ANALGESIC, ANTI-INFLAMMATORY, ANTIPYRETIC EVALUATION OF ETHANOLIC EXTRACT OF LEAF OF POLYALTHIA LONGIFOLIA

Polyalthia longifolia leaves ethanolic extracts produced significant analgesic activity in both Hot plate and acetic acid induced writhing models in mice. In hot plate method percentage increase in reaction time was determined where as in acetic acid induced writhing model percentage decrease in writhings was determined. From the results obtained it can be concluded that Polyalthia longifolia leaves has analgesic, anti inflammatory and antipyretic activity.


Introduction
In India numerous invaluable plants are used in ethnomedical practices as well as in Ayurveda and sidha. The pharmacological properties of many such plants are not sufficiently evaluated in the light of modern science. 1 Non steroidal anti-inflammatory drugs (NSAID's) are widely used in the treatment of pain, pyrexia and inflammation. However these drugs have side effects especially on the gastro intestinal tract. 2 Through this evaluation of pharmacological activities in Polyalthia longifolia leaves for analgesic, antiinflammatory and antipyretic activity in experimental animal models was taken up.
Polyalthia longifolia (Annonaceae) is used as an antipyretic agent in indigenous system of medicine. Recently a lactone with promising antibacterial activity has been isolated from the stem. 3 The plant possesses significant analgesic, antiinflammatory and vasodepressant activities. Although this plant is used in traditional medicine to combat fever, its antipyretic effect has not been experimentally evaluated. 4 In view of the reported active constituents present in the various parts of the plant Polyalthia longifolia like alkaloids, clerodane di-terpines, quercetin, bulbocapnin, β-sitosterol, stigmasterol campesterol, enihalimane diterpenes, and sesquiterpenoids.. An attempt is made to evaluate the analgesic, antiinflammatory and antipyretic potential of the ethanolic extract of leaves of Polyalthia longifolia.

Materials, Methods
he acute toxicity study conducted for ethanolic extracts indicated that they are safe up to 2000 mg/kg body weight.
Polyalthia longifolia leaves ethanolic extracts produced significant analgesic activity in both Hot plate and acetic acid induced writhing models in mice. In hot plate method percentage increase in reaction time was determined where as in acetic acid induced writhing model percentage decrease in writhing was determined.

Collection and authentication of plant material
Leaves of Polyalthia longifolia belonging to the family opiliaceae were collected from parts of Wayanad District of Kerala. It was identified and confirmed by botanist.

Animal approval
The study was conducted after obtaining the approval from Institutional Animal Ethics Committee (IAEC), and the experimental procedure were in accordance to the guidelines of IAEC (No:688/02/c/CPCSEA). 5,6,7,8,9 The powdered leaves of Polyalthia longifolia were defatted with petroleum ether extracted with water successively by hot water reflux and continuous hot percolation method. The temperature and the duration of the extraction procedure were determined using investigational studies. An aliquot portion of the collected sample was transferred to a high grade round bottom flask and continuously refluxed for a calculated time period of three hours at a pre-determined extraction temperature of 60-70°C. Subsequently, alcohol precipitation was followed (using various concentration) and the precipitate obtained was redissolved in ethanol. The extracts were concentrated under reduced pressure and refrigerated.

Preliminary Phytochemical Studies
Preliminary phytochemical tests were performed for chemical constituents such as alkaloids, carbohydrates, glycosides, steroids, tannins, proteins and aminoacids, fixed oils and fats, flavonoids and saponins and it was found that flavonoids were present.
Evaluation of anti inflammatory activity was done by Formalin induced paw edema model, Croton oil ear edema model and carrageenan induced paw edema model respectively. In Formalin induced paw edema model mean change in paw volume and percentage protection were calculated. In croton oil ear edema model the difference between untreated ear and treated ear were determined which indicated degree of inflammatory edema. In carrageenan induced paw edema model the change in paw volume and percentage protection were calculated.

Results
Results of preliminary phytochemical screening: Thus we can conclude from above observations that ethanolic extract contain steroids, saponins, tannins, phenolic compounds and flavonoids. (Table No. 5.0)

Analgesic activity of polyalthia longifolia leaves
The ethanolic extracts of leaves of Polyalthia longifolia were evaluated for analgesic activity by hot plate and acetic acid induced writhing models, the results obtained are as follows,

Hot plate method:
The ethanolic extracts significantly and dose dependently protected the mice against thermally induced pain stimulus. All the extracts at various time intervals at which they were tested produced increase in reaction time. (Fig No.5.1).       Values are expressed as mean+SEM; number of animals used are 6 in each group; ** P <0.01, *** P<0.001 (students t test) compared with yeast control.

PLEE -Polyalthia longifolia ethanolic extract
In the present study, in the yeast control group the rise in temperature was consistent and significant in comparison to the initial values. Polyalthia longifolia ethanolic extract (PLEE 100,200,400) produced very good antipyretic effect in a dose-dependant manner and the observed effect was almost similar to that in the paracetamol-treated group.

Conclusion
From the results obtained it can be concluded that Polyalthia longifolia leaves has analgesic, anti inflammatory and antipyretic activity.