The triterpene mixture, a - and h -amyrin, isolated from Protium heptaphyllum resin was evaluated on capsaicin- evoked nociception in mice. Orally administered a - and h -amyrin (3 to 100 mg/kg) significantly suppressed the nociceptive behaviors—evoked by either subplantar (1.6 A g) or intracolonic (149 A g) application of capsaicin. The antinociception produced by a - and h -amyrin against subplantar capsaicin...