Chemical and biological screening of deep-water sponges from Antarctic regions

 

The majority of marine natural products (MNPs) originate from tropical and temperate shallow water invertebrates, such as sponges [1]. Recent studies indicate the presence of great genetic diversity in deep-waters that may be linked to unprecedented chemistry due to evolution/adaptation to extremely harsh environmental conditions. However, only less than 2% of MNPs derive from the deep-sea organisms [2]. Antarctic ecosystems are rich in biodiversity [3] and exposed to unique environmental characteristics resulting in communities structured both by biotic interactions (e.g. predation, competition) and abiotic factors (e.g. seasonality, ice-scouring) [4], suggesting a high chemical diversity. In this work, we investigated 39 deep-water sponges collected from the Antarctic Weddell Sea and adjacent areas (depths -100 – 600 m). The freeze-dried sponge samples were extracted with water, followed by MeOH and CH₂Cl₂ separately. The combined organic extracts were tested for activity against cancer cells [HepG2 (liver) and HT29 (bowel) cancer cell lines], bacteria [ESKAPE panel: Enterococcus faecalis, Staphylococcus aureus (MRSA), Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli) and fungi (yeasts Candida albicans, Cryptococcus neoformans). Several Latrunculia sponge extracts displayed high anticancer activity against both cell lines (IC₅₀ values 0.50 – 3.16 µg/ml). The organic extract of the glass sponge Rossella cf. antarctica showed moderate antibiotic activity towards MRSA and E. faecalis with IC₅₀ values of 96 and 213 µg/ml, respectively. All extracts have undergone chemical profiling/dereplication studies by HPLC-DAD-MS and ¹H NMR spectroscopy. The results of chemical and biological screening will assist in selection and activity-guided isolation of Antarctic deep-water sponge metabolites.

Acknowledgements: China Scholarship Council is acknowledged for funding.

Keywords: Antarctic deep-water sponge, screening, anticancer, antibacterial, dereplication.

References:

[1] Leal MC, Puga J, Serôdio J, Gomes NC, Calado R. Trends in the discovery of new marine natural products from invertebrates over the last two decades – where and what are we bioprospecting? PLoS One 2012; 7: e30580

[2] Skropeta D, Wei LQ. Recent advances in deep-sea natural products. Nat Prod Rep 2014; 31: 999 – 1025

[3] Brandt A, Gooday AJ, Brandão SN, Brix S, Brökeland W, Cedhagen T, Choudhury M, Cornelius N, Danis B, De Mesel I, Diaz RJ, Gillan DC, Ebbe B, Howe JA, Janussen D, Kaiser S, Linse K, Malyutina M, Pawlowski J, Raupach M, Vanreusel A. First insights into the biodiversity and biogeography of the Southern Ocean deep sea. Nature 2007; 447: 307 – 311

[4] Avila C, Taboada S, Núñez-Pons L. Antarctic marine chemical ecology: what is next? Mar Ecol 2008; 29: 1 – 71