Study On The Chemical Constituents Of Elephantopus Scaber

Elephantopus scaber Linn (Compositae) regionally distributes in Guangdong, Guangxi, Zhejiang, Fujian, Guizhou and Yunnan province of China. The roots of E. scaber are traditionally used in southern China for the treatment of common cold, pertussis, and inflammations. The previously biological tests revealed that the herb exhibits in vitro antibacterial, anticancer, and antiviral activities. Sesquiterpene lactones are one of the active constituents of the herb. Therefore, the objective of this thesis is to conduct a further study on chemical constituents of the herb, hoping to obtain more active compounds and accumulate the amount of sesquiterpene lactones for anticancer mechanistic study.The ethanolic extracts of E. scaber were isolated by column chromatogramphies on silica gel, ODS, and Sephadex LH-20 columns, respectively, to afford 25 compounds. Twenty one of them were identified with spectroscopic analyses and their physical and chemical properties to be scabertopin (DDC-1), isoscabertopin (DDC-2), deoxyelephantopin (DDC-3), isodeoxyelephantopin (DDC-4), friedlin (DDC-5), epifriedlin (DDC-6), lupeol (DDC-7),3,4-di-O-caffeoyl quinic acid (DDC-8),3,4-di-O-caffeoyl quinic acid methyl easter (DDC-9),4,5-di-O-caffeoyl quinic acid (DDC-10),1,2-di-O-caffeoyl-cychopenta-3-ol (DDC-11), tricin (DDC-12), isovanillic acid (DDC-13), syringic acid (DDC-14), E-3-(3-ethoxy-4-hydroxyphenyl) acrylic acid (DDC-15), ferulic acid (DDC-16), 2-hydroxybenzolate acid (DDC-17), stigmasterol-3-O-β-D-glucoside (DDC-18),azelaic acid (DDC-19),stigmasterol (DDC-20),β-sitosterol (DDC-21). Among them, compounds DDC-15 is a new natural product, and compounds DDC-8, DDC-9, DDC-11, DDC-14, DDC-17 and DDC-19 were isolated from E. scaber for the first time. In addition, two active sesquiterpene lactones, deoxyelephantopin (DDC-3) and isodeoxyelephantopin (DDC-4) were accumulated to be 200 and 50 mg, respectively.The antibacterial activity of four sesquiterpene lactones was tested by broth dilution method. The result indicated that all of them were valid on three bacteria, Escherichia coli, Staphyloccocus aureus andβ-streptococcus. The previously biological tests revealed that sesquiterpene lactones inhibited the growth of CNE, HL-60, PC-3 cancer cells. Therefore, sesquiterpene lactones are one of the active constituents of th herb, possessing both anticancer and antibacterial activities.