Noriyuki Kogure

Metabolomics-oriented isolation and structure elucidation of 37 compounds including two anthocyanins from Arabidopsis thaliana.

In order to conduct metabolomic studies in a model plant for genome research, such as Arabidopsis thaliana (Arabidopsis), it is a prerequisite to obtain structural information for the isolated metabolites from the plant of interest. In this study, we isolated metabolites of Arabidopsis in a relatively non-targeted way, aiming at the construction of metabolite standards and chemotaxonomic comparison. Anthocyanins (5 and 7) called A8 and A10 were isolated and their structures were elucidated as cyanidin 3-O-[2-O-(beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-E-p-coumaroyl)-beta-D-glucopyranoside]-5-O-[6-O-(malonyl)-beta-D-glucopyranoside] and cyanidin 3-O-[2-O-(2-O-(E-sinapoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-E-p-coumaroyl)-beta-D-glucopyranoside]-5-O-[beta-D-glucopyranoside] from analyses of 1D NMR, 2D NMR ((1)H NMR, NOE, (13)C NMR, HMBC and HMQC), HRFABMS, FT-ESI-MS and GC-TOF-MS data. In addition, 35 known compounds, including six anthocyanins, eight flavonols, one nucleoside, one indole glucosinolate, four phenylpropanoids and a derivative, together with three indoles, one carotenoid, one apocarotenoid, three galactolipids, two chlorophyll derivatives, one steroid, one hydrocarbon, and two dicarboxylic acids, were also isolated and identified from their spectroscopic data.

Asymmetric Total Synthesis of a Pentacyclic Lycopodium Alkaloid: Huperzine‐Q

Right on Q: the first asymmetric total synthesis of (-)-huperzine-Q, which possesses six stereogenic centers and a spiroaminal moiety, has been achieved in 19 steps and 16.4 % overall yield. This synthesis involved a novel stereoselective Pauson-Khand reaction, a vinyl Claisen rearrangement, and a biomimetic spiroaminal formation. TBDPS=tert-butyldiphenylsilyl.

First Asymmetric Total Syntheses of Fawcettimine-Type Lycopodium Alkaloids, Lycoposerramine-C and Phlegmariurine-A

A successful asymmetric total synthesis of lycoposerramine-C involving such key steps as a cobalt-mediated Pauson-Khand reaction and vinyl Claisen rearrangement and its biomimetic transformation to phlegmariurine-A are described.

A new indole alkaloid, 7-hydroxyspeciociliatine, from the fruits of Malaysian Mitragyna speciosa and its opioid agonistic activity

A new indole alkaloid, 7-hydroxyspeciociliatine (1), was isolated from the fruits of Malaysian Mitragyna speciosa Korth., together with 11 known indole and oxindole alkaloids (3–13). The structure of the new compound was determined by spectroscopic analysis and chemical conversion. The opioid agonistic activity of the new alkaloid was investigated in guinea-pig ileum experiments. The compound was found to have a weak stimulatory effect on μ-opioid receptors.

Asymmetric Total Syntheses of Cyclic Nitrone-Containing Phlegmarine-Type Lycopodium Alkaloids, Lycoposerramines-X and -Z

The total syntheses of cyclic nitrone-containing phlegmarine-type Lycopodium alkaloids, lycoposerramines-X and -Z, were accomplished starting from (R)-3-methylcyclohexanone via Pd-catalyzed Suzuki-Miyaura coupling, Johnson-Claisen rearrangement, stereoselective hydroboration-oxidation reaction, and Mitsunobu reaction, thereby establishing the structures including the absolute configuration.

Biogenetically inspired total syntheses of Lycopodium alkaloids, (+)-flabellidine and (-)-lycodine.

The first asymmetric total synthesis of (+)-flabellidine (2) and the shortest total synthesis of (-)-lycodine (3) were accomplished by a strategy featuring the one-pot construction of a tetracyclic lycodine skeleton from a linear precursor, which was inspired by the biosynthetic consideration of Lycopodium alkaloids.

Seven New Monoterpenoid Indole Alkaloids from Gelsemium elegans

Seven new indole alkaloids were isolated from the roots of Gelsemium elegans Benth. and their structures were determined by spectroscopic analysis and chemical transformation from known alkaloids. Kounaminal (1) is a new koumine-type alkaloid that contains an unusual aminal moiety. Humantenoxenine (2) and 15-hydroxyhumantenoxenine (3) are humantenine-type alkaloids that contain a novel β-amino-α,β-unsaturated ketone residue. The other four novel alkaloids are two gelsedilam-related and two gelsenicine-related alkaloids.

Design, Synthesis, and Antitumor Activity of 4-Halocolchicines and Their Pro-drugs Activated by Cathepsin B

Novel colchicine derivatives possessing various substituents at the C4 position were prepared. Among them, 4-halo derivatives 3-6 were found to exhibit higher activity against cancer cell lines (A549, HT29, HCT116) as well as on mice transplanted with the HCT116 human colorectal carcinoma cell line than colchicine (1). Further, utilizing the 4-substituted colchicines, we prepared pro-drugs having a dipeptide side chain and demonstrated that these pro-drugs were activated by cathepsin B, an enzyme overexpressed in tumor cells, and exhibited selective toxicity to the tumor cells.

Flavonols from Bauhinia malabarica

Bauhinia malabarica Roxb. has been used in Thai traditional medicine for wound healing, as a diuretic, to fight dysentery and as an emmenagogue. Seven flavonols, including 6,8-di-C-methylkaempferol 3-methyl ether, kaempferol, afzelin, quercetin, isoquercitrin, quercitrin, and hyperoside were isolated from the methanol extract of leaves.

Asymmetric total synthesis of novel pentacyclic indole alkaloid, kopsiyunnanine E, isolated from Kopsia arborea.

A new pentacyclic indole alkaloid, kopsiyunnanine E, was isolated from Yunnan Kopsia arborea, and its structure, which was inferred from spectroscopic data, was established by a 16-step asymmetric total synthesis that proved that the natural alkaloid was not enantiomerically pure.