Bioactive alkaloids from the Red Sea marine Verongid sponge Pseudoceratina arabica

Isolation and structure elucidation of natural products of three soft corals and a sponge from the coast of Madagascar

“…Samples of the sponge P. arabica from the Red Sea have already been investigated for their chemical constituents, resulting in the isolation of brominated compounds derived from tyrosine. [73][74][75] Specimens of P. arabica were obtained from the waters around Nosy Be, Madagascar, at a depth of about 18-25 m. The samples were homogenized and then extracted with methanol at room temperature. The combined organic layers were filtered and concentrated in vacuo to obtain the crude methanol extract, which was extracted with hexane and then dichloromethane.…”

“…83,87,89 Separation of the two diastereoisomers by HPLC was achieved by Lin and coworkers 91 and Santalova et al, 81 who also provided 1 H NMR data for the separated isomers. Even though the sponge P. arabica has already been investigated for its chemical constituents, [73][74][75] compounds 14a and 14b have not been isolated from this species so far.…”

“…84,86,88,89 In contrast, the parent ketone and related derivatives are described to be active against a variety of pathogens. 73,88,89,92 Some derivatives show antimigratory activity against the highly metastatic MDA-MB-231 human breast cancer cell line, 74,75 induce apoptosis in human breast tumor cells, 93 or inhibit Na + -K + -ATPase activity. 94 It can be assumed that some as yet unidentified components, possibly also dibromotyrosine derivatives, are responsible for the antimicrobial activity of the extracts.…”

Cytotoxic Psammaplysin Analogues from the Verongid Red Sea Sponge Aplysinella Species

“…Psammaplysins' backbone consists of two dibrominated subunits, 8,10-dibromo-4-hydroxy-9-methoxy-1,6-dioxa-2-azaspiro [4.6]undeca-2,7,9-triene-3-carboxylic acid (subunit A) and 3-(4-(2-aminoethyl)-2,6-dibromophenoxy)propan-1-amine subunit (subunit B, moloka'iamine) [14], connected together through an amidic linkage between the carboxylic moiety (C-9) of the substituted spirooxepinisoxazoline unit and the terminal amino group at C-10 of the moloka'iamine ( Figure 1) to give the first reported compound of this class, psammaplysin A, (N-(3-(4-(2-aminoethyl)-2,6-dibromophenoxy)propyl)-8,10-dibromo-4-hydroxy-9-methoxy-1,6-dioxa-2azaspiro [4.6]undeca-2,7,9-triene-3-carboxamide) [2]. Interestingly, moloka'iamine (subunit B) and its substituted derivatives were reported from several Verongid sponges [9,[13][14][15], but there is no single report in the literature about the existence or isolation of the separated dibrominated spirooxepinisoxazoline moiety (subunit A). The substituted and dibrominated spirooxepinisoxazoline unit has been always associated with the moloka'iamine moiety via an amidic linkage [2][3][4][5][6][7][8][9][10][11][12][13].…”

“…As a part of our ongoing work on the Red Sea Verongiid sponges [15], we investigated the cytotoxic extracts of the sponge Aplysinella species. Two new bromotyrosine-derived compounds, psammaplysin Z (1) and 19-hydroxypsammaplysin Z (2), together with the known psammaplysins A (3) [2] and E (4) [4], were isolated.…”