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Antioxidant and cytoprotective potentials of Parmeliaceae lichens and identification of active compounds

mycobiont within the symbiosis, and they normally are shown in some cases to substantially misrepresent
compounds with a relatively low molecular weight and diversity (11, 12).
chemical diversity (aliphatic and aromatic) that accumulate
in the cortex (such as atranorin and usnic acid) or in the In view of the previous information, and considering
medulla of the lichen thallus (such as protocetraric and the existence of few studies on intracellular ROS (reactive
physodic acids) as extracellular crystals (2, 3). Concerning oxygen species) modulation by lichen extracts and
pharmacological properties, lichens constitute a poorly metabolites (13), none focused on their role as preventive
known group of natural products in comparison to others compounds in nervous system-like cells under oxidative
(such as vascular plants and fungus); however, over the stress conditions, we carry out the present work. The aim
past 2 decades, there has been a renewed and growing of the study deals with the evaluation for the first time of
interest in lichens as a source of novel pharmacologically the in vitro neuroprotective potential, based on
active biomolecules (4). antioxidative effects, displayed by the methanol extract of
Parmeliaceae lichens; for that purpose, we initially
Parmeliaceae (Ascomycota, Lecanorales) is the most perform an initial screening of antioxidant capacity of
numerous and widespread family among lichenized fungi, various molecularly identified lichen specimens. In
comprising more than 2700 species grouped in about 80 addition, we aim to identify the main constituents of the
genera; in addition, it is probably the most interesting most promising lichens.
family from a pharmacological point of view (5). For
instance, the representative lichen Usnea ghattensis have 2. MATHERIAL AND METHODS
displayed in previous investigations interesting
antimicrobial properties together with a promising 2.1. Reagents
antioxidant potential, as evidenced by chemical tests in
vitro (6, 7). Similarly, Bugni et al. demonstrated the Cell culture products were obtained from Gibco (Grand
presence of active anti-inflammatory constituents in the Island, NY) and all other chemicals were from Sigma–
lichen Parmotrema saccatilobum (8). Aldrich (St. Louis, MO).

The lichen forming fungal family Parmeliaceae, and 2.2. Lichen samples
fungi in general, exhibit few taxonomically useful
characters, many of which are homoplasious. The The 29 lichen sample used in the present study were
interpretation of morphological features is sometimes collected in different countries and continents,
difficult to evaluate, and accurate identification of authenticated by expert lichenologists (P.K. Divakar y A.
lichenized fungal species remains challenging (9, 10). In Crespo) and deposited in the Herbarium of the Faculty of
many cases, characters used for species identification may Pharmacy (MAF), University Complutense of Madrid,
be subtle to discern, and diagnostic morphological and with the identifying data presented in Table 1. Lichenic
chemical characters could be lacking in juvenile or material was examined at morphological level with a
fragmentary samples. The traditional phenotype-based binocular loupe Nikon SMZ800. For microscopic
approach to species recognition in Parmeliaceae has been observations, an Olympus DP11 microscope was used.

Table 1. The 19 species of Parmeliaceae lichens used in the study, together with the location of their recollection and MAF codes.

Lichen specie Origin MAF code

Bulbothrix meizospora (Zahlbr.) India, W. Himalaya, Dugenbilta Mahhu Valley MAF-LICH 16929

Cetraria aculeata (Schreb.) Spain, Canary Islands, Gran Canarias, MAF-LICH 16927
Cetraria canadensis (Muell.Arg.) Valleseco MAF-LICH 15621

USA, California

Cetraria nigricans (Muell.Arg.) India, North sikkim, Chubuk MAF-LICH 16940

Cetrelia braunsiana (Muell.Arg.) India, W. Himalaya, Kuachula Khark MAF-LICH 16943

Cetrelia cetrarioides (Muell.Arg.) India, North sikkim, Chubuk MAF-LICH 16941

Cetrelia olivatorum (Muell.Arg.) India, North sikkim, Yumthang MAF-LICH 16942

Evernia prunastri (L.Ach.) England, New Forest MAF-LICH 16930

Flavoparmelia citrinescens (L.Ach.) Argentina, Rio Negro, Missuti MAF-LICH 16946

Flavoparmelia euplecta (L.Ach.) Australia, New South Wales MAF-LICH 15375

@Real Academia Nacional de Farmacia. Spain 165