Barnacle settlement inhibitors

The extracts of the brown alga Bifurcaria bifurcata that had shown seasonal variation were examined as settlement inhibitors of two marine bacteria and the barnacle Balanus amphitrite [131]. The increased activity during April-June corresponded to the seasonal maximum concentration of the major diterpene ele-ganediol 43 found in the crude extracts [132], but isolated compounds were not individually tested for their antifouling activity [131]. 

These molecules were shown to be potent inhibitors of chitinase, an enzyme involved in the ecdysis of many insects and crustaceans, whose inhibitors are supposed to control the settlement of barnacles and, therefore, could have a potential application as antifouling agents. Unfortunately, no data are available in the literature about cytotoxic, immunosuppressive, or antibacterial activities of styloguanidines and, thus, a comparison with the potently bioactive congeners palau amines is not possible. 

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