Xian-Min Zhang

Kuguacins F-S, cucurbitane triterpenoids from Momordica charantia.

Chemical investigation of the vines and leaves of Momordica charantia resulted in isolation of fourteen cucurbitane triterpenoids, kuguacins F-S (1-14), including two pentanorcucurbitacins (6 and 7), one octanorcucurbitacin (8), and two trinorcucurbitacins (11 and 12), along with six known analogues. Their structures were elucidated on the basis of extensive spectroscopic and single-crystal X-ray diffraction analyses. Compounds 1-14 exhibited weak anti-HIV-1 activities in vitro.

Two novel lanostane triterpenoids from Ganoderma sinense.

Two novel lanostane-type triterpenes, Ganolactone B and Ganoderiol A triacetate, were isolated from the fruiting bodies of G. sinense, together with six known compounds. The structures of the two new triterpenes were determined as 3beta,7beta- dihydroxy-11,15-dioxo-lanosta-8-en-24-->20 lactone (1) and 3beta,24,26-triacetoxy-5alpha-lanosta-7,9(11)-dien-25-ol (2), respectively, by chemical and spectroscopic means.

Pregnane alkaloids from Pachysandra axillaris

Nine new pregnane alkaloids, pachysamines J-R (1-9), together with seven known ones, were isolated from Pachysandra axillaris. The chemical structures of the new alkaloids were elucidated by spectroscopic methods. All the compounds were evaluated for their inhibitory activities against HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1 cell lines. Compound 15 possessed moderate activities against A-549, SK-BR-3, and PANC-1 cells, with the IC(50) values of 11.17, 4.17, and 10.76 microM, respectively. Besides, compound 11 showed cytotoxicities against A-549 cell, with the IC(50) values as 24.94 microM.

Cytotoxic triterpenoid alkaloids from Buxus microphylla.

Five new triterpenoid alkaloids, buxmicrophyllines E-I (1-5), and six known ones (6-11) were isolated from the leaves and stems of Buxus microphylla. The structures of compounds 1-5 were elucidated by NMR and MS spectroscopic analysis, and the relative stereochemistry of 5 was determined by single-crystal X-ray crystallography. Compounds 3 and 9 were cytotoxic against HepG2 cells, with IC(50) values of 0.89 and 0.78 microM, and compounds 2, 3, 7, 8, and 9 were cytotoxic against K562 cells, with IC(50) values of 2.95, 4.44, 1.70, 5.61, and 0.37 microM, respectively.

Rational design and synthesis of highly potent anti-acetylcholinesterase activity huperzine A derivatives

By targeting multi-active sites of acetylcholinesterase (AChE), a series of huperzine A (Hup A) derivatives with various aromatic ring groups were designed and synthesized by Schiff reaction. They were evaluated as AChE and butyrylcholinesterase (BChE) inhibitors. Results showed very significant specificity that the group of imine derivatives could inhibit TcAChE and hAChE, but no inhibitory effect on hBChE was detected. The experiment was explained by a docking study. In the docking model, we confirmed that aromatic ring of Hup A derivatives played the pi-pi stacking against aminophenol residues of AChE, and the structure-activity relationship (SAR) was discussed.

Cytotoxic Serratane Triterpenes from Diphasiastrum complanatum with a Hydroxy Group at C-27

Four serratane-type triterpenes ( 1- 4) were isolated from D. COMPLANATUM. Their chemical structures were elucidated as 14alpha,15alpha,20beta,21beta,24,27alpha,29-heptahydroxyserrat-3-one ( 1), 3beta,14alpha,15alpha,20beta,21beta,24,27alpha,29-octahydroxyserratane ( 2), 3alpha,14alpha,20beta,21beta,24,27alpha,29-heptahydroxyserratane ( 3) and 3beta,14alpha,21beta,24,27alpha-pentahydroxyl-serratane-29-yl ( E)- P-coumarate ( 4) by spectroscopic methods (MS, 1D and 2D NMR) and X-ray crystallography. Interestingly, the most characteristic methylene (C-27) of the serratane ring C was oxidized to a methine. Compound 4 showed significant cytotoxic activity against the human leukemia K562/S and the doxorubicin-resistant K562/R cell lines, but the other compounds were inactive.