Masaru Kawasaki

Scopadulcic acid-A and -B, new diterpenoids with a novel skeleton, from a Paraguayan crude drug “typychá kuratũ” (scoparia dulcis L.)

Abstract Scopadulcic acid-A and -B, diterpenoids with a novel skeleton, have been isolated from the whole plants of Scopari dulcis L., and their structures, including the absolute configuration, were determined based on the 2-D NMR and CD spectral data.

8-Hydroxytricetin 7-glucuronide, a β-glucuronidase inhibitor from Scoparia dulcis

Abstract A new flavone glycoside has been isolated from Scoparia dulcis together with 11 known compounds. The new glycoside was determined as 5,7,8,3′,4′,5′-hexahydroxyflavone glucuronide by spectral analysis. The new glycoside and isovitexin showed inhibitory activity against β-glucuronidase.

Two chemotypes ofScoparia Dulcis in Paraguay

Abstract HPLC analysis of diterpene acids in individual plants of Paraguayan Scoparia dulcis revealed the presence of two chemotypes based on the major component, i.e. scopadulcic acid B type (SDB) and scoparic acid A type (SA). SDB and SA were found to be contained mainly in leaves. The hereditary nature of these phenotypes was confirmed by analysis of the progeny of the chemotypes.

Production of diterpenoids by cultured cells from two chemotypes of Scoparia dulcis

Abstract Callus and multiple shoot cultures from two chemotypes of Scoparia dulcis were established. A relatively small amount of scoparic acid A (SA) was produced, and the production of scopadulcic acid B (SDB) was strongly repressed in all callus tissues tested. On the other hand, the multiple shoots contained either SA or SDB and produced the same type of diterpene as that produced by the parent plants. These results suggest that SA is an important intermediate in the biosynthesis of SDB and that the production of SDB is related to the differentiation of leaves.

Some Phytochemicals and Related Compounds in Vegetables as Potent Inhibitors of Human DNA Topoisomerase II

An established human DNA topoisomerase II inhibitory assay is described, and the screening results for some phytochemicals in vegetables and related compounds that may useful for chemoprevention through food are reported. The assay requires a small amount of sample and is rapid compared to bioassays using cell lines or animals. The topoisomerase II inhibitory assay is useful for screening compounds in vegetables. More than 80 compounds were screened, and 28 compounds were found to be potent inhibitors at the 10 μg/ml level. Many of the phytochemicals commonly found in vegetables are thus useful for chemoprevention.