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Biomedical subjects

T S Wu

Publications and source records attributed to T S Wu.

At least 19 recordsLinked to original sources
PubMed2001

Cinnamophilin as a novel antiperoxidative cytoprotectant and free radical scavenger.

The antioxidant properties of cinnamophilin were evaluated by studying its ability to react with relevant reactive oxygen species, and its protective effect on cultured cells and biomacromolecules under oxidative stress. Cinnamophilin concentration-dependently suppressed non-enzymatic iron-induced lipid peroxidation in rat brain homogenates with an IC50 value of 8.0+/-0.7 microM and iron ion/ADP/ascorbate-initiated rat liver mitochondrial lipid peroxidation with an IC50 value of 17.7+/-0.2 microM. It also exerted an inhibitory activity on NADPH-dependent microsomal lipid peroxidation with an IC50 value of 3.4+/-0.1 microM without affecting microsomal electron transport of NADPH-cytochrome P-450 reductase. Both 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azo-bis(2-amidinopropane) dihydrochloride-derived peroxyl radical tests demonstrated that cinnamophilin possessed marked free radical scavenging capacity. Cinnamophilin significantly protected cultured rat aortic smooth muscle cells (A7r5) against alloxan/iron ion/H2O2-induced damage resulting in cytoplasmic membranous disturbance and mitochondrial potential decay. By the way, cinnamophilin inhibited copper-catalyzed oxidation of human low-density lipoprotein, as measured by fluorescence intensity and thiobarbituric acid-reactive substance formation in a concentration-dependent manner. On the other hand, it was reactive toward superoxide anions generated by the xanthine/xanthine oxidase system and the aortic segment from aged spontaneously hypertensive rat. Furthermore, cinnamophilin exerted a divergent effect on the respiratory burst of human neutrophil by different stimulators. Our results show that cinnamophilin acts as a novel antioxidant and cytoprotectant against oxidative damage.

Animals↗
PubMed2001

New constituents and antiplatelet aggregation and anti-HIV principles of Artemisia capillaris.

Five new constituents including a flavonoid, artemisidin A (1), and four coumarins, artemicapins A (2), B (3), C (4) and D (5), together with 70 known compounds (6-75), have been isolated and characterized from the aerial part of Artemisia capillaris. The structures of these compounds were determined from spectral analyses and/or chemical evidence. Among them, 15 compounds (3, 6, 10, 18. 30-32, 38-41, 44, 45, 51, and 55) showed antiplatelet aggregation activity and three compounds (10, 17, and 51) demonstrated significant activity against HIV replication in H9 lymphocytic cells.

Acetylene↗
PubMed2001

Constituents of the root bark of Severinia buxifolia collected in Hainan.

Two new tetranortriterpenoids, 7-isovaleroylcycloseverinolide (1) and 7-isovaleroylcycloepiatalantin (2), together with 28 known compounds, were isolated and characterized from the root bark of Severinia buxifolia collected in Hainan. The structures of 1 and 2 were elucidated on the basis of spectral evidence including 2D NMR and X-ray techniques. The cytotoxicity of several acridone alkaloid isolates (3-8) was evaluated against a small tumor cell panel.

Acridines↗
PubMed2001

Cytotoxicity of Ganoderma lucidum triterpenes.

Two new triterpenoids, lucidenic acid N (1) and methyl lucidenate F (2), together with four known compounds, lucidenic acid A, lucidenolactone, lucidenic acid C, and ganoderic acid E, were isolated from the dried fruiting bodies of Ganoderma lucidum. Their structures were elucidated by spectral and chemical transformation studies. Among them, lucidenic acid N (1), lucidenic acid A, and ganoderic acid E showed significant cytotoxic activity against Hep G2, Hep G2,2,15, and P-388 tumor cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Alkaloids of the wood of Cryptocarya chinensis.

