Preliminary Cytotoxic Screening of Turbinaria ornata–Derived Endophytic Fungi Using Brine Shrimp Lethality Assay

Abstract

Turbinaria ornata, a chemically rich brown seaweed, is known to possess cytotoxic activity potential; however, the biological properties of its fungi-associated endophytes remain largely unknown. This study aimed to evaluate the preliminary cytotoxic potential of ethyl acetate extracts derived from endophytic fungi isolated from T. ornata using the Brine Shrimp Lethality Test (BSLT). Four fungal isolates (TO1–TO4) were obtained through surface sterilization followed by direct planting and dilution–plating methods, cultivated on rice media, and extracted via maceration in ethyl acetate. Preliminary cytotoxicity assays revealed that only isolate TO4 exhibited toxicity, with an LC₅₀ value of 807.20 ppm, while the remaining extracts were categorized as non-toxic. TLC profiling of the active extract indicated the presence of alkaloids and terpenoid/sterol constituents. T. ornata-derived endophytes may produce metabolites with modest cytotoxicity, with TO4 representing the most promising candidate. Further fractionation and chemical characterization, followed by advanced human cancer cell lines cytotoxic evaluation, are warranted to identify potential lead compounds.