INTRODUCTION:

Sesamum indicum Linn. (Pedaliaceae) is an annual shrub with white bell-shaped flowers with a hint of blue, red or yellow with branches or without branches. It is grown for the production of seeds which is rich in oil content. It comes in a variety of colors, cream-white to charcoal-black. In general, the paler varieties of sesame seem to be more valued in West and Middle East, while the black varieties are prized in the Far East. It is commonly known as til (Hindi), hu ma (Chinese), sesame (French), goma (Japanese), gergelim (Portuguese) and ajonjolí (Spanish). Sesame is found in tropical, subtropical, and southern temperate areas of the world, particularly in India, China, South America and Africa. It has utmost economical importance and is primarily grown by small farmers in developing countries. The plant grows best in tropical climates (spring to fall). Sesame grows best in sandy well drained soil with hot climate and moderate rainfall¹. Sesame and its components serve as viable natural sources of antioxidants for food and non-food applications². The antioxidant and free radical scavenging activities of sesamol using a nanosecond pulse radiolysis technique have been reported by several scientists^3,4. Externally it is used to treat hemorrhoids and ulcers⁵. The seed are rich in high calories so overweight peoples should use them very cautiously⁶.The oil is laxative and also promotes menstruation⁷.

MATERIALS AND METHODS:

Plant material:

The leave of Sesamum indicum Linn. (Family- Pedaliaceae) were collected in the botanical garden of National Botanical Research Institute, Lucknow in September 2010. The plant material was identified and authenticated taxonomically at National Botanical Research Institute, Lucknow, India.

Preparation of extract:

The fresh leaves of Sesamum indicum were washed with distilled water to remove dirt and soil, and were shade dried. The dried materials were pulverized and passed through a 10-mesh sieve. The coarsely powdered material was extracted thrice with ethanol (50% v/v). The extracts were filtered and concentrated at reduced temperature (-5^oC) on rotary evaporator (Buchi, USA) and then freeze-dried (freezone^@4.5, Labconco, USA) under high vacuum (133X10^-3m Bar) at temperature of -40±2^oC. The drug extract was suspended in doubly distilled water containing carboxymethyl cellulose (CMC 1% m/v). Standard orogastric cannula was used for oral drug administration.

Animal:

Albino mice (18-24g) of either sex were purchased from the animal house of the Central Drug Research Institute, Lucknow. They were kept in departmental animal house in well cross-ventilated room at 27±2^oC, and relative humidity 44-56%, light and dark cycles of 10 and 14^th respectively, for one week before and during the experiments. Animals were providing with standard rodent pellet diet (Amrut, India) and the food was withdrawn 24hr before the experiment but water was allowed ad libitum.

Strychnine nitrate induced seizure:

Mice of either sex were randomly allotted to the different control and test groups. The control mice were administered with SN (2.5 mg/kg, i.m.)⁸, 30 min after normal saline (10 ml/kg, p.o.). The positive control group of mice received SN (2.5 mg/kg, i.m.) 15 min after phenobarbitone sodium (40 mg/kg, i.p.). Graded doses (100, 200 and 400 mg/kg, p.o) of ESI were given to the test groups 30 min before administration of strychnine nitrate (2.5 mg/kg, i.m.). Onset to forelimb clonic and tonic seizures was recorded. Mice that did not convulse 30 min administration were considered protected⁹.

Pentylenetetrazole (PTZ) - induced seizures:

Mice of either sex were randomly allotted to the different control and test groups. The control mice were administered with PTZ (70 mg/kg, i.p.)¹⁰ 30 min after normal saline (10 ml/kg, p.o.) The positive control group of mice received PTZ (70 mg/kg, s.c). 15 min after phenobarbitone sod. (40 mg/kg, i.p.). Grade doses (100, 200 or 400 mg/kg, p.o.) of extract were given to the test groups 30 min before administration of PTZ (70 mg/kg, i.p.). Onset to forelimb clonic and tonic as well as hind limb extension (tonic convulsion) was recorded. The onset and number of death after showing tonic hind limb extension were also recorded. Mice that did not convulse 30 min after pentylenetetrazole administered were considered protected¹¹.

