to Cajanus indicus is given different names like Red Gram. Pigeon Pea, Congo Pea and “Tur” by the local people of India.

The plant is an erect shrub which grows height of 1.5 to 3 meters with many branches. The leaves are pinnately trifoliate and the leaflets are oblong-lanceolate and entire. The species Cajanus cajan Linn belonging to family fabaceae grows widely inmost part of India. The plant is usually cultivated and the gram, a rich source of protein is widely used in India. The leaves are traditionally used as astringent, diuretic laxative, anti-inflammatory and oral ulcers^{1, 2}.

In India, the young leaves are applied to sores. Indochinese claim that powdered leaves help expel bladder stones. Salted leaf juice is taken for jaundice. Leaves are also used for toothache, mouthwash, sore gums, child-delivery, and dysentery. Scorched seed, added to coffee, are said to alleviate headache and vertigo.³The purpose of the present study is to evaluate the analgesic activity of aqueous extract of Cajanus cajan L.

MATERIALS AND METHODS:

Collection and identification of the plant material

Leaves of the plant were collected during August 2010 in Tasgaon (Sangli District). The plant was authenticated by Dr. Yadhav, Dept. of Botany, Sangli.

Animals

Albino mice (18-25 g) of either sex were used in these experiments. Animals were maintained at a temperature of 25±2°C, humidity of 55±5% and with 12 h light - dark cycle and provided with standard food and water ad libitum. All animal procedures have been approved and prior permission from the Institutional Animal Ethical Committee was obtained as per the prescribed guidelines.

Preparation of the extract:

The powdered plant material was extracted with 10% v/v chloroform water by maceration in a closed container for three days. This extract then squeezed through muslin cloth and the excess quantity of water was evaporated on water bath, evaporation was continued in shade which gave a greenish – black colored sticky residue.

Preliminary phytochemical investigation

Aqueous extract of Cajanus cajan L was investigated for phytoconstituents like sterols, glycosides, saponins, carbohydrates, alkaloids, flavonoids, tannins, proteins, triterpenoids. Phytochemical screening of the extracts was performed using the standard procedures⁴.

PHARMACOLOGICAL SCREENING

1 Writhing test

Albino mice are divided into 04 groups, each having six animals. Control received normal saline (10 ml/kg, i.p.), Indomethacin (10 mg/kg, i.p.) was used as reference drugs and Group III- IV treated with aqueous extract (200 and 400 mg/kg, p.o.), One hour after the administration of the test extract, the mice were given an intraperitoneal injection of 0.1% v/v acetic acid solution (volume of injection 0.1 ml/10 g). The mice were placed individually into glass beakers and five min were allowed to elapse. The number of writhes produced in these animals was counted for 30 min. For scoring purposes, a writhe is indicated by stretching of the abdomen with simultaneous stretching of at least one hind limb^5,6.

2. Formalin induced test in rats ⁷

Albino mice are divided into 04 groups randomly, each having six animals. Group I served as control and treated with normal saline (10 ml/kg, i.p.). Group II served as standard and received (10 mg/kg). Group III and IV treated as aqueous extract at (200 and 400 mg/kg). After one hour of treatment each animal received 0.1 ml of 1% formalin injection by sub-plantar route. After formalin injection the number of paw licking noted for 0-5 min (first phase) and then 25- 30 min (second phase) for each animal. Licking and biting of paw indicates the pain response, mean pain response and percentage inhibition was calculated by comparing with control^{8,
9, 10}.

RESULT: The results were shown in table nos. 1 to 3.

Table no. 1 Preliminary phytochemical screening of Cajanus cajan Linn. (+ Positive test, - negative test) ¹¹

Test/ Extract

Test for Steroids

Test for Cardiac Glycosides

Tests for saponin glycosides

Test for Carbohydrates

Test for Alkaloids

Test for Flavonoids

Test for Tannins

Aq. Extract of Cajnus cajan Linn

Table no. 2 Effect of of aqueous extract of Cajanus cajan Linn leaves on mice by writhing test.

Sr. no.	Treatment	Dose	No. of writhes
1	Control (Normal saline)	5ml/kg	15 ± 0.31
2	Standard (Indomethacin)	10mg/kg	02 ± 0.50
3	Aqueous extract of Cajanus cajan Linn	200mg/kg	08± 0.70
4	Aqueous extract of Cajanus cajan Linn	400mg/kg	06± 0.70

All values are mean ± SEM; Statistical analysis by one-way ANOVA followed by Dunnet’s multiple comparison test; P < 0.01; N =6.

Table no. 3. Effect of aqueous extract of Cajanus cajan leaves on formalin induced pain response in mice

Treatment	First Phase (0-5 min)		Second Phase (25-30 min)
	Mean pain response	Percentage inhibition	Mean pain response	Percentage Inhibition
Control	95.21±0.70	--	35.42±1.10	--
Standard (Indomethacin) (10 mg/kg)	14.01±0.70	85.30	7.82±0.76	77.92
Aq CC (200 mg/kg)	30.00 ±0.50	68.43	13.00 ±0.59	63.29
Aq CC (400 mg/kg)	20.00 ±0.80	78.95	11.00 ±0.72	68.94

All values are mean ± SEM; Statistical analysis by one-way ANOVA followed by Dunnet’s multiple comparison test; *P < 0.05 ; N =6.

DISCUSSION:

In conclusion, the results showed the analgesic activity of Cajanus cajan Linn leaves extract and indicated that leaves extract of Cajanus cajan preliminary screening contain glycosides, saponin, tannin, carbohydrates and the active constituents capable of relieving or modifying responses to pain. In the present study, Cajanus cajan Linn leaves significantly increased reaction time in test, suggesting its central analgesic activity. Prostaglandins and bradykinin were suggested to play an important role in the pain process^12,13.Other chemicals like histamine, acetylcholine, lactic acid, serotonin and potassium may also involve in the initiation of impulses. Therefore, it was likely that Cajanus cajan Linn leaves might suppress the formation of these substances and exerts analgesic activity in.

In conclusion, the present study demonstrated that Cajanus cajan Linn leaves have interesting analgesic activity.

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Received on 10.03.2011

Modified on 11.04.2011

Accepted on 16.04.2011

Research J. Science and Tech. 3(3): May-June. 2011: 161-163