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Biomedical subjects

Xue-Mei Niu

Publications and source records attributed to Xue-Mei Niu.

14 recordsLinked to original sources
PubMed2006

Synthesis and cytotoxicity of some new eriocalyxin B derivatives.

Eriocalyxin B (1) was regarded as the promising candidate for new anticancer agent because of its potent activity and novel mechanism of action. Systematic modifications of 1 were done, and nineteen derivatives were synthesized and their cytotoxicities against five tumor cell lines were evaluated. The structure-activity relationship (SAR) of 1 confirmed that the alpha,beta-unsaturated ketone moieties in ring A and D are the leading active sites; the 7,20-epoxy moiety, OH-6 and OH-7 play an important role in keeping the cytotoxicity. The 6,7-seco derivative 19 had remarkable activity while derivative 20 oxidized from 19 was completely inactive, which suggested that the carboxyl group could destroy the cytoxicity of 20 despite the presence of alpha,beta-unsaturated ketone moiety.

Antineoplastic Agents↗
PubMed2006

Prenylated phenolics from Ganoderma fornicatum.

Three new prenylated phenolic compounds, fornicins A-C (1-3), were obtained from the fruiting bodies of Ganoderma fornicatum. The structure elucidation was achieved by interpretation of spectroscopic data. These compounds exhibited moderate cytotoxic activity with IC(50) values of 15 to 30 microg/mL in Hep-2 cells.

Antineoplastic Agents↗
PubMed2005

Four new cucurbitane glycosides from Hemsleya jinfushanensis.

A phytochemical study of the tubers of Hemsleya jinfushanensis L. T. Shen resulted in the isolation of four new cucurbitane glycosides, jinfushanosides A-D (1- 4), as well as four known compounds 5-8. Compounds 1-7 were tested for bioactivity against rabbit platelet aggregation induced by PAF, ADP, or AA. Among them, compounds 1, 5, 6 and 7 weakly inhibited PAF-induced platelet aggregation.

Amino Acids↗
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

Two new coumarin derivatives from the roots of Heracleum rapula.

Two new coumarins, 13- O-[ beta- D-apiofuranosyl(1-->6)- beta- D-glucopyranosyl]-(12 R)-heraclenol ( 1) and (12 R,12" R)-diheraclenol ( 2) were isolated from the acetone extract of the fresh roots of Heracleum rapula. Their structures were determined by means of spectroscopic analysis and, in the case of compound 1, the structure elucidation was supported by acid hydrolysis. Compound 1 is a coumarin glycoside while 2 is a coumarin dimer. The inhibitory effects of 1, its aglycone ( 3), and 2 on rabbit platelet aggregation induced by PAF, AA and ADP were tested. Weak activities were observed for each compound with the percentages of inhibition in the range of 0.7 - 24.8 %.

Animals↗
PubMed2003

Chemical constituents from Amentotaxus yunnanensis and Torreyayunnanensis.

In a chemical study of taxonomically related Taxaceae plants of Yunnan Province, China, seven compounds, including a new amentoflavone biflavonoid, 2,3-dihydro-7,7' '-dimethoxyamentoflavone (1), were isolated from Amentotaxus yunnanensis, and 12 isolates were obtained from Torreya yunnanensis. From the latter plant, a new abietane diterpene, torreyayunnin (7), is reported for the first time. The known isolates from A. yunnanensis have been identified as sequoiaflavone (3), sotetsuflavone (4), 7,7' '-dimethoxyamentoflavone (5), lutein, beta-sitosterol, and sequoyitol. Amentoflavone (2), sotetsuflavone (4), sciadopitysin (6), 12-hydroxydehydroabietinol, meridinol, balanophonin, (+)-pinoresinol monomethyl ether, (+)-pinoresinol monomethyl ether glucoside, erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-[2-formyl-(E)-vinyl]-2- methoxyphenoxy]propane-1,3-diol, threo-1-(4-hydroxy-3-methoxyphenyl)-2- [4-[2-formyl-(E)-vinyl]-2-methoxyphenoxy] propane-1,3-diol, and (E)-2-butenedioic acid were identified as known isolates from T. yunnanensis. The presence of the amentoflavone biflavonoids (1, 3-5) in A. yunnanensis supports its placement in the Taxaceae. The occurrence of the biflavonoid sotetsuflavone (4) in both A. yunnanensis and T. yunnanensis suggests that these two genera are closely related. The identification and structural elucidation of these isolates were based on spectral data analysis including 1D and 2D NMR.

Abietanes↗
PubMed2002

Diterpenoids from Isodon enanderianus.

Four ent-kauranoids, 6-epiangustifolin and enanderinanins F-H, as well as 11 known ent-kaurane diterpenoids, macrocalin B, xerophilusin A, trichorabdal A, trichorabdal B, effusin, angustifolin, longikaurin D, longikaurin F, enanderinanin B, xerophilusin G and shikokianin were isolated from the aerial parts of Isodon enanderianus. The new diterpenoids were identified as 6-epiangustifolin (11alpha-hydroxy-6alpha-methoxy-6,19-epoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), enanderinanin F (19-acetoxy-6,20:6,11beta-diepoxy-6,7-seco-ent-kaur-16-en-15-one-1beta,7-olide), enanderinanin G (1beta,6beta,7beta-trihydroxy-19-acetoxy-16beta-methoxymethyl-7alpha,20-epoxy-ent-kaur-15-one) and enanderinanin H (6beta,7beta,14beta-trihydroxy-1alpha,11beta-acetonide-7alpha,20-epoxy-ent-kaur-16-en-15-one), respectively, on the basis of spectral data, especially by 2D NMR techniques. 6-Epiangustifolin showed significant cytotoxic activity against K562 cell.

