Polymethoxyflavones from Nicotiana plumbaginifolia (Solanaceae) exert antinociceptive and neuropharmacological effects in mice

Polymethoxylavones (PMFs) are known to exhibit significant anti-inflammatoryand neuroprotective properties. Nicotiana plumbaginifolia, an annual Bangladeshiherb, is rich in polymethoxyflavones that possess significant analgesic andanxiolytic activities. The present study aimed to determine the antinociceptive andneuropharmacological activities of polyoxygenated flavonoids namely- 3,3′,5,6,7,8-hexamethoxy-4′,5′-methylenedioxyflavone (1), 3,3′,4′,5′,5,6,7,8-octamethoxyflavone(exoticin) (2), 6,7,4′,5′-dimethylenedioxy-3,5,3′-trimethoxyflavone (3), and 3,3′,4′,5,5′,8-hexamethoxy-6,7-methylenedioxyflavone (4), isolated and identified fromN. plumbaginifolia. Antinociceptive activity was assessed using the acetic-acid inducedwrithing, hot plate, tail immersion, formalin and carrageenan-induced paw edematests, whereas neuropharmacological effects were evaluated in the hole cross, openfield and elevated plus maze test. Oral treatment of compounds 1, 3, and 4 (12.5–25mg/kg b.w.) exhibited dose-dependent and significant (p p N. Plumbaginifolia couldbe considered as suitable candidates for the development of analgesic and anxiolyticagents