Xiu-Feng He

Trigochinins A-C: three new daphnane-type diterpenes from Trigonostemon chinensis.

Three highly oxygenated new diterpenes, trigochinins A-C (1-3) were isolated from Trigonostemon chinensis. Their structures with the absolute configuration were determined by a spectroscopic method, X-ray crystallography, and CD analysis. This study suggested the revision of the C-6 stereochemistry of trigonothyrins A-C reported quite recently. Compound 3 showed significant inhibition against MET tyrosine kinase activity with a IC(50) value of 1.95 microM.

Sesquiterpenes and Dimeric Sesquiterpenoids from Sarcandra glabra

Two new sesquiterpenes, sarcandralactones A (1) and B (2), and five new dimeric sesquiterpenoids, sarcandrolides A-E (3-7), along with 10 known compounds were isolated from the whole plants of Sarcandra glabra. Their structures were elucidated on the basis of spectroscopic analysis. Some of the new isolates exhibit significant cytotoxicities when tested against a small panel of tumor cell lines.

Trigochilides A and B, Two Highly Modified Daphnane-Type Diterpenoids from Trigonostemon chinensis

Trigochilides A (1) and B (2), two highly modified daphnane-type diterpenoids with 12-carbon-containing polyketide appendages at C-16 forming a macro-lactone with C-3, were isolated from the twigs and leaves of Trigonostemon chinensis. Their structures were elucidated by spectroscopic analysis. Trigochilides A (1) showed modest cytotoxicity against two tumor cell lines.

Two Novel Triterpenoids from Dysoxylum hainanense

Two novel rearranged oleanane-type triterpenes, dysoxyhainanin A ( 1) possessing a unique 1,3- cyclo-2,3- seco A ring with a formamido-containing appendage and dysoxyhainanin B ( 2) featuring an unprecedented 1,2-dinor-3,10:9,10- bisseco skeleton, were isolated from Dysoxylum hainanense. Dysoxyhainanin A ( 1) exhibited significant antibacterial activity against Gram-positive bacteria.

Mesendanins A-J, Limonoids from the Leaves and Twigs of Melia toosendan

Ten new limonoids, namely, mesendanins A-J (1-10), together with 14 known compounds, have been isolated from the leaves and twigs of Melia toosendan. Their structures were established on the basis of spectroscopic data analysis.

Ring A-seco triterpenoids with antibacterial activity from Dysoxylum hainanense

Five new ring A-seco triterpenoids, dysoxyhainic acids F-J (1-5), along with a known ring A-seco triterpenoid koetjapic acid (6) were isolated from the twigs and leaves of Dysoxylum hainanense. Their structures were established on the basis of extensive spectroscopic analysis. Antimicrobial activity of all the compounds against fungi and bacteria were tested. Compounds 2-4 and 6 exhibited significant antimicrobial activity against Gram-positive bacteria, and the antibacterial SAR (structure-activity relationship) was also briefly discussed.

Monoterpenoid Indole Alkaloids Bearing an N4‐Iridoid from Gelsemium elegans

Five new alkaloids, gelseganines A-D (1-4) and humantenine N(4)-oxide (5), were isolated from the stems and leaves of Gelsemium elegans. Compounds 1-4 represent a rare class of monoterpenoid indole alkaloids that bear an N(4)-iridoid unit. The structures of 1-5 were determined by spectroscopic analysis, single-crystal X-ray diffraction, and chemical correlation, and their absolute configurations were elucidated by CD analysis. A plausible biogenetic pathway for alkaloids 1-5 was also postulated.

Limonoids and Diterpenoids from Toona ciliata Roem. var. yunnanensis

Three new limonoids (toonaciliatins N-P, 1-3)and four new pimaradiene-type diterpenoids(toonacilidins A-D, 4-7) were isolated from the leaves and twigs of Toona ciliata Roem. var. yunnanensis.Their structures were elucidated on the basis of spectroscopic methods. Toonacilidin B(5)showed moderate inhibitory activity against H. pylori-SS1 with an MIC of 50 μg/mL.