Antibacterial, cytotoxic and trypanocidal activities of marine-derived fungi isolated from Philippine macroalgae and seagrasses

Abstract

AbstractThe occurrence and bioactivities of marine-derived fungi are evaluated in this paper. A total of 16 morphospecies of marine-derived fungi (MDF) were isolated from four host macroalgae and two seagrasses and identified as belonging to the generaAspergillus,Fusarium,Paecilomyces,Penicillium,Sclerotinia,ThamnidiumandTrichoderma, including fivemycelia sterilia.Among these host organisms, the rhodophyteLaurencia intermediaharboured the highest number of isolated MDF. Selected MDF were then assayed and showed to inhibitPseudomonas aeruginosa(8-19 mm zone of inhibition) andStaphylococcus aureus(6-19 mm zone of inhibition), and were cytotoxic against the brine shrimpArtemia salinanauplii (LD50: 201.56-948.37 μg mL−1). The screening led to the selection of five of the most bioactive morphospecies, all belonging to the genusAspergillus. These marine aspergilli were subjected toβ-tubulingene sequence analysis for species identification, and to mass production in different culture media with or without marine salts, and screening of the crude culture extracts for their cytotoxic and trypanocidal activities.Aspergillus tubingensiscultivated in potato dextrose broth with marine salt proved to be the most cytotoxic against P388 (IC50: 1028 ng mL−1) and HeLa (IC50: 1301 ng mL−1) cancer cells. On the other hand,A. fumigatuscultivated in malt extract broth without marine salt was shown to be the most potent againstTrypanosoma congolense(IC50: 298.18 ng mL−1). Our study therefore showed that salinity may influence the bioactivities of some species of MDF.