Antiinflammatory screening of the medicinal plant Gynura procumbens

Gynura procumbens isused in Thai folk medicine to treat topicalinflammation, rheumatism, and viral ailments. In thepresent work, attempts were made to verify the folkmedicinal claim that the crude ethanolic extract ofG. procumbens has antinflammatory action and torelate the activity to particular fractions using acroton oil-induced mouse ear inflammation model. Theoriginal ethanolic extract of G. procumbens waspartitioned between water and ethyl acetate. Theresidues were subjected to antinflammatoryevaluation. While the water extract did not show anyantinflammatory activity, the administration of theoriginal organic extract significantly inhibited theincrease in ear thickness in response to crotonoil (n = 5). The activity of 0.75 mg/ear originalorganic extract showed similar antinflammatoryactivity (inhibition 65.2%) to that of 6 mg/earhydrocortisone 21-hemisuccinate sodium salt(inhibition 64.8%). The organic extract was thenfractionated with a series of solvents in order ofincreasing polarity. Each fraction was dried,dissolved in acetone and monitored using the samebioassay. These experiments showed that the hexaneand toluene fractions showed significant inhibitionsof 44.6% and 34.8%, respectively. These twofractions had similar activities to 4 mg/ear ofhydrocortisone (inhibition 35.0%). The possiblechemical constituents in the extracts and fractionswere investigated using thin layer chromatography andspecific color reagents. These tests showed thatsteroids might be one class of antinflammatorycompounds in this plant.