Erythrinan Alkaloids from Seeds of Erythrina velutina

Abstract

In the course of our search for biologically and structurally unique compounds from medicinal plants in tropical and subtropical regions, 1) we have continued to investigate the constituents of Erythrina species. The genus Erythrina (Leguminosae) consists of more than a hundred species of trees, shrubs and herbaceous plants that are widely distributed throughout tropical and warm regions of the world. 2)Erythrina velutina WILLD. is commonly called Mulungu in Brazil, and its bark is used as a remedy for insomnia, convulsion, nervous cough and rheumatism in the north of Brazil. 3)Phytochemical analyses have demonstrated that Erythrina plants accumulate Erythrinan alkaloids,4,5) benzylisoquinoline alkaloids, 6) isoflavonoids 7) and pretocarpanes.8) The Erythrinan alkaloids are characterized by their unique tetracyclic spiro-amine framework. Therefore, their structures with various biological properties have recently attracted attention as a synthetic target. 9,10) In previous papers, we described the isolation and structural characterization of an indole derivative, hypaphorine, and its sleep-inducing effect on normal mice, 11) as well as the isolation and structural characterization of a new Erythrinan alkaloid, erysodine N-oxide, together with known compounds, and the evaluation of the isolated compounds in terms of the enhanced activity for tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). 12) In this paper, we describe the isolation and structural elucidation of four new Erythrinan alkaloids (1-4), including novel sulfated alkaloids from the high polarity portion extracted with n-BuOH, of the seeds of Erythrina velutina. The new constituents isolated from E. velutina were elucidated by spectroscopic methods, including 1 H-and 13 C-NMR, high resolution (HR)-MS and comparison with data in the literature. Results and DiscussionThe seeds of E. velutina were crushed and then extracted with MeOH and 80% MeOH. These MeOH-soluble materials were successively partitioned between petroleum ether, EtOAc and 3% tartaric acid. Each water-soluble material was adjusted to pH 10 with Na 2 CO 3 and then partitioned between CHCl 3 and n-BuOH to obtain alkaloidal portions. The nBuOH-soluble materials were subjected to amino-silica-gel and silica-gel column chromatography. The obtained fractions were further purified using a silica-gel column and silica-gel HPLC to afford four new compounds 1-4 and a known compound, hypaphorine.Compound , suggesting the presence of a sulfate group. The UV spectrum showed l max (MeOH) at 226 (log e 4.20) and 277 (log e 3.39) nm. The gross structure of 1 was deduced from detailed analysis of the 1 H-and 13 C-NMR-aided 2D-NMR experiments ( 1 H-1 H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond connectivity (HMBC)), which indicated the presence of four methylenes, one sp 3 quaternary carbon, one sp 3 oxy-methine, three sp 2 methines, one sp 2 quaternary carbon, two aromatic methine carbons, two aromatic quaternary carb...

Constituents of Erythrina - a Potential Source of Secondary Metabolities: A Review

“…Erythrina is a prominent source of alkaloid. A bunch of alkaloids are isolated from these fifteen species of Erythrina such as -Erysovine-N-oxide (1), Erysosalvinone (2), Erysodine (3), 1H-indole-3-propanamide (4), Glucoerysodine (5), Erysotrine (6), Erysovine (7), Erythraline (8), Erythramine (9), Erysopine (10), Erythrocarine (11), Erythrinine (17), 10, 11-Dioxyerysotrine (34), Erysosalvine (41), Erymelanthine (43) (Amer et al, 1991;Boland et al, 1998;Cui et al, 2009;Faria et al, 2007;Garin-Aguilar et al, 2000;Haggins et al, 1981;Hauschild et al, 2010;Hussain, 2002;Jang et al, 2008;Kabenei et al, 2011;Kumar et al, 2010;Soto-Hernadez et al, 2012;Lundquist, 1973;Miyazawa et al, 2006;Nakayama et al, 1978;Ozawa et al, 2011;Rodriguez et al, 2004;Watjen et al, 2008;Rahman et al, 2007;Rahman et al, 2010;Rodriguez et al, 2004;Rukachaisirikul et al, 2008;Soto-Hernadez et al, 2012;Tanaka et al, 2001;Wanjala et al, 2002;Zheng et al, 2013;Zhou et al, 2011). (Boland et al, 1998;Chacha et al, 2005;Hussain et al, 2008;Hussain et al, 2011;Jang et al, 2008;Kobayashi et al, 1997;Koo et al, 2013;Kumar et al, 2010;Lundquist, 1973;…”

Erythrina, a Potential Source of Chemicals from the Neotropics

“…A new Erythrina alkaloid, 10-hydroxy-11-oxo-erysotrine has been isolated from the flowers of E. herbacea (Tanaka & Hattori, 2008). From the bark of E. crista-galli two new alkaloids, cristanines A and B were isolated ( Ozawa, et al, 2010) and from the seeds of E. velutina were isolated four new alkaloids, three of them were found to be novel sulfated erythrinane alkaloids (Ozawa, et al, 2011).…”

Bioactive Compounds in Phytomedicine

“…A new Erythrina alkaloid, 10-hydroxy-11oxo-erysotrine has been isolated from the flowers of E. herbacea (Tanaka & Hattori, 2008). From the bark of E. crista-galli two new alkaloids, cristanines A and B were isolated ( Ozawa, et al, 2010) and from the seeds of E. velutina were isolated four new alkaloids, three of them were found to be novel sulfated erythrinane alkaloids (Ozawa, et al, 2011).…”