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Biomedical subjects

D Q Yu

Publications and source records attributed to D Q Yu.

At least 19 recordsLinked to original sources
PubMed2003

Purification, characterization of two peptides from Buthus martensi Karch.

A new peptide named Martentoxin I and an analogue Martentoxin were purified and characterized from the venom of Buthus martensi Karch. Martentoxin I consisted of 36 amino acid residues with molecular mass as 3908.0 Da determined by matrix-assisted laser desorption ionization time-of-flight-MS. The amino acid sequence was determined as GLIDVKCFASSECWTACKKVTGSGQGKCQNNQCRCY by Edman degradation. Martentoxin consisted of 37 amino acid residues with a molecular mass as 4055.3 Da and it showed highly sequence identity to Martentoxin I as FGLIDVKCFASSECWTACKKVTGSGQGKCQNNQCRCY. Estimation from circular dichroism spectra indicated Martentoxin I owned 18.0% alpha-helix, 53.0% beta-sheet structure and 3.9% turn while Martentoxin contained 13.3% alpha-helix, 64.3% beta-sheet structure and 1.1% turn. The toxicity assay showed both peptides had no toxic effects on mice up to the dose of 10 mg/kg. Electrophysiological studies showed that Martentoxin I and Martentoxin at the concentration of 1 microm significantly inhibited voltage-dependent Na+ current (INa) and voltage-dependent delayed rectifier K+ current (IK) but had no effects on transient K+ current (IA). Both interactions with Na+ and K+ channels were irreversible.

Amino Acid Sequence↗
PubMed2001

A steroidal saponin from the seeds of Allium tuberosum.

A steroidal saponin, named tuberoside, together with seven known compounds, were isolated from the seeds of Allium tuberosum Rottl. ex Spreng. Its structure was established by spectroscopic data, hydrolysis, and comparison with spectral data of known compounds to be (2alpha, 3beta, 5alpha, 25S)-2,3,27-trihydroxyspirostane 3-O-alpha-L-rhamnopyranoyl-(1-->2)-O-[alpha-L-rhamnopyranoyl-(1-->4)]-beta-D-glucopyranoside.

Allium↗
PubMed2001

Five new diprenylated flavonols from the leaves of Broussonetia kazinoki.

Five new diprenylated flavonols, broussonol A (1), broussonol B (2), broussonol C (3), broussonol D (4), and broussonol E (5), along with two known compounds, were isolated from an ethanolic extract of the leaves of Broussonetia kazinoki. Their structures were elucidated by chemical and spectral methods. Cytotoxic activities were evaluated against several different cell lines.

Dose-Response Relationship, Drug↗
PubMed2001

Two new bislabdane-type diterpenoids and three new diterpenoids from the roots of Cunninghamia lanceolata.

Two new bislabdane-type diterpenoids lanceolatin (1), lancelatol (2) and three new diterpenoids 15-nor-14-oxo-8(17),12-labdanien-14,18-dionic acid (3), 8(17),12,14-labdantrien-18-oic acid (4) and 8(17),12,14-labdantrien-18-ol (5), together with 7 known diterpenoids were isolated from the roots of Cunninghamia lanceolata. Their structures were determined by spectroscopic and chemical methods. All of these compounds were isolated from the species for the first time. One of the isolated compounds showed a significant inhibition effect on mouse hind-paw edema induced by carrageenan.

Animals↗
PubMed2001

Chemical constituents from the leaves of Magnolia denudata.

20 compounds were isolated from the leaves of Magnolia denudata including 16 lignans, which belong to 6 structural types. Except for (7R, 8S, 1'S)-delta8' -1', 4'- dihydro-5'-methoxy-3,4-methylenedioxy-4'-oxo-7.0.2', 8.1'-neolignan (6), magliflonenone (9), 2, 5'-diene-2', 8'-epoxy-5'-methoxy-8-methyl-4'-oxo-3,4- methylenedioxy-spiro (5, 5)-undecane (10), veraguensin (16) and beta-sitosterol (20), the other 15 compounds were obtained from this species for the first time. The absolute configurations of 3 compounds (1, 4, 10) were determined by CD spectroscopy for the first time. The anti-inflammatory activities of compounds 1, 2 and 16 were assessed and 2 was shown to have significant inhibition effect on mice hind-paw edema induced by carrageenan.

Animals↗
PubMed2000

New annonaceous acetogenins from the roots of Uvaria calamistrata.

Five new annonaceous acetogenins, calamistrins C-G (1-5), were isolated from an ethanolic extract of the roots of Uvaria calamistrata. Compounds 1-3 were mono-THF ring acetogenins; compounds 4 and 5 were bis-THF acetogenins, with the THF rings from C-18 to C-25. The absolute configurations of 3, 4, and 5 as well as the partial absolute configurations of 1 and 2 were determined by (13)C NMR spectroscopy and advanced Mosher methodology.

Drug Screening Assays, Antitumor↗
PubMed2000

[Studies on the chemical constituents of Murraya kwangsiensis].

