Abstract
Lyophilised aqueous extract of Euphorbia hirta L. (Euphorbiaceae) has been evaluated for analgesic, antipyretic and anti-inflammatory
properties in mice and rats, in order to complete its activity profile, after the
confirmation of the existence of a central depressant activity particularly expressed
by a strong sedative effect, associated with anxiolytic effects. This study leads
us to the conclusion that this plant extract exerts central analgesic properties.
Such a dose-dependent action was obtained against chemical (writhing test) and thermic
(hot plate test) stimuli, respectively, from the doses of 20 and 25 mg/kg and it was
inhibited by a naloxone pretreatment, a specific morphinic antagonist compound. An
antipyretic activity was obtained at the sedative doses of 100 and 400 mg/kg, on the
yeast-induced hyperthermia.
Finally, significant and dose-dependent anti-inflammatory effects were observed on
an acute inflammatory process (carrageenan-induced edema test in rats) from the dose
of 100 mg/kg. On the other hand, plant extract remained inactive on chronic processes
such as Freund's adjuvant-induced rheumatoid arthritis, after a chronic treatment
during fourteen days at the daily dose of 200 or 400 mg/kg; however, if inefficacy
was observed on rat backpaws edema and on loss of weight, the aqueous extract reduced
the inflammatory hyperalgia.
Key words
Euphorbia hirta
- central analgesics - antipyretics - anti-inflammatory compounds
