Antifouling 26,27-Cyclosterols from the Vietnamese Marine Sponge Xestospongia testudinaria

Abstract

Three new C29 sterols with a cyclopropane ring cyclized between C-26 and C-27 of the side chain, aragusterol I (1), 21-O-octadecanoyl-xestokerol A (4), and 7β-hydroxypetrosterol (5b), were isolated from the Vietnamese marine sponge Xestospongia testudinaria, along with the known compounds, aragusterol B (2), xestokerol A (3), 7α-hydroxypetrosterol (5a), 7-oxopetrosterol (6), and petrosterol (7). The structures of the new compounds were established by analysis of spectroscopic data including 1D and 2D NMR, and high-resolution electrospray ionization mass spectrometry (HRESIMS). Their capacity to inhibit the adhesion of isolated bacteria from marine biofilms was evaluated against the bacterial strains Pseudoalteromonas sp. D41, Pseudoalteromonas sp. TC8, and Polaribacter sp. TC5. Aragusterol B (2) and 21-O-octadecanoyl-xestokerol A (4) exhibited the most potent antifouling activity with EC50 values close to these reported in the literature for tributyltin oxide, a marine anti-biofouling agent now considered to be a severe marine pollutant. Due to its comparable activity to tributyltin oxide and its absence of toxicity, the new 26,27-cyclosterol, 21-O-octadecanoyl-xestokerol A (4) constitutes a promising scaffold for further investigations.

Sterols from Thai Marine Sponge Petrosia (Strongylophora) sp. and Their Cytotoxicity

“…The 13 C NMR (Table 2, Figure S2), DEPT, and HSQC spectra revealed the presence of twenty-nine carbons, comprising five methyls, ten methylenes, eleven methines, and three quaternary carbons. These data established the compound 1 as a C 29 -steroidal structure with a cyclopropane ring at C-25–C-27, and its NMR spectra revealed close similarity to those of aragusterol I ( 6 ), which was also isolated in this study and reported previously from the marine sponge Xestospongia testudinaria [22]. The only difference was the presence of signals for oxymethine (δ H 4.13, s/δ C 67.0) at C-7 in 1 instead of the signal for methylene in aragusterol I ( 6 ), suggesting that the C-7 position of 1 was substituted with the hydroxyl group.…”

“…The orientations of three hydroxyl groups at C-3, C-7, and C-12 were established by the 1 H- 1 H coupling constants of H-3, H-7, and H-12, respectively. Two broad singlets of H-3 and H-7 were deduced as 3α-OH and 7α-OH configurations [21,22] while the dd ( J = 10.8 and 2.6 Hz) of H-12 was assigned as 12β-OH-configuration [21]. In addition, α-orientation of hydroxyl group at C-3 was confirmed based on the similarity of 13 C chemical shift of 1 (δ 65.8) with those reported for aragusterol I (δ 66.5, 3α-OH) [22].…”

“…led to the isolation of cyclosterols [4,5,6], polyacetylenic alcohols [7,8,9,10,11,12], meroditerpenes [13,14,15], 1,2-dihydroisoquinolines [16], halenaquinones [17], and pyridoacridine alkaloids [18]. Among them, some exhibited significant biological effects such as cytotoxicity [9,10,12,19,20,21], neurotrophic [11], antifouling [22] and antimicrobial activities [21], inhibitions against proteasome [15], protein Tyrosine phosphate 1B [13], cholinesterase [18], as well as inhibitory effects of the receptor activator of nuclear factor κB ligand (RANKL) induced osteoclastogenesis [17]. In this paper, we report the isolation and structure determination of eight new ( 1 – 5 and 11 – 13 ) and eight known ( 6 – 10 and 14 – 16 ) steroids from marine sponge Petrosia sp.…”

Composition and Predictive Functional Analysis of Bacterial Communities in Seawater, Sediment and Sponges in the Spermonde Archipelago, Indonesia

“…Tyrosine is an amino acid that occurs in proteins belonging to signal transduction processes, plays a role in photosynthesis and is a precursor to alkaloids and phenols [89,90]. Enrichment in the tyrosine and phenylalanine metabolic pathways and the importance of these pathways for the biosynthesis of alkaloids and phenols are in line with the numerous bioactive compounds that have been isolated from X. testudinaria and H. erectus [91][92][93][94][95]. Numerous bioactive compounds have also been isolated from Stylissa species including dimeric alkaloids (e.g., dibromophakellin and sceptrin), brominated pyrrole alkaloids and other brominated alkaloids.…”

Further Highly Hydroxylated Steroids from the Vietnamese Starfish <i>Archaster typicus</i>

“…The relative configurations of 2 were assigned by the coexistence of 2 and 4 in A. typicus, good agreement of the 1 H-and 13 C-NMR data for the steroid nucleus of 2 with those of (23E)-27-nor-25-oxo-5α-cholest-23-ene-3β,6α,8,14,15α-pentaol 15-O-sulfate so dium salt, 7) and by NOESY experiment. The proton signal of H-3 at δ H 3.50 (1H, m, J 1/2 =11.0 Hz) is indicative for its α-orientation 12) (versus t, J=2.5 or 3.0 Hz for β-orientation of H-3 without a large J value attributable to a diaxial coupling 13,14) ). This was further confirmed by the 13 C-NMR chemical shift for C-3 of 2 at δ C 72.1 7,12,15) and a NOESY correlation of H-3 (δ H 3.50) with H-5 (δ H 1.06).…”