Introduction:

Gymnema Sylvestre is a herb native to the tropical forest of southern  and central India where it has been used as a naturopathic treatment for diabetes for nearly two millennia. The plant Gymnema sylvestre is familiar as madhunashini and commonly known as gurmar in Hindi. It is an important medicinal climber belonging to the James Asclepiadaceae. The plant is extremely used in Indian system of medicine for the treatment of various ailments like rheumatism, cough, ulcers etc. It is also useful in inflammation, dyspepsia, constipation and jaundice. Roots have been used as a remedy for snake bite in native medicine. Leaves of Gymnema Sylvestre are active against glycosuria and many other disorders^1,2 . The active ingredient is thought to be gymnemic acid which as the structure similar to saccharose. Extracts of  Gymnema Sylvestre is not only claimed to curb the sweet tooths but also for treatment of hyperglycemia, according to the

Materials and Methods

Collection and extraction of root

The plant was collected in Tanjavur and was authenticated by Prof. G. Shiva Murthy of Botany department, Manasa Gangothri University Mysore. The root was removed, and dried under shade and powdered in a mechanical grinder. The root powder was extracted with ethanol and the ethanolic extract is used for pharmacological studies. All chemicals and reagents used for the study are of analytical grade.

Preparation of the extract

The powdered roots were extracted with ethanol at room temperature for 72 hrs. The extract was prepared using suitable solvent system by continuous extraction in a soxhelator and the extract was concentrated under reduced pressure at 50-55°C. The extract obtained  100, 150 and 200 mg/kg was suspended in 1% (w/v) of aqueous carboxymethyl cellulose for administration to animals.

Experimental animals:

Albino wistar rats (160-200g) of either sex were used for experimental study. The animals were procured from National Institute of Nutrition, Hyderabad. The animals were housed in cages and are provided with light. All the animals were acclimatised to laboratory environment for 1 week to 10 days before the experiment. They were provided with free access to food (Supplied by Natural Institute of Nutrition Hyderabad) and water ad libitum.

Carrageenan Induced rat paw Oedema

Oedema was induced by sub plantar injection of 0.1 ml of 1% freshly prepared suspension of λ-carrageenan (Supplied by Tablets India, Chennai). The paw volume was measured using a plethysometer before 0 and 3 hr after the injection of carrageenan³.

The ethanolic extract of Gymnema Sylvestre (100, 150 and 200 mg/kg) and diclofenac sodium 25mg/kg were orally administered to different groups of rats. All the treatments were given orally 1 hr. prior to the injection of carrageenan.

Histamine Induced rat paw Oedema

The paw oedema was produced by sub plantar administration of 0.1 ml of a 0.1% freshly prepared solution of histamine in to the right hand paw of rats. The paw volume was recorded before 0 and 1 hr after histamine injection^4. Different groups of animals were pretreated with ethanolic extract (100, 150 and 200mg/kg) and with 5 ml/kg of 1% w/v carboxymethylcellulose and diclofenac sodium 25mg/kg standard drug. The doses were administered orally 1 hr before eliciting paw oedema. The percentage inhibition of oedema was calculated for all above models as described by T Sai and Lin⁵ (1999). 

Table 1: Effect of ethanolic extract of Gymnema Sylvestre on carrageenan induced rat paw oedema.

Each value represent the mean  ± SEM  n = 6

p<0.001

Table 2: Effect of ethanolic extract of Gymnema Sylvestre on histamine induced rat  paw oedema.

Each value represent the mean  ± SEM  n = 6

a.p<0.001

Results and Discussion

The ethanolic extract at doses 100, 150 and 200mg/kg exhibited significant (P<0.001) anti inflammatory activity in all the animal models. The ethanolic extract (200mg/kg) exhibited maximum inhibition of 39.75% in carrageenan induced rat paw oedema where as diclofenac sodium produced 52.19% of inhibition after 3hr of carrageenan injection (Table 1). The ethanolic extract (100, 150 and 200mg/kg) significantly (P<0.001) inhibited histamine induced rat paw oedema. Surprisingly with (150 & 200mg/kg) the inhibition activity found to be very encouraging percentage inhibition are 37.33% & 41.08% respectively.

The present study establishes the anti inflammatory activity of the ethanolic extract of Gymnema Sylvestre in number of experimental rat models. This study demonstrates the efficacy of Gymnema Sylvestre as an anti inflammatory agent and also justifies the use of the plant as an anti inflammatory agent in folk medicine.

Acknowledgements

The authors wish to thank vice-president Tablets India Ltd for providing standard reference drug samples and lyla impex vijayawada for providing facilities to carry out the work.

References

1. K.M. Nadkarni, A.K. Nadkarni and R.N. Chopra, Indian Material Medica, Bombay, Popular Prakashan Pvt. Ltd., (1967)p. 474.
2. K.R. Kirtikar, B.D. Vasu, B. Singh and M. Singh (Editors), 2^nd Ed. Indian Medicinal Plants Vol. 3 Dehradun India, jayyed Press (1975).
3. GunaKunru.A, Padmanabhan.K, Thirumal.P, Vengatesan.N, Gnan Sekhar.N, Raja.S, Raja rajan.A.T, Vijay Kumar.S.G. 2004 Chemical Investigation and anti inflammatory activity of fixed oil of Butea monosperma seeds. Natural Products Science10, 55-58.
4. Parmar nN.S., Ghosh.M.N 1978 anti inflammatory activity of gossypin a bioflavonoid isolated from Hibiscus vitifolius Linn. India Journal of Pharmacology 10, 277-293.
5. Tsai.C.C, Lin, C.C 1999Anti Inflammatory effects of Taiwan folk medicine ‘Teng-Khia-U’ on Carrageenan and adjuvant Induced paw oedema in rats. Journal of Ethnopharmacology 64,85-89.