Biomedical subjects

Han-Dong Sun

Publications and source records attributed to Han-Dong Sun.

81 records · Page 5Linked to original sources

PubMed2002

Cytotoxic ent-kaurane diterpenoids from Isodon sculponeata.

Four new ent-kaurane diterpenoids, sculponeatins F-I (1-4), together with six known compounds, sculponeatin E (5), epi-nodosin (6), epi-nodosinol (7), enmein (8), and macrocalyxoformins A and B (9 and 10), were isolated from the leaves of Isodon sculponeata. Also obtained were ursolic acid, 2alpha,3beta-dihydroxy-urs-12-en-28-oic acid, 2alpha,3beta,19alpha-trihydroxy-urs-12-en-28-oic acid, beta-sitosterol, daucosterol, quercetin, pedalitin, rosmarinic acid, caffeic acid and ethyl caffeic acid. Their structures were determined by spectral methods (1D-, 2D-NMR and MS). Some diterpenoids were tested for their cytotoxicity to inhibit three kinds of human tumor cells K562, A549 and T24. Compounds 3, 4, 6, 8, and 10 showed significant inhibitory effect toward K562 with IC(50) values ranging from 3.2 microg/ml to 8.2 microg/ml, while 3 and 6 exhibited potent antitumor activity against T24, but none exhibited cytotoxicity toward the cells of A549.

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

Dihydroisotanshinone I protects against menadione-induced toxicity in a primary culture of rat hepatocytes.

Dihydroisotanshinone I is a phenanthrenequinone derivative isolated from the roots of Salvia trijuga Diels. The present study demonstrated the hepatoprotective effect of dihydroisotanshinone I against menadione-induced cytotoxicity in a primary culture of rat hepatocytes. Pretreating the cells with dihydroisotanshinone I at concentrations ranging from 2.5 microM to 20 microM for 24 hours caused dose-dependent protection against hepatotoxicity induced by menadione. Intracellular glutathione level and activity of DT-diaphorase have been suggested to play important roles in menadione-induced cytotoxicity. However, treating the hepatocytes with 20 microM dihydroisotanshinone I for 24 hours did not cause a significant change in glutathione level and DT-diaphorase activity. On the contrary, adding dihydroisotanshinone I to freshly isolated hepatocytes at concentrations between 50 nM to 200 nM inhibited NADH-induced superoxide production dose-dependently as indicated by the decrease of lucigenin-amplified chemiluminescence. In addition, dihydroisotanshinone I at concentrations ranging from 5 microM to 20 microM inhibited tert-butyl hydroperoxide-induced lipid peroxidation dose-dependently in isolated hepatocytes as indicated by the level of malondialdehyde. These results suggest that the protective action of dihydroisotanshinone I against menadione-induced hepatotoxicity is attributed to its antioxidant properties including the free radical scavenging activity and inhibition of lipid peroxidation. Abbreviations. DTD:DT-diaphorase GSH:glutathione LDH:lactate dehydrogenase MDA:malondialdehyde MTT:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide TBHP: tert-butyl hydroperoxide

Animals↗

PubMed2002

Constituents of Clerodendrum bungei.

Two new compounds, 5-O-ethylcleroindicin D (1) and bungein A (2), together with 12 known compounds (3-14), were isolated from the aerial parts of the medicinal plant Clerodendrum bungei. The structures of 1 and 2 were elucidated as a perhydrobenzofuran derivative and a peroxide dimer by spectral and chemical evidence. Compounds 3-14 have been obtained from this species for the first time.

Clerodendrum↗

PubMed2002

Two new diterpenoid dimers, fritillebinide D and E, from bulbs of Fritillaria ebeiensis.

Two new ent-kaurane diterpenoid dimers, fritillebinide D (1) and fritillebinide E (2), were isolated from bulbs of Fritillaria ebeiensis G.D. Yu et G.Q. Ji. Their structures have been determined to be ent-3beta-acetoxy-kauran-16beta, 17-acetal ent-3beta-acetoxy-16beta-kauran-17(R)-aldehyde (1) and ent-3beta-acetoxy-kauran-16beta,17-acetal ent-3beta-acetoxy-16beta-kauran-17(S)-aldehyde (2) by means of spectral analysis.

Diterpenes↗

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↗

PubMed2002

Triterpene saponins from Craniotome furcata.

Three saponins, craniosaponin A (1) and buddlejasaponins Ia (2) and I (3) were isolated from the n-butanol soluble fraction of Craniotome furcata for the first time. Among them, craniosaponin A (1) was identified to be a new compound. The structure of craniosaponin A was assigned mainly by spectral methods. A preliminary assay in vitro was applied to evaluate their cytotoxicity against several tumor cell-lines.

Animals↗

PubMed2002

[Laggera pterodonta--a Yunnan Herbal Medicine]

OBJECTIVE: A systematic study of Laggera pterodonta was performed in order to identify its bioactive compounds. METHODS: Solvent partition and column chromatography used to isolate and purify Laggera pterodonta compounds. The isolated compounds were further elucidated by high field NMR spectroscopy. RESULTS: Fifty-two compounds were separated and the structures of 39 compounds were elucidated. Twenty-four compounds have not been previously reported. For example, the structure of compound 19, a previously undetected compound was elucidated as 4gamma, 9alpha,11-triol-enantio-eudesmane using both 1D and 2D NMR spectroscopy. Major secondary metabolites of the Laggera pterodonta included eudesmane-type sesquiterpenes and flavone derivatives. CONCLUSION: A systematic study of a yunnan herbal medicine Laggera pterodonta resvealed several novel compounds that may have clinical significance. Further in vivo animal studies should be performed to assess their bioactive role.

Journal Article↗