Xiaona Fan

Chemical constituents of Heteroplexis micocephala.

Eleven new compounds including two sesquiterpenes with an unusual 2,2,5,9-tetramethylbicyclo[6.3.0]undecane carbon skeleton (1 and 2), five phytane-type diterpene dilactones (3-7), an ent-clerodane diterpene dilactone (8), and three phenylpropenol esters (9-11), together with a diacylphenol (12) and 38 known compounds, have been isolated from an ethanolic extract of Heteroplexis micocephala. Their structures including absolute configurations were elucidated by spectroscopic and chemical analyses. In the in vitro assays, compound 6 showed a selective cytotoxic activity against A2780 with an IC(50) value of 4.37 microM, while sinapyl diangelate (13) showed a potent activity inhibiting HIV-1 replication with an IC(50) value of 4.04 microM.

Yaoshanenolides A and B: New Spirolactones from the Bark of Machilus yaoshansis

Two novel tricyclic spirolactones bearing long linear alkyl chains, yaoshanenolides A (1) and B (2), formed by Diels-Alder[4 + 2] cycloaddition of a molecule of each butenolide with β-phellandrene, were isolated from the bark of Machilus yaoshansis. Their structures and absolute configurations were determined by extensive spectroscopic methods, especially 2D NMR and ECD data analysis. The proposed biosynthetic pathway is discussed. Both compounds exhibited nonselective cytotoxic activities against several human cancer cell lines.

Chemical constituents of the roots of Euphorbia micractina.

Nine minor new tirucallane (1-7) and euphane (8 and 9) triterpenoids including five hydroperoxides, together with 18 known compounds, have been isolated from an ethanolic extract of the roots of Euphorbia micractina. Their structures including absolute configurations were elucidated by spectroscopic and chemical analysis. In the in vitro assays, betulin (10) showed a selective cytotoxic activity against A2780 ovarian cells with an IC(50) value of 6.1 microM and inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with an IC(50) value of 15.3 microM. Jolkinol B (11) showed a potent activity against HIV-1 replication with an IC(50) value of 12.6 muM. However, compounds 1-9 and the other known compounds were inactive in the three assays used.

Abietane and C20-norabietane diterpenes from the stem bark of Fraxinus sieboldiana and their biological activities.

Fourteen new abietane (1-14) and seven new C(20)-norabietane (15-21) diterpenes, together with five known analogues, have been isolated from the stem bark of Fraxinus sieboldiana. Their structures were elucidated by spectroscopic data analysis. In the in vitro assays, at 10(-5) M, compounds 8, 16, and 22 showed inhibitory activity against the release of β-glucuronidase in rat polymorphonuclear leukocytes induced by platelet-activating factor, with 59.7 ± 4.8%, 56.1 ± 5.6%, and 65.9 ± 3.1% inhibition, respectively. Compound 23 was active against H5N1 avian influenza virus with an IC(50) value of 4.8 μM. Compounds 3 and 5 exhibited selective cytotoxic activities against A2780 (IC(50) 1.7 μM) and A549 (IC(50) 6.0 μM), respectively.

Glycosidic Constituents of the Tubers of Gymnadenia conopsea

Ten minor new glycosidic constituents (1- 10), together with 10 known compounds, have been isolated from a neuroprotective fraction of an ethanolic extract of the tubers of Gymnadenia conopsea. The structures of 1-10 were determined using spectroscopic and chemical methods. The compounds isolated were evaluated for activity in in vitro assays for acetylcholine esterase and monoamine oxidase inhibitory activities.

Machilusides A and B: Structurally Unprecedented Homocucurbitane Glycosides from the Stem Bark of Machilus yaoshansis

Two structurally novel homocucurbitane triterpenoid glycosides, machilusides A (1) and B (2), possessing an unprecedented C(36) skeleton with a D-fructose moiety incorporated into a cucurbitane nucleus forming unique cage-like tricyclic ring moieties, were isolated from the stem bark of Machilus yaoshansis. Their structures were determined by spectroscopic methods. Both compounds exhibited nonselective cytotoxic activities against several human cancer cell lines. The biosynthetic pathway of 1 and 2 was postulated.

Butanolide derivatives from the bark of Machilus yaoshansis

Six new butanolide derivatives with long aliphatic side chains (1–6), together with 23 known lipophilic constituents, were isolated from the bark of Machilus yaoshansis. Their structures were elucidated by spectroscopic and chemical methods. All the isolates were evaluated for cytotoxic and anti-inflammatory activities.

Phenylpropene diglycosides from the bark of Machilus wangchiana

Five new phenylpropene diglycosides (1–5), together with three known analogs, have been isolated from an ethanol extract of the bark of Machilus wangchiana. Their structures were determined by spectroscopic and chemical methods. In the preliminary assay, compounds 2 and 5–8 reduced dl-galactosamine (GalN)-induced hepatocyte (WB-F344 cells) damage with 37–41% inhibitions at 10 μM.

Methoxylated fatty acids from the bark of Fraxinus sieboldiana

Nine new fatty acid derivatives, including seven methoxylated (1, 2, and 4–8) and two hydroxylated (3 and 9) fatty acids, have been isolated from the ethanol extract of the stem bark of Fraxinus sieboldiana. Their structures were determined by spectroscopic methods including IR, MS, 1D, and 2D NMR experiments. The 3- or 9-methoxylated fatty acids are reported for the first time in nature.