Antinociceptive Effects of an Extract of Securigera securidaca and Their Mechanisms in Mice

We examined the effects of an aqueous extract from seeds of Securigera securidaca L. (S. s.), a plant used in folk medicine, on experimentally induced pain in balb-c mice. The tail-flick test (somatic pain evoked by thermonociceptive stimulation) and writhing test (visceral pain after i.p. injections of acetic acid) were used. Three doses of the extract (85, 170, 340 mg of dry substance per 1 kg body mass) were i.p. injected before the tests. Significant antinociception effects were observed in both tests; a dose of 170 mg/kg appeared to be optimum. Antinociceptive effects of the S. s. extract were comparable with those of 1 mg/kg morphine. Naloxone, metoclopramide, ondancetron, and scopolamine (antagonists of opioid, dopamine, serotonin, and cholinergic receptors, respectively) completely eliminated antinociceptive effects of the S. s. extract in the tail-flick test; the effects of these antagonists were not so clear in the writhing test. The mechanisms of analgesic actions of the S. s. extract are discussed; the respective effects are probably related (at least partly) to the presence of flavonoids in this extract. Further investigations are necessary for adequate interpretation of the above mechanisms.