Diversity of Marine Algicolous Endophytic Fungi: In Search of Novel Anticancer Compounds
Subhadarsini Sahoo1, Kamalraj Subban2 and Jayabaskaran Chelliah*
Department of Biochemistry, Indian Institute of Science, Bangalore, India
Marine organisms, which account for over half of all biodiversity on Earth, are one of the finest sources for a variety of therapies. Fungi are a class of marine organisms that are a remarkable and important source of bioactive secondary metabolites from a biotechnological perspective. It is generally known that several fungi from different orders may survive in hypersaline conditions by synthesizing various secondary metabolites. Many of these unique secondary metabolites are also very effective cancer therapies.
In the current study, 31 endophytic fungi that were dwelling inside red, green, and brown marine algae have been isolated and identified via morphological as well as molecular-based (ITS sequencing). Maximum likelihood analysis and diversity indices disclosed the evolutionary link between the fungus and the abundance of each species. Aspergillus, comprising seven species out of 27 distinct species, was found to be the leading genus of endophytic fungus among 17 different genera, including Ascomycetes (13), Basidiomycetes (1), Hyphomycetes (14), and Coelomycetes (3). Each isolated endophytic fungal extract was tested for cytotoxicity against HeLa (cervical cancer), and A431 (epidermoid carcinoma). Nine fungal extracts showed considerable cytotoxicity against both cell lines with greater than 60% cell death. The mycelial extracts of these nine fungi harbored powerful cytotoxic chemicals rather than secreting them to the culture medium. Purifying these potent bioactive compounds from the cytotoxic fungal extracts could enable us to deduce the mechanism underlying the anticancer activity.