Yun-Sen Li

A new Pinoresinol-type lignan from Ligularia Kanaitizensis

A new pinoresinol-type Lignan, 9α-angloyloxypinoresinol (1), was isolated from the roots and rhizomes of Ligularia kanaitizensis (Franch.) Hand.-Mazz, in addition to a known compound, 9α -hydroxypinoresinol (2). The structure of this new lignan (1) was established on the basis of 1D and 2D NMR experiments. Anti-HIV-1 RT biological assay showed that 1 was inhibitory to HIV-1 RT.

Serratane-type Triterpenoids from Huperzia Serrata

Sixteen serratane-type triterpenoids including three new compounds, 14β,15β- epoxyserratan-3β,21β,29-triol (1), serrat-14-en-3β,21β,29-triol (2) and serrat-14-en-3α,21β,24,29-tetraol (3), were isolated from the whole plant of Huperzia serrata (Thunb) Trev. The structures of these new compounds (1–3) were elucidated on the basis of spectral analysis.

A novel bis-furan derivative, two new natural furan derivatives from Rehmannia glutinosa and their bioactivity.

A novel bis-furan derivative and two new natural furan derivatives were isolated from the CHCl3 extracts of the dried roots of Rehmannia glutinosa (Gaerth) Lilosch. Their structures were identified as 1,5-bis(5-methoxymethyl)furan-2-yl-penta-1,4-dien-3-one 1, (E)-4-(5-(methoxymethyl)furan-2-yl)but-3-en-2-one 2 and (E)-4-(5-(hydroxymethyl)furan-2-yl)but-3-en-2-one 3 on the basis of spectral data. Moreover, biological assay showed that 1 (10 µg/mL) and 3 (10 µg/mL) can promote immune activity, 2 (100 µg/mL) and 3 (100 µg/mL) inhibit immune activity and 1 can inhibit blood platelet aggregation.

A novel bieremophilanolide from Ligularia lapathifolia

A new bieremophilanolide was isolated from the roots and rhizomes of Ligularia lapathifolia. Its structure was established as 8,8′-bi-3β-angeloyloxy-eremophil-7(11)-en-12,8α(14β,6α)-diolide (1) by IR, MS, 1D, and 2D NMR experiments.

Sensitized photooxidation of furanoeremophilane with singlet oxygen and their biogenetic relationship

In an attempt to explore the biogenetic relationship of furanoeremophilane derivatives and eremophilan-8α,12-olides, produced in Ligularia and their structure-activity relationship, we studied the photosensitized oxidation of furanoeremophilane–type sesquiterpenes. Under the condition of several solvents solution Irradiation with a 200 W incandescent lamp of furanoeremophilan-14β,6α-olide isolated from Ligularia vellerea, in various solutions with methylene blue, rose bengal, toluidine blue and safranine T gave several products. The products were isolated by chromatographic procedure and their structures were elucidated as eremophilan-14β,6α,8α,12-diolide derivatives by NMR, IR and MS methods. A reaction mechanism has been proposed.