title: Bioactivity-guided fractionation of the volatile oil of Angelica sinensis radix designed to preserve the synergistic effects of the mixture followed by identification of the active principles.
abstract: In natural product research, it is a common experience that fractionation of biologically-active crude extracts can lead to the loss of their original activity. This is attributed to synergistic effects, where two or more components are required to be present together for full activity of the sample. Our previous study showed that a volatile oil of Angelica sinensis radix (VOAS) inhibited endothelial cell proliferation in culture. Here we have used a bioactivity-guided fractionation method to preserve any synergistic effects of VOAS combining countercurrent chromatography (CCC), the MTS cell viability assay and gas chromatography (GC). Using a two-phase CCC solvent system (heptane-ethyl acetate-methanol-water at a volume ratio of 27:23:27:23%), forty-five fractions were isolated, nine of which exhibited anti-endothelial properties. GC analysis showed two bioactive alkylphthalides, Z-ligustilide and n-butylidenephthalide (BP) were the major compounds detected in the bioactive fractions, and were absent in non-bioactive fractions. Our results indicate that Z-ligustilide and BP are the main constituents responsible for the anti-endothelial properties of VOAS. This rapid and reliable approach in preserving sample activity while isolating and identifying its active compounds suggests that this protocol can be a powerful tool for drug discovery from natural products.
authors.affiliation: Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK.
authors.forename: Ju-Ching
authors.initials: JC
authors.lastname: Yeh
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Garrard
authors.forename: Chin-Wen Chantal
authors.initials: CW
authors.lastname: Cho
authors.forename: S W
authors.initials: SW
authors.lastname: Annie Bligh
authors.forename: Guang-hua
authors.initials: GH
authors.lastname: Lu
authors.forename: Tai-Ping
authors.initials: TP
authors.lastname: Fan
authors.forename: Derek
authors.initials: D
authors.lastname: Fisher
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D029971:Angelica sinensis / Q000737:chemistry*; D048708:Cell Growth Processes / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003377:Countercurrent Distribution / Q000295:instrumentation / Q000379:methods; D004357:Drug Synergism; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D009822:Oils, Volatile / Q000737:chemistry* / Q000494:pharmacology*; D010796:Phthalic Anhydrides / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*; D012371:Robotics
chemical_list: D009822:Oils, Volatile; D010796:Phthalic Anhydrides; D010936:Plant Extracts; C027820:ligustilide; D015107:4-Butyrolactone; C026105:butylidenephthalide