Four new pavine alkaloids, (+)-eschscholtzidine-N-oxide (1), (-)-12-hydroxycrychine (2), (-)-12-hydroxy-O-methylcaryachine (3), and (-)-N-demethylcrychine (4), and four new proaporphine alkaloids, isocryprochine (5), prooxocryptochine (6), isoamuronine (7), and (+)-8,9-dihydrostepharine (8), together with nine known compounds were isolated from an ethanol extract of the wood of Cryptocarya chinensis. Their structures were elucidated by spectral analysis (NMR and MS), and the structures of 2 and 5 were confirmed by X-ray crystallography.

Alkaloids↗
PubMed2001

Alkaloids from the leaves of Cryptocarya chinensis Hemsl.

Investigation of the leaves of Cryptocarya chinensis resulted in the isolation of three new alkaloids, named (-)-isocaryachine-N-oxide, isoboldine-beta-N-oxide, and 1-hydroxycryprochine, together with seven known compounds. Their structures were elucidated by spectral analysis. The structures of (-)-isocaryachine-N-oxide and 1-hydroxycryprochine were further confirmed by X-ray techniques.

Alkaloids↗
PubMed2000

Constituents from the leaves of Aristolochia elegans.

One new biphenyl ether, aristogin C (1), and two new porphyrins, aristophylls A (2) and B (3), as well as 11 known compounds, were isolated from the leaves of Aristolochia elegans. Their structures were elucidated according to the spectroscopic (NMR and MS) analyses or by comparison with literature values.

Chromatography, High Pressure Liquid↗
PubMed2000

Constituents from the stem and root of Aristolochia kaempferi.

Three new phenanthrene derivatives, aristoliukine-C, aristofolin-E and aristolochic acid-Ia methyl ester, and one new sesquiterpene, madolin-P, together with 58 known compounds were isolated from the stem and root of Aristolochia kaempferi. The structures of these compounds were determined by spectral analysis. The cytotoxicity and antiplatelet activity of the isolated compounds are also discussed.

Antineoplastic Agents, Phytogenic↗
PubMed2000

The constituents of the root and stem of Aristolochia cucurbitifolia Hayata and their biological activity.

Four new compounds, three phenanthrene derivatives, aristolochic acid-III methyl ester (1), cepharanone C (2), and sodium 7-hydroxyl-8-methoxyaristolate (3), and the benzoate derivative, sodium 3,4-dimethoxybenzoate (4), together with 53 known compounds were isolated and characterized from the fresh root and stem of Aristolochia cucurbitifolia. Their structures were elucidated by spectral analyses and chemical transformations. The cytotoxicity and antiplatelet activity of the isolated compounds are also discussed.

Animals↗
PubMed2000

The constituents of the root and stem of Aristolochia heterophylla Hemsl.

Seven new compounds, sodium aristolochate-VII (1), aristolactam-CIV (2), madolin-I (3), -J (4), -K (5), -L (6) and -M (7) together with 71 known compounds were isolated and characterized from the fresh root and stem of Aristolochia heterophylla Hemsl. Their structures were determined by spectral methods. Compound 8 was revised as aromadendrane-4beta, 10beta-diol by spectral data and single-crystal X-ray analysis.

Crystallography, X-Ray↗
PubMed2000

Chemical constituents of Glycosmis citrifolia (Willd.) Lindl. Structures of four new acridones and three new quinolone alkaloids.

The structures of two new dimeric acridone alkaloids, glycobismine-D (1) and -E (2), having a novel linkage as binary acridones, three monomeric acridones, glycocitrine-IV (3), -V (4), and -VI (5), and three quinolone alkaloids, glycocitlone-A (6), -B (7), and -C (8) from Glycosmis citrifolia (Willd.) Lindl. (Rutaceae) have been elucidated by spectrometric studies.

Acridines↗
PubMed2000

Acridone alkaloids from the root bark of Severinia buxifolia in Hainan.

