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Yu-Liang Yang

Publications and source records attributed to Yu-Liang Yang.

11 recordsLinked to original sources
PubMed2016

Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking.

The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry (MS) techniques are well-suited to high-throughput characterization of NP, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social Molecular Networking (GNPS; http://gnps.ucsd.edu), an open-access knowledge base for community-wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS, crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of 'living data' through continuous reanalysis of deposited data.

Biological Products↗
PubMed2006

Anti-inflammatory and cytotoxic diterpenes from formosan Polyalthia longifolia var. pendula.

A new clerodane diterpenoid 16-hydroxycleroda-13-ene-15,16-olide-3-one (1) was isolated from the bark of Polyalthia longifolia var. pendula, along with 23 known compounds and phytosteroids. Among these compounds, 5 - 7, 10, and 24 were obtained for the first time from the family Annonaceae . The structures of the isolated compounds were determined by mass and spectroscopic analysis. The clerodane diterpenoids, 2 - 4, showed significant cytotoxicity towards Hep G2 and Hep 3B hepatoma cell lines. Furthermore, compound 5 exhibited potent anti-inflammatory activity towards formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide generation by neutrophils with IC50 = 0.60 +/- 0.09 microg/mL.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2006

Structural elucidation of phosphoglycolipids from strains of the bacterial thermophiles Thermus and Meiothermus.

The structures of two major phosphoglycolipids from the thermophilic bacteria Thermus oshimai NTU-063, Thermus thermophilus NTU-077, Meiothermus ruber NTU-124, and Meiothermus taiwanensis NTU-220 were determined using spectroscopic and chemical analyses to be 2'-O-(1,2-diacyl-sn-glycero-3-phospho) -3'-O-(alpha-N-acetyl-glucosaminyl)-N-glyceroyl alkylamine [PGL1 (1)] and the novel structure 2'-O-(2-acylalkyldio-1-O-phospho)-3'-O-(alpha-N-acetylglucosaminyl)-N-glyceroyl alkylamine [PGL2 (2)]. PGL2 (2) is the first phosphoglycolipid identified with a 2-acylalkyldio-1-O-phosphate moiety. The fatty acids of the phosphoglycolipids are mainly iso-C(15:0), -C(16:0), and -C(17:0) and anteiso-C(15:0) and -C(17:0). The ratios of PGL2 (2) to PGL1 (1) are significantly altered when grown at different temperatures for three strains, T. thermophilus NTU-077, M. ruber NTU-124, and M. taiwanensis NTU-220, but not for T. oshimai NTU-063. Accordingly, the ratios of iso- to anteiso-branched fatty acids increase when grown at the higher temperature.

Chromatography, High Pressure Liquid↗
PubMed2006

New constituents from stems of Goniothalamus amuyon.

Two new compounds, goniothalesacetate (1) and goniothalesdiol A (2) together with goniodiol-7-monoacetate, goniodiol-8-monoacetate, leiocarpin C, liriodenine, griffithazanone A, 4-methyl-2,9,10-(2H)-1-azaanthracencetrione, velutinam and aristolactam BII were isolated and characterized from the stems of Goniothalamus amuyon. Structures of new compounds were determined by spectral analysis.

Annonaceae↗
PubMed2006

New sesquiterpene lactones from the aerial parts of Pseudoelephantopus spicatus.

Two new sesquiterpene lactones, spicatolide C (1) and spicatocadinanolide A (2), have been isolated along with the known piptocarphol isomers (3, 4) and one eudismane type sesquiterpene (5) from the EtOAc extract of the aerial parts of Pseudoelephantopus spicatus. The structures and the relative stereochemistries of the new metabolites were determined by spectroscopic methods.

Asteraceae↗
PubMed2005

An anti-inflammatory ent-kaurane from the stems of Annona squamosa that inhibits various human neutrophil functions.

We have previously shown that 11 ent-kauranes isolated from the stems of Annona squamosa exhibited immunomodulating effects in leukocytes. In this study, a cellular model using isolated human neutrophils, which are important in the pathogenesis of rheumatoid arthritis, ischemia-reperfusion injury, chronic obstructive pulmonary disease, asthma and other inflammatory diseases, was established in order to elucidate the anti-inflammatory functions of 16beta,17-dihydroxy-ent-kauran-19-oic acid (1). Reactive oxygen species (ROS) and granule proteases produced by neutrophils contribute to the pathogenesis of inflammatory diseases. Compound 1 inhibited the generation of superoxide anion, the formation of ROS, and the release of elastase in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils in a concentration-dependent manner with IC (50) values of 3.95 +/- 0.68, 12.20 +/- 2.16, and 12.52 +/- 2.26 microM, respectively. The anti-inflammatory actions were not attributable to cytotoxicity because incubation of the neutrophils with 1 did not result in lactate dehydrogenase release. Compound 1 did not display antioxidant or superoxide anion-scavenging activity. Furthermore, neither subcellular NADPH oxidase activity nor cAMP-dependent pathways were altered by 1. Compound 1 significantly inhibited rapid calcium release from internal calcium stores induced by FMLP but not by thapsigargin. In summary, the presented results indicate that the inhibitory effects of 1 on respiratory burst and degranulation of human neutrophils are through the inhibition of cytosolic calcium mobilization, but not via the cAMP-dependent pathways.

