Bisindole Alkaloids from a New Zealand Deep-Sea Marine Sponge Lamellomorpha strongylata

Abstract

Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, Lamellomorpha strongylata, resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles—(Z)-coscinamide D (1), (E)-coscinamide D (2)—and four compounds isolated for the first time as natural products—lamellomorphamides A (3), B (4), C (5) and D (6). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantiodivergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.

Recent Advances on Marine Alkaloids from Sponges

“…[10] The indole moiety is widely distributed in marine natural products, especially sponges. [11][12][13] The structures of indole alkaloids produced by marine sponges are shown in Figure 1.…”

“…[23] Two novel double indoles alkaloids 23 and 24 were accessed from marine sponge Lamellomorpha strongylata containing the unusual α-ketovinylamide functionality. [12] Compounds 25 and 26 were firstly isolated from the sponge Spongosorites calcicola. [24] The nucleophilicity of tryp-tophan resulted in the condensation of two 8ketotryptamine derivative units.…”

“…Indole alkaloids with a benzopyrrole skeleton possess diverse bioactivities such as cytotoxic, antineoplastic, antibacterial and antimicrobial activities [10] . The indole moiety is widely distributed in marine natural products, especially sponges [11–13] . The structures of indole alkaloids produced by marine sponges are shown in Figure 1.…”

“…The intermediate isatin was detected during the biosynthesis of compounds 21 and 22 [23] . Two novel double indoles alkaloids 23 and 24 were accessed from marine sponge Lamellomorpha strongylata containing the unusual α ‐ketovinylamide functionality [12] . Compounds 25 and 26 were firstly isolated from the sponge Spongosorites calcicola [24] .…”

Recent advances in indole dimers and hybrids with antibacterial activity against methicillin‐resistant Staphylococcus aureus

“…The guanidine‐containing pyrazine moiety was critical for the high activity, and replacement of this fragment by pyrazin‐2(1 H )‐one or piperazin‐2‐one led to a great loss of anti‐MRSA activity, as evidenced by the fact that dimers 2 (MIC: 20 µg/ml) and 3 (MIC: 20 to >40 µg/ml) only showed a weak‐to‐moderate anti‐MRSA activity, and the activity was far inferior to that of vancomycin (MIC: 1.5 µg/ml). [ 27–29 ] Overall, dragmacidin G could serve as a lead compound for further structural optimization.…”