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Eleven highly halogenated chamigrane sesquiterpenoids, compositacins A-K, including one unusual rearranged chamigrane sesquiterpenoid, compositacin A, were isolated from the red alga Laurencia composita Yamada, along with seven known structural analogues. Compositacins B and D are the first examples of chamigranes bearing an ether bridge involving C-5/C-9 and C-3/C-5, respectively, while compositacins B and C represent the first chamigranes with a C-10 carbonyl group. Their structures were elucidated on the basis of extensive spectroscopic analysis. The absolute configuration of compositacin B was determined by ECD calculation, whereas the absolute configurations of compositacins A and C-L were proposed on biosynthetic grounds by comparison to compositacin B and the related known sesquiterpenoids johnstonol and yicterpene A. We also suggest that the structure of the previously reported sesquiterpenoid laurokamin A should be revised. Cytotoxicity and antifungal activity of these isolates were also investigated. The results showed that compositacin G exhibited good antifungal activity against Microsporum gypseum (Cmccfmza) with a MIC 80 value of 4 μg/mL relative to positive controls. Four of the chamigrane halosesquiterpenoids showed marginal cytotoxicity against the A-549 human lung adenocarcinoma cell line with IC 50 values ranging from 48.6 to 85.2 μM., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

An unusual tetrahalogenated indole with the exceptionally rare inclusion of the three halogens bromine, chlorine, and iodine was found using mass spectrometry within a fraction of a semipurified extract obtained from the red alga Rhodophyllis membranacea. We report herein the isolation and structure elucidation, using a combination of NMR spectroscopy and mass spectrometry, of 11 new tetrahalogenated indoles (1-11), including four bromochloroiodoindoles (5-7, 10). Several were evaluated for cytotoxic and antifungal activities against the HL-60 promyelocytic cell line and Saccharomyces cerevisiae, respectively.

From a sample of the red alga Plocamium cartilagineum, four polyhalogenated monoterpenes [1-4] were isolated and characterized with (3R*, 4R*)-1-bromo-7-chloromethyl-3,4-dichloro-3-methyl-1E,5E,7-octatrie ne [1] being a new compound. Also reported are antifungal, antibacterial, and molluscicidal activities, as well as the brine shrimp toxicity of these metabolites.