Hiromu Kameoka

An insect growth inhibitory lignan from flower buds of Magnolia fargesii

Abstract Bioassay-guided isolation afforded a new lignan, (+)-epimagnolin A, from the flower buds of Magnolia fargesii . This lignan exhibited growth inhibitory activity against larvae of Drosophila melanogaster . The structure of a new lignan was determined on the basis of spectral methods.

Phenolic lignans from flower buds of Magnolia fargesii

Abstract Three phenolic lignans were isolated from flower buds of Magnolia fargesii . One was a new lignan named (+)-de- O -methylmagnolin and the other two were the newly found lignans from this plant, (+)-phillygenin and (+)-pinoresinol. The structures of these lignans were determined by spectroscopic studies. The structure of (+)-magnolin isolated from this plant was also investigated in detail by spectral data.

Biotransformation of sesquiterpenoids, (-)-globulol and (+)-ledol by Glomerella cingulata

Abstract The biotransformation of (−)-globulol and (+)-ledol by Glomerella cingulata was investigated. (−)-Globulol gave only one product which was hydroxylated at C-13. By contrast, (+)-ledol gave a number of products. The major metabolite contained a carboxylic group C-11 which was formed by Me-13. The structure of the new compound has been elucidated on the basis of its spectral data coupled with some chemical evidence.

Biotransformation of (+)-magnolin and (+)-yangabin in rat

Abstract The neutral lignans (+)-magnolin and (+)-yangabin, each containing the 2,6-diaryl-3,7-dioxabicyclo [3,3,0]octane skeleton, were administered separately

Antioxidizing component, musizin, inrumex japonicus houtt

A substance with antioxidant properties was obtained from the hexane extract of roots ofRumex japonicus Houtt. The active component of the hexane extract was isolated and characterized as 2-acetyl-1,8-dihydroxy-3-methyl naphthalene, trivially named musizin (MUS). The antioxidant activities of MUS in six types of fats and oils were higher than that of butyl hydroxyanisole (BHA) and δ-tocopherol (δ-TOC). Together, TOC and MUS have a synergistic effect, because comparable amounts of either had lower antioxidant activity than various combinations of the two antioxidants. When we studied the antioxidant properties of a mixture of MUS and δ-TOC with methyl linoleate (MeLH), we found that the rates of destruction of the two antioxidants were comparable, but that their destruction occurred sequentially, with MUS first followed by δ-TOC, after which the oxidation of MeLH quickly occurred. Comparison of the antioxidant activity of MUS and its analogs suggests that only one of the two hydroxyl groups in MUS is involved in its antioxidant activit. Intermolecular hydrogen bonding may be involved.

Biotransformation of sesquiterpenoids, ( + )-aromadendrene and ( − )-alloaromadendrene by Glomerella cingulata

Abstract The biotransformation of ( + )-aromadendrene and ( − )-alloaromadendrene by a plant pathogenic micro-organism, Glomerella cingulata, was investigated. Glomerella cingulata oxidized ( + )-aromadendrene and ( − )-alloaromadendrene at the double bond and at one of the geminal methyl groups on the cyclopropane ring regioselectivity to form triols which were hydroxylated at C-10, C-13 and C-14. The structures of the new compounds have been elucidated on the basis of their spectral data coupled with some chemical evidence.

Biotransformation of lignans: a specific microbial oxidation of (+)-eudesmin and (+)-magnolin by Aspergillus niger

Abstract Biotransformation of the lignans, (+)-eudesmin, (+)-magnolin and (+)-yangabin, by Aspergillus niger has been investigated. (+)-Eudesmin was metabolized and transformed to (+)-de-4′- O -methyleudesmin and (+)-pinoresinol. Additionally, (+)-pinoresinol was examined and oxidized to (+)-5′-hydroxypinoresinol. (+)-Magnolin was transformed to (+)-de- O -methylmagnolin and (+)-de-4′--methyl-5′-hydroxymagnolin. In these metabolic processes, other products were not generated, although (+)-yangabin and (+)-de-4′- O -methyl-5′-hydroxymagnolin were hardly metabolized by this fungus. This suggested that the veratryl and guaiacyl groups of these lignans were possibly metabolized preferentially, with oxidation proceeding predominantly through de- O -methylation at the p -position of veratryl groups. By contrast, 3,4,5-trimethoxyphenyl and 4,5-dihydroxy-3-methoxyphenyl groups of this type of lignan were stable and not attacked by A. niger . The structures of metabolic products were determined by spectroscopic methods as well as by comparison of spectral data with those of known related compounds.

Biotransformation of the sesquiterpenoid β-selinene using the plant pathogenic fungus Glomerella cingulata as a biocatalyst

Abstract The biotransformation of β-selinene was investigated using the plant pathogenic fungus Glomerella cingulata as a biocatalyst. β-Selinene was oxidized at the double bond of the isopropenyl group and at the C-1 position regioselectively to (1 S ,6 S ,9 S ,10 R ,11 RS )-1,11,13-trihydroxy- β -selinene. The structures of the metabolic products have been elucidated on the basis of their spectral data.

Volatile components of Ephedra sinica Stapf

The composition of the volatile oil from Ephedra sinica Stapf. has been investigated by capillary GC, GC–MS and 1H–NMR. The oil contained 146 volatile components of which 38.9% were terpenoids. The main constituents were α-terpineol (13.0%), tetramethylpyrazine (3.9%), terpinen-4-ol (3.9%), linalol (3.2%), 2,3-dihydro-2-methylbenzofuran (3.1%) and cis-p-menth-2-en-7-ol (3.1%).

Biotransformation of (−)-α-bisabolol by plant pathogenic fungus, Glomerella cingulata

Abstract Microbial transformation of (−)-α-bisabolol by Glomerella cingulata has been investigated. (−)-α-Bisabolol was initially transformed to (1S,3R,4R,7S)-3,4-dihydroxy-α-bisabolol and bisabolol oxide B. (1S,3R,4R,7S)-3,4-Dihydroxy-α-bisabolol was further transformed to (1S,3R,4R,7S,10S)-3,4-dihydroxy-bisabolol oxide B. Bisabolol oxide B was also further transformed to (1S,3R,4R,7S,10S)- and (1S,3S,4R,7S,10S)-3,4-dihydroxy-bisabolol oxide B. The structures of the metabolic products were determined by spectroscopic methods. Metabolic pathways of the biotransformation of (−)-α-bisabolol by G. cingulata are also discussed.