Usnea Sp. - Beard lichen

Usnea hirta - Sugar-frosted beard

Bioindicator

"Fritze et al. (1989) measured soil microbial parameters along a 20,000-m transect away from a copper and nickel smelter in Finland. Within 500 m of the smelter there was an absence of epiphytic lichens and their place taken by an alga. Hypogymnia physoides and Pseudevernia furfuracea were more tolerant of heavy metal exposure than Usnea hirta, Bryoria fuscescens, and Platismatia glauca, demonstrating a differential tolerance within epiphytic lichens. Fungal hyphal length and soil respiration increased significantly at greater than 10 km from the smelter. The pattern of distribution of both lichens and mosses was found to correlate with levels of heavy metal loading in the environment (Kosta-Rick et al., 2001), where they found that the level of several heavy metals (Cd, Cu, Hg, Pb, Sb, Sn, and Zn) was significantly higher in lichens than in mosses. This is possibly attributable to the presence of fungal mycelia in the lichen, which may have a higher affinity for metals than moss tissue." ^{[Dighton FEP]}

Usnea intermedia - Exploding beard

Usnea lapponica - Powder-ringed beard

Usnea longissima - Methuselah's beard

Medicinal Use

"Usnea longissima is known for its wounds healing properties and is effective against tumor (Crockett et al., 2003)." ^{[Amritesh AM]}

Usnea longissima and Usnea diffracta used in TCM to "clear heat and resolve toxin", "dispel damp and free network vessels", "expel worms", "regulate menstruation and stanch bleeding", "relieve cough and dispel phlegm", "bleeding due to external injury", "cough with profuse phlegm", "flooding and spotting", "headache", "malaria", "poisonous snake bite", "red eyes", "scrofula", "swollen welling abscess", and "vaginal discharge". ^[EncyTCMV.6]

Pharmacology

"Shahi and Patra (2003) synthesized bioactive nanoparticles of usnic acid from the lichen-forming fungus Usnea longissima in a defined medium. The nanoparticles they obtained were uniform in shape, with a diameter of 50–200 nm, and their bioactivity was investigated both in vitro and in vivo in a nanoemulsion. The in vitro results showed that the nanoemulsion had a minimum inhibitory concentration (MIC) of 0.1 µl/ml against the dermatophytes Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The in vivo results showed that the nanoemulsion was safe and effective in controlling dermatophyte infections in humans." ^{[AppliedMycology]}

"The broad-spectrum antibacterial properties of silver nanoparticles may also lead to a future role in pharmaceutical development (Ingle et al., 2008). Similarly, the bioactive nanoparticles synthesized by the lichen-fungi Usnea longissima may have potential as a future natural nanomedicine against microbial infections (Shahi and Patra, 2003)." ^{[AppliedMycology]}

Biochemicals

β-Glutinol - "Glutin-5-en-3β-ol C30H50O (426.73). White amorphous material, mp 211ºC, mp 212ºC, [α]D25 = 63.3º (c = 0.71, CHCl3). Pharm: Anti-inflammatory (modified assay of Tan and Berridge, 400μg/mL, InRt = 11.44%, control Aspirin, InRt = 70.45%)[5316]; cell viability (hmn isolated neutrophils, 12.5μg/mL, cell viability = 100%, 100μg/mL, cell viability = 100%, 200μg/mL, cell viability = 72.29%)[5316]. Source: BA WANG BIAN Euphorbia royleana, CHI YANG Alnus japonica, MENG GU LI Quercus mongolica, SONG LUO Usnea longissima, TAI WAN XIU XIAN JU Spiraea formosana. Ref: 6, 611, 2575, 5316." ^[EncyTCMV.2]

Barbatic acid - "[17636-16-7] C19H20O7 (360.37). mp 191ºC, 186ºC. Source: SONG LUO Usnea longissima, HUAN JIE SONG LUO Usnea diffracta. Ref: 6, 660." ^[EncyTCMV.1]

