Antinociceptive properties of extracts and two flavonoids isolated from leaves of Danae racemosa.

Abstract

The antinociceptive properties of the hydro-methanolic extract (HME) and two flavonoids isolated from Danae racemosa have been investigated in several nociceptive rat models. The HME from D. racemosa (100-400 mgkg(-1), i.p.) produced significant dose-related inhibition of acetic acid-induced abdominal constriction. In the same dose range, the HME produced dose-related inhibition in both phases of a formalin-test. Treatment of animals with naloxone (5 mgkg(-1), i.p.) completely reversed the antinociceptive effect caused by morphine (5 mgkg(-1), s.c.) and the HME (200 mgkg(-1), i.p.) when assessed against the first phase of the formalin-test, but this effect was less significant for the HME in the second phase. Furthermore, when assessed via a hot-plate test, the HME (100-400 mgkg(-1), i.p.) caused a significant increase in response latency. The HME, given daily for to 7 consecutive days, develop tolerance, but did not induce cross-tolerance to morphine. These data demonstrate that the HME elicites pronounced antinociception against several pain models. The actions of the HME involve, at least in part, an interaction with the opioid system, but does not seem to be related with non-specific peripheral or central depressant actions. Finally, the active principle(s) responsible for the antinociceptive action of D. racemosa is likely to be partially related to the presence of quercetin and kaempferol.