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

ABSTRACT

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.