Endophytic Fungi of Marine Alga From Konkan Coast, India—A Rich Source of Bioactive Material

Abstract

Endophytes are an unexploited source of pharmacologically relevant compounds owing to their species richness and diversity. In this study, a total of 26 endophytic fungi were isolated and identified from 10 marine algal samples collected from the Konkan coast, Goa, India. Eighteen of the fungal isolates belonged to phylum Ascomycota while one belonged to phylum Basidiomycota based on ITS sequencing. Further, the genus Aspergillus sp. was the most common and abundant endophyte found in the sampled algal species. A significant antibacterial activity against five pathogenic bacteria was exhibited by the extracts of fungal isolates AG1.1, AG1.1 (G) and VG2.6 (agar diffusion assay). The extracts of fungal endophytes VB1.1, PG1.2 and VG2.6 demonstrated good antioxidant activity (DPPH scavenging assay). Further, cytotoxicity of all the endophytic extracts on human cancer cell lines was determined by MTT and resazurin assay. The crude extract of Aspergillus unguis (AG 1.2) showed the highest cytotoxic potential on cervical cancer (HeLa), breast cancer (MCF-7), lung cancer (A549), and skin cancer (A431) cell lines in a concentration dependent manner. Moreover, Gas Chromatography-Mass Spectroscopy analysis of the extract of A. unguis (AG 1.2) confirmed the presence of several bioactive metabolites including azelaic acid, azetidine, and furopyrans. The extract of A. unguis (AG 1.2) demonstrated G1 phase cell cycle arrest, reactive oxygen species (ROS)-dependent MMP loss and apoptosis-dependent cell death in A431 cells. The algae-derived fungal endophytes of Konkan coast are a rich source of novel pharmaceutically active compounds as indicated by this work.

Endophytic fungus, Chaetomium globosum, associated with marine green alga, a new source of Chrysin

“…Marine algae associated endophytic fungi community is looked upon as a hopeful source of potent anti-cancer compounds and as an alternative source of plant-based products. The Konkan coast of India is a relatively unexplored environment for endophytic fungi and their bioactive compounds 18 . Earlier studies have acknowledged marine algicolous endophytic fungi as hot factories of bioactive compounds because of their unique environmental settings 27 .…”

“…In this study, endophytic fungus C. globosum was isolated from a marine green alga 18 . A total of 26 different fungi were isolated and screened for their cytotoxic potential in our earlier study 18 . C. globosum isolated from alga Chaetomorpha sp.…”

“…The phylogenetic tree constructed showed its closeness to other Chaetomium sp. including Chaetomium subaffini , Chaetomium cochlioides , Chaetomium pseudocochlioides, and Chaetomium acropullum 18 . The genus Chaetomium has been a prolific source of a wide array of chaetoglobosins, epipolythiodioxopiperazines, azaphilones, xanthones, anthraquinones, chromones, depsidones, steroids, and terpenoids.…”

“…The fungus Chaetomium globosum PG 1.6 (accession number MH645800) was isolated in our previous study from a marine green alga C. media collected from the Konkan coast, India 18 . The fungus was maintained on Potato Dextrose agar supplemented with 250 mg/mL of streptomycin and artificial sea salts 18 .…”

“…The marine ecosystem is an extremely diverse reservoir of life harboring myriads of organisms. Extensive drug discovery and secondary metabolite screening investigations over the past few decades have demonstrated marine seaweeds and its associated endophytic fungi to be rich sources of unique bioactive natural products 18 . To the best of our knowledge, there is no report of chrysin production from any marine organisms.…”