Tadataka Noro

Sesquiterpene lactones from Lactuca laciniata

Abstract From the roots of Lactuca laciniata , six new sesquiterpene lactones, 9a-hydroxyzaluzanin C, 9α-hydroxy-11,13α-dihydrozaluzanin C, lactucopicriside, lactulide A, lactuside A and lactuside B, have been isolated together with known compounds, macrocliniside A, glucozaluzanin C, 11, 3α-dihydroglucozaluzanin C,11β,13-dihydrolactucin and dihydrosantamarin. The structures were established by spectral data and X-ray diffraction analysis.

Steroidal glycosides from the aerial part of Asclepias incarnata

The aerial part of Asclepias incarnata afforded 34 pregnane glycosides. These were confirmed to have lineolon, isolineolon, ikemagenin, 12-O-nicotinoyllineolon, deacylmetaplexigenin, metaplexigenin, rostratamine, 12-O-acetyllineolon, 15beta-hydroxylineolon and 15beta-hydroxyisolineolon moieties as their aglycones, and 2.6-dideoxyhexopyranose, glucopyranose and allopyranose as the corresponding sugar constituents. Their structures were determined using both spectroscopic and chemical methods.

Steroidal glycosides from roots of Cynanchum caudatum

Roots of Cynanchum caudataum afforded 15 pregnane glycosides which had cynanchogenin, caudatin and gagaminin as the aglycone moiety and 2,6-dideoxy-3-O-methylhexopyranoses and glucopyranose as component sugars. The structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Steroidal glycosides and cardenolide glycosides from Asclepias fruticosa

Asclepias fruticosa afforded, in addition to five known pregnane glycosides and 11 known cardenolide glycosides, four new pregnane glycosides and eleven new cardenolide glycosides. Structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Methyl cinnamate derivatives enhance UV-induced mutagenesis due to the inhibition of DNA excision repair in Escherichia coli B/r

UV-induced mutagenesis in Escherichia coli B/r WP2 was enhanced by certain derivatives of methyl cinnamate which themselves were not mutagenic. Methyl ferulate, methyl isoferulate and methyl sinapate showed this effect markedly. Such an enhancement effect was absent with the derivatives of cinnamic acid and ethyl cinnamate and was not observed in Escherichia coli WP2s uvrA. Methyl sinapate also enhanced 4NQO-induced mutation and suppressed liquid-holding recovery in the above repair-proficient strain. The presence of methyl sinapate in plating agar medium decreased the survival of UV-irradiated cells of a recombination-repair-deficient strain, CM571 recA. However, the effect was not observed with those of WP2s uvrA. In an in vitro experiment in which the removal rate of thymine dimers was measured, methyl sinapate clearly inhibited this repair event. From these results, we conclude that methyl sinapate inhibits DNA excision repair, thus enhancing UV mutagenicity.

Cardenolide glycosides from Asclepias fruticosa

Abstract Asclepias fruticosa afforded, in addition to two known cardenolides and two known cardenolide glycosides, one new cardenolide and nine new cardenolide glycosides. The structures of these compounds were elucidated by spectroscopic methods and chemical evidence.

Steroidal glycosides from the roots of Metaplexis japonica

Abstract The roots of Metaplexis japonica afforded eleven new pregnane glycosides which had 12-O-acetylpergularin, metaplexigenin and deacylmetaplexigenin as the aglycone moiety and 2,6-dideoxy and 2,6-dideoxy-3-O-methylhexopyranoses as component sugars. The structures of these compounds were elucidated by spectroscopic methods and chemical evidence.

Steroidal glycosides from Cynanchum caudatum.

The aerial part of Cynanchum caudatum afforded 10 new pregnane glycosides which had sarcostin or deacylmetaplexigenin as the aglycone moiety. The structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

8,14-Secopregnane glycosides from the aerial parts of Asclepias tuberosa

Twenty pregnane glycosides, tuberoside A(1)-L(5), were isolated from the diethyl ether-soluble fraction of the MeOH extract from the aerial parts of Asclepias tuberosa (Asclepiadaceae). The pregnane glycosides were composed of 8,12;8,20-diepoxy-8,14-secopregnane as aglycon, and D-cymarose, D-oleandrose, D-digitoxose and/or D-glucose as the component sugars. Their structures were established using NMR spectroscopic analysis and chemical methodologies.

Enhancing effects of cinoxate and methyl sinapate on the frequencies of sister-chromatid exchanges and chromosome aberrations in cultured mammalian cells.

Sister-chromatid exchanges (SCEs) induced by mitomycin C (MMC), 4-nitroquinoline-1-oxide (4NQO) or UV-light in cultured Chinese hamster ovary cells (CHO K-1 cells) were enhanced by cinoxate (2-ethoxyethyl p-methoxycinnamate) or methyl sinapate (methyl 3,5-dimethoxy 4-hydroxycinnamate). Both substances are cinnamate derivatives and cinoxate is commonly used as a cosmetic UV absorber. Methyl sinapate also increased the frequency of cells with chromosome aberrations in the CHO K-1 cells treated with MMC, 4NQO or UV. These increasing effects of methyl sinapate were critical in the G1 phase of the cell cycle and the decline of the frequencies of UV-induced SCEs and chromosome aberrations during liquid holding was not seen in the presence of methyl sinapate. Both compounds were, however, ineffective in cells treated with X-rays. In cells from a normal human embryo and from a xeroderma pigmentosum (XP) patient, MMC-induced SCEs were also increased by the post-treatment with methyl sinapate. The SCE frequencies in UV-irradiated normal human cells were elevated by methyl sinapate, but no SCE-enhancing effects were observed in UV-irradiated XP cells. Our results suggest that the test substances inhibit DNA excision repair and that the increase in the amount of unrepaired DNA damage might cause the enhancement of induced SCEs and chromosome aberrations.