ABSTRACT
Chamomile is a beneficial herbal drug that is used as an anti-inflammatory, sedative and anti-allergic agent. The mechanism of action of matricaria recutita [MR], a specious of chamomile, in nociception in male and female animals is not fully understood. In this study, the sedative effect of a species of chamomile, MR, on acute pain was investigated in both male and female adult mice in the presence and absence of sex hormones. Male and female NMRI mice weighing 28 +/- 3 grams were used. Animals of each sex were divided into intact and gonadectomized groups. Intact group received saline or MR extract [10, 30, 50 mg/kg, intraperitoneally]. Gonadectomized group contained two subgroups: a] group that received saline or MR hydro alcoholic extract [50 mg/kg, I.P.], and b] group that received sex hormones [testosterone in male mice and estradiol benzoate and progesterone in female mice], both with and without MR extract [50mg/kg, IP]. The analgesia times in all groups were evaluated by hot plate test. MR increased analgesia time both in intact and gonadectomized male and female mice, but had no effect in the presence of pharmacological doses of testosterone [2 mg/kg, subcutaneous] in male mice, and estradiol benzoate [0.1 mg/kg, SC] and progesterone [0.5 mg/kg, SC] in female mice. It seems that MR can induce a pain-relieving effect with and without physiological doses of sex hormones in male and female mice, but sex hormones probably interact with its analgesic effect in their pharmacological doses