Antimicrobial polyacetylenes from Panax ginseng hairy root culture.

Two new polyacetylenes, 1-hydroxydihydropanaxacol (3) and 17-hydroxypanaxacol (4), were isolated from Panax ginseng hairy root culture, along with dihydropanaxacol (1), panaxacol (2) and ginsenoyne D (5). Highly hydroxylated compounds 1-4 were isolated from the medium and compound 5, which was a biosynthetic precursor of compound 1, was isolated from the roots. Compounds 1-4 showed antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Cryptococcus neoformans and Aspergillus fumigatus. It is suggested that P. ginseng plants release antimicrobial polyacetylenes into the surrounding soil from the roots as defense compounds.

Steroidal glycoalkaloids from the berries of Solanum distichum.

Two steroidal glycoalkaloids, Solanidine 3-O-[alpha-L-rhamnopyranosyl-(1'' --> 4)-[alpha-L-rhamnopyranosyl-(1' --> 2)]-beta-D-glucopyranoside] (1) and Solanidine 3-O-[alpha-L-rhamnopyranosyl-(1'' --> 4)-beta-D-glucopyranoside] (2) commonly known as alpha-chanonine and beta 2-chanonine, were isolated from the berries of Solanum distichum. The structures of the isolated compounds were studied by 1D and 2D NMR techniques and FAB MS analysis. The 13C NMR signal assignments and direct elucidation of the glycoside linkages were established. Glycoalkaloids level in the dried berries, determined by a simple colorimetric method, was found to be 5.08 +/- 0.18 g%.

Abietane diterpenoids from suspension cultured cells of Torreya nucifera var. radicans.

Three abietane diterpenoids were isolated from the suspension cultured cells of Torreya nucifera var. radicans along with four known abietane diterpenoids. Based on spectroscopic evidence, the structures of the three were elucidated as (3S,5R,10S)-7-oxo-12-methoxyabieta-8,11,13-triene-3,11-diol, (3S,5R,10S)-7-oxo-12-methoxyabieta-8,11,13-triene-3,11,14-triol and (5R,10S)-3-oxo-7R,12-dimethoxyabieta-8,11,13-trien-11-ol, respectively.

Antimicrobial sesquiterpenoids from Laurus nobilis L.

Activity-guided fractionations of leaf extracts from Laurus nobilis L. led to the isolation of a known sesquiterpene lactone, deacetyl laurenobiolide (1). Compound 1 showed antimicrobial activity against periopathic pathogens (Actinomyces viscosus, Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans), opportunistic Gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes) and fungi (Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus). Furthermore, acetylation and cyclisation of deacetyl laurenobiolide (1) yielded laurenobiolide (2) and a new compound, (5S,6R,7S,8S,10R)-6,8-dihydroxyeudesma-4(15),11(13)-dien-12-oic acid 12,8-lactone (3), respectively. Compounds 2 and 3 also showed antimicrobial activities. All compounds 1-3 demonstrated growth inhibitory effects with minimum inhibitory concentrations ranging from 31 to 1000 µg mL(-1). This is the first report of compounds 1-3 showing antimicrobial activities.

Biosynthesis of acteoside in cultured cells of Olea europaea.

Five phenylethanoid glycosides (acteoside, isoacteoside, beta-oxoacteoside, beta-hydroxyacteoside, and salidroside) were isolated from a cell suspension culture of Olea europaea. We examined the biosynthesis of acteoside in olive cell cultures by using feeding experiments with stable isotope labeled precursors. The hydroxytyrosol moiety of acteoside is biosynthesized from tyrosine through dopamine, whereas the caffeoyl moiety of acteoside is biosynthesized from phenylalanine via a cinnamate pathway. Dopamine is incorporated into acteoside through oxidation to the corresponding aldehyde, reduction to the alcohol, and then beta-glycosylation.

Apoptosis-inducing activity of compounds screened and characterized from cinobufacini by bioassay-guided isolation.

