By means of chromatographic and crystallization techniques, a flavanone named lupinifolin was isolated from the stem of Myriopteron extensum Schum. The identification of the compound was based on the spectroscopic data. This compound has never been reported to be found in this species before. The determination of free sugar in the aqueous portion of the Myriopteron extensum Schum. stem's extract revealed the presence of sucrose which was a major sweetener of the plant.