Qi-Tai Zheng

Lancifodilactone A, a novel bisnortriterpenoid from Schisandra lancifolia

A novel bisnortriterpenoid, lancifodilactone A, has been isolated from the leaves and stems of Schisandra lancifolia. Its structure and stereochemistry were determined primarily from ID and 2D NMR spectroscopic data, and were confirmed by a single crystal X-ray analysis

Nortriterpenoids and lignans from Schisandra sphenanthera

Nortriterpenoids, sphenadilactone C (1) and sphenasin A (2), together with four known lignans (3-6), were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and compound 2 was further confirmed by single-crystal X-ray diffraction. Compound 1 features a partial enol moiety and an acetamide group in its structure. In addition, compounds 1, 3-6 showed weak anti-HIV-1 activity with EC(50) values in the range of 15.5-29.5 microg/mL.

Langduin C, a novel dimeric diterpenoid from the roots of Euphorbia fischeriana

Langduin C, a novel dimeric diterpenoid, was isolated from the roots of Euphorbia fischeriana and its structure was established by spectral data and single-crystal X-ray diffraction analysis.

Tetranortriterpenoids from the Leaves of Cipadessa cinerascens.

Seven known and six new tetranortriterpenoids, cineracipadesins A-F (1-6), were isolated from the leaves of Cipadessa cinerascens. Compound 1 has a mexicanolide-type structural skeleton with a rare 9alpha,11alpha-epoxide ring; compound 2 has a methyl angolensate-type structure with 9,11-dihydroxy groups, representing the first example of a precursor of a trijugin-type limonoid; and 3 is the first reported methyl angolensate-type limonoid with a ketone group at ring C. Their structures were determined with extensive spectroscopic analysis. X-ray crystallography confirmed the structure of 1. The ability of compounds 1-7 to inhibit the growth of the P-388 murine leukemia cell line was evaluated.

Two novel ent-kaurane diterpenoids isolated from Isodon eriocalyx var. laxiflora

Two novel 3,6-epoxy-6,7:8,15-seco-7,20-olide-ent-kaurane diterpenoids laxiflorin F (1) and laxiflorin G (2) have been isolated from the leaves of Isodon eriocalyx var. laxiflora. The structure elucidation of 1 and 2 was accomplished by spectroscopic Methods including 2D NMR analysis. The relative stereochemistry of 1 was established by single crystal X-ray crystallography, which also confirmed the novel carbon skeleton of the new ent-kaurane diterpenoid. Both compounds were tested for their cytotoxicity toward human leukemia K562 cells

Cytotoxic 7,20-epoxy ent-kauranoids from Isodon xerophilus

Four 7,20-epoxy ent-kaurane diterpenoids, xerophilusins G (1) and I-K (2-4), were isolated from the leaves of Isodon xerophilus, along with four known ones, enanderianin C (5), rosthorin A (6), longikaurin B (7), and rabdoternin D (8). Their structures were determined primarily using NMR spectroscopic techniques. The structure and stereochemistry of 3 were confirmed by X-ray crystallography. Compounds 4 and 7 exhibited broad cytotoxicity against four kinds of human tumor cells (K562, HL-60, HCT, and MKN-28 cells) in the range of 2.23-15.35 and 0.30-8.61 microg/ml, respectively.

A novel diterpene hydroperoxide, glutinosin C, from Isodon glutinosa

A novel diterpene hydroperoxide, glutinosin C, has been isolated from the leaves of Isodon glutinosa. Its structure and relative stereochemistry were established on the basis of the spectral features and confirmed by single crystal X-ray analysis

Three new C21-steroidal glycosides from the roots of Cynanchum inamoenum.

Three new C21-steroidal glycosides presenting an unusual 13,14:14,15-disecopregnane-type skeleton, named inamosides A–C (1–3), together with two known C21-steroidal glycosides, were isolated from the MeOH extract of the roots of Cynanchum inamoeum (Maxim.) Loes (Asclepiadaceae). The aglycone of compounds 1, 2, and 3 has a 2β-hydroxyl, which has not yet been reported in the literature. The structure and relative configuration of the aglycone of compounds 1, 2, and 3 were established by X-ray crystallographic analysis.

Crystal structure of cucubaldiol, a novel norsesquiterpenoid incorporating a bicyclo[2.2.2]octene ring system from Cucubalus baccifer (Caryophyllaceae)

Cucubaldiol (1), a novel norsesquiterpenoid incorporating a bicyclo[2.2.2]octene ring system, was isolated from the whole plants of Cucubalus baccifer L. Its structure was determined on the basis of spectroscopic data especially by 2D-NMR and X-ray diffraction analyses.

A New Fernane-Type Triterpenoid from Teucrium integrifolium

Abstract A new fernane-type triterpene, named integrifolin (1), was isolated and characterized from the aerial parts of Teucrium integrifolium. The structure of the new compound was deduced to be 3β-hydroxy-fern-9(11)-en-23-oic acid through its spectral properties and X-ray crystallographic analysis.