Diterpenes↗
PubMed2002

Abietane diterpenoids from Coleus xanthanthus.

Eight new abietane diterpenoids, coleon U 11-acetate (1), 16-acetoxycoleon U 11-acetate (2), and xanthanthusins F-K (3-8), together with five known analogues, coleon U (9), 16-O-acetylcoleon C (10), coleon U-quinone (11), 8alpha,9alpha-epoxycoleon U-quinone (12), and xanthanthusin E (13), were isolated from the aerial parts of Coleus xanthanthus. The structures of 1-8 were elucidated on the basis of spectral methods. Compounds 1, 5, and 11-13 were evaluated for their cytotoxicity against K562 human leukemia cells.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Cytotoxic 3,20-epoxy-ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora.

Four new ent-kaurane diterpenoids, laxiflorins J-M (1-4), along with maoecrystal A (5) and maoecrystal P (6), were isolated from the leaves of Isodon eriocalyx var. laxiflora. Their structures were determined by spectroscopic analyses. All the compounds were assayed for their cytotoxic effects on human tumor K562, A549, and T24 cell lines. Compounds 1 and 6 showed significant inhibitory effects on human tumor K562 and T24 cells, with IC(50) values less than 0.5 microg/mL. Compound 3 also demonstrated cytotoxic activities against all three types of human tumor cells, with IC(50) values in the range of 1-25 microg/mL.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Taxuyunnanines S-V, new taxoids from Taxus yunnanensis.

Four new 11(15-->1)-abeotaxoids with an opened oxetane ring system, taxuyunnanines S, T, U and V (1 - 4) were isolated from the bark of Taxus yunnanensis. Taxuyunnanine S (1), is the most hydroxylated abeotaxoid discovered to date from Taxus species. The structures were determined by spectroscopic means including 1D and 2D NMR experiments.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Cytotoxic ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora.

Three new ent-kaurane diterpenoids laxiflorin E (1), laxiflorin H (6) and laxiflorin I (8) were isolated from the leaves of Isodon eriocalyx var. laxiflora, along with nine known diterpenoids, eriocalyxin A (2), laxiflorin C (3), laxiflorin D (4), laxiflorin A (5), maoecrystal S (7), maoecrystal Q (9), eriocalyxin B (10), maoecrystal C (11) and enmelol (12). The structures of the new compounds were determined by spectroscopic methods. Compounds 1-5 are 6,7-seco-ent-kaurane-7,20-olide diterpenoids, and 6-12 belong to 7,20-epoxy-ent-kauranoids. The spectral data of enmelol (12) are reported here for the first time. Ten of these compounds were tested for their cytotoxicity toward K562 and T24 human tumor cells. Compounds 1, 3 and 10 showed significant inhibitory effects on K562 cells with IC50 values 0.077, 0.569 and 0.373 microg/mL, and compounds 1 and 10 also demonstrated significant inhibitory activities toward T24 cells with IC50 values 0.709 and 0.087 microg/mL. Compounds 8 and 11 also displayed inhibitory effect on both two kinds of cells with IC 50 value less than 6.5 microg/mL.

Antineoplastic Agents, Phytogenic↗
PubMed2002

ent-Kaurane diterpenoids from the leaves of Isodon xerophilus.

From the ethanolic extract of the leaves of Isodon xerophilus, three new ent-kaurane diterpenoids named xerophilusins L-N (1 - 3), together with three known ones designated as rabdoternin A (4), longikaurin F (5) and ponicidin (6), were isolated and structurally elucidated. Compound 6 demonstrated most potent cytotoxic activity against K562 and T24 human tumor cell lines with IC(50) = 0.09 and 0.32 microg/ml, respectively.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Constituents from the roots of Heracleum rapula Franch.

A new coumarin glucoside, 8-hydroxy-5-O-beta-D-glucosylpsoralen, along with 17 known coumarins and one steroid, was isolated from the roots of Heracleum rapula Franch. Four coumarin glucosides, including the new one, were obtained from the water-soluble fraction. The other coumarins isolated from the ethyl acetate-fraction included 10 furanocoumarins, a simple coumarin and three types of bicoumarins. Their structures were elucidated by means of spectroscopic analysis.

Coumarins↗
PubMed2002

Non-taxane compounds from the bark of Taxus yunnanensis.

From the bark of Taxus yunnanensis, 15 non-taxane compounds were isolated. Through spectroscopic methods such as ID and 2D NMR and MS experiments, one of them was determined as a new abietane-type diterpenoid named taxayunnin (1). The other 14 known compounds were identified as taxamairin C (2), taxamairin A (3), 3beta-hydroxy-sandaracopimaric acid (4), (+)-3-hydroxy-isodrimenin (5), rubrosterone (6), ponasterone A (7), ecdysterone (8), 20-hydroxy-echysone-20,22-monoacetonide (9), 7-oxositosterol (10), stigmast-4-en-6beta-ol-3-one (11), 5alpha,6beta-dihydroxy-daucosterol (12), beta-sitosterol (13), daucosterol (14), 1-O-beta-D-glucopyranosyl-(2S, 3R, 4E, 8Z)-2-N-(2'-hydroxypalmitoy])-octadeca-sphinga-4,8-dienine (15), respectively. Compounds 4-6, 9-12 and 15 were isolated from Taxus plants for the first time.

Plant Bark↗