Paralemnalia thyrsoides-associated fungi: phylogenetic diversity, cytotoxic potential, metabolomic profiling and docking analysis

Background Cancer continues to be one of the biggest causes of death that affects human health.

Chemical resistance is still a problem in conventional cancer treatments.

Fortunately, numerous natural compounds originating from different microbes, including fungi, possess cytotoxic characteristics that are now well known.

This study aims to investigate the anticancer prospects of five fungal strains that were cultivated and isolated from the Red Sea soft coral Paralemnalia thyrsoides .

The in vitro cytotoxic potential of the ethyl acetate extracts of the different five isolates were evaluated using MTS assay against four cancer cell lines; A549, CT-26, MDA-MB-231, and U87.

Metabolomics profiling of the different extracts using LC-HR-ESI-MS, besides molecular docking studies for the dereplicated compounds were performed to unveil the chemical profile and the cytotoxic mechanism of the soft coral associated fungi.

Results The five isolated fungal strains were identified as Penicillium griseofulvum (RD1), Cladosporium sphaerospermum (RD2), Cladosporium liminiforme (RD3), Penicillium chrysogenum (RD4), and Epicoccum nigrum (RD5).

The in vitro study showed that the ethyl acetate extract of RD4 exhibited the strongest cytotoxic potency against three cancer cell lines A549, CT-26 and MDA-MB-231 with IC_50 values of 1.45 ± 8.54, 1.58 ± 6.55 and 1.39 ± 2.0 µg/mL, respectively, also, RD3 revealed selective cytotoxic potency against A549 with IC_50 value of 6.99 ± 3.47 µg/mL.

Docking study of 32 compounds dereplicated from the metabolomics profiling demonstrated a promising binding conformation with EGFR tyrosine kinase that resembled its co-crystallized ligand albeit with better binding energy score.

Conclusion Our results highlight the importance of soft coral-associated fungi as a promising source for anticancer metabolites for future drug discovery.