Adult↗
PubMed2004

Inhibitory effects of ent-kauranes from the stems of Annona squamosa on superoxide anion generation by human neutrophils.

Eleven ent-kauranes, isolated from the fresh stems of Annona squamosa L. (Annonaceae), were subjected to assays on the generation of superoxide anion (O2.--) by human neutrophils. Except for ent-kaur-16-en-19-oic acid, 16beta,17-dihydroxy- ent-kauran-19-al, and 16alpha,17-dihydroxy -ent-kauran-19-al, all ent-kauranes showed significant inhibitory effect on O2.-- generation in response to formyl- L-methionyl- L-leucyl- L-phenylalanine (fMLP/CB). In contrast, phorbol myristate acetate (PMA)-induced O2.-- generation was not suppressed by any ent-kauranes. Especially, ent-kaur-16-en-19-oic acid could significantly increase O2.-- production. The structure-activity relationship of these compounds is also discussed herein. Furthermore, the effect of ent-kauranes on nitric oxide generation by NR8383 macrophages in response to lipopolysaccharide (LPS) was examined. None of the compounds showed an inhibitory effect on nitric oxide generation.

Adolescent↗
PubMed2003

Cytotoxic styrylpyrones from Goniothalamus amuyon.

Two new styrylpyrones, (6R,7R,8R)-8-methoxygoniodiol (1) and (6R,7R,8R)-8-chlorogoniodiol (2), together with seven known styrylpyrones and eight other known compounds, were isolated from the leaves and/or stems of Goniothalamus amuyon. The structures of 1 and 2 were elucidated by spectral data interpretation, and the absolute stereochemistry of styrylpyrones in the diol and triol series was confirmed by X-ray crystallographic analysis and CD spectral data. Compound 2 demonstrated significant selective cytotoxicity toward the HONE-1 cancer cell line.

Annonaceae↗
PubMed2003

Secoiridoid glycoside and alkaloid constituents of Hydrangea chinensis.

A new secoiridoid glycoside, hydrachoside A (1), along with 14 known compounds, was isolated from the leaves of Hydrangea chinensis. The absolute stereochemistry of the side chain attached to C-15 on the secoiridoid glycoside hydrangenoside E (2) was determined by NMR spectral analysis. The structures of compounds 1 and 2 were elucidated on the basis of spectral data. The previously reported structure, hydrachine A (3), was revised as its epimer, (-)-neodichroine (4), a new compound.

Alkaloids↗
PubMed2002

New ent-kaurane diterpenoids with anti-platelet aggregation activity from Annona squamosa.

A phytochemical investigation on the stems of Annona squamosa led to the isolation of six new ent-kaurane diterpenoids, annomosin A (16beta-hydroxy-19-al-ent-kauran-17-yl 16beta-hydro-19-al-ent-kauran-17-oate) (1), annosquamosin C (16alpha-hydro-17-hydroxy-19-nor-ent-kauran-4alpha-ol) (2), annosquamosin D (16beta-acetoxy-17-hydroxy-19-nor-ent-kauran-4alpha-ol) (3), annosquamosin E (16beta-hydroxy-17-acetoxy-19-nor-ent-kauran-4alpha-formate) (4), annosquamosin F (16beta-hydroxy-17-acetoxy-18-nor-ent-kauran-4beta-hydroperoxide) (5), and annosquamosin G (16beta,17-dihydroxy-18-nor-ent-kauran-4beta-hydroperoxide) (6), along with 14 known ent-kaurane diterpenoids. The structures of 1-6 were elucidated by spectroscopic data interpretation. Compound 1 is the first dimeric ent-kaurane derivative to have been reported from a plant in the family Annonaceae. Certain useful NMR data were generalized to determine the stereochemistry of C-16 among the ent-kaurane diterpenoids investigated. ent-Kaur-16-en-19-oic acid (9) and 16alpha-hydro-19-al-ent-kauran-17-oic acid (17) showed complete inhibitory effects on rabbit platelet aggregation at 200 microM.

Animals↗