Diffractaic acid - "[436-32-8] C20H22 7 (inhibits a tumor which induces Epstein-Barr virus activation). Source: SONG LUO Usnea longissima, HUAN JIE SONG LUO Usnea diffracta. Ref: 6, 658, 660." ^[EncyTCMV.2]

Longissiminone - "A C10H10O5 (210.19). White amorphous solid, mp 132ºC. Pharm: Anti-inflammatory (modified assay of Tan and Berridge, 400ȝg/mL, InRt = 72.13%, IC50 50 = (50.30±4.42)ȝg/mL); cell viability (hmn isolated neutrophils, 12.5ȝg/mL, cell viability = 89.68%, 50ȝg/mL, cell viability = 90.05%, 100ȝg/mL, cell viability = 52.91%). Source: SONG LUO Usnea longissima. Ref: 5316." ^[EncyTCMV.3]

Longissiminone B - "C10H9ClO5 (244.63). White amorphous material, mp 113ºC. Pharm: Anti-inflammatory (modified assay of Tan and Berridge, 400ȝg/mL, InRt = 34.34%, control Aspirin, InRt = 70.45%); cell viability (hmn isolated neutrophils, 12.5ȝg/mL, cell viability = 78.81%, 50ȝg/mL, cell viability = 100%, 200ȝg/mL, cell viability = 68.85%). Source: SONG LUO Usnea longissima. Ref: 5316." ^[EncyTCMV.3]

Ramalic acid - "[500-37-8] C18H18O7 (346.34). mp 203ºC (dec). Source: SONG LUO Usnea longissima. Ref: 6." ^[EncyTCMV.4]

Usnea longissima - Usnic acid, barbatic acid, diffractaic acid, glutinol, longissiminone A, longissiminone B, salazinic acid, protocetraric acid, evernic acid, 4-O-demethyl- barbatic acid
Diffractaic acid and usnic acid -
Antibacterial/antifungal/ antitumor/insecticidal -
Sachin et al. (2018), Crockett et al. (2003), and Zugic et al. (2018)^{[Amritesh AM]}

"C-Methylation also features in the biosynthesis of us- nic acid (Figure 3.88), an antibacterial metabolite found in many lichens, e.g. Usnea and Cladonia species, which are symbiotic combinations of alga and fungus. However, the principal structural modification encountered involves phenolic oxidative coupling (see page 28). Two molecules of methylphloracetophenone are incorporated, and these are known to derive from a pre-aromatization methyla- tion reaction, not by methylation of phloracetophenone (Figure 3.88). The two molecules are joined together by an oxidative coupling mechanism which can be rational- ized via the one-electron oxidation of a phenol group in methylphloracetophenone giving radical A, for which res- onance forms B and C can be written. Coupling of B and C occurs. Only the left-hand ring can subsequently be re- stored to aromaticity by keto–enol tautomerism; this is not possible in the right-hand ring because coupling occurred on the position para to the original phenol and this po- sition already contains a methyl. Instead, a heterocyclic ring is formed by attack of the phenol onto the enone system (see khellin, above). The outcome of this reac- tion is enzyme controlled; two equivalent phenol groups are present as potential nucleophiles, and two equivalent enone systems are also available. Potentially, four differ- ent products could be formed, but only one is typically produced. Loss of water then leads to usnic acid. Usnic acid is found in both (+)- and (−)-forms in nature, according to source. The product from using the alterna- tive hydroxyl nucleophile in heterocyclic ring formation is isousnic acid, also known as a natural product in some species of lichens. Usnic acid is used as an antibacterial and preservative in toiletries." ^{[MNP Dewick]}

^{[MNP Dewick]}

Usnea nidulans - Nested beard

Usnea pacificana - Pacific beard

Usnea rubicunda - Red beard

Usnea scabrata - Scarecrow's beard

Usnea silesiaca - Neptune's beard

Usnea subfloridana - Nit beard

Usnea substerilis - Embossed beard

Usnea trichodea - Deadman's beard

Usnea Sp.

