Phytochemical screening, safety evaluation, anti-inflammatory and analgesic studies of the leaf extracts of Sterculia tragacantha.

BACKGROUND

Sterculia tragacantha (Sterculiaceae) is used in the treatment of boils, diarrhea, dyspepsia, fever, gonorrhea, snake bite, syphilis, and tapeworm in some West African nations. This study is to investigate its anti-inflammatory and analgesic activities since the plant is being used to treat fever.

METHODS

Fresh leaves of the plant were collected and dried at room temperature and pulverized into powder form and 200 g of this powder was dissolved first in hexane for 72 h and the extract was filtered and the filtrate was concentrated while the substrate was further dissolved in chloroform, ethyl acetate and methanol at different times and similar procedure adopted as for the hexane. The organic solvents were used based on order of increasing polarity. Graded concentrations of the solvent extracts were prepared and used for the study. Pilot toxicity test was carried out to determine safety dose using hematology and serum chemistry as indices of toxicity. Thereafter anti-inflammatory and analgesic studies were conducted using standard tests such as carrageenan, histamine-induced-edema, tail flick test and acetic writhing test. Phytochemical screening of the plant was also conducted.

RESULTS

Phytochemical screening of the powdered material showed that alkaloid, flavonoid and reducing sugar were present while tannin, cardiac glycosides, saponins and anthraquinones were absent. Pilot toxicity test using aqueous extract at 100 mg/mL concentration showed that no mortality was recorded although the animals that received 3,000 mg/kg dose exhibited slight dullness after 48 h. No significant changes were also observed for the packed cell volume, hemoglobin, white blood cell counts, platelet counts, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, blood urea nitrogen, albumin, globulin except for the 200 and 3,000 mg/kg doses that caused significant increase in the level of total protein. The n-hexane, chloroform, ethyl acetate, and methanol extracts of S. tragacantha and indomethacin produced significant (p<0.05) inhibition of paw edema compared with the control using histamine and carrageenan methods of paw edema induction. There was significant (p<0.05) reduction in writhing movements at 100 mg/kg and 200 mg/kg of n-hexane, chloroform, and ethyl acetate leaf extracts of S. tragacantha and indomethacin (10 mg/kg) when compared to the control. This effect using tail flick test was not as effective when compared to the writhing test.

CONCLUSIONS

The different leaf extracts of S. tragacantha exhibited anti-inflammatory and analgesic properties and they are also safe for medicinal use.