Pharmacological studies of Clerodendron colebrookianum Walp, a potent hypotensive plant.

Clerodendron colebrookianum Walp., (Fam: Verbenaceae) locally known is "NEFAFU" is widely used for curing various diseases. Here some pharmacological properties of this plant were studied using rat & mice of either sex. Methanol extract (MLE) of various concentrations (50, 100, 200 mg/kg of body wt) were tested on animals. Carrageenin induced rat paw oedema model with three hours for oedema formation was used to test anti-inflammatory activity. It was observed that the plant extract significantly inhibits the Carrageenin induced rat paw oedema. The acetic acid induced writhing test by injecting 0.6% acetic acid (i.p.) followed by injecting MLE & tail immersion test, both in hot & cold water was used to test the analgesic effect of the plant. In all the four experiments MLE (200 mg/kg, of body wt.) has been found mostly effective in inhibiting Carrageenin induced rat paw oedema, the number of writhings induced by acetic acid & elevated pain threshold in hot & cold-water test. It reduced the number of abdominal writhing induced by acetic acid and elevated pain threshold in hot tail flick test. The effect of methanol extract (MLE) on phenobarbitone induced sleeping time was also tested, here again MLE (200 mg/kg of body wt) showed remarkable prolongation in sleeping time. Seasonal variation on the activities of the plant extract was also investigated in the study. The plant samples were collected in the months of January and July of the year. It has been observed that the January collection of the plant showed higher activities in most of the parameters in these experiments and also showed significantly higher values in the proximate analysis. The leaves of the C. colebrookianum were practically found to be non-toxic.