Bisindole Alkaloids of the Topsentin and Hamacanthin Classes from a Marine Sponge Spongosorites sp.

Abstract

Seven new (1 and 3-8) and seven known (2 and 9-14) bisindole alkaloids of the topsentin and hamacanthin classes were isolated from the MeOH extract of a marine sponge Spongosorites sp. by bioactivity-guided fractionation. The structure of compound 7 is a revision from our previous report. The planar structures were established on the basis of NMR and MS spectroscopic analyses. Configurations of these compounds were defined by NMR spectroscopy and optical rotation. It is noteworthy that both R and S isomers were isolated for the hamacanthins (1-4, 9, 10, 15, and 16), while a single stereoisomer was isolated for dihydrohamacanthins (5, 11-14, 17, and 18). Compounds 1-4, 6, and 8-14 showed marginal cytotoxicity against five human solid tumor cell lines, and compound 2 showed weak antibacterial activity against clinically isolated methicillin-resistant strains.

Methicillin-resistant Staphylococcus aureus (MRSA) Pyruvate Kinase as a Target for Bis-indole Alkaloids with Antibacterial Activities

“…The structures of A-D were established through recourse to standard spectroscopic techniques including NMR and high-resolution electron impact mass spectrometry data. Spectral data for these compounds were in good agreement with those reported previously (15,18,29,(33)(34)(35) and are available upon request.…”

“…2), including spongotine A (A) (33,34), bromotopsentin (B) (18,29), cis-3,4-dihydrohamacanthin B (C) (29,35), and bromodeoxytopsentin (D) (15,29). Compounds A-D were evaluated for their potent inhibitory activities toward MRSA PK (Fig.…”

“…Antimicrobial activity was found to reside predominantly in the 60% aqueous MeOH fraction (1.87 g) obtained from the initial polymeric reversed phase separation of 14.8 g of the orange methanolic sponge extract. Exhaustive reversed phase C18 HPLC (aqueous MeOH, 0.05% TFA) of a portion (420 mg) of the 60% aqueous methanol fraction yielded the known bis-indole alkaloids spongotine A (A, 18 mg) (33,34), bromotopsentin (B, 36 mg) (18,29), cis-3,4-dihydrohamacanthin (C, 3 mg) (29,35), and bromodeoxytopsentin (D, 23 mg) (15,29) (Fig. 2).…”

3,6-Bis(5’-bromo-3’-indolyl)-1,4-dimethypiperazine-2,5-dione

“…Isolated from the marine sponge series Dragmacidin, Hexadella, and Spongosorites, unique bisindolylpiperazine alkaloids have received significant attention in recent years for their antiviral, cytotoxic, and anti-inflammatory properties [1][2][3][4][5][6][7][8][9][10]. The dragmacidin series of alkaloids each contain a central piperazine ring with indole units attached at the 2-and 5-positions.…”

Cytotoxic Polyketides from the Marine Sponge Discodermia calyx

“…5 Three sulfated ceramides, calyceramides, have also been isolated from the same sponge as inhibitors of neuraminidase. 7 As a part of our continuing research aimed at the discovery of biologically active secondary metabolites from marine organisms, [8][9][10] we isolated two C-21 furanoterpenes and eight bisindole alkaloids from the marine sponge Discodermia calyx, as a first report from a sponge belonging to the subclass Tetractinomorpha. 11 In the continuation of our study on this marine sponge, we isolated two pederin polyketides (1 and 3) from the 90% MeOH fraction.…”