Food Use

"Boiled by the Lime Village Tanaina of Alaska and eaten with fish, grease, or berries" ^{[Turner&Kuhnlein]}

Medicinal Use

"Ethnobotanists, in studying plant usages throughout the world's indigenous cultures, typically cross-reference plant usage among many cultures. If usnea {Usnea spp.) is commonly found to have strong antibiotic properties throughout the world's cultures, ethnobotanists tend to think that some aspect of usnea has been transculturally discovered and suggest conducting laboratory studies to try to verify its medicinal effects. However, when faced with universal attribution of nonphysical activity by a plant, they are usually not so bold." ^{[Buhner SHHB]}

"Usnea barbata is effective against Bacillus subtilis and Pseudomonas fluores- cens. Besides, it also possesses antioxidant properties (Bazarnova et al., 2018)." ^{[Amritesh AM]}

"Usnea ghattensis shows antimicrobial activity against gram-negative and gram- positive pathogenic bacteria (Staphylococcus aureus, Streptococcus faecalis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium). Lecanora muralis, Peltigera polydactyla, Ramalina farinacea, and Xanthoria elegans also possess antibacterial activity (Srivastava et al., 2013)." ^{[Amritesh AM]}

"Antimicrobial activity against some bacteria viz. Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and a fungus Candida albicans was shown by Melanohalea exasperata, Physcia aipolia, Usnea florida, Usnea subfloridana and Xanthoria parietina. Antimicrobial activity by lichens was reported both against gram positive and gram-negative strains (Çobanoğlu et al., 2016)." ^{[Amritesh AM]}

Reproductive Strategies: "Both sexual and asexual propagules are formed by some spe- cies of Cladonia and Usnea, however, as in many bryophytes, and this pattern may be more common in temperate than in tropical regions. Sexuality is regarded as the primitive condition. Where pairs of related species are recognised, one sorediate and the other apotheciate, the former is generally the more widespread and abundant but it may be less well equipped to contend with future environmental change." ^{[Longton BPB]}

"Asexual reproduction may be particularly important in lichens as the propagules contain both mycobiont and photobiont. Many rock surfaces on Signy I are densely covered by unbranched individuals of Usnea antarc- tica only a few millimetres in length, and Hooker (1980d) demonstrated a predominance of small, presumably young thalli on imported timber. As apothecia are rarely produced, he suggested that large numbers of young plants become established from soredia, with relatively few surviv- ing to maturity. There is thus little evidence that the abundance of mature thalli is controlled by problems of establishment." ^{[Longton BPB]}

"In boreal regions, Cladonia stellaris commonly becomes established from thallus fragments some years after fire (Chapter 3). In contrast to the pattern in Usnea antarctica, subsequent clonal development by a var- iety of different branching patterns results in a logistic increase in the number of individuals, the maximum density of about 900 podetia m^-2 being reached after a further 30 years (Yarranton, 1975)." ^{[Longton BPB]}

Arctic reproduction: "Dodge (1973) regards sexual reproduction as 'almost universal' among fungi in cold- and frigid-Antarctic lichens, although he notes that apothecia are rare in most Antarctic species of Usnea and Cladonia. How- ever, Lindsay (1977) reports that in many Antarctic lichens, including Usnea fasciata (Fig. 2.2), apothecia are abundant but mature ascospores rarely develop." ^{[Longton BPB]}

Biochemicals

Usnea ghattensis - Usnic acid, norstictic acid - Antibacterial/antioxidant - Verma et al. (2008) and Srivastava et al. (2013) ^{[Amritesh AM]}

"Usnic acid (7.53)—a highly biologically active dibenzofuran—is a phenol oxidation product of an acylphloroglucinol. It is produced by numerous lichens, including several Usnea species. Apart from its antibiotic and anti-leukemic activity, it has insect anti-feedant activity. Its presence may account for the observation that many lichens are resistant to serious insect attack." ^{[ChemofFungi]}

