Monanchomycalin C, a New Pentacyclic Guanidine Alkaloid from the Far-Eastern Marine Sponge Monanchora Pulchra

Abstract

A new pentacyclic guanidine alkaloid, monanchomycalin C (1), along with the earlier known ptilomycalin A (2), were isolated from the Far-Eastern marine sponge Monanchora pulchra. The structure of 1 was elucidated using 1D and 2D NMR spectroscopic and mass spectrometric data. Compounds 1 and 2 exhibited cytotoxic activities against human breast cancer MDA-MB-231 cells with IC 50 values of 8.2 µM and 4.3 µM, respectively.

Normonanchocidins A, B and D, New Pentacyclic Guanidine Alkaloids from the Far-Eastern Marine Sponge Monanchora pulchra

“…It was suggested that the C-37 atom is located in an acyclic residue, but not in a morpholinone ring, in contrast with other known monanchocidins. Analysis of the NMR data (Table 1) and taking into account that the molecular weight of normonanchocidin A (1) is less than that of monanchocidin A by 101 amu, we concluded that its "anchor" part is a derivative of 1,3-diaminopropane (substructure "a", Figure 1), which has never before been found in Far-Eastern and tropical pentacyclic guanidine alkaloids [1][2][3][4][10][11][12][13][14][15][16][17][18][19]. Further analysis of the 1 H NMR data of 1 revealed the presence of branching in the chain fragment, indicated by the triplet for CH 3 -43 at δ H 0.84, similarly to that found earlier in the spectrum of monanchocidin A [1].…”

Marine Cyclic Guanidine Alkaloids Monanchomycalin B and Urupocidin A Act as Inhibitors of TRPV1, TRPV2 and TRPV3, but not TRPA1 Receptors

“…Fluorescent assays were performed as described in [6]. The alkaloid’s solutions of desired concentration were obtained by serial dilution of water stock solutions (10 mg/mL) in calcium assay buffer (10 mM HEPES/HBSS, pH 7.4).…”

“…In recent years it has been shown that the far-eastern marine sponge Monanchora pulchra is also a rich source of novel pentacyclic [3,4,5,6,7], bicyclic [8] and acyclic guanidine alkaloids [9,10]. It is interesting that alkaloids produced in the sponges from different locations and depths had a variety of structures.…”

Structure, synthesis and biological properties of the pentacyclic guanidinium alkaloids

“…in 1989 by Kashman and co-workers. 11 In the following years, several PGA families, namely the crambescidins 12–15 , neofolitispates 16 , fromiamycalin 17 , celeromycalin 17 , monanchocidins 18,19 , monanchomycalins 20,21 and normonanchocidins 22 have been isolated, primarily from marine sponges and other aquatic organisms.…”