Li-Bin Yang

Propindilactones E-J, Schiartane Nortriterpenoids from Schisandra propinqua var. propinqua

Six new nortriterpenoids, propindilatones E-J (1-6), and two known (7, 8) schiartane-type nortriterpenoids were isolated from the stems of Schisandra propinqua var. propinqua. Their structures were elucidated by extensive spectroscopic analyses, and the structure of compound 4 was confirmed through single-crystal X-ray diffraction. The absolute configuration of compounds 1-3 was established using CD methods. Compounds 4-6 were noncytotoxic against K562, A549, and HT-29 human cancer cells.

ent-Kaurane diterpenoids from Isodon pharicus.

Phytochemical investigation of the aerial parts of Isodon pharicus led to the isolation of 13 new ent-kaurane diterpenoids, compounds 1-13, together with 12 known analogues (14-25). The structures of the new compounds were determined by means of extensive spectroscopic techniques including interpretation of 1D and 2D NMR spectra. Selected compounds were evaluated for their cytotoxicity against NB4, A549, PC-3, MCF-7, and SH-SY5Y cell lines.

Cytotoxic ent-kaurane diterpenoids from Isodon sinuolata.

Five (1-5) ent-kaurane diterpenoids and 17 other known ones, were isolated from the leaves and stems of Isodon sinuolata. Their structures were determined on the basis of spectroscopic methods including 1D and 2D NMR spectroscopic analysis. All compounds were evaluated for cytotoxicity against a small panel of cell lines. Some compounds exhibited significant cytotoxicity.

Cycloartane triterpenoids from the stems of Schisandra glaucescens and their bioactivity

Five new cycloartane triterpenoids, schiglausins K-O (1-5), including one hexanortriterpenoid (1) and one octanortriterpenoid (2), as well as two known compounds (6-7), were isolated from the stems of Schisandra glaucescens Diels. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR spectra. Compounds 2-7 were tested for their FXR agonistic and antagonistic effects. Compound 7 exhibited significant antagonistic effect against FXR with IC(50) of 1.50 μM.

Lanostane Triterpenoids from the Stems of Schisandra glaucescens

Ten new triterpenoids, schiglausins A-J (1-10), as well as four known compounds, were isolated from the stems of Schisandra glaucescens. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR spectra and CD experiment. Compound 8 was determined to be a norlanostane triterpenoid. The crystal structure of compound 1 has been determined using single-crystal X-ray analysis while its absolute configuration was assigned on the basis of the CD spectrum. All isolates were tested for their FXR agonistic and antagonistic effects.

ent-Kaurane Diterpenoids from Isodon scoparius

Nine new ent-kaurane diterpenoids, isoscoparins D-L (1-9), and an artificial product, the acetonide of rabdoloxin A (10), along with 16 known analogues (11-26), were isolated from the leaves of Isodon scoparius. The new structures were determined by 1D and 2D NMR spectroscopic analysis. Selected compounds were evaluated for their cytotoxicity against NB4, A549, PC-3, MCF-7, and SH-SY5Y cell lines.

ent-Kaurane Diterpenoids from Isodon nervosus

A pentacyclic ent-kauranoid, nervonin A ( 1), with an unprecedented cyclobutane moiety in the structure, and nine other new ent-kaurane diterpenoids, nervonins B-J ( 2- 10), along with 10 known ones ( 11- 20), were isolated from Isodon nervosus. Their structures were elucidated by detailed spectroscopic analysis. All diterpenoids were assayed for their cytotoxicity against K562, A549, and HepG2 human cell lines. Compounds 2, 11, 16, 17, and 20 showed significant cytotoxicity.

19-Oxygenated ent-Kaurane Diterpenoids from Isodon pharicus

Eight new 19-oxygenated ENT-kaurane diterpenoids were isolated from the aerial parts of Isodon pharicus. Their structures were determined by means of extensive spectroscopic techniques including interpretation of 1D and 2D NMR spectra. Selected compounds were evaluated for their cytotoxicity against NB4, A549, PC-3, MCF-7, and SH-SY5Y cell lines.

Propinic lactones A and B, two new triterpenoids from Schisandra propinqua var. propinqua and the significance in biosythesis pathway.

Abstract Aim To study the chemical constituents of the aerial parts of Schisandra propinqua var. propinqua . Method Silica gel, C 18 reversed phase silica gel and HPLC were used. The structures were elucidated by extensive spectroscopic methods. Result Two new triterpenoids, propinic lactone A ( 1 ) with 3, 4- seco -cycloartane skeleton, and propinic lactone B ( 2 ) possessing 3, 4:9, 10- seco -cycloartane skeleton, together with a known typical cycloartane triterpenoid, schizandronic acid ( 3 ), have been isolated and identified. Conclusion These two new triterpenoids serve as two important bridge intermediates from cycloartane triterpenoids to Schisandra nortriterpenoids biogenetically.

ent-Kaurane Diterpenoids from Isodon japonicus

Two new 6,7-seco-ent-kaurane diterpenoids, isojaponins A (1) and B (2), together with 18 known ent-kaurane diterpenoids were isolated from the aerial parts of Isodon japonicus. The structures of the two new compounds were elucidated by extensive 1D- and 2D-NMR spectroscopic methods in combination with MS experiments.