Vol 13, Issue 10, 2020 Online - 2455-3891 Print - 0974-2441 ANTIFUNGAL ACTIVITY OF USNEA VARIETIES DAYANNA CABRA GACHA 1 , LUIS POMBO OSPINA 2 , JANETH ARIAS PALACIOS 3 , OSCAR RODRÍGUEZ AGUIRRE 4 * 1 Universidad Distrital Francisco José de Caldas. Facultad de Ciencias y Educación, Bogotá, Colombia. 2 Fundación Universitaria Juan N. Corpas, Centro de investigación (GIFVTA) Bogotá, Colombia. 3 Department of Microbiology, Industrial Microbiology Program, Industrial Environmental and Biotechnology Research Group, Pontificia Universidad Javeriana, Bogotá, Colombia. 4 Environmental Engineering Program, Faculty of Engineering, Research Group CHOC-IZONE, Universidad El Bosque, Bogotá, Colombia. Email: rodriguezoscare@unbosque.edu.co Received: 07 July 2020, Revised and Accepted: 29 August 2020 ABSTRACT Objective: Antifungal activity of total ethanolic extract and fractions of Usnea varieties were proved against Aspergillus niger, Penicillium digitatum, and Rhizopus nigricans fungi. Methods: To perform the study of relative antifungal activity (AFR), fluconazole and ketoconazole were used as standards. The inhibition coefficient 50 (IC 50 ) for each extract and the fractions was determined. Results: It was established that the highest activity was presented by the acetone fraction with a value of 58.53. In the study of antifungal activity, the fraction that presented the best activity against P. digitatum was ethanolic with a value of 44.33, while for R. nigricans was petrol extract, with a value of 75.35 and finally for A. niger was the total extract with a value of 35.48. Conclusions: Comparing the values obtained from the extract and the different fractions resulted in the dichloromethane fraction showing the best values. Keywords: Aspergillus niger, Penicillium digitatum, Rhizopus nigricans, Relative antifungal activity AFR, Usnea varieties. INTRODUCTION Plants produce a diverse assortment of organic compounds, the majority of which do not participate directly in growth and development of the plant. These substances traditionally referred as secondary metabolites; there functions many of which remain unknown. On the other hand, metabolites products such as phytosterols, lipids, nucleotides, amino acids, and organic acids are found in all plants and perform an essential and evident role in growth and development. The secondary metabolites are distributed among limited taxonomical groups within the plant kingdom [1]. Lichens are complex plant individuals thought to be derived from higher or lower fungi and unicellular algae. Naturally, they have the ability to establish a symbiotic relationship with an algae or cyanobacteria (phycobiont) and a fungus (mycobiont), the result of this symbiosis generates the production of secondary metabolites by the mycobiont from the carbohydrates it receives from the photobiont, through photosynthesis. These individuals store and produce phenolic compounds with high concentrations where more than 1000 active substances produced have been recognized, which are mostly produced as a chemical defense against their predators and parasites. As a worldwide spread consortium of self-supporting associations, lichens represent a symbiotic association between the photobiont (algae) and the mycobiont (fungi). Lichens grow anywhere and on anything covering approximately 8% of Earth’s surface [2]. These lichens are slow-growing organisms that occupy harsh environments of life. This property of lichen marks it as pollution, indicating organisms and the best biomonitors of air quality [3]. Lichens carry thousands of secondary chemicals in them, and over the past two decades, there has been a growing interest in lichens as a source of novel and pharmacologically active biomolecules [4]. The use of lichens as folk medicine has been reported across the world for centuries, particularly in temperate and arctic regions due to its nutritive value and impressive medicinal properties [5]. In traditional medicine, lichens have multiple uses; In many countries in Europe, numerous species are used in the treatment of stomach diseases, diabetes, pulmonary tuberculosis, cancer treatment, and among others [6]. Green medicine texts include genera of lichens with medicinal properties. Such is the case of Cladonia, Evernia, Lobaria, Parmelia, Peltigera, Pertusaria, Physia, Rocella, Usnea, and Xanthoria, one evidence is that during the middle ages, lichens were prioritized in many herbaria for treatment of different diseases. The genus Usnea grows throughout the temperate zones of the northern hemisphere, especially in the sub-arctic and coastal tropical forests of Europe, Asia, and North America. Species belonging to the genus have traditionally been used for pain relief and fever control, as well as being effective in tuberculosis as well as other lower respiratory tract infections [7]. Likewise, the usnic acid present in this genus was used as an ointment for wounds and burns, with greater effectiveness than penicillin. [8]. Some reports suggest that the main biochemical characteristics that may have antimicrobial activity and that are part of the secondary metabolism of the lichen species in terms of its production are mainly focused on the synthesis of products such as some acids; as well as the production of some depsidones and depsides to a lesser extent [9]. It is known that within the characteristic properties of the activity of usnic acid is its antibacterial activity against some microorganisms such as Pneumococci, Streptococci, Staphylococci, and some genera of mycobacteria; in addition, it is known that its concentration varies according to the type of genus that be studied since not all lichens produce the same amount of metabolite, so it can also vary according to the conditions in which the organism is usually found [10]. © 2020 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2020.v13i10.38962 Research Article