Biomedical subjects

Qi-Tai Zheng

Publications and source records attributed to Qi-Tai Zheng.

At least 19 recordsLinked to original sources

PubMed2006

Dichotomains A and B: two new highly oxygenated phenolic derivatives from Dicranopteris dichotoma.

[structure: see text] Dichotomains A (1) and B (2), two new highly oxygenated phenolic derivatives that feature a spirodilactone moiety in their structures, were isolated from the fronds of Dicranopteris dichotoma. Their structures were elucidated on the basis of NMR and MS spectroscopic data, and the stereochemistry of 1 was finally determined by single-crystal X-ray diffraction. Compound 2 showed weak anti-HIV-1 activity.

Anti-HIV Agents↗

PubMed2006

Sphenadilactones A and B, two novel nortriterpenoids from Schisandra sphenanthera.

[structure: see text] Two novel nortriterpenoid compounds, sphenadilactones A (1) and B (2), have been isolated from the leaves and stems of Schisandrasphenanthera. The structural elucidation of 1 and 2 was accomplished by extensive NMR analysis. The relative stereochemistry of 1 was established by single-crystal X-ray crystallography. Both compounds were tested for their cytotoxicities against K562, A549, and HT-29, and compound 1 was further tested for its anti-HIV-1 activity.

Anti-HIV Agents↗

PubMed2006

Rubriflordilactones A and B, two novel bisnortriterpenoids from Schisandra rubriflora and their biological activities.

Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on the basis of extensive spectroscopic methods, including two-dimensional NMR techniques, and confirmed by X-ray crystallographic analysis. Compound 1 showed weak anti-HIV-1 activity, and compound 2 exhibited an EC50 value of 9.75 microg/mL (SI=12.39) against HIV-1 replication with low cytotoxicity.

Anti-HIV Agents↗

PubMed2006

Five new steroidal compounds from Ypsilandra thibetica.

Five new steroids, including the four new steroidal saponins ypsilandroside B (1), ypsilandroside A (2), isoypsilandroside A (4), and isoypsilandroside B (5), as well as the new steroidal sapogenin isoypsilandrogenin (3), were isolated from the whole plant of Ypsilandra thibetica Franch. Their structures were determined on the basis of spectroscopic analyses, including extensive 2D-NMR techniques. The structure and relative configuration of ypsilandroside B (=(3beta,12alpha,25R)-3-[(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-apiofuranosyl)oxy]spirost-5-ene-12,27-diol; 1) was unequivocally determined by single-crystal X-ray diffraction. The antifungal and antibacterial activities of 1-5 towards various types of fungi and bacteria are reported.

Anti-Bacterial Agents↗

PubMed2006

Triterpenoids from Schisandra lancifolia with anti-HIV-1 activity.

A new trinorcycloartane triterpenoid, lancifodilactone H (1), and a new A ring-secocycloartane triterpenoid, lancifoic acid A (2), together with a known compound, nigranoic acid (3), were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated by spectroscopic data analysis. Compound 1 features a biosynthetically modified seven-membered lactone ring, which was confirmed by single-crystal X-ray diffraction. Compounds 1-3 exhibited weak anti-HIV-1 activity in vitro.

Anti-HIV Agents↗

PubMed2006

Nortriterpenoids from Schisandra lancifolia.

Six new nortriterpenoids, lancifodilactones I-N (1-6), as well as nine known ones, were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated on the basis of spectroscopic methods including 2D NMR analysis, and the structures of compounds 1 and 4 were further confirmed by single-crystal X-ray crystallography. In addition, all new compounds were tested for anti-HIV-1 activity.

Anti-HIV Agents↗

PubMed2006

Taxoids from Taxus chinensis.

Two new taxoids, 13,15-epoxy-13-epi-taxayunnasin A (1) and taxchinin N (2), were isolated from the leaves and stems of Taxus chinensis. Compound 2 is the first taxoid to be reported with an alpha,beta-unsaturated lactone at C-4, C-5, C-20, and C-2. The structure of 1 was elucidated by spectroscopic analysis and confirmed by semisynthesis from taxayunnasin A, while 2 was determined structurally using spectroscopic methods and by single-crystal X-ray diffraction.

Crystallography, X-Ray↗

PubMed2005

Kadlongilactones A and B, two novel triterpene dilactones from Kadsura longipedunculata possessing a unique skeleton.

[structure: see text] Two novel triterpene dilactones with an unprecedented rearranged hexacyclic skeleton, kadlongilactones A (1) and B (2), have been isolated from the leaves and stems of Kadsura longipedunculata Finet et Gagnep (Schisandraceae). Their structures were established by comprehensive 1D and 2D NMR spectroscopic analysis, coupled with single-crystal X-ray crystallographic diffraction. Compounds 1 and 2 exerted significant inhibitory effects against human tumor K562 cells with IC(50) = 1.40 and 1.71 microg/mL, respectively.

Cell Line, Tumor↗

PubMed2005

Structure and anti-HIV activity of micrandilactones B and C, new nortriterpenoids possessing a unique skeleton from Schisandra micrantha.

Two new highly oxygenated nortriterpenoids with a unique norcycloartane skeleton, micrandilactones B and C, were isolated from Schisandra micrantha; micrandilactone C exhibited an EC50 value of 7.71 microg/mL (SI > 25.94) against HIV-1 replication with minimal cytotoxicity, and the potent anti-HIV-1 activity and unique structural features of make it a promising lead for therapeutic development of a new generation of anti-HIV drug.

