Two New Quinoline and Tris(4-hydroxycinnamoyl)spermine Derivatives from Microdesmis keayana Roots

Abstract

Microdesmis keayana LÉONARD (Pandaceae) is a tropical shrub, the leaves of which are used in the Ivory Coast against malaria and some other parasites. Its antiplasmodial, 1,2) antitrypanosomal 3) and anthelmintic 4) activities have already been tested. Its roots are also used by traditional healers as a remedy for sexual dysfunction. An aqueous extract of these roots, recently tested, exhibited vasorelaxing properties, explained by an increase in nitric oxide (NO) in the vascular bed, via antioxidant properties and stimulation of endothelial nitric oxide synthase (eNOS) mRNA expression.5) In a previous paper three new tris(4-hydroxycinnamoyl)spermidines have been reported. 6) Continuing investigations on the roots of M. keayana have now led to the isolation and structural elucidation of two other new compounds, one quinoline derivative xanthoquininamide 1 and one tris(4-hydroxycinnamoyl)spermine keayanine 2. Results and DiscussionXanthoquininamide (1) was obtained as a pale yellow powder soluble in methanol. It showed an [MϩH] ϩ peak at m/z 189 in the ESI-MS data. The 1 H-NMR spectrum in MeOD was very simple and all chemical shifts and couplings which were observed between d H 7.3 and d H 8.8, including a not-so-common Jϭ4.5 Hz between H-2 and H-3, 7) were consistent for a quinoline derivative which was substituted on C-6 or C-7 (because of the ABX system) and on C-4. Mono-( 1 H and 13 C) and bidimensional (COSY, HMQC, HMBC) NMR experiments, as well as comparison with data of previously described quinine-like alkaloids, 8) made it possible to establish the structure of 1 as 6-hydroxyquinoline-4-carboxamide.1 H-and 13 C-NMR chemical shifts are given in Table 1. To our knowledge, this is the first report of both the natural occurrence of 1 and of its complete spectroscopic data, although it has already been synthesised from xanthoquininic acid by amidification. 9)Compound 2 was characterized both by ESI-MS and NMR data. In the electrospray mass spectrum, a [MϩH] ϩ peak was observed at m/z 701. Typical fragments were observed on ESI-MS spectrum at m/z 147 and m/z 177, corresponding to one coumaroyl and two feruloyl residues respectively, according to the relative heights of both signals. The subtraction of these three elements from the molecular mass of the compound (m/z 700) gave a mass of 199, compatible with a tri-substituted spermine. The positions of all three acyl moieties were determined by ESI-MS (see Fig. 2 Purification of a Microdesmis keayana hydromethanolic root extract led to the isolation of two new natural compounds, xanthoquininamide (6-hydroxyquinoline-4-carboxamide) and tris(4-hydroxycinnamoyl)spermine (N 5 -(p-coumaroyl)-N 1 ,N 14 -diferuloylspermine) which was named keayanine. Their structures were determined using spectroscopic analyses (ESI-MS, 1D-and 2D-NMR).

A Novel Polyamine Acyltransferase Responsible for the Accumulation of Spermidine Conjugates in Arabidopsis Seed

“…We could identify doublets at 6.45 and 7.70 ppm with 3 J HH 16 Hz in 1:1 ratio, which correlate in the COSY spectrum, and which we assign as trans-ethylenic peaks by comparision with literature reports (Zamble et al, 2006(Zamble et al, , 2007 for tris (4-hydroxycinnamoyl)spermidines. We predict, based on literature and symmetry considerations, that the presence of only two 16-Hz doublets favors the assignment as N 1 -((49-O-glycosyl)-sinapoyl),N 8 -sinapoylspermidine and 1 H NMR predictions (see Supplemental Figure 1 online) using both HNMR (ACD Labs) and ChemNMR (ChemDraw Ultra) to strengthen this prediction.…”

A review of the potential of medicinal plants in the management and treatment of male sexual dysfunction

“…Microdesmis keayana LÉONARD (Pandaceae) is a tropical shrub which occurs predominantly from eastern Nigeria down to DR Congo and Uganda and is used in African traditional medicine for erectile dysfunction (Zamblé et al., ; Zamble, Hennebelle, Sahpaz, & Bailleul, ). Zamblé et al.…”

Comparison of the origin and phenolic contents ofLycium ruthenicumMurr. by high-performance liquid chromatography fingerprinting combined with quadrupole time-of-flight mass spectrometry and chemometrics

“…The MS 2 of the signals confirmed the presence of dihydrocaffeoyl , caffeoyl groups, and a spermidine amide group. The fragment ions at m/z 222 and 234 could be explained by the cleavage of the C 4 -N 5 and N 5 -C 6 bond in the spermidine moiety, respectively [20]. This pattern was also applied in structural elucidation for other analogues.…”