Properties

"Some fruticose lichens, such as Usnea, have a differentiated stiff central strand, which gives the lichen considerable strength and flexibility." ^{[Laursen CIAC]}

Habitat

"In forested areas, atmospheric water condensation zones are characterized by the presence of epiphytes, in particular hanging lichens of the genera Usnea (U. articulata) and Telechistes spp., but also ferns and orchids, and American bromeliads such as the “Spanish moss” Tillandsia usneoides and T. recurvata." ^{[Houerou BBA]}

"Lichen communities show similar trends. In the maritime zone there are extensive areas where fruticose lichens are dominant, the fruticose and foliose lichen formation, typically on the sides of rocks or boulders forming marine benches or similar areas (Figure 13.2). This distribution seems to be determined by improved water relations and it is easy to see how snow gathers in such areas, how wind is reduced and how light is high but rarely direct sunlight. Such sites are well illustrated in Kappen (1993a). The genera Usnea (Figure 13.3) and Umbilicaria are typically dominant and plants can reach large sizes, 20 + cm across for Umbilicaria specimens. These formations are rarer in the continental zone but do occur, for example, Birthday Ridge (Kappen 1985a) and Botany Bay, Granite Harbour (unpub- lished, in preparation)." ^{[Pugnaire FPE]}

"Arctic Climate growth rate: "Macrolichen phytomass reaches 800-1750 g m^-2 in Umbilicaria, Himantormia and Usnea spp, with productivity up to 250 gm^-2 in Usnea fasciata (Smith, 1984a), in the more wide- spread, open communities of lichens and small acrocarpous mosses on drier terrain. Lichen production in terms of relative growth rate ranges from 34 mg g^-1 yr^-1 in Sphaerophorus globosus to 84 mg g^-1 yr^-1 in Cladonia rangiferina. It is strongly age-related in Usnea fasciata, falling from 50-200 mg g^-1 yr^-1 in young thalli to 35 mg g^-1 yr^-1 in mature, and 1-5 mg g^-1 yr^-1 in old individuals (Hooker, 1980c, d)." ^{[Longton BPB]}

Lichenicolous Fungi

"Stromatopogon baldwinii, which grows on various species of Usnea, is known only from Tasmania and the South Sandwich Islands (Diederich 1992)." ^{[BOF Elsevier]}

Habitat Restoration

Usnea Sp. are listed as "Medicinal and aromatic plants capable of growing on contaminated soils", with the "whole plant" listed as the part used. ^{[Lichtfouse SAR 17]}

"However, these same tree islands are very important for recolonization of disturbed habitats by forest-dwelling birds (Mackenzie and Steventon 1996; Tittler et al. 2001b), arthropods (Lindgren et al. 1999), lichens, liverworts, and mosses (Peck and McCune 1997). The size of residual tree patches influences their effectiveness. In northwestern Quebec, for example, abundance of Usnea spp., the most sensitive of the common epiphytic lichens, is negatively affected when retained patches are less than 1 ha (Rheault et al. 2003)." ^{[Burton TSMBF]}

Journals of Interest

• Ivanovic, J., Meyer, F., Misic, D., Asanin, J., Jaeger, P., Zizovic, I., and Eggers, I. (2013) influence of different pre- treatment methods on isolation of extracts with strong antibacterial activity from lichen Usnea barbata using carbon dioxide as a solvent. J. Supercrit. Fluids, 76, 1–9.
• Zugic, A., Tadic, V., & Kundakovic, T. (2018). Chemical composition and biological activities of the extracts and secondary metabolites of Lichens belonging to the genus Usnea, Parmeliaceae. ResearhGate, Lekovite Sirovine, 38, 68–80.
• Diederich, P., and M.S. Christiansen. 1994. Biatoropsis usnearum Räsänen, and other heterobasidiomycetes on Usnea. Lichenologist 26:47–66.