Yusuke Hirasawa

THE LYCOPODIUM ALKALOIDS

Lycopodium alkaloids are unique heterocyclic alkaloids having C 11 N, C 15 N 2 , C 16 N, C 16 N 2 , C 22 N 2 , and C 27 N 3 types from genus Lycopodium and have attracted great interest from biogenetic and biological points of view as well as providing challenging targets for total synthesis. This review covered the structure elucidation and biological activity of new Lycopodium alkaloids and total synthesis of some Lycopodium alkaloids reported in the literature from 2004 to July in 2008.

Alkaloids from the seeds of Peganum harmala showing antiplasmodial and vasorelaxant activities

Bioassay-guided purification from the seeds of Peganum harmala led to the isolation of harmine (1), harmaline (2), vasicinone (3), and deoxyvasicinone (4). Harmine (1) and harmaline (2) showed a moderate in vitro antiplasmodial activity against Plasmodium falciparum. Quinazoline alkaloid, vasicinone (3), showed a vasorelaxant activity against phenylephrine-induced contraction of isolated rat aorta.

Complanadine A, a new dimeric alkaloid from Lycopodium complanatum

Abstract A new dimeric alkaloid with a lycodine-type skeleton, complanadine A ( 1 ), has been isolated from the club moss Lycopodium complanatum , and the structure including the absolute stereochemistry was elucidated on the basis of spectroscopic data.

Ceramicines B-D, new antiplasmodial limonoids from Chisocheton ceramicus

Three new limonoids, ceramicines B-D (1-3), have been isolated from the bark of Chisocheton ceramicus. Structures and stereochemistry of 1-3 were fully elucidated and characterized by 2D NMR analysis. Ceramicines exhibited a moderate antiplasmodial activity.

Alstiphyllanines E–H, picraline and ajmaline-type alkaloids from Alstonia macrophylla inhibiting sodium glucose cotransporter

Three new picraline-type alkaloids, alstiphyllanines E-G (1-3) and a new ajmaline-type alkaloid, alstiphyllanine H (4) were isolated from the leaves of Alstonia macrophylla together with 16 related alkaloids (5-20). Structures and stereochemistry of 1-4 were fully elucidated and characterized by 2D NMR analysis. Alstiphyllanines E and F (1 and 2) showed moderate Na(+)-glucose cotransporter (SGLT1 and SGLT2) inhibitory activity. A series of a hydroxy substituted derivatives 21-28 at C-17 of the picraline-type alkaloids have been derived as having potent SGLT inhibitory activity. 10-Methoxy-N(1)-methylburnamine-17-O-veratrate (6) exhibited potent inhibitory activity, suggesting that the presence of an ester side chain at C-17 may be important to show SGLT inhibitory activity. Structure activity relationship of alstiphyllanines on inhibitory activity of SGLT was discussed.

Cassiarins C-E, antiplasmodial alkaloids from the flowers of Cassia siamea.

Three new alkaloids, cassiarins C-E (1-3), and a new chromone, 10,11-dihydroanhydrobarakol (4), which showed moderate antiplasmodial activity against Plasmodium falciparum 3D7, were isolated from flowers of Cassia siamea, and the structures of 1-4 were elucidated by 2D NMR analysis and chemical transformation. Cassiarin D (2) was a dimeric compound consisting of 5-acetonyl-7-hydroxy-2-methylchromone and cassiarin C (1), and cassiarin E (3) was a dimer of cassiarins A and C (1).

Bisnicalaterines B and C, atropisomeric bisindole alkaloids from Hunteria zeylanica, showing vasorelaxant activity.

Two new bisindole alkaloids, bisnicalaterines B and C (1 and 2) consisting of an eburnane and a corynanthe type of skeletons, were isolated from the bark of Hunteria zeylanica. Their absolute structures were determined by combination of NMR, CD, and computational methods, and each of them was shown to be in an atropisomeric relationship. Bisnicalaterines B and C (1 and 2) showed potent vasorelaxant activity on isolated rat aorta.

Alsmaphorazines A and B, Novel Indole Alkaloids from Alstonia pneumatophora

Two novel indole alkaloids, alsmaphorazines A and B, were isolated from the leaves of Alstonia pneumatophora (Apocynaceae), and their structures were determined on the basis of the 2D NMR and MS spectral analysis. These alkaloids possessed a new skeleton consisting of an 1,2-oxazinane and an isoxazolidine chromophore. The absolute configuration of alsmaphorazine B was determined by using CD spectral analysis. Alsmaphorazine A inhibited the NO production in the LPS-stimulated J774.1 cells dose-dependently without affecting the cell viability.

Studies on the constituents from the fruits of Phaleria macrocarpa

From the fruits of Phaleria macrocarpa, icariside C3 (1), phalerin (2), and mangiferin (3) were isolated and their structures were identified on the basis of spectroscopic data. Icariside C3 (1) showed a slow vasorelaxant activity against noradrenaline-induced contraction of isolated rat aorta. The structure of phalerin (2) was revised as 2,4′,6-trihydroxy-4-methoxybenzophenone-2-O-β-d-glucoside.

Chrotacumines A—D, Chromone Alkaloids from Dysoxylum acutangulum

Four new chromone alkaloids, chrotacumines A-D (1-4), consisting of a 5,7-dihydroxy-2-methylchromone, an N-Me piperidine ring, and an ester side chain were isolated from Dysoxylum acutangulum, and their structures including absolute configurations were elucidated on the basis of spectroscopic data interpretation including 2D NMR, CD spectra, and X-ray analysis. The known compound rohitukine (5) showed moderate cytotoxicity against human HL-60 promyelocytic leukemia and HCT-116 colon cancer cells.