effect of aqueous extract of origanum vulgare and melilotus officinalis on production of nitric oxide (no) in cultured vascular endothelial cells (mouse endothelioma f-2 cell line)

background and purpose: during recent years, nitric oxide (no) has been considered as a molecule involved in migraine headaches. this free radical involves in initiation of migraine headaches via no/cgmp signaling pathway and vascular relaxation specially big intracranial arteries. therefore, we studied the effects of aqueous extract of origanum vulgare and melilotus officinalis prescribed in migraine treatment in traditional & modern medicine, on no level in cultured endothelial cells. materials and methods: each crude herb (25g) was mixed with 200 ml distilled water. end extract obtained after filtering and drying. endothelial cells propagated in dmem medium containing 10% fcs and 1-2% penicillin-streptomycin. the nitrite concentration was measured as an indicator of nitric oxide production according to the griess reaction and with elisa in 540 nm. results: concentrations of 100, 200 and 400 g/ml of origanum vulgare, reduced no levels compared with control to 13.1 % (p<0.05), 25.8% (p<0.01) and 33.9% (p<0.001) respectively. however, despite our expectation melilotus officinalis increased no level. the concentrations of 100, 200 and 400 g/ml of the herb, increased no levels to 12.7 (p<0.05), 36.5% (p<0.001) & 72.9% (p<0.001) respectively. conclusion: we concluded that aqueous extract of origanum vulgare probably decreases migraine headaches by reducing no and aqueous extract of melilotus officinalis does not act through this mechanism.