Secondary metabolic profiling and antibacterial activities of different species of Usnea collected in Northern Philippines

Abstract

Lichen metabolites have multiple functions in nature and these include several biological activities against pathogens and multi-drug resistant bacteria. This study shows the antibacterial properties of 18 Usnea species collected from five provinces in the northern part of Luzon, Philippines. A total of 41 lichen specimens were extracted using acetone to a final concentration of 10 mg/ml. The crude extracts were initially subjected to TLC. Interestingly, 17 different lichen metabolites were identified. The 41 crude lichen extracts were then tested against Staphylococcus aureus and Bacillus subtilis using paper-disk diffusion assay, most of which were found to be more active against the latter test organism. In addition, 28 of the 41 lichen extracts were also tested against Mycobacterium phlei. Interestingly, most of the samples exhibited much greater activities than that of the antibiotics used as indicated by the zones of inhibition. Moreover, 15 crude extracts showing distinct spots in their TLC profiles were tested against Nocardia asteroides using TLCbioautography. Results showed that usnic acid, norstictic acid, and salazinic acid were the bioactive lichen metabolites.

Diversity and Anti-microbial Activities of Actinomycetes Associated with Three Species of Lichens

“…Up to now, known kind of lichens is about thirty thousand species in the whole world (Feuerer and Hawksworth 2007;Wang 2012). More thousands of bioactive compounds were discovered from lichen, mainly usnic, gyrophoric and diffractaic acid, polysaccharides, anthraquinones and terpene, and a part of them were used in clinic (Kupchan and Kopperman 1975;Sunil and Klaus 1999;Vertika et al 2010;Santiago et al 2013; Sinem and Kadir 2013). Recent years, some actinomycetes were isolated and identified from lichens (González et al 2005;Li et al 2007;An et al 2009;Hideki et al 2011;Olga et al 2011;Pankratov 2012).…”

The Use of Anisaldehyde Sulfuric Acid as an Alternative Spray Reagent in TLC Analysis Reveals Three Classes of Compounds in the Genus <em>Usnea</em> Adans. (Parmeliaceae, lichenized Ascomycota)

“…We found only reference to zeorin [12,[23][24][25][26] and four other terpenes in Usnea longissima Ach. [26].…”

Greener pathway toward the synthesis of lichen‐based ZnO@TiO2@SiO2 and Fe3O4@SiO2 nanocomposites and investigation of their biological activities

“…In fact, they act as bioreducer to prevent the side effects of free radicals inside the human bodies. Beside the medicinal effects of antioxidant phytochemicals inside the lichens, they have a very good potential to reduce and stabilize metallic salts and convert them to the metal nanoparticles through an electron transfer mechanism, (Kumar, Kumar, & Kumar, 2016;Agbanelo, Adesalu, 2016;Nugraha et al 2019;Jayanthi, Priya, Monica Devi, & Benila Smily, 2012;Santiago, Sangvichien, Boonprago, & Dela Cruz, 2013;Rankovic, Kosanic, 2015;Boustie, & Grube, 2005).…”