In previous general screening experiments was found a potent spasmolytic effect in guinea-pig ileum promoted by a furanoflavan-type flavonoid 3,4,5,8-tetramethoxy-(6,7,2”,3”)-furanoflavan named diplotropin, obtained from the stem-barks of Lonchocarpus araripensis Benth., which effect is due, in part, to the inhibition of Ca2+ influx through voltage-dependent Ca2+ channels. This study demonstrates for the first time in the chemistry literature a new furanoflavoquinone derivative 5,6-dimethoxy-7-phenyl-6,7-dihydro-5H-furo[3,2-g]chromen-4,9-dione, codified as DPTN-Sint. 1, obtained after chemoselective oxidation of natural prototype (diplotropin) and evaluation of its biological activity in rat aorta and uterus, guinea-pig ileum and trachea. The new derivative present a selective spasmolytic effect on guinea-pig trachea not found with the prototype molecule.