Jian-Wei Tang

Scopariusicides, Novel Unsymmetrical Cyclobutanes: Structural Elucidation and Concise Synthesis by a Combination of Intermolecular [2 + 2] Cycloaddition and C–H Functionalization

Scopariusicides A (1) and B (2), two novel immunosuppressive unsymmetrical cyclobutane derivatives, were isolated from the aerial parts of Isodon scoparius. Moreover, based on the results of phytochemical investigation, a concise stereocontrolled synthesis of scopariusicide A and its analogues with enhanced biological activities was efficiently achieved using the main diterpenoid (3) isolated from this plant as a readily available starting material. A crossed intermolecular [2 + 2] photocycloaddition and a Pd-catalyzed sp(3) C-H bond β-arylation were used synergistically to access the highly congested unsymmetrical cyclobutane core with four contiguous stereocenters.

Structural Characterization of Kadcoccinin A: A Sesquiterpenoid with a Tricyclo[4.4.0.03,10]decane Scaffold from Kadsura coccinea

Kadcoccinin A (1), a cage-like sesquiterpenoid possessing a tricyclo[4.4.0.0(3,10)]decane scaffold, and the biosynthetically related kadcoccinin B (2) were isolated from the stems of Kadsura coccinea. Their structures and absolute configurations were determined from extensive spectroscopic analysis and quantum chemical calculations. Additionally, their cytotoxic and antifungal effects were initially evaluated, and a plausible biosynthetic pathway was proposed.

Structurally Diverse Diterpenoids from Isodon scoparius and Their Bioactivity

Fourteen new diterpenoids (1-14) based on four skeletal types and two known analogues (15 and 16) were isolated from the aerial parts of Isodon scoparius. Compound 2 is the first ent-kaurane diterpenoid featuring a 1,11-ether bridge, and the structures of these new compounds were established mainly by NMR and MS methods. The absolute configurations of 1 and 5 and the relative configuration of 3 were determined using single-crystal X-ray diffraction. The absolute configuration of 14 was determined by comparison of the experimental and calculated electronic circular dichroism spectra. Compounds 1, 4, and 15 were active against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), and they also inhibited NO production in LPS-stimulated RAW264.7 cells, with IC50 values of 1.0, 3.1, and 1.8 μM, respectively.

LC-MS-Guided Isolation of Penicilfuranone A: A New Antifibrotic Furancarboxylic Acid from the Plant Endophytic Fungus Penicillium sp. sh18

Penicilfuranone A (1), a novel furancarboxylic acid, and its proposed biosynthetic precursor, gregatin A (2), were isolated from the cultures of the fungus Penicillium sp. sh18 endophytic to the stems of Isodon eriocalyx var. laxiflora guided by HPLC-MS. X-ray crystallography was applied to the structure determination of furancarboxylic acid for the first time, allowing unambiguous assignment of 1. Penicilfuranone A displays a significant antifibrotic effect in activated hepatic stellate cells via negative regulation of transforming growth factor-β (TGF-β)/Smad signaling.

Laxiflorol A, the first example of 7,8:15,16-di-seco-15-nor-21-homo-ent-kauranoid from Isodon eriocalyx var. laxiflora

Laxiflorol A (1), an unprecedented 7,8:15,16-di-seco-15-nor-21-homo-ent-kauranoid, and its precursor analogue, laxiflorol B (2), were isolated from the leaves of Isodon eriocalyx var. laxiflora. The absolute configuration of 1 was determined by spectral methods and quantum chemical calculations. Compound 2 exhibited weak cytotoxicity.

Ent-Abietanoids Isolated from Isodon serra

Four new ent-abietane diterpenoids, along with four known ones were isolated from the aerial parts of Isodon serra, a traditional Chinese folk medicine. The new diterpenoids were named as serrin K (1), xerophilusin XVII (2), and enanderianins Q and R (3 and 4), while the known ones were identified as rubescansin J (5), (3α,14β)-3,18-[(1-methylethane-1,1-diyl)dioxy]-ent-abieta-7,15(17)-diene-14,16-diol (6), xerophilusin XIV (7), and enanderianin P (8), respectively. Their structures were elucidated by extensive spectroscopic analysis and comparison with the literature. Compound 1 showed remarkable inhibitory activity towards NO production in LPS-stimulated RAW264.7 cells (IC50 = 1.8 μM) and weak cytotoxicity towards five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480).

Gypmacrophin A, a Rare Pentacyclic Sesterterpenoid, Together with Three Depsides, Functioned as New Chemical Evidence for Gypsoplaca macrophylla (Zahlbr.) Timdal Identification

The phytochemical investigation on 1 g of materials from Gypsoplaca macrophylla (Zahlbr.) Timdal resulted in the discovery of gypmacrophin A, a rare pentacyclic sesterterpenoid; brialmontin III, a new polysubstituted depside and two known ones, brialmontins I and II. The structure and absolute configurations of gypmacrophin A were elucidated by spectroscopic analyses and computational methods. Gypmacrophin A showed weak inhibition of AchE with an IC50 value of 32.03 μM. The four compounds provided new chemical evidence for G. macrophylla identification.