Antinociceptive effect and toxicological study of the aqueous bark extract of Barringtonia racemosa on rats.

Barringtonia racemosa Linn. (Family Lecythidaceae) possess several bioactivities and is used in traditional medicine of Sri Lanka, but its analgesic potential has not been investigated so far. The aim of this study was therefore to examine the antinociceptive potential of an aqueous bark extract (500, 750, 1000 or 1500 mg/kg) of B. racemosa in male rats using three models of nociception (tail flick, hot plate and formalin tests). The results showed that the extract has antinociceptive activity (when evaluated in hot plate and formalin test but not in tail flick test) without producing unwanted side effects or toxicity. Further, the extract did not alter fertility, gestational length, peri- and neonatal development and appears to be non-teratogenic. The antinociceptive effect was mediated mainly via opioid mechanisms. Such inhibition of pain could arise from phenolic and steroidal constituents as was shown to be present in the extract.