Recent Progress in the Chemistry of Lichen Substances

Elix, John A.; Whitton, AA; Sargent, Melvyn V.

doi:10.1007/978-3-7091-8717-3_2

Cited by 34 publications

(22 citation statements)

References 275 publications

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“…14 Lichen extracts contain a wide variety of metabolites, such as polysaccharide (homo-D-glucan) and phenolic (depside, depsidon, and dibenzofurane) compounds 15,16 that can potentially act as reducing agents for silver ions. P. praesorediosum presents unique properties in that it has two aliphatic acids, ie, (+)-praesorediosic acid [2-(14′-carboxytetradecyl)-4-methyl-5-oxo-2,5-dihydrofuran-3-carboxylic acid] and (+)-protopraesorediosic acid [2-(14′-carboxytetradecyl)-4-methylene-5-oxo-2,5-tetrahydrofuran-3-carboxylic acid], which can play a significant role in the synthesis of AgNPs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of silver nanoparticles with antibacterial activity using the lichen Parmotrema praesorediosum

Mie¹,

Samsudin²,

Din³

et al. 2013

IJN

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Development of a green chemistry process for the synthesis of silver nanoparticles has become a focus of interest. This would offer numerous benefits, including ecofriendliness and compatibility for biomedical applications. Here we report the synthesis of silver nanoparticles from the reduction of silver nitrate and an aqueous extract of the lichen Parmotrema praesorediosum as a reductant as well as a stabilizer. The physical appearance of these silver nanoparticles was characterized using ultraviolet-visible spectroscopy, electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques. The results show that silver nanoparticles synthesized using P. praesorediosum have an average particle size of 19 nm with a cubic structure. The antibacterial activity of the synthesized silver nanoparticles was tested against eight micro-organisms using the disk diffusion method. The results reveal that silver nanoparticles synthesized using P. praesorediosum have potential antibacterial activity against Gram-negative bacteria.

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Section: Introductionmentioning

confidence: 99%

Synthesis of silver nanoparticles with antibacterial activity using the lichen Parmotrema praesorediosum

Mie¹,

Samsudin²,

Din³

et al. 2013

IJN

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“…These sequences could n ot be classified as chem ical races because chemical interm ediates were com m on. A ccording to Elix [14] the sequences could be defined as chem osyndrom ic variations. Extrem e form s o f chem osyndrom ic v ariation are discussed as chem otypes here.…”

Section: The Secondary Product Patterns O F the Species Studiedmentioning

confidence: 99%

Studies on the Chemistry of the Lichen Genus Umbilicaria Hoffm.

Posner

Feige

Huneck

1992

Zeitschrift Für Naturforschung C

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“…In addition to the variation caused by variation in fat, ash, and protein content as presented above, variations in fiber content between species could be explained by variable content of mono-and oligosaccharides and other lowmolecular weight substances, like for example the lichen acids (Elix et al 1984).…”

Section: Species a B C (A+b)mentioning

confidence: 97%

Lichen polysaccharides and their relation to reindeer/caribou nutrition

Svihus¹

2000

REM

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Samples of Cetraria islandica, Cetraria nivalis, Cladina stellaris, Cladina arbuscula, Cladina rangiferina and Stereocaulon paschale were collected at 3 sites in 2 mountain areas in Norway. A l e c t o r i a o c h r o l e u c a was collected at 3 sites in 1 of the mountain areas. Lichens contained between 83 and 93% fiber, measured by the dietary fiber analysis, with C l a d i n a spp. containing significantly more fiber than the other lichen species. The fiber consisted mainly of mannose, galactose, and glucose, but the relative content of each monosaccharide differed between species. Fibers from Cetraria spp. and Alectoria ochroleuca contained significantly more glucose than those from Cladina spp. and Stereocaulon paschale, while C l a d i n a spp. and Stereocaulon paschale contained significantly more mannose and galactose. The higher glucose content in Cetraria spp. and Alectoria ochroleuca was reflected in a high lichenan content in these species, while the Cladina spp. and Stereocaulon paschale contained no lichenan. Solubility of the fiber fraction in hot water was strongly correlated to lichenan content, and great differences existed between species. Less than 5% of the dietary fiber was soluble in lichens of the Cladina genus, while more than 50% of the fiber was soluble in Cetraria islandica and Alectoria ochroleuca. Twenty-one percent of the dietary fiber was soluble in Cetraria nivalis. In vitro gas production experiments using rumen inocula from reindeer revealed a higher gas production rate the first 5 hours of incubation in C e t r a r i a islandica, Cetraria nivalis, and in Alectoria ochroleuca compared to C l a d i n a spp. and Stereocaulon paschale. Maximum production rate was observed at about 13 hours and dropped rapidly thereafter. No systematical differences in gas production rate between lichens species were observed after the initial phase. Differences in gas production rate in the initial phase resulted in higher total gas production in Cetraria islandica, Cetraria nivalis and in Alectoria ochroleuca compared to Cladina spp. and Stereocaulon paschale the first 9 hours of incubation. Total gas production after 52 hours of incubation did not vary between species. Gas production characteristics indicate that the amount of readily fermentable fraction was greater, whereas the amount slowly fermentable fraction was lower in lichens of the Cetraria genus and in Alectoria ochroleuca compared to Cladina spp. and Stereocaulon paschale . The water-soluble fraction is easy available for rumen micro-organisms and the results indicate a close relationship between high gas production in the initial phase and high proportion of water soluble fibers and/or lichenan content. Content, composition, and solubility of the fiber fraction could thus be potentially important factors determining nutritive value of the lichen for reindeer/caribou. ResumenSe colectaron muestras de Cetaria islandica, Cetaria nivalis, Cladina stellaris, Cladina arbuscula, Caldina rangiferina y Stereocaulon paschale en 3 si...

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Recent Progress in the Chemistry of Lichen Substances

Cited by 34 publications

References 275 publications

Synthesis of silver nanoparticles with antibacterial activity using the lichen Parmotrema praesorediosum

Synthesis of silver nanoparticles with antibacterial activity using the lichen Parmotrema praesorediosum

Studies on the Chemistry of the Lichen Genus Umbilicaria Hoffm.

Lichen polysaccharides and their relation to reindeer/caribou nutrition

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