Chemical profiling of mycosporine-like amino acids in Bostrychia spp. and novel sulphated and brominated compounds from Bostrychia calliptera (Ceramiales, Rhodophyta)

The genus Bostrychia (Ceramiales, Rhodomelaceae) consists of approximately 40 species which are taxonomically accepted at present [1]. However, cryptic species are known to occur in several species complexes of Bostrychia, such as B. tenella, B. simpliciuscula, B.calliptera and B. intricata [2], [3]. All of them produce a variety of chemically different mycosporine-like amino acids (MAAs), compounds that are known for their outstanding UV absorption capacity and their photoprotective role in nature [4]. In order to get a deeper understanding of the chemical diversity of MAAs in the genus, a previously developed LC-MS method was successfully applied for the analysis of various Bostrychia spp. This approach enabled the investigation of their MAA pattern and revealed distinct differences among the species. Bostrychia scorpioides, for example showed a unique MAA pattern, thus leading to the isolation and identification of six new MAAs. Regarding B. calliptera, earlier studies suggested the existence of either two or three genetic lineages within this species based on molecular DNA sequencing data [3], [5]. Phytochemical profiling of those samples that were used for the DNA sequencing also revealed distinct differences in their chemical composition. Overall, the presence or absence of brominated and sulphated compounds or variations in their MAA pattern allowed a clear discrimination between the first and the other two lineages. The most important marker substances were isolated from B. calliptera and their structures elucidated. The respective compounds are considered as suitable biomarkers for chemotaxonomic studies within this polyphyletic group.

• References

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