Chie Honda

Phenanthrenes from Dendrobium plicatile

From Dendrobium plicatile stems, three phenanthrenes were isolated. The structures are 2,5-dihydroxy-4,9,10-trimethoxyphenanthrene, 2,5-dihydroxy-4-methoxyphenanthrene and 2,5,9-trihydroxy-4-methoxy-9,10-dihydrophenanthrene.

The stilbenoids from Dendrobium plicatile

Abstract Seven stilbenoids were isolated from stems of Dendrobium plicatile and their structures were elucidated on the basis of spectroscopic data. Six of them were known compounds, 3-methoxy-3′,5-dihydroxybibenzyl, 3,3′,4′-trimethoxy-5-hydroxybibenzyl, 2-methoxy-4,7-dihydroxy-9,10-dihydrophenanthrene, 2,4-dimethoxy-3,7-dihydroxyphenanthrene, 3,4-dimethoxy-2,7-dihydroxy-9,10-dihydrophenanthrene and ephemeranthoquionone. The seventh, 2,2′-dimethoxy-4,4′,7,7′-tetrahydroxy-9,9′,10,10′-tetrahydro-1,1′-biphenanthrene, was a new dimer.

Intracellular Metabolism of α,β-Unsaturated Carbonyl Compounds, Acrolein, Crotonaldehyde and Methyl Vinyl Ketone, Active Toxicants in Cigarette Smoke: Participation of Glutathione Conjugation Ability and Aldehyde-Ketone Sensitive Reductase Activity.

The major toxicants in cigarette smoke, α,β-unsaturated aldehydes, such as acrolein (ACR) and crotonaldehyde (CA), and α,β-unsaturated ketone, methyl vinyl ketone (MVK), are known to form Michael-type adducts with glutathione (GSH) and consequently cause intracellular GSH depletion, which is involved in cigarette smoke-induced cytotoxicity. We have previously clarified that exposure to cigarette smoke extract (CSE) of a mouse melanoma cell culture medium causes rapid reduction of intracellular GSH levels, and that the GSH-MVK adduct can be detected by LC/MS analysis while the GSH-CA adduct is hardly detected. In the present study, to clarify why the GSH-CA adduct is difficult to detect in the cell medium, we conducted detailed investigation of the structures of the reaction products of ACR, CA, MVK and CSE in the GSH solution or the cell culture medium. The mass spectra indicated that in the presence of the cells, the GSH-CA and GSH-ACR adducts were almost not detected while their corresponding alcohols were detected. On the other hand, both the GSH-MVK adducts and their reduced products were detected. In the absence of the cells, the reaction of GSH with all α,β-unsaturated carbonyls produced only their corresponding adducts. These results show that the GSH adducts of α,β-unsaturated aldehydes, CA and ACR, are quickly reduced by certain intracellular carbonyl reductase(s) and excreted from the cells, unlike the GSH adduct of α,β-unsaturated ketone, MVK. Such a difference in reactivity to the carbonyl reductase might be related to differences in the cytotoxicity of α,β-unsaturated aldehydes and ketones.

Phosphodiesterase I in cultured cells of Mentha arvensis

Abstract Alkaline phosphodiesterase I (5′-nucleotide phosphodiesterase, EC 3.1.4.1) in cultured cells of Mentha arvensis , was purified about 75-fold by ammonium sulphate fractionation and three chromatographic steps. The optimum pH of the enzyme was 9.5. Its M r was estimated by gel filtration to be ca 105 000. The enzyme was strongly inhibited by SH reagents and HgCl 2 . It did not require divalent cations such as Mg 2+ or Ca 2+ . It hydrolysed thymidine 5′- p -nitrophenylphosphate but did not act on DNA or RNA. These properties, such as divalent cation requirement and substrate specificity, were different from those of phosphodiesterase I obtained from carrot.

Preparation of branched cyclomaltoheptaose with 3-O-α-l-fucopyranosyl-α-d-mannopyranose and changes in fucosylation of HCT116 cells treated with the fucose-modified cyclomaltoheptaose

From a mixture of 4-nitrophenyl α-L-fucopyranoside and D-mannopyranose, 3-O-α-L-fucopyranosyl-D-mannopyranose was synthesised through the transferring action of α-fucosidase (Sumizyme PHY). 6(I),6(IV)-Di-O-(3-O-α-L-fucopyranosyl-α-D-mannopyranosyl)-cyclomaltoheptaose {8, 6(I),6(IV)-di-O-[α-L-Fuc-(1→3)-α-D-Man]-βCD} was chemically synthesised using the trichloroacetimidate method. The structures were confirmed by MS and NMR spectroscopy. A cell-based assay using the fucosyl βCD derivatives, including the newly synthesised 8, showed that derivatives with two branches of the α-L-Fuc or α-L-Fuc-(1→3)-α-D-Man residues possessed slight growth-promoting effects and lower toxicity in HCT116 cells compared to those with one branch. These compounds may be useful as drug carriers in targeted drug delivery systems.

Preparation, characterization, and biological evaluation of 6I,6IV-di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose

6(I),6(IV)-Di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-cyclomaltoheptaose (βCD) {6(I),6(IV)-di-O-[α-l-Fuc-(1→6)-β-d-GlcNAc]-βCD (5)} and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-β-d-glucopyranosyl]-βCD {6-O-[α-l-Fuc-(1→6)-β-d-GlcNAc]-βCD (6)} were chemically synthesized using the corresponding authentic compounds, bis(2,3-di-O-acetyl)-pentakis(2,3,6-tri-O-acetyl)-βCD as the glycosyl acceptor and 2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(1→6)-3,4-di-O-acetyl-2-deoxy-2-(2,2,2-trichloroethoxycarbonylamino)-d-glucopyranosyl trichloroacetimidate as the fuco-glucosaminyl donor. NMR confirmed that α-l-Fuc-(1→6)-d-GlcNAc was bonded by β-linking to the βCD ring. To evaluate biological efficiency, the biological activities of the new branched βCDs were examined. The cell detachment activity of 5 was lower than that of 6 in real-time cell sensing (RT-CES) assay, indicating that 5 has lower toxicity. In SPR analysis, 5 had a higher special binding with AAL, a fucose-recognizing lectin. These results suggest that 5 could be an efficient drug carrier directed at cells expressing fucose-binding proteins.

Determination of Branched β-Cyclodextrin–Prostaglandin Complexes Using Electrospray Ionization Mass Spectrometry

Mass spectral measurements by electrospray ionization mass spectrometry (ESI-MS) detected the ions of β-cyclodextrin (βCD) or branched βCDs (glucosyl-, galactosyl-, mannosyl- and maltosyl-βCD)–prostaglandins (PGs: PGA2, PGD2, PGE1, PGE2, PGF2α and PGJ2) complexes, i.e., βCD–PG complexes, with a host:guest ratio of 1:1 in the negative ion mode. This is the first study to report the ions of branched βCD–PG complexes using ESI-MS. The inclusion complexes were determined by a flow injection analysis using acetonitrile/water. We could confirm by this method the presence of a βCD–PGE2 complex with a host:guest ratio of 1:1 in a solution-dissolved pharmaceutical formulation consisting of βCD–PGE2 (ProstarmonTM E tablet).