Lie-Jun Huang

Two Unusual Polycyclic Polyprenylated Acylphloroglucinols, Including a Pair of Enantiomers from Garcinia multiflora.

Two polycyclic polyprenylated acylphloroglucinols, garcimulins A and B ((±)-1 and 2), including a pair of enantiomers with the unique caged tetracyclo[5.4.1.1(1,5).0(9,13)]tridecane skeleton were isolated from Garcinia multiflora. Their structures and absolute configurations were determined by extensive analysis of spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 exhibited cytotoxic activities against five human cancer cell lines in vitro (IC50 3.42-13.23 μM). The acidification of lysosomes in HeLa cell was obviously affected by compound 2.

Seco-pregnane steroidal glycosides from the roots of Cynanchum atratum and their anti-TMV activity.

Fifteen new seco-pregnane steroidal glycosides cynanosides A-O (1-15) together with twenty-seven known ones were isolated from the roots of Cynanchum atratum. The structures of 1-15 were determined by extensive analysis of spectroscopic data. The anti-tobacco mosaic virus (TMV) activity of these steroidal glycosides was screened by the conventional half-leaf method, enzyme-linked immunosorbent assay, and Western blot methods, most of them showed potent anti-TMV activity. Among them, compounds 1, 7, 13, 28 and 31 showed significantly anti-TMV activity with an IC50 value of 20.5, 18.6, 22.0, 19.2 and 22.2 μg/mL, respectively, and were much more effective than the positive control, ningnanmycin (IC50=49.6 μg/mL).

Alkaloids from Daphniphyllum oldhami

Four new Daphniphyllum alkaloids, daphnioldhanines H-K ( 1- 4), along with 34 known alkaloids, were isolated from Daphniphyllum oldhami. The known alkaloid dehydrodaphnigraciline ( 5) is now reported as a natural product. Their structures were elucidated by spectroscopic methods, especially 2D NMR techniques. The effects against platelet aggregation of compounds 1, 3, and 5 were evaluated, and 3 showed stronger activity against platelet aggregation induced by PAF. This is the first report of quinolizidine alkaloids from the genus Daphniphyllum.

Studies on cytotoxic pregnane sapogenins from Cynanchum wilfordii.

To investigate their cytotoxicity, seventeen C21-steroidal pregnane sapogenins 1-17 were isolated from the hydrolytic extracts of the roots of Cynanchum wilfordii. Among them, sapogenins 1-7 are new compounds, whose structures were determined by extensive analysis of spectroscopic data and X-ray crystallographic analysis. Especially, sapogenins with salicyl or vanilloyl group, and a new aberrant pregnane skeleton with ether linkage between C-12 and C-20 were found for the first time. Compound 1 revealed significant cytotoxicities on HL-60 (IC50 6.72μM) and MCF-7 (IC50 2.89μM), and compounds 14 and 15 also revealed strong inhibitory activities against K-562 (IC50 6.72μM) or MCF-7 (IC50 2.49μM), respectively.

Diterpene alkaloids and diterpenes from Spiraea japonica and their anti-tobacco mosaic virus activity

Five new naturally occurring natural products, including two atisine-type diterpene alkaloids (1 and 2), two atisane-type diterpenes (3 and 4), and a new natural product spiramine C2 (5), along with nine known ones (6-14), were isolated from the ethanolic extracts of the whole plant of Spiraea japonica var. acuminata Franch. Their structures were elucidated by extensive spectroscopic analysis. The anti-tobacco mosaic virus (TMV) activities of all the compounds were evaluated by the conventional half-leaf method. Six compounds (2, 3, 6, 7, 11, and 12) exhibited moderate activities at 100 μg/mL with inhibition rates in the range of 69.4-92.9%, which were higher than that of the positive control, ningnanmycin. Their preliminary structure-activity relationships were also discussed.

Synthesis and evaluation of antifungal activity of C21-steroidal derivatives

The antifungal activities of eleven C21-steroidal compounds isolated from Cynanchum wilfordii, together with thirty-six derivatives of caudatin and qingyangshengenin were evaluated on Sclerotinia sclerotiorum and other five fungal strains by the mycelium growth rate method. Four derivatives 1k, 1y, 10d, and 10j exhibited much stronger inhibitions on growth of S. sclerotiorum with IC50 values of 0.0084, 0.0049, 0.0053, and 0.0034 μM, respectively.

A novel isocoumarin with anti-influenza virus activity from Strobilanthes cusia

Strobilanthes A (1), a novel isocoumarin with an unusual tetrahydro-4H-pyran-4-one moiety fused isocoumarin core skeleton, together with a known compound (2) was isolated from Strobilanthes cusia. Its chemical structures were elucidated by 2D NMR spectroscopy, mass spectrometry and single-crystal X-ray diffraction analysis. The biosynthetic pathway of 1 could be supposed to be originally derived from 3-methylisocoumarin, a product of AA-MA pathway. Both of two compounds displayed anti-influenza virus activity in vitro.

Chromanopyrones and a flavone from Hypericum monogynum

Six new compounds, including three pyrone derivatives (2-4), one new flavone (5), and two new naturally-occurring compounds (1 and 6), together with 16 known compounds were isolated from the leaves and twigs of Hypericum monogynum. In addition, compounds 2-4 are racemates. Their structures and absolute configurations were determined on the basis of extensive analysis of spectroscopic data and ECD calculation. All compounds were evaluated for the inhibitory effects on α-glucosidase, compounds 1, 5, and 7 showed moderate inhibitory activities with IC50 values of 161.46, 257.78, and 11.54μg/ml, respectively. Compound 8 exhibited weak anti-oxidant activity with IC50 value of 12.55μg/ml.