Suppression by a sesquiterpene lactone from Carpesium divaricatum of inducible nitric oxide synthase by inhibiting nuclear factor-kappaB activation.

Excessive nitric oxide (NO) produced by inducible NO synthase (iNOS) acts as a causative regulator in various inflammatory disease states. Carpesium divaricatum has been used in Korean traditional herbal medicine for its antipyretic, analgesic, vermifugic, and anti-inflammatory properties. We investigated the molecular mechanism for the suppression of lipopolysaccharide/interferon-gamma (LPS/IFN-gamma)-induced NO production in RAW 264.7 macrophages by the sesquiterpene lactone 2beta,5-epoxy-5,10-dihydroxy-6alpha-angeloyloxy-9beta-isobutyloxy-germacran-8alpha,12-olide (C-1), which has been identified recently as a new compound from C. divaricatum. C-1 decreased NO production in LPS/IFN-gamma-stimulated RAW 264.7 cells in a concentration-dependent manner, with an IC50 of approximately 2.16 microM; however, it had no direct effect on the iNOS activity of fully LPS/IFN-gamma-stimulated RAW 264.7 cells. Furthermore, treatment with C-1 led to a decrease in iNOS protein and mRNA. These effects appear to be due to inhibition of nuclear factor-kappaB (NF-kappaB) activation through a mechanism involving stabilization of the NF-kappaB/inhibitor of the kappaB (I-kappaB) complex, since inhibition of NF-kappaB DNA binding activity by C-1 was accompanied by a parallel reduction of nuclear translocation of subunit p65 of NF-kappaB and I-kappaBalpha degradation. Taken together, the results suggest that the ability of C-1 to inhibit iNOS gene expression may be responsible, in part, for its anti-inflammatory effects.

A new cyanogenic glycoside from Sorbaria sorbifolia var. stellipila.

A new cyanogenic glycoside, sutherlandin-5-trans-p-coumarate was isolated along with a known cardiosdiospermin-5-(4-hydroxy) benzoate fr the aerial parts of Sorbaria sorbifolia (L.) A. Br. var. stellipila MAX. (Rosaceae). The structure of the new compound was established based on spectral evidence.

Inducible nitric oxide synthase inhibitors from Melia azedarach var. japonica.

In bioassay-guided search for inducible nitric oxide synthase (iNOS) inhibitory compounds from higher plants of South Korea, two beta-carboline alkaloids, 4-methoxy-1-vinyl-beta-carboline (1) and 4,8-dimethoxy-l-vinyl-beta-carboline (2) have been isolated from the cortex of Melia azedarach var. japonica. The structures of these compounds were elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed marked inhibitory activity of iNOS on LPS- and interferon-gamma-stimulated RAW 264.7 cells.

Two new lignans from Lindera obtusiloba blume.

Two new furanolignans (3, 5), together with three known lignans (1, 2, 4), were isolated from the stem of Lindera obtusiloba (Lauraceae). The structures of the compounds were determined as actifolin (1), pluviatilol (2), 5,6-dihydroxymatairesinol (3), (+)-syringaresinol (4), and (+)-9'-O-trans-feruloyl-5,5'-dimethoxylariciresinol (5) on the basis of physicochemical and spectroscopic evidences. Compounds 1, 2, 3, and 5 showed cytotoxicity against a small panel of human tumor cell lines with ED50 values of 3.40 to approximately 19.27 microg/ml.

A new cytotoxic acyclic diterpene from Carpesium divaricatum.

A new acyclic diterpene (1) and a known acyclic diterpene, 12(S)-hydroxygeranylgeraniol (2) were isolated from the aerial parts of Carpesium divaricatum. The structure of 1 was determined to be (2E,10E)-1,12-dihydroxy-18-acetoxy-3,7,15-trimethylhexadeca- 2,10,14-triene (1) on the basis of spectroscopic studies. Compounds 1 and 2 exhibited cytotoxicity against cultured human tumor cell lines, A549, SK-OV-3, SK-MEL-2, XF498, and HCT15, with ED50 values ranging from 4.3-10.2 micrograms/ml and 4.1-8.3 micrograms/ml, respectively.

Anti-allergic components from the peels of Citrus unshiu.

In a bioassay-guided search for anti-allergic compounds from higher plants of Korea, polymethoxyflavones, 3',4',5,6,7,8-hexamethoxyflavone (1), 5-hydroxy-3',4',6,7,8-pentamethoxyflavone (II) and 3',4',5,7,8,-pentamethoxyflavone (III) have been isolated from the immature peels of Citrus unshiu. Structures of these compounds were elucidated on the basis of spectroscopic techniques. Compounds I and II inhibited dose-dependently histamine release from the rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE.

Two new monogalactosylacylglycerols from Hydrocotyle ramiflora.

Two new monogalactosylmonoacylglycerols ( 1, 2) and two known compounds ( 3, 4) were isolated from Hydrocotyle ramiflora. Based on physicochemical evidence and spectral data, the structures of 1, 2, 3, and 4 were determined as (2 S)-1- O-(7 Z,10 Z,13 Z-hexadecatrienoyl)-3- O-beta-galactopyranosylglycerol, (2 S)-1- O-(9 Z,12 Z-octadecadienoly)-3- O-beta-galactopyranosyl-glycerol, alpha-spinasterol, and capsidiol 3-acetate, respectively.

Isolation of a multidrug resistance inhibitor from Aconitum pseudo-laeve var. erectum.

To overcome multidrug resistance (MDR) in cancer chemotherapy, we prepared various plant extracts and searched for a component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level of mdr1 gene. Of various plant extracts, the MeOH extract of the root of Aconitum pseudo-laeve var. erectum was found to have potent inhibitory activity on MDR. The bioassay-guided fractionation of the MeOH extract of the plant led to the isolation of an alkaloid, lycaconitine, as an active principle. And the IC50 of lycaconitine for KB V20C cells was 74 micrograms/ml.

Four new cytotoxic germacranolides from Carpesium divaricatum.

In a bioassay-guided search for cytotoxic compounds from higher plants of South Korea, four new sesquiterpenes of the germacranolide type, named cardivins A (1), B (2), C (3), and D (4), have been isolated from the aerial parts of Carpesium divaricatum. Structures of these compounds were elucidated on the basis of spectroscopic techniques. Compounds 1, 2, 3, and 4 showed cytotoxicity to the human tumor cells, A-549 (nonsmall cell lung), SK-OV-3 (ovary), SK-MEL-2 (skin), XF-498 (central nervous system), and HCT-15 (colon).

Artekeiskeanin A: a new coumarin-monoterpene ether from Artemisia keiskeana.

A new coumarin-monoterpene ether, artekeiskeanin A (1) and two known coumarins, dracunculin (2) and scopoletin (3) were isolated from the aerial parts of Artemisia keiskeana. The structure of 1 was determined to be 7-(trans-8-oxogeranyloxy)-6-methoxycoumarin on the basis of spectroscopic studies.