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

Abstract

New pentacyclic guanidine alkaloids, normonanchocidins A, B and D (1-3) along with the earlier known monanchocidin A were isolated from the Far-Eastern marine sponge Monanchora pulchra. Structures of 1-3 were elucidated using 1D-and 2D-NMR spectroscopic and mass spectrometric data. Compound 1 and a mixture of 2 and 3 (1:1) exhibited cytotoxic activities against human leukemia THP-1 cells with IC 50 values of 2.1 µM and 3.7 µM, respectively, and against cervix epithelial carcinoma HeLa cells with IC 50 of 3.8 µM and 6.8 µM, respectively.

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

“…Pentacyclic guanidine alkaloids (PGAs) are a class of biologically active secondary metabolites found in tropical and Far-Eastern marine sponges [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Their structures conventionally distinguish three structural blocks, such as: "vessel" part, "anchor" part and polymethylene chain.…”

“…The polycyclic part contains a new structural element, an n-propyl group attached to C-19. Most recently, the isolation was reported of three new PGAs from the sponge M. pulchra, named normonanchocidins having a new type of "anchor" part, a derivative of 1,3-diaminopropane [17].…”

Structure, synthesis and biological properties of the pentacyclic guanidinium alkaloids

“…In the past decade, the isolation of several potent PGA families from the marine sponge Monanchora pulchra has reignited the desire to explore the treasure trove of biology surrounding these exciting natural products. 18–22 In particular, cellular mechanisms regarding how PGAs affect cancer cells have been the subject of study recently due to their potential exploitation in antitumor therapy; however, the detailed function at a molecular level remains largely unknown, with several hypotheses and limited model studies. Herein, we wish to summarize the previous studies on the mechanism of action of PGAs.…”

“…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.…”

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

“…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.…”