Diversity and bioactivity of endolichenic fungi in Usnea lichens of the Philippines
2021
Santiago, Krystle Angelique A. | dela Cruz, Thomas Edison E. | Ting, Adeline Su Yien
Endolichenic fungi (ELF; asymptomatic microorganisms living inside healthy lichen thalli) were isolated from three Usnea species, namely U. baileyi, U. bismolliuscula and U. pectinata, collected near the town of Sagada, Philippines. A total of 101 ELF were recovered representing 12 genera (classes Sordariomycetes and Eurotiomycetes), with the genera Nemania (50.5%, 51 isolates) and Xylaria (22.8%, 23 isolates) being the most abundant. Comparative analyses on the antimicrobial activities of lichens and ELF revealed that lichen crude extracts were effective against the Gram-positive bacterium Staphylococcus aureus and the yeast Candida albicans, while ELF crude extracts were effective against S. aureus, C. albicans and the Gram-negative bacterium Escherichia coli. The broad-spectrum nature of ELF has provided medicinal and industrial advantages over the slow-growing lichens as shown on their respective bioactivities. Extracts from ELF also had a higher total flavonoid content (TFC; 6.29–85.69 mg QE/g of extract) and stronger antioxidant activities (IC50: 0.57–19.63 mg/ml) than lichen-derived extracts. Although only culturable ELF were identified, this study provides the first evaluation of the diversity and bioactivities of culturable ELF from fruticose lichens of the genus Usnea in the Philippines.
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