Yoshio Hano

Alkaloids and phenylpropanoids from Peganum nigellastrum.

Two canthin-6-one alkaloids, luotonins C and D, and two phenylpropanoids, dihydrosinapyl ferulate and dihydroconiferyl ferulate, were isolated from the aerial parts of Peganum nigellastrum along with four known alkaloids, harmine, 3-phenylquinoline, 3-(4-hydroxyphenyl)quinoline and 3-(1H-indol-3-yl)quinoline. Their structures were elucidated by spectroscopic techniques. The structures of luotonins C and D were also confirmed by chemical synthesis.

Constituents of the cultivated mulberry tree.

From extracts of root bark of the cultivated mulberry tree (a variety of Morus alba L.) three new isoprene-substituted flavanones, Kuwanon D, E and F were isolated. Their structures were shown to be I, II and III, respectively.

Iridals from Iris tectorum and Belamcanda chinensis

Three iridals, iridotectorals A and B, and iridobelamal. A, were isolated from rhizomes of Iris tectorum and Belamcanda chinensis, respectively, along with five known iridals. Their structures were elucidated on the basis of spectral evidence. The human promyelocytic leukemia (HL-60) cell-adhesion activity of the eight iridals is also discussed.

Mass Spectrometry of Prenylated Flavonoids

The fragmentation patterns originating from the degradation of prenyl group(s) in positive ion electron ionization (EI), fast-atom bombardment (FAB) and chemical ionization (CI) mass spectrometry (MS) of prenylated flavonoids were reviewed. The EI spectra showed the characteristic fragmentation patterns reflecting the location of prenyl group in the flavonoid compounds, whereas the FAB and CI spectra showed relatively monotonous patterns. It was described how the EI and FAB fragmentation patterns are useful for the identification of prenylated flavonoids

Chemistry and biosynthesis of isoprenylated flavonoids from Japanese mulberry tree

Many isoprenylated flavonoids have been isolated from Japanese mulberry tree (Moraceae). Among them, kuwanons G (1) and H (2) were the first isolated active substances exhibiting a hypotensive effect. These compounds are considered to be formed through an enzymatic Diels-Alder type reaction between an isoprenyl portion of an isoprenylphenol as the diene and an α, β-double bond of chalcone as the dienophile. The absolute configurations of these Diels-Alder type adducts were confirmed by three different methods. The stereochemistries of the adducts were consistent with those of ones in the Diels-Alder reaction involving exo- and endo-addition. Some strains of Morus alba callus tissues have a high productivity of mulberry Diels-Alder type adducts, such as chalcomoracin (3) and kuwanon J (4). The biosynthetic studies of the mulberry Diels-Alder type adducts have been carried out with the aid of the cell strain. Chalcomoracin (3) and kuwanon J (4) were proved to be enzymatic Diels-Alder type reaction products by the administration experiments with O-methylchalcone derivatives. Furthermore, for the isoprenoid biosynthesis of prenylflavonoids in Morus alba callus tissues by administration of [1,3-13C2]- and [2-13C]-glycerol, a novel way through the junction of glycolysis and pentose-phosphate cycle was proved. Two independent isoprenoid biosynthetic pathways, that for sterols and that for isoprenoidphenols, operate in the Morus alba cell cultures. The former is susceptible to compactin (ML-236) and the latter resists to compactin in the cell cultures, respectively.

Artonins E and F, Two New Prenylflavones from the Bark of Artocarpus communis Forst.

Two new prenylflavones, artonins E (1) and F (2), were isolated from the bark of Artocarpus communis Forst. (Moraceae), along with a known compound, cycloartobiloxanthone (3). The structures of artonins E and F were shown to be 1 and 2, respectively, on the basis of spectroscopic data

A novel way of determining the structure of artonin I, an optically active Diels–Alder type adduct, with the aid of an enzyme system of Morus alba cell cultures

The structure of artonin I, an optically active Diels–Alder type adduct from Artocarpus heterophyllus, an Indonesian moraceous plant, was established utilizing the enzyme system of Morus alba cell cultures which specifically produce the natural Diels–Alder type adducts, as well as spectroscopic evidence.

Biosynthesis of optically active Diels–Alder type adducts revealed by an aberrant metabolism of O-methylated precursors in Morus alba cell cultures

Addition of O-methylated chalcone, as precursors, to Morus alba cell cultures has resulted in the formation of optically active O-methyl derivatives of chalcomoracin (1) and kuwanon J (2), corroborating the pivotal step of the biosynthesis of (1) and (2) to be the enzymic Diels–Alder reaction.

Components of the bark of Artocarpus rigida BL. II: Structures of four new isoprenylated flavone derivatives artonins M, N, O, and P

Four new isoprenylated flavone derivatives, artonins M (1), N (2), O (3), and P (4), were isolated from the bark of Artocarpus rigida Bl., and Indonesian moraceous plant. The structures of artonins M, N, O, and P were determined to be formulae 1, 2, 3, and 4, respectively, on the basis of spectroscopic studies and chemical evidence

Chemistry and Biological Activities of Isoprenylated Flavonoids from Medicinal Plants (Moraceous Plants and Glycyrrhiza Species)

ABSTRACT: Among a large number of phenolic compounds isolated from natural source, various isoprenoid-substituted phenolic compounds have often been found in plants. Moraceous plants and licorice ( Glycyrrhiza species) are rich sources of the isoprenoid-substituted phenolic compounds, including flavonoids. Some of the Morus flavonoids, such as kuwanons G and H, have been regarded as optically active Diels-Alder type adducts. Furthermore, some of the isoprenylated-flavonoids from the moraceous plants and licorice showed the interesting biological activities. This article reviews the biological activities of the isoprenylated-flavonoids from the root barks and/or barks of moraceous plants and from Glycyrrhiza species by our group. The chemical studies concerning the biological activities of these compounds are also described briefly.