Effect of Salinity on Growth and Cytotoxicity of Extracts from a Marine-Derived Penicillium sp. (LY1L5)

Abstract

Some studies have indicated that the production of metabolites from marine-derived fungi is sensitive to seawater concentration, and this would have implications in drug discovery programmes using marine-derived microorganisms. The objective of this study is to assess the effect of salinity on the growth of marine fungi and in cytotoxic metabolite production. A marine-derived Penicillium sp. (isolate LY1L5) showing cytotoxicity was assessed for their tolerance to salinity (0, 2, 4, 6, 8 and 10 % sea-salt concentration) with respect to their growth and cytotoxic metabolite production. The growth of Penicillium sp. (LY1L5) was enhanced in the presence of salt, but the growth decreased at 10 % salinity. Growth rate declined after 18–20 days’ incubation. This isolate showed better IC50 values at salinity of 4 and 6 %, but was not active in the absence of salt. All extracts showed traces of cycloaspeptide A. Traces of the cytotoxic α-cyclopiazonic acid were detected only in five active extracts (F5975-B, F5975-C, F5975-D, F5975-E and F5975-F) but none in the inactive extract (F5975-A). The results from this study showed that salinity affected the growth of Penicillium sp. (LY1L5); however, a more extensive study needs to be done to obtain more comprehensive results because growth may also be dependent upon other parameters such as temperature whether or not adaptation by the fungi to salinity has occurred.