Chemical Constituents and Cytotoxicity from the Stem Bark of Citrus medica

A new biscoumarin, namely citrumedin-A [6,6',7,7'-tetramethoxy-3,3'-biscoumarin] (1), together with twenty two known compounds were isolated from the stem bark of Citrus medica L. var.sarcodactylis Swingle.The structure of this new compound was completely elucidated using a combination of 2D NMR techniques (COSY, NOESY, HMQC and HMBC) and HR-EI-MS analyses.The known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literatures.The isolates were also screened their cytotoxicity against Daoy, Hep2, MCF-7 and Hela cell lines.Lonchocarpol A (12) showed marginally cytotoxic activity against those four cancer cell lines.Citrus medica L. var.sarcodactylis Swingle belongs to genus of Citrus (Rutaceae) and mainly distributed in the south of China, India, Vietnam and Malaysia.It was introduced from Fujian, China to Taiwan around 1700.The fruit of the genus of Citrus can be used as food, and its peel, leaves and root can be also used as folk medicine or spice in Taiwan. 1 Several active constituents, such as coumarins, 2 flavonoids, 3 tetranortriterpenoids 4 and monoterpenoids, 5 were isolated and reported from the Citrus species.Recently, Wu et al. 6~23 reported the isolation of several acridone alkoids from Citrus genus.C. medica L. var.sarcodactylis Swingle is used as a folk medicine for the treatment of stomach ache, edema, headache, rheumatism, infectious hepatitis and arthritis in Taiwan. 24In continuation of our interest on the bioactive compounds from the natural resource led us to investigate the constituents and bioactivity of the