Bioactive Properties and Metabolite Profiles of Endolichenic Fungi in Mangrove Ecosystem of Negombo Lagoon, Sri Lanka

Abstract

Endolichenic fungi (ELF) serve as a novel source of natural products with distinctive bioactivities. A total of 58 ELF isolated from 29 lichens collected from mangrove and mangrove-associated plants of Negombo lagoon, Sri Lanka were identified using morphological and DNA barcoding techniques. Ethyl acetate extracts of 18 such identified ELF isolates were subjected to in vitro assays to determine antioxidant, anti-inflammatory, tyrosinase inhibitory and antibacterial potency. Liquid chromatography–mass spectrometry (LC–MS) dereplication was conducted on the crude extracts in order to detect the secondary metabolites present. The extracts of Daldinia eschscholtzii and Hypoxylon lividipigmentum had the highest radical scavenging activity with SC50 values 14.27 ± 0.24 µg/mL and 18.34 ± 1.37 µg/mL, respectively. D. eschscholtzii also exhibited remarkable anti-inflammatory activity (IC50 7.97 ± 0.09 µg/mL). Tyrosinase inhibitory activity was highest in Cytospora xylocarpi (IC50 68.50 ± 0.34 µg/mL), while the highest activity against aerobic bacterial species Escherichia coli, Bacillus subtilis, Staphylococcus aureus and the anaerobic bacterial strain Streptococcus mutans was observed in the extracts of Xylaria feegenesis and Curvularia lunata. After a thorough study of the LC–MS profiles, it was found that the chemical profiles of Neofusicoccum occulatum, H. lividipigmentum and Myramaececium rubricosum were previously poorly explored in the literature.

Biodeterioration of low-density polyethylene by mangrove-associated endolichenic fungi and their enzymatic regimes

“…2018; Weerasinghe et al . 2021) current biodeterioration study was undertaken using mangrove‐associated ELF as the candidate organisms. The genera of isolates were identified (Table S1) and out of them, 77% belonged to the phylum Ascomycota and the rest belonged to the phylum Basidiomycota.…”

“…DNA sequences of the identified ELF species were deposited at the GenBank (Weerasinghe et al . 2021) and the accession numbers are given in Table S1.…”

“…A total of 31 ELF isolates were isolated from 22 lichen specimens collected from mangrove ecosystems in Negombo lagoon, Sri Lanka. Since our previous research on ELF, isolated from harsh environmental conditions prevailing in mangrove ecosystems, showed many interesting bioactivities (Maduranga et al 2018;Weerasinghe et al 2021) current biodeterioration study was undertaken using mangrove-associated ELF as the candidate organisms. The genera of isolates were identified (Table S1) and out of them, 77% belonged to the phylum Ascomycota and the rest belonged to the phylum Basidiomycota.…”

“…The study site was "Kadolkele" (7Á195528 N, 79Á84389 E). Detailed lichen collection information was previously published in Weerasinghe et al (2021).…”

“…Sequences were manually edited using BioEdit sequence Alignment Editor (Version 7.2.5) and were compared with existing nucleotide sequences in the National Center for Biotechnology Information (NCBI) database, using Basic Local Alignment Search Tool (BLAST). DNA sequences of the identified ELF species were deposited at the GenBank (Weerasinghe et al 2021) and the accession numbers are given in Table S1.…”