Marine-derived Penicillium sp.: fungal diversity as a promising source of bioactive compounds

In the last decade, marine environment has been increasingly investigated in search for new bioactive compounds with possible pharmaceutical interest. Besides other organisms, marine-derived fungi represent a large, but still little explored potential source of new substances, due to the high level of biodiversity found in the various marine ecosystems, and their capability to adjust their metabolism to environmental conditions [1]. Taxonomically, the genus Penicillium is one of the most complex of the fungal world, with about 225 species accepted and a continued discovery of new species [2]. Penicillium species are known to produce a large range of compounds including polyketides, alkaloids, terpenoids and peptides. Marine strains are of particular interest as they are the source of 81 out of 180 cytotoxic compounds described from this genus so far.

In the presented work, sampling of marine sediments in the Atlantic coast of France showed that Penicillium strains represent 47% of the microfungi isolated, revealing high abundance and diversity. Twelve strains belonging to 9 species were cultured on various saline media. Variations in morphological appearance and growth speed of colonies were observed, and HPLC-UV/DAD-MS metabolic profiling and dereplication of crude extracts showed that their composition was dependant on species, strain and culture medium. Several novel compounds (unusual derivatives of cytochalasanes) were discovered in an extract of P. expansum by comparison with spectral libraries, databases, bioguided fractionation, and structural analyses. Finally, the fact that 27 out of 43 extracts from 12 Penicillium strains exhibited cytotoxicity on KB cell line or neuroactivity on blowfly larvae, implicated that marine-derived Penicillium strains constitute a promising source of unique bioactive compounds.

References: 1. Bugni, T.S., Ireland, C.M. (2004) Nat. Prod. Rep. 21: 143–163 2. Pitt J.I. et al. (2000) Integration of modern taxonomic methods for Penicillium and Aspergillus classification. Harwood Academic Publishers. Amsterdam. pp.9–47