Biomedical subjects

Geng Lin

Publications and source records attributed to Geng Lin.

7 recordsLinked to original sources

PubMed2006

Anti-hepatoma activity and mechanism of ursolic acid and its derivatives isolated from Aralia decaisneana.

AIM: To investigate the anti-tumor activity of ursolic acid (UA) and its derivatives isolated from Aralia decaisneana on hepatocellular carcinoma both in vitro and in vivo. METHODS: In vivo cytotoxicity was first screened by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Morphological observation, DNA ladder, flow cytometry analysis, Western blot and real time PCR were employed to elucidate the cytotoxic mechanism of UA. Implanted mouse hepatoma H22 was used to evaluate the growth inhibitory effect of UA in vivo. RESULTS: UA could significantly inhibit the proliferation of HepG2 and its drug-resistance strain, R-HepG2 cells, but had no inhibitory effect on primarily cultured normal mouse hepatocytes whereas all the six derivatives of UA could not inhibit the growth of all tested cell lines. Further study on mechanism demonstrated that apoptosis and G0/G1 arrest were involved in the cytotoxicity and cleavage of poly-(ADP-ribose)-polymerase (PARP). Downregulation of cyclooxygenase-2 (COX-2) protein and upregulation of heat shock protein (HSP) 105 mRNA correlated to the apoptosis of HepG2 cells treated with UA. In addition, UA also could inhibit the growth of H22 hepatoma in vivo. CONCLUSION: UA is a promising anti-tumor agent, but further work needs to be done to improve its solubility.

Aralia↗

PubMed2006

A new labdane type diterpenoid from Trollius ledebouri.

A new labdane type diterpenoid, (8alpha,13R)-epoxy-14-labden-6beta,7beta-diol-7-beta-D-(4'-acetyl) fucopyranoside, named ledebourene 1, was isolated from the flowers of Trollius ledebouri. The absolute stereostructure was elucidated on the basis of the spectroscopic analysis.

China↗

PubMed2005

Flavone C-glycosides from flowers of Trollius ledebouri.

The ethanol extract of the flowers of Trollius ledebouri yielded four flavone C-glycosides, 2''-O-vanilloylvitexin, 2''-O-feruloylorientin, 2''-O-beta-L-galactopyranosylvitexin, and 2''-O-beta-L-galactopyranosylorientin, along with known compounds, 6''-O-acetylorientin, 2''-O-(4'''-hydroxybenzoyl)vitexin, vitexin, and orientin. Their structures were elucidated by means of UV, IR, MS and NMR spectroscopic analyses.

Flowers↗

PubMed2005

Isolation and structure determination of cypritibetquinone A and B, two new phenanthraquinones from Cypripedium tibeticum.

AIM: To study the chemical constituents of Cypripedium tibeticum. METHODS: Compounds were isolated by repeated silica gel chromatography and purified on Sephadex LH-20 and structures were determined by spectral analysis. RESULTS: Cypritibetquinones A and B were isolated from the ethyl acetate residue and their structures were determined as 7-hydroxy-2-methoxy-1 4-phenanthraquinone (1) and 7-hydroxy-2, 10-dimethoxy-l1 4-phenanthraquinone (2), respectively, by extensive spectral analyses. CONCLUSION: Cypritibetquinones A and B are two new phenanthraquinones.

Anthraquinones↗

PubMed2002

Beesiosides A-F, six new cycloartane triterpene glycosides from Beesia calthaefolia.

Six new cycloartane triterpene glycosides (1-6), beesiosides A-F, were isolated from whole plants of Beesia calthaefolia, and their structures were elucidated on the basis of extensive NMR experiments and chemical methods. Beesiosides A-F were assigned as (20S,24R)-epoxy-9,19-cyclolanostane-3beta,16beta,18,25-tetraol-3-O-beta-D-xylopyranoside (1), (20S,24R)-epoxy-9,19-cyclolanostane-3beta,12beta,16beta,18,25-pentaol-3-O-beta-D-xylopyranoside (2), (20S,24R)-epoxy-9,19-cyclolanostane-3beta,12alpha,16beta,18,25-pentaol-3-O-beta-D-xylopyranoside (3), (20S,24R)-16beta-acetoxy-20,24-epoxy-9,19-cyclolanostane-3beta,12alpha,18,25-tetraol-3-O-beta-D-xylopyranoside (4), (20S,24R)-epoxy-9,19-cyclolanostane-3beta,15alpha,16beta,18,25-pentaol-3-O-beta-D-xylopyranoside (5), and (20S,24R)-16beta-acetoxy-20,24-epoxy-9,19-cyclolanostane-3beta,12beta,25-triol-3-O-beta-D-xylopyranoside (6), respectively.

Chromatography, Thin Layer↗

PubMed2002

Beesiosides G, H, and J-N, seven new cycloartane triterpene glycosides from Beesia calthifolia.

Seven new cycloartane glycosides (1-7), beesiosides G, H, and J-N, together with beesioside I (8) and beesioside A, were isolated from the rhizomes of Beesia calthifolia, and their structures were established by spectroscopic and chemical methods. Beesiosides G, H, and J-N were assigned as 20xi(1),24xi(2)-epoxy-9,19-cyclolanostane-3beta,16beta,18,25-tetraol-3-O-beta-D-glucopyranoside (1), 20xi(1),24xi(2)-epoxy-9,19-cyclolanostane-3beta,16beta,18,25-tetraol-3-O-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (2), (20S,24R)-15alpha,16beta-diacetoxy-20,24-epoxy-9,19-cyclolanostane-3beta,18,25-triol-3-O-beta-D-xylopyranoside (3), (20S,24S)-16beta-acetoxy-18,24;20,24-diepoxy-9,19-cyclanostane-3beta,15beta,25-triol-3-O-beta-D-xylopyranoside (4), (20S,24S)-16beta-acetoxy-18,24;20,24-diepoxy-9,19-cyclanostane-3beta,25-diol-3-O-beta-D-xylopyranoside (5), 20xi(1),24xi(2)-epoxy-15alpha-acetoxy-9,19-cyclolanostane-3beta,16beta,25-triol-3-O-beta-D-xylopyranoside (6), and 20xi(1),24xi(2)-epoxy-9,19-cyclolanostane-3beta,12alpha,15alpha,16beta,25-pentaol-3-O-beta-D-xylopyranoside (7), respectively.

Chromatography, Thin Layer↗

PubMed2002

[Structures and pharmacological activities of beesiosides O and P].

AIM: To investigate the chemical constituents of the rhizomes of Beesia calthaefolia native to China in order to obtain a more comprehensive understanding of its effective components. METHODS: Compounds were isolated by column chromatography with silica gel. Their structures were elucidated by spectral analysis and chemical evidence. Compounds identified were subjected to pharmacological evaluation. RESULTS: Two novel compounds were isolated and identified as (20S, 24S)-15 alpha-acetoxy-16 beta, 24; 20, 24-diepoxy-9, 19-cyclolanostane-3 beta, 25-diol-3-O-beta-D-xylopyranoside (I) and (20S, 24R)-15 alpha-acetoxy-9, 19-cyclolanostane-3 beta, 16 beta, 20, 24, 25-pentaol-3-O-beta-D-xylopyranoside (II), named beesioside O and beesioside P. CONCLUSION: Compounds I and II are new compounds. Compounds I exhibited immunosuppressive activity and could inhibit angiogenesis as well as inhibit the proliferation of osteoblast. Compound II displayed remarkable inhibition activity against calcium channel receptor.

Angiogenesis Inhibitors↗