Anticonvulsant effect of Ficus religiosa: Role of serotonergic pathways
Introduction
Ficus Linn being the largest genus of the family Moraceae comprises about 755 fig tree species worldwide (Van Noort et al., 2007). According to the reports of traditional healers, ficus species like Ficus schimperiana and Ficus sycomorus has been used for the treatment of epilepsy from ancient time (Mainen et al., 2005). Ficus sycomorus had shown anticonvulsant and sedative activity in animal models (Umar et al., 2003).
Ficus religiosa (Moraceae) commonly known as Bodhi tree is regarded as a sacred tree to both Hindus as well as Buddhists; it is used for medicinal as well as religious purposes in India (Kala et al., 2006). Ficus religiosa is reported to have numerous therapeutic uses in folk medicine viz.: leaf juice has been used for the treatment of asthma, cough, sexual disorders, diarrhea, haematuria, ear-ache and toothache, migraine, eye troubles, gastric problems and scabies; leaf decoction has been used as an analgesic for toothache; fruits for the treatment of asthma, other respiratory disorders and scabies; stem bark is used in gonorrhea, bleeding, paralysis, diabetes, diarrhea, bone fracture, antiseptic, astringent and antidote (Ripu and Rainer, 2006). In Ayurveda it is claimed that Ficus religiosa possesses anticonvulsant activity (Vyawahare et al., 2007). Many such reports had been validated pharmacologically for its actions on CNS viz.: different parts of Ficus religiosa showed acetyl cholinesterase inhibitory activity (Vinutha et al., 2007) and antianxiety activity (Ratnasooriya et al., 1998). Figs (fruits) of this plant contain numerous amino acids like asparagine and tyrosine in fruit edible part, alanine, threonine, tyrosine, and valine in seeds, alanine and valine in proteins (Ali and Qadry, 1987). Apart from amino acids figs of this plant has been reported to contain highest amount of serotonin (5-HT) as compare to figs of other Ficus species (Bliebtrau, 1968) and serotonergic neurotransmission is known to modulate a wide variety of experimentally induced seizures and is involved in seizure protection in various animal models of epilepsy by altering various GABAergic and glutamatergic functions (Bagdy et al., 2007). Reports, demonstrating the use of Ficus religiosa in ethnomedical treatment of epilepsy and presence of high serotonin content in its figs led us to hypothesize that figs of Ficus religiosa may possess anticonvulsant properties via modulating brain serotonin levels, which will be of clinical usefulness.
Hence, the present study was undertaken to investigate the anticonvulsant activity of methanolic extract of Ficus religiosa figs.
Section snippets
Plant material and preparation of extract
Ficus religiosa figs were collected from Botanical Garden of Guru Nanak Dev University, Amritsar, Punjab. The botanical identity of the plant material was verified and specimens were deposited at the Herbarium, Department of Botany, Punjabi University, Patiala, Punjab, for reference (vouchered no. 49371). Authenticated figs were washed with water, shade-dried, ground to a moderately coarse powder. The powdered figs were subjected to extraction by refluxing with 70% methanol (1:10, w/v) in a
Results
The optimal UV spectrum for serotonin detection was calibrated at 277 nm. The HPLC chromatogram of standard serotonin solution showed an absorption peak with a retention time of 12.563 min (Fig. 1). A similar peak was observed in the HPLC chromatogram of Ficus religiosa extract at same retention time indicating the presence of serotonin in the extract (Fig. 2).
In acute toxicity test no mortality was observed in animals treated with the extract at all doses (25, 50, 100, 250, 500 and 1000 mg/kg).
Discussion
Most of conventional antiepileptic drugs are associated with many side effects such as neurotoxic effects, cognitive deficits and teratogenic effects, which decrease their clinical utility (Trimble, 1987, Yerby, 1988, Meador et al., 1990). Recently, the search for novel pharmacotherapy from medicinal plants for neurological and psychiatric diseases has progressed significantly owing to their less side effects and better tolerability (Zhang, 2004). In the present study the anticonvulsant
Conclusions
Ficus religiosa extract increased the threshold of MES and picrotoxin induced convulsions with no neurotoxic effects, in a dose dependent manner. Inhibition of antiepileptic effect of extract with cyproheptadine pretreatment showed that the extract might be mediating its effect via modulating serotonin dependent GABAergic and/or glutamatergic neurotransmission. However, further research is warranted to determine the specific mode of its anticonvulsant activity.
References (26)
- et al.
Which animal models should be used in the search for new antiepileptic drugs? A proposal based on experimental and clinical considerations
Epilepsy Research
(1988) Depressants of the central nervous system
- et al.
New records of Ficus (Moraceae) species emphasize the conservation significance of inselbergs in Mozambique
South African Journal of Botany
(2007) - et al.
Screening of selected Indian medicinal plants for acetylcholinesterase inhibitory activity
Journal of Ethnopharmacology
(2007) Therapeutic effects of herbal extracts and constituents in animal models of psychiatric disorders
Life Sciences
(2004)- et al.
Amino acid composition of fruits and seeds of medicinal plants
Journal of the Indian Chemical Society
(1987) - et al.
Serotonin and epilepsy
Journal of Neurochemistry
(2007) The Parable of the Beast
(1968)- et al.
Neurochemical correlates of antiepileptic drugs in the genetically epilepsy prone rat (GEPR)
Life Sciences
(1996) - et al.
Identification of oxalic acid and tartaric acid as major persistent pain-inducing toxins in the stinging hairs of the Nettle, Urtica thunbergiana
Annals of Botany
(2006)