The antinociceptive effects of a standardized ethanol extract of the Bidens odorata Cav (Asteraceae) leaves are mediated by ATP-sensitive K + channels.

ETHNOPHARMACOLOGICAL RELEVANCE: Bidens odorata Cav (Asteraceae) is used for the empirical treatment of inflammation and pain.

AIM OF THE STUDY: This work evaluated the in vitro and in vivo toxicity, antioxidant activity, as well as the anti-inflammatory and antinociceptive effects of an ethanol extract from Bidens odorata leaves (BOE).

MATERIALS AND METHODS: The in vitro toxicity of BOE (10-1000µg/ml) was evaluated with the comet assay in PBMC. The in vivo acute toxicity of BOE (500-5000mg/kg) and the effect of BOE (10-1000µg/ml) on the level of ROS in PBMC were determined. The in vivo anti-inflammatory activity of BOE was assessed using the TPA-induced ear edema in mice. The antinociceptive activities of BOE (50-200mg/kg p.o.) were assessed using the acetic acid and formalin tests. The antinociceptive mechanism of BOE was determined using naloxone and glibenclamide.

RESULTS: BOE lacked DNA damage, and showed low in vivo toxicity (LD50 > 5000mg/kg p.o.). BOE inhibited ROS production (IC50 = 252.13 ± 20.54µg/ml), and decreased inflammation by 36.1 ± 3.66%. In both antinociceptive test, BOE (200mg/kg) exerted activity with similar activity than the reference drugs.

CONCLUSION: B. odorata exerts low in vitro and in vivo toxicity, antioxidant effects, moderate in vivo anti-inflammatory activity, and antinociceptive effects mediated by ATP-sensitive K+ channels.