Abstract: This invention discloses a compound (I) of the following formula. This invention also includes a method for extracting the compound (I), and a pharmaceutical composition containing the compound (I). The extracting method includes the following steps: taking the corpus radicis and/or radix fibrosa of a ginseng spp. plant—ginseng or pseudo-ginseng, extracting with industrial alcohol and n-butanol to extract the total saponins, and then purifying by silicon gel column chromatography and reversed phase column chromatography to obtain the compound (I). The compound (I) and pharmaceutical composition can be used to cure acute ischemic cerebral-vascular diseases.