Eight new acridone alkaloids, buxifoliadines-A--H together with nine known acridone compounds, were isolated and characterized from the root bark of Severinia buxifolia which was collected in Hainan province, China. Their structures were determined by spectroscopic methods. The relationship between acridone alkaloids with collecting area is discussed. The 13C-NMR spectra of the prenyl substituents at C-2 and/or C-4 of N-unsubstituted acridone alkaloids are also discussed.

Acridines↗
PubMed1999

Differential effects of IL-2 and IL-15 on the death and survival of activated TCR gamma delta+ intestinal intraepithelial lymphocytes.

TCR gamma delta+ cells are enriched in the intestine mucosa and constitute approximately half of the intestinal intraepithelial lymphocytes (iIEL) in mice. They are likely activated by self and foreign Ags in situ, but little is known about how the activated gamma delta iIEL are regulated. In the iIEL compartment, IL-2 is produced by activated TCR alpha beta+ iIEL, and IL-15 message is detected in iIEL and in the epithelial cells. We found surface expression of IL-2 as well as IL-15Rs on activated gamma delta iIEL, and examined the effects of IL-2 and IL-15 on the survival and death of gamma delta iIEL during secondary stimulation through TCR. We found that both cytokines supported growth of the restimulated gamma delta iIEL, but exerted different effects on their survival. A significant higher number of live cells were recovered from the gamma delta iIEL cultures restimulated in IL-15 than in IL-2. Quantitation of apoptotic cells showed more cell death in the IL-2 group than in the IL-15 group. The cell death was associated with restimulation through TCR and was not caused by insufficient growth factor, thus representing activation-induced cell death. Western blot analyses found no difference in the levels of Bcl-2 and Bax proteins between the two groups. However, the level of Bcl-xL protein diminished with time in the IL-2 group whereas the level was sustained in the IL-15 group, which may contribute to the pro-survival effect of IL-15. These results demonstrated that the survival of activated gamma delta iIEL is differentially regulated by IL-2 and IL-15.

Animals↗
PubMed1999

Sesquiterpene esters of aristolochic acid from the root and stem of Aristolochia heterophylla.

Three novel sesquiterpene esters of aristolochic acid, aristoloterpenate-II (2), -III (3), and-IV (4), together with known aristoloterpenate-I (1), were isolated and characterized from the root and stem of Aristolochia heterophylla. Their structures were elucidated by spectroscopic methods. The absolute configuration of these compounds at C-4' was determined as R by circular dichroic studies. These compounds showed cytotoxicity against hepatoma G2, 2, 2, 15 cells.

Animals↗
PubMed1999

Terpenoids of Syzygium formosanum.

A new natural product, 4-epifriedelin (1), and 12 known terpenoids have been isolated from the leaves of Syzygium formosanum. The known compounds include caryophyllene oxide, friedelin, canophyllal, glutinol, alpha-terpineol, phytol, betulinic acid, uvaol, lupeol, betulin, ursolic acid, and oleanolic acid. All of these compounds are reported for the first time from S. formosanum.

Leukemia Virus, Murine↗
PubMed1999

The bakkenolides from the root of Petasites formosanus and their cytotoxicity.

Thirty-two new bakkenolides, bakkenolides-Db (1)--Dh(7), -Fa(8), -Fb(9), -I(10)--M(14), -Na(15), -Nb(16), -O(17)--T(22), -Ua (23), -Ub(24), -V(25)--X(27), -Ya(28), -Yb(29), -Za(30), -Zb(31) and -III(32), from the roots of Petasites formosanus together with thirty known compounds were isolated. The structures were characterized by spectral analysis. The locations, C-1 and/or C-9 of bakkenolide skeleton, of the substituents, such as acetoxy, isobutyroyloxy and isovaleroyloxy groups, can be determined by the chemical shifts of their signals and the H-1 and/H-9 in the 1H-NMR spectra. The cytotoxicity was also discussed.

Animals↗