Bioactive Secondary Metabolites from the Red Sea Marine Verongid Sponge Suberea Species

Abstract

In a continuation of our efforts to identify bioactive compounds from Red Sea Verongid sponges, the organic extract of the sponge Suberea species afforded seven compounds including two new dibrominated alkaloids, subereamollines C and D (1 and 2), together with the known compounds aerothionin (3), homoaerothionin (4), aeroplysinin-1 (5), aeroplysinin-2 (6) and a revised subereaphenol C (7) as ethyl 2-(2,4-dibromo-3,6-dihydroxyphenyl)acetate. The structures of the isolated compounds were assigned by different spectral data including optical rotations, 1D (1H and 13C) and 2D (COSY, multiplicity-edited HSQC, and HMBC) NMR and high-resolution mass spectroscopy. Aerothionin (3) and subereaphenol C (7) displayed potent cytotoxic activity against HeLa cell line with IC50 values of 29 and 13.3 µM, respectively. In addition, aeroplysinin-2 (6) showed potent antimigratory activity against the human breast cancer cell line MDA-MB-231 with IC50 of 18 µM. Subereamollines C and D are new congeners of the previously reported compounds subereamollines A and B with methyl ester functionalities on the side chain. These findings provide further insight into the biosynthetic capabilities of members of the genus Suberea and the chemical diversity as well as the biological activity of these compounds.

Bromotyrosine Alkaloids with Acetylcholinesterase Inhibitory Activity from the Thai Sponge Acanthodendrilla sp

“…This is in agreement with the previous report [6]. Among the alkaloids possessing an alkyl diamine chain (1)(2)(3)(4)(5)(6)(7)(8)(9), the presence of a ketone group in the chain (3-5, 8, and 9) diminished the inhibitory activity up to 2-8 fold. Although additional structure-related alkaloids are required for concrete evidence, among the four active compounds (1, 2, 6, and 7), the specific length of the alkyl diamine chain is important for the enzyme inhibitory potency.…”

“…collected from Koh-Ha Islets, Krabi, Thailand, showed a strong AChE inhibitory activity (80% inhibition of electric eel AChE (EeAChE) at 100 µg/mL). Extensive chemical purification of the extract by chromatographic combination of silica gel, Sephadex ® LH-20, and RP-HPLC columns led to the isolation of 20 bromotyrosine-derived alkaloids, including a new compound 13-oxosubereamolline D (5), together with 19 known compounds, subereamolline C (1), subereamolline D (2) [9], 3, 4 [10], aerothionin (6) [11][12], homoaerothionin (7) [11], 11oxoaerothionin (8) [13], oxohomoaerothionin (9) [14], fistularin 1 (10) [15], 11,19-dideoxyfistularin 3 (11) [12], 19-deoxyfistularin 3 (12) [16], 3,5-dibromo-1-hydroxy-4,4-dimethoxy-2,5-cyclohexadiene-1-acetamide (13) [17][18], verongiaquinol (14) [19][20], cavernicolin-1 (15), cavernicolin-2 (16) [21], 7β-bromo-5chlorocavernicolin (17), 7α-bromo-5-chlorocavernicolin (18) [22], 5,7β-dichloro-cavernicolin (19), and 5,7α-dichloro-cavernicolin (20) [23]. Bromotyrosine-derived alkaloids are a well-known group of marine secondary metabolites isolated from sponges, mostly belonging to the order Verongida [24].…”

Science, Diplomacy, and the Red Sea’s Unique Coral Reef: It’s Time for Action

“…A biodiversity hotspot, the Red Sea has a high degree of endemism (Dibattista et al, 2016;Osman et al, 2020). Its unique reefs are also a rich potential source of natural products and medicines (Shaala et al, 2015;Ibrahim et al, 2017). The high degree of endemism and adaptation to high salinity and high temperature could potentially have led to the appearance of unique molecules and metabolites not to be found in other reef systems of the world (O'Rourke et al, 2016(O'Rourke et al, , 2018Kremb et al, 2017).…”

Synthesis and Absolute Configuration of Acanthodendrilline, a New Cytotoxic Bromotyrosine Alkaloid from the Thai Marine Sponge <i>Acanthodendrilla</i> sp.

“…1), were previously reported by other research groups as cytotoxic agents against several cancer cell lines. 3,4,12,18) Further investigation of the crude ethyl acetate (EtOAc) extract from this sponge resulted in the isolation of a new bromotyrosine alkaloid, acanthodendrilline (1, Fig. 2).…”

“…1) The remarkable diversities of their chemical structures, together with the wide range of bioactivities, including antimicrobial, [2][3][4][5][6] antiviral, 7) antiprotozoal, 8) cytotoxic, 3,4,[9][10][11][12] anti-inflammatory, 13) and enzyme inhibitory activities, [14][15][16] make them highly attractive to both natural product chemists and molecular biologists. In the course of our search for bioactive secondary metabolites from Thai marine organisms, we recently reported the isolation of a series of bromotyrosine alkaloids from the Thai marine sponge Acanthodendrilla sp.…”