Xiao Luo

Cytotoxic ent-kaurane diterpenoids from Isodon rubescens var. lushiensis.

Ten new ent-kaurane diterpenoids, isolushinins A-J (1-10), together with 20 known compounds, were isolated from the aerial parts of Isodon rubescens var. lushiensis. The structures of 1-10 were elucidated by spectroscopic analysis. Several of the compounds isolated were evaluated for their cytotoxicity against the HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1 human cancer cell lines, and some exhibited quite potent inhibitory activities.

Schilancitrilactones A–C: Three Unique Nortriterpenoids from Schisandra lancifolia

Three unique nortriterpenoids, schilancitrilactones A-C (1-3), were isolated from the stems of Schisandra lancifolia . Compound 1 possesses a 5/5/7/5/5/5-fused hexacyclic ring system with a C(29) backbone, while 2 and 3 feature a C(27) skeleton with a 5/7/5/5/5-fused pentacyclic ring system. Their absolute stereochemistries were established by CD and single-crystal X-ray diffraction experiments. Compound 3 showed anti-HIV-1 activity with an EC(50) value of 27.54 μg/mL, and 1 exhibited antifeedant activity at 15.73 μg/cm(2).

Lignans with Anti-HIV Activity from Schisandra propinqua var. sinensis

Fourteen new lignans, tiegusanins A-N (1-14), together with 13 known compounds were isolated from the aerial parts of Schisandra propinqua var. sinensis. The structures and absolute configurations of 1-13 were established using a combination of spectroscopic techniques. Compound 14 was obtained as a racemate. When evaluated for inhibitory activity against HIV-1, tiegusanin G (7) showed anti-HIV-1 activity with an EC(50) value of 7.9 microM and a therapeutic index (TI) of more than 25.

Schicagenins A-C: Three Cagelike Nortriterpenoids from Leaves and Stems of Schisandra chinensis

Schicagenins A-C (1-3), three unprecedented nortriterpenoids characterized with a tetracyclic oxa-cage motif and C(9) side chain, were discovered from the leaves and stems of Schisandra chinensis. Their structures were determined on the basis of extensive spectroscopic analysis, and the absolute stereochemistries were established by single-crystal X-ray diffraction and CD experiments. A plausible biosynthetic pathway of 1-3 was also discussed.

Bioactive Nortriterpenoids from Schisandra grandiflora

Three new nortriterpenoids, schigrandilactones A-C (1-3), along with eight known compounds, were isolated from an organic solvent extract of Schisandra grandiflora. Compounds 1 and 2 feature a spirocyclic moiety in their structures, and compound 3 was characterized with a new oxygenated pattern. The relative configurations of 1 and 3 were determined through single-crystal X-ray experiments. In addition, compounds 1 and 2 displayed cytotoxic activity against two human cancer cell lines, and compound 3 showed anti-HIV-1 inhibition in infected C8166 cells.

Structure and Cytotoxicity of Diterpenoids from Isodon eriocalyx

A new ent-atisanoid, eriocatisin A (1), six new ent-abietanoids, eriocasins B-E (2-4, 7), 3-acetyleriocasin C (5), and 3β-acetoxyeriocasin D (6), and seven new ent-kauranoids, maoesins A-F (8, 10-14) and 3α-acetoxy-maoesin A (9), together with 21 known compounds, were isolated from the aerial parts of Isodon eriocalyx. The structures of 1-14 were determined by spectroscopic data interpretation. All compounds isolated were evaluated for their in vitro growth inhibitory activity against the HT-29, BEL-7402, and SK-OV-3 human cancer cell lines. Compounds 17, 18, and 20 showed inhibitory effects for all three tumor cell lines used, with IC(50) values in the range 2.1-7.3 μM.

Lancolides, Antiplatelet Aggregation Nortriterpenoids with Tricyclo[6.3.0.0(2,11)]undecane-Bridged System from Schisandra lancifolia

A new class of highly oxygenated Schisandra nortriterpenoids, lancolides A-D (1-4), from Schisandra lancifolia, represents the first example of natural products that possess a tricyclo[6.3.0.0(2,11)]undecane-bridged system. Their structures were elucidated by NMR spectra, X-ray diffraction, and quantum chemical calculations. Lancolides A (1) and D (4) had specific antiplatelet aggregation induced by platelet-activating factor (PAF).

Antiproliferative Diterpenoids from the Leaves of Isodon rubescens

A phytochemical study of Isodon rubescens leaves led to the isolation of five new diterpenoids, isorubesins A-E ( 1- 5), and fifteen known diterpenoids. The structures of these new compounds were elucidated by spectroscopic evidence. Most of the diterpenoids were tested for cytotoxicity against NB4, A549, SHSY5Y, PC3, and MCF7 human tumor cells. Some of them showed potent inhibitory activity. Compound 5 is the first reported atisane-type diterpenoid from this plant.