Test for anticonvulsant potency (MES model):

Electro-convulsive shock, including Hind Limb Tonic Extension (HLTE) in 99% of the animal¹² was previously determined by a current-percent effect curve¹³. The electrical stimulus (50 mA, 50Hz, 1sec duration) was applied through ear-clip electrodes using a stimulator apparatus (MGH-777, Iran) 9 group of 12 mice each pretreated i.p., with the ESI extract (100, 150, 200, 250, 300, and 350 mg/kg), phenytoin (25 mg/kg, as positive control), saline (10 ml/kg, as control) and Tween preparation (10 ml/kg, as control) as received the transauricular electroshock.

The time of the peak effect of phenytoin (30 min after administration) was previously established ¹⁴. The time for the extract to reach its maximum effect was determined as 30 min after i.p. injection. The criterion for the anticonvulsant effect was abolition of HLTE within 10 sec after delivery of the electroshock

Statistical analysis:

Results are presented as mean ± S.E.M. Statistical significance between the groups was analyzed by means of an analysis of variance followed by Dunnett^’s multiple comparison test.

P values less than 0.05 were considered significant.

RESULT AND DISCUSSIONS:

TABLE-1: Effect of ESI ethanol Extract on Tonic Seizure by Strychnine Induce Seizure

TREATMENT AND DOSE	SEIZURE ONSET ± S.E.M(min)
TREATMENT AND DOSE	Clonic	Tonic
Control NS(10ml/kg, p.o)	3.1±0.2	4.1±0.3
ESI (100 mg/kg, p.o.)	6.0±0.3	7.7±0.3
ESI (200 mg/kg, p.o.)	13.5±0.2	14.9±0.2
ESI (400 mg/kg, p.o.)	NC	NC
Phenobarbitone (40 mg/kg, i.p.)	NC	NC

Values are means ±S.E.M. NS: normal saline ESI: 50% Ethanol extract of Sesamum indicum leaves NC: No convulsion, Significant P<0.05 compared to control, ANOVA; N=6

TABLE-2: Effect of ESI Ethanol Extract on Tonic Seizure Induced By Pentylenetetrazole in Mice

TREATMENT AND DOSE	SEIZURE ON SET ±S.E.M (min)		MORTALITY FRACTION
TREATMENT AND DOSE	Clonic	Tonic	MORTALITY FRACTION
Control NS (10 mg/kg,p.o)	3.5±0.3	7.3±0.7	7/7
ESI (100 mg/kg,p.o.)	3.7±0.2	7.2±0.6	7/7
ESI (200 mg/kg,p.o)	3.8±0.2	7.4±0.8	4/7^•
ESI (400 mg/kg, p.o.)	3.7±0.5	7.9±1.1	0/7^•
Phenobarbitone(40 mg/kg,i.p.)	23±2.3^•	NC	0/7^•

Values are mean ±S.E.M. NS: Normal saline, ESI: 50% Ethanol extract of Sesamum indicum leaves NC: No convulsion, Significant p<0.05 compared to control, ANOVA; n=7

TABLE-3: Effect of Sesamum Indicum Leaves Ethanol Extract on Tonic Seizure Induced By Maximal Electroshock in Mice

TREATMENT	DOSE	CONVULSIOIN
Saline	10 ml/kg	100
Tween80 (5%v/v)	10 ml/kg	100
Phenytoin	25 mg/kg	0^••
S. indicum	100 mg/kg	91.6
S.indicum	150 mg/kg	80
S indicum	200 mg/kg	55^•
S.indicum	250 mg/kg	55^•
S.indicum	300 mg/kg	10^••
S.indicum	350 mg/kg	0^••

Data represent percentage of tonic seizure (n=12-20) ^•p<0.05 and ^••p<0.001 compared to values

In the present study we have evaluated the effect of the leaves extract of sesamum indicum on seizure induced by strychnine nitrate in table 1

At 100 and 200 mg/kg, ESI produced significant (p<0.05) prolongation of both clonic and tonic seizure latencies, and at 400 mg/kg, complete protection against strychnine nitrate seizure were found.

Strychnine nitrate has been demonstrated to be by directly antagonizing the inhibitory spinal cord and brain stem reflexes of glycine and thus increasing spinal reflexes¹⁵.