AIM: To investigate the chemical constituents of Murraya kwangsiensis. METHODS: Compounds were isolated by silica gel column chromatography and TLC method, respectively. Structures of compounds were elucidated by spectral (UV, IR, MS, 1HNMR and 13CNMR) analysis. RESULTS: Five carbazole alkaloids and two other compounds were isolated and identified. Six of them are known compounds: murrayafoline A, murrayanine, koenine, isomahanine, palmitic acid and beta-sitosterol. One is a new alkaloid, named kwangsine. CONCLUSION: A new alkaloid, named kwangsine, was isolated from Murraya kwangsiensis Var. Six known compounds were isolated from this plant for the first time.

Alkaloids↗
PubMed1999

Calamistrins A and B, two new cytotoxic monotetrahydrofuran annonaceous acetogenins from Uvaria calamistrata.

Two new bioactive monotetrahydrofuran acetogenins, calamistrins A (1) and B (2), and two known compounds, uvarigrin (3) and uvarigranin (4), have been isolated from the roots of Uvaria calamistrata. The structures of the new compounds were elucidated by spectroscopic and chemical methods. The absolute stereochemistry of the stereogenic centers was established by Mosher ester methodology.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Styryllactones from the rhizomes of Goniothalamus griffithii.

Three new styryl-lactones 8-acetylgoniofufurone(1), 7-acetylgonio-pypyrone(3), and 5-acetylgoniopypyrone(4), along with ten known compounds, goniofufurone(2), goniopypyrone(5), goniothalamin, goniothalenol, (+)-isoaltholactone, goniodiol, 7-acetylgoniodiol, goniotriol, 8-acetylgoniotriol, 9-deoxygoniopypyrone were isolated from the rhizomes of Goniothalamus griffithii Hook f. et. Thoms. Their structures were elucidated by IR, MS, NMR spectra and chemical evidence. All compounds showed cytotoxic activities against human cancer cell lines.

Lactones↗
PubMed1999

A new furofuran mono-lactone from Forsythia suspensa.

A new furofuran mono-lactone, named forsythenin, was isolated from the fruits of Forsythia suspensa, together with the known compounds, ocotillone, ocotillol monoacetate, (6'-O-palmitoyl)-sitosterol-3-O-beta-D-glucoside and palmitic acid. The structure of the new compound was elucidated on the basis of spectroscopic means and X-ray crystallography.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed1999

New polyoxygenated cyclohexenes from Uvaria calamistrata.

Five new polyoxygenated cyclohexenes, named uvacalol A (1), B (2), C (3), D (4) and E (5) were isolated from the roots of Uvaria calamistrata. On the basis of spectral analysis and chemical derivatization, including the preparation of Mosher esters, the structures of compound 1-5 were established as (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene3,4-diol-3-benzoate, (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4-diol-4-benzoate, (2R,3S,4R,5S)-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,4-triol-3-benzoate, (2R,3S,4R,5S)-3-methoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,5-triol and (2R,3S,4R,5S)-2-acetoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4,5-triol-5-benzoate, respectively.

Alcohols↗
PubMed1999

Two new caffeyol glycosides from Forsythia suspensa.

Two new caffeoyl glycosides of phenethyl alcohol, suspensaside A (1) and suspensaside B (2), were isolated from the fruits of Forsythia suspensa. Also obtained in this investigation were two known compounds forsythiaside (3) and suspensaside (4). The structures of compounds 1 and 2 were established by ID and 2D NMR techniques and chemical methods.

Caffeic Acids↗
PubMed1999

Sphingosine derivatives from the seeds of Allium tuberosum.

A new ceramide, named tuber-ceramide (2), along with a known cerebroside (1) were isolated from the seeds of Allium tuberosum. The structure of tuber-ceramide was determined on the basis of spectral data as N-(2',3'-dihydroxy-tetracosenoyl)-2-amino-1,3,4-trihydroxy octadecane (2). This is the first report of sphingosine derivatives isolated from the genus Allium.

Allium↗
PubMed1999

Structural chemistry and biological activities of natural products from Chinese herbal medicines.

This is a brief account of recent developments (1978-1994) in natural product chemistry and bioactivity related to Chinese herbal medicine. In the period covered, more than thousand chemically new constituents were isolated and their structures elucidated. We have presented most of the structural formulae for the sake of clarity, along with passing mentions of pertinent biological activities. The isolates were grouped under different headings according to structure types.

Animals↗
PubMed1998

Linear acetogenins from Goniothalamus donnaiensis.

Four linear acetogenins, donhepocin (1), 34-epi-donhepocin (1'), donhexocin and donbutocin, have been isolated from the roots of Goniothalamus donnaiensis. 1 and 1', isolated as an epimeric pair, contain a rare gamma-hydroxymethyl-gamma-lactone. Their structures have been established on the basis of spectral and chemical evidence.

4-Butyrolactone↗