Animals↗

PubMed2005

Lancifodilactone G: a unique nortriterpenoid isolated from Schisandra lancifolia and its anti-HIV activity.

[structure: see text]. Lancifodilactone G (1), a novel, highly oxygenated nortriterpenoid featuring a partial enol structure and a spirocyclic moiety, was isolated from the medicinal plant Schisandra lancifolia. Its structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data, coupled with single-crystal X-ray analysis. Compound 1 exerted minimal cytotoxicity against C8166 cells (CC50 > 200 microg/mL) and showed anti-HIV activity with EC50 = 95.47 +/- 14.19 microg/mL and a selectivity index in the range of 1.82-2.46.

Anti-HIV Agents↗

PubMed2005

Lancifodilactone F: a novel nortriterpenoid possessing a unique skeleton from Schisandra lancifolia and its anti-HIV activity.

[structures: see text] Lancifodilactone F (1), possessing an unprecedented rearranged pentanortriterpenoid backbone derived from cycloartane, was isolated from the leaves and stems of Schisandra lancifolia (Rehd. et Wils) A. C. Smith. Its structure was established by comprehensive NMR and MS spectroscopic analysis, coupled with single-crystal X-ray experiment. Compound 1 exerted minimal cytotoxicity against C8166 cells (CC50 > 200 microg/mL) and showed anti-HIV activity with EC50 = 20.69 +/- 3.31 microg/mL and a selectivity index > 6.62.

Anti-HIV Agents↗

PubMed2005

Terpenoids from the roots and rhizomes of Nardostachys chinensis.

A new diterpene, 10-isopropyl-2,2,6-trimethyl-2,3,4,5-tetrahydronaphtha[1,8-bc]oxocine-5,11-diol (1), and a new monoterpene, 6-hydroxy-7-(hydroxymethyl)-4-methylenehexahydrocyclopenta[c]pyran-1(3H)-one, together with four known sesquiterpenes, delta1(10)-aristolene-9beta-ol, debilon, nardosinone, and kanshone A, were isolated from the roots of Nardostachys chinensis. The structures of the new compounds were established on the basis of their spectroscopic data, and the structure of 1 was confirmed by X-ray crystallographic analysis.

Diterpenes↗

PubMed2005

[A new hetisine-type alkaloid from the stems and leaves of Aconitum coreanum].

AIM: To study the chemical constituents of the stems and leaves of Aconitum coreanum (Lèvl.) Rapaics. METHODS: The constituents of Aconitum coreanum were isolated by using various kinds of modern chromatographic methods. The new alkaloid was identified on the basis of spectral analysis. RESULTS: Two compounds were isolated and identified as: 13-dehydro-1beta-acetyl-2alpha,6beta-dihydroxyhetisine (I) and Guanfu base G (II). CONCLUSION: Compound I is a new alkaloid.

Aconitum↗

PubMed2004

Maoecrystal V, cytotoxic diterpenoid with a novel C19 skeleton from Isodon eriocalyx (Dunn.) hara.

Maoecrystal V (1), a novel C(19) diterpenoid possessing a unique 6,7-seco-6-nor-15(8-->9)-abeo-5,8-epoxy-ent-kaurane skeleton, was isolated from the leaves of a Chinese medicinal herb, Isodon eriocalyx. Its structure was determined by comprehensive NMR and MS spectroscopic analysis and confirmed by single-crystal X-ray diffraction study. Compound 1 showed remarkable inhibitory activity toward HeLa cells with IC(50) = 0.02 microg/mL (cis-platin: IC(50) = 0.99 microg/mL).

Crystallography, X-Ray↗

PubMed2004

Coriatone and corianlactone, two novel sesquiterpenes from Coriaria nepalensis.

Both coriatone (1). a novel highly oxygenated picrotoxane-type sesquiterpene, and corianlactone (2). with an unprecedented sesquiterpene basic skeleton, named coriane, were isolated from Coriaria nepalensis Wall. The structures of 1 and 2 were determined by analysis of their two-dimensional NMR data, and the structure of 2 was confirmed by X-ray analysis. Compounds 1 and 2 showed no remarkable inhibitory activity toward K(562) cells. They are cytotoxic with IC(50) > 50 microg/mL (cis-platinim: IC(50) = 0.49 microg/mL).

Crystallography, X-Ray↗

PubMed2004

Cycloartane-type triterpenoids from Sphaerophysa salsula.

Four novel cycloartanes, named sphaerophysone A (1), B (2), C (3) and D (4), were isolated from the ethanol extract of Sphaerophysa salsula (Pall.) DC. The structures were elucidated on the basis of spectral evidence, and the stereochemistry of compound 1 was defined by X-ray crystallographic analysis. Sphaerophysone B (2) may be an artifact formed in the isolation procedure.

Drugs, Chinese Herbal↗

PubMed2003

Micrandilactone A: a novel triterpene from Schisandra micrantha.

[structure: see text] A novel nortriterpene, micrandilactone A, was isolated from the medicinal plant Schisandra micrantha. This is the first example of an unusual, natural, highly oxidized cycloartane skeleton with a biosynthetically modified eight-membered ring D isolated from the family Schisandraceae.

Lactones↗

PubMed2003

5alpha-steroidal glycosides from Parepigynum funingense.

Four new 5alpha-steroidal glycosides with an unusual framework, funingenosides A (1), B (2), C (3), and D (4), were isolated from the roots of Parepigynum funingense. Their structures were elucidated on the basis of 1D and 2D NMR techniques. The structure and relative stereochemistry of compound 1 were demonstrated by X-ray crystallographic analysis.

Apocynaceae↗