In the PTZ Model, however, ESI did not increase onset to either clonic or tonic seizure, but at higher doses of 200 and 400 mg/kg like phenobarbitone sodium (table 2), it produces dose-related significant reduction in incidences of mortality following tonic hind limb tonus. Inability of ESI to inhibit clonic seizure in the PTZ (test) suggests that it may not have the ability to raise seizure threshold.

Essentially, the effectiveness of a drug against PTZ seizure indicates its probable effectiveness against absence seizure. PTZ has been reported to inhibit chloride conductance by binding to picrotoxin sites of GABA_A receptor complex. Based on this partial effectiveness. It is difficult to report ESI having anticonvulsant effect against PTZ seizure; however, ability to reduce mortality after seizure might suggest some potential usefulness of drug against neurotoxicity which normally causes death following extensive seizure by chemicals.

Based on the results, it is therefore probable that the 50% ethanol extract of Sesamum indicum leaves has considerable anticonvulsant action that might involve both GABAergic and glycinergic inhibitory mechanism.

In the present study we have evaluated the effect of the leaves extract of sesamum indicum on seizure induced by MES in mice is indicated in table 3.

It has often been stated that antiepileptic drugs that block MES induced tonic extension act by blocking seizure spread. Moreover, MES-induced tonic extension can be prevented either by drug that inhibit voltage-dependent Na⁺ channels, such as phenytoin valproate, felbamate and lamotrigine.

ACKNOWLEDGEMENT:

The plant material was identified and authenticated taxonomically at National Botanical Research Institute, Lucknow, India. Sesamum indicum Linn. (Pedaliaceae)

REFERENCES:

1. Hu, Y.M., Ye, W.C., Yin, Z.Q., Zhao, S.X.: 2007 Acta Pharmaceutica Sinica., 42:3: 286-291.

2. Shahidi, F., Chandrika, M., Liyana-Pathirana, Dana S.W.: Food Chemistry. 99: 3: 478-483.

3. Joshi, R., Kumar, M.S., Satyamoorthy, K., Unnikrisnan, M.K., Mukherjee, T.: 2006 J 2005 Agricultural and Food Chemistry. 53:7:2696-2703.

4. Juan, Xu., Chen, S., Qiuhui, Hu.: 2005 Food Chemistry , 91:1:79-83.

5. Chopra, R.N., Nayar, S. L., Chopra, I. C. 1986:Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi.

6. Uzun, B., Arslan, C., karhan, M., Toker, C.: Food Chemistry., 2007 102:1: 45-49.

7. Grieve, A Modern Herbal. Penguin (1984).

8. Ngo Bum, E., Dawack, D. L., Schmutz, M., Rakotonirina, a., Rakkotonirina, S.V., Portet, C., Jeker. A., Olpe, H.R., Herrling, P.: 2004Anticonvulsant activity of Mimosa pudica decoction. Fitoterapia 75: 309-314.

9. Yemitan, o.k., Ajibade, A.M., Adeyemi, O.O., Anticonvulsant activity of Dalbergia saxatilis. Nigerian Journal of Neuroscience 4 33-40. (2001).

10. Achliya, G.S., Wadodkar, S.G., Dorle, A.K., Evaluation of sedative and anticonvulsant activites of Unmadnashak ghrita, 2004: Jounaral of Ethnopharmacology 94: 77-83.

11. Olufunmilayo, O. A., Omoniyi, K.Y., Olayemi, O.A, journal of Ethopharmacology 2007 113. 111-114.

12. Swinyard. E.A., 1969. Laboratory evaluation of antiepileptic drugs. Review of laboratory method. Epilepsia 10, 107-119.

13. Litchfield, S.T., Wilcoxon, F.A., 1949 A Simplified Method Of evaluation dose-effect experimental Therepeutics 96, 99-105.

14. Pourgholami, M.H., 1995 Kamalinejad, M., Javadi, M., Majzoob, S., Sayyah, M., 1999. Evaluation of the anticonvulsant activity of the essential oil of Eugenia caryophyllata in male mice. Journal of ethnopharmacology 64, 167-171.

15. Rang, H.P., Dale, M.M., Ritter, J.M., (Eds.). 2000: pharmacology, 4^th ed. Churchill Livingstone, 606-613.

Received on 14.07.2011 Modified on 10.08.2011

Research J. Pharm. and Tech. 4(12): Dec. 2011; Page 1822-1824