Amount Of Usnic Acid Research Articles

Fungal metabolite isolated from Mycosphaerella nawae AM20 and its protective role in cerebral ischemia

Usnic acid is one of the important metabolites showed cardiovascular protective properties. The main aim of the study was to analyze antioxidant and cerebral ischemia preventive role in experimental Albino rats. The amount of usnic acid in the Mycosphaerella nawae AM20 culture extract was determined by High Performance Liquid Chromatography. Antioxidant property was evaluated by various methods and usnic acid has potential Fe2+ chelating activity. The influence of usnic acid on special learning and memory was studied in vivo using Albino rats. Morris water maze (MWM) analysis revealed that the experimental ischemic rats treated with usnic acid reached the platform at minimum time than ischemic rats without usnic acid treatment. At 0.1 mL usnic acid concentration, hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) inhibition activity was 18.4 ± 1.1% and it increased as 80.3 ± 2.4% at 0.5 mL concentration in the reaction mixture. Likewise, acetylcholinesterase (ACE) inhibitor activity was observed and was dose dependent. At 0.2 mL concentration, 21.8 ± 1.7% enzyme activities inhibited and it increased as 48.3 ± 1.8% at 0.5 mL sample concentration. Fibrinolytic analysis revealed 13 ± 0 mm zone of clearance at 0.5 mL sample concentration and the standard plasmin showed 17 ± 2 mm zone of clearance. Biochemical analysis revealed that the amount of malondialdehyde (MDA) was higher in the hippocampal region of ischemia group animal (59.4 ± 3.5 μM). Moreover, usnic acid treated ischemia group showed reduced MDA content (29.8 ± 3.5 μM). Superoxide dismutase (SOD) activity was reduced in ischemic albino rat and improved SOD activity was observed in the treated animal.

The amount of lichen secondary metabolites in Cladonia foliacea (Cladoniaceae, lichenised Ascomycota)

The terricolous species Cladonia foliacea (Cladoniaceae, lichenised Ascomycota) widely distributed in open, dry lowland steppe and rocky mountain grassland vegetation in Europe was chosen as a potential test organism for ecological experiments, since their thalli are producing cortical solar radiation-protective and UV screening pigment dibenzofuran usnic acid and medullary secondary substance depsidone fumarprotocetraric acid. Significant seasonal differences were found in the amounts of lichen secondary metabolites analysed by HPTLC and HPLC-PDA between summer and winter collected thalli in sandy grassland area in Hungary. The concentrations of usnic acid varied between 7.34 and 15.52 mg/g in summer collected samples and 13.90 and 21.61 mg/g in winter collected ones. A comparable amount (11.61±0.29 mg/g) was measured in pulverised samples. The concentrations of fumarprotocetraric acid varied between 0.60 and 3.01 mg/g in summer collected samples and 2.26 and 5.81 mg/g in winter collected thalli. A comparable amount (2.45±0.21 mg/g) was found in pulverised samples. The range of concentration values is comparable with data known from lichens. A higher amount of usnic acid is produced in winter probably to ensure sufficient protection also for summer. The fumarprotocetraric acid content of the medulla might contribute to the solar irradiation reflecting role of the pale lower surface lobes turning upwards in dry condition.

Allelopathic effects of lichen metabolite usnic acid on growth and physiological responses of Norway spruce and Scots pine seedlings

Lichens are globally widespread organisms playing an important role in diverse ecosystems. They produce secondary metabolites, unique compounds, which play many important ecