Anti inflammatory activity of Andrographis serpyllifolia root extract in experimental animals

The ethanolic extract of Andrographis Serpyllifolia root has been evaluated for anti-inflammatory activity against Oedema produced by carrageenan and histamine. The effect was compared with the activity of diclofenac sodium against the two types of inflammation. The ethanolic extract at doses of 50mg, 100 and 200mg/kg exhibited significant (P<0.001) anti inflammatory activity in inflammatory models. At 200mg/kg the ethanolic extract showed maximum inhibition of 38-95% in carrageenan-induced rat paw oedema while the standard diclofenac sodium inhibited 57-80% after 3 hr of carrageenan injection. The ethanolic extract (50,100, and 200mg/kg) significantly (P< 0.001) at dose dependent inhibited histamine induced rat paw oedema. The results obtained suggest marked anti inflammatory activity of the extract at the dose levels examined.

authenticated by Prof. G. Shiva Murthy of Botany department, Manasa Gangothri University Mysore.The root of the plant was removed, dried under shade and powdered in a mechanical grinder.The root powder was extracted with ethanol and the ethanolic extract was 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 50, 100 and 200 mg/kg was suspended in 1% (w/v) of aqueous carboxymethyl cellulose for administration to animals.

Phytochemical Study of the extract
Phytochemical screening was carried out to ascertain the qualitative chemical composition of Andrographis Serpyllifolia.The extract tested positive for terpenes, sterols, phenols, flavanoids and carbohydrates.

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 carrageenan 2 .
The ethanolic extract of Andrographis Serpyllifolia (50,100 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 injection³.Different groups of animals were pretreated with ethanolic extract (50,100 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 Lin 4 (1999).

RESULTS AND DISCUSSION
The ethanolic extract at doses 50,100 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 38.95% in carrageenan induced rat paw oedema where as diclofenac sodium produced 57.80% of inhibition after 3hr of carrageenan injection Table 1.The ethanolic extract (50,100 and 200mg/ kg) significantly (P<0.001) and dose dependently inhibited histamine induced rat paw oedema 38.76% respectively and this was compared with the activity produced by diclofenac sodium.Inflammation is the response of living tissues to injury.It involves a complex array of enzyme activation, mediator release, extravasations of fluid, cell migration, tissue break down and repair.It is also known that anti inflammatory effects can be elicited by variety of chemical agents and that there is little correlation between the pharmacological activity and chemical structure 5 .This associated with the complexity of the inflammatory process, makes the use of different experimental models essential when conducting pharmacological trials.The present study establishes the anti inflammatory activity of the ethanolic extract of Andrographis serpyllifolia in number of experimental rat models.This study demonstrates the efficacy of Andrographis serpyllifolia as an anti inflammatory agent and also justifies the use of the plant as an anti inflammatory agent in folk medicine.