Bioactive Bromotyrosine-Derived Alkaloids from the Polynesian Sponge Suberea ianthelliformis

Abstract

Herein, we describe the isolation and spectroscopic identification of eight new tetrabrominated tyrosine alkaloids 2–9 from the Polynesian sponge Suberea ianthelliformis, along with known major compound psammaplysene D (1), N,N-dimethyldibromotyramine, 5-hydroxy xanthenuric acid, and xanthenuric acid. Cytotoxicity and acetylcholinesterase inhibition activities were evaluated for some of the isolated metabolites. They exhibited moderate antiproliferative activity against KB cancer cell lines, but psammaplysene D (1) displayed substantial cytotoxicity as well as acetylcholinesterase inhibition with IC50 values of 0.7 μM and 1.3 μM, respectively.

Quorum Sensing Inhibitory and Antifouling Activities of New Bromotyrosine Metabolites from the Polynesian Sponge Pseudoceratina n. sp.

“…HMBC correlations of these two protons with the aromatic C-4 at δ C 133.3 and the amidic carbonyl C-1 at δ C 168.9 allowed to assign the position of this double bond between these two fragments. These data are consistent with those reported for psammaplysenes [10][11][12], which also contain a CH-2-CH-3 double bond. All these observations led us to assign the structure 3 to aplyzanzine E (Figure 4).…”

“…As previously reported in the literature, the NMR spectra of this family of compounds are complicated by the multiplicity of signals due to the presence of two rotational isomers trans/cis along the tertiary amide bond [11]. This behavior has been noted for tetrabromotyrosine derivatives such as anomians C-F and psammaplysenes F-I as well [10]. In Tables 1 and 2 When compared to aplyzanzine C (1), the molecular formula lacked 57 mu corresponding to a C 3 H 7 N fragment.…”

“…Setting aside misidentification of organisms and cross-contamination, this reminds us to remain cautious about the use of secondary metabolites for sponge taxonomy [8]. These bromotyrosine derivatives have very diverse structures, from the simplest such as subereaphenols [9], with two bromophenolic units such as psammaplysenes [10][11][12], amomoians [10,13,14], and aplyzanzines [14,15], to the most complex polycyclic such as archerines [16] or fistularins [17]. Among the most recently discovered structures, ma'edamines C and D are characterized by a tetrasubstituted pyridinium moiety, a novelty for this type of compound [18].…”

“…Aplyzanzine A, previously isolated from Aplysina sp. [15], is known for its antibacterial and antifungal activities [53], while aplyzanzine B and other close structures, such as anomoians and psammaplysenes, are mildly cytotoxic against a panel of different cancer cell lines [10,14]. Psammaplysene D, also isolated from a French Polynesian Verongiidae, displayed a substantial inhibition of acetylcholinesterase, probably as an anti-predatory defense through fish antifeedant activity [10].…”

Potential of fascaplysin and palauolide from Fascaplysinopsis cf reticulata to reduce the risk of bacterial infection in fish farming

“…A preliminary assay was performed on P. reticulata by balneation, as described previously for environmental toxicity studies of acetylcholinesterase (AChE) inhibitor pesticides (Wester and Vos 1994;Bocquené and Galgani 2004;El-Demerdash et al 2018). Fascaplysin-enriched fraction ethanolic solution was further tested in duplicate at 1 and 5 μg ml -1 during 72 h (chronic toxicity) and at 50 μg ml -1 during 1 h (acute toxicity) in 2-L tanks, each containing five fishes.…”