Cinobufacini (huachansu), an aqueous extract from the skin of the toad Bufo bufo gargarizans Cantor, is a traditional Chinese medicinal preparation widely used in clinical cancer therapy in China. Here, we screened and identified active compounds of cinobufacini and investigated their apoptosis-inducing effect on HepG2 cells. Screening was performed using bioassay-guided isolation. The effects of different fractions on the proliferation of HepG2 cells were detected by the MTT assay. The extraction and isolation of active fractions were performed by chloroform extraction, silica column chromatography, preparative thin-layer chromatography and high-performance liquid chromatography. Nuclear magnetic resonance (NMR) imaging and electron ionization-mass spectrometry (EI-MS) were used to identify the structure of the active compounds. The extent of cell apoptosis was detected by Hoechst 33258 staining and flow cytometric analysis. Western blot analysis was used to detect the expression of the apoptosis-related proteins Bax and Bcl-2. Through bioassay-guided isolation, two compounds were isolated from cinobufacini. NMR and EI-MS data revealed these compounds to be resibufogenin and cinobufagin. Cinobufagin was determined to be the more efficient of the two in inhibiting the proliferation of HepG2 cells. Hoechst 33258 staining and flow cytometric analysis indicated that cinobufagin induced marked changes in apoptotic morphology and significantly increased the proportion of apoptotic cells in HepG2 cells. Western blot analysis showed that cinobufagin up-regulated Bax expression and down-regulated Bcl-2 expression. In conclusion, we screened and identified two anti-proliferation compounds of cinibufacini, resibufogenin and cinobufagin. The most effective compound, cinobufagin, inhibited cell proliferation by inducing the apoptosis of HepG2 cells. This was potentially triggered by regulation of the Bax/ Bcl-2 ratio.

A silkworm baculovirus model for assessing the therapeutic effects of antiviral compounds: characterization and application to the isolation of antivirals from traditional medicines.

Ganciclovir, foscarnet, vidarabine and ribavirin, which are used to treat viral infections in humans, inhibited the proliferation of a baculovirus (Bombyx mori nucleopolyhedrovirus) in BmN4 cells, a cultured silkworm cell line. These antiviral agents inhibited the proliferation of baculovirus in silkworm body fluid and had therapeutic effects. Using the silkworm infection model, the antiviral activity of Kampo medicines was screened and it was found that cinnamon bark, a component of the traditional Japanese medicine Mao-to, had a therapeutic effect. Based on the therapeutic activity, the antiviral substance was purified. Nuclear magnetic resonance analysis of the purified fraction revealed that the antiviral activity was due to cinnzeylanine, which has previously been isolated from Cinnamomum zeylanicum. Cinnzeylanine inhibits the proliferation of herpes simplex virus type 1 in Vero cells. These results suggest that the silkworm-baculovirus infection model is useful for screening antiviral agents that are effective for treating humans infected with DNA viruses.

Biosynthesis of polyacetylenes in Ambrosia maritima hairy roots.

Thiophene A and thiophene A diol are the major polyacetylenes isolated from the hairy roots of Ambrosia maritima (Asteraceae) cultured under continuous light irradiation. The biosynthesis of thiophene A was studied using [1-(13)C]-, [2-(13)C]-, [1,2-(13)C]-acetates. The biosynthesis of thiarubrine A, produced by hairy roots cultured in the dark, was studied using [1,2-(13)C]-acetates and [18-(13)C]-linoleic acid. Our results suggest a catabolic pathway for polyacetylenes biosynthesis from linoleic acid in hairy roots of Ambrosia maritima.

Production of triterpene acids by cell suspension cultures of Olea europaea.

Olive (Olea europaea) contains large quantity of triterpene acids including oleanolic acid (6) as a major one. Varieties of biological activities exhibited by triterpene acids attracted our attentions, especially from pharmaceutical viewpoints. Cell culture of olive plant was induced and its triterpene constituents were studied. From the cell suspension cultures, six ursane type triterpene acids; ursolic acid (9), pomolic acid (10), rotundic acid (11), tormentic acid (12), 2alpha-hydroxyursolic acid (13) and 19alpha-hydroxyasiatic acid (14), and two oleanane type acids; oleanolic acid and maslinic acid (7), have been isolated. Quantity of ursane type triterpene acids produced by cell cultures was larger than that of oleanane type. Further, a multifunctional oxidosqualene cyclase (OSC) named OEA was cloned by homology based PCRs from the same cultured cells. Major product of OEA is alpha-amyrin (ursane skeleton), showing good accordance to higher content of ursane-type triterpene acids in the cultured cells, and strongly suggesting OEA to be a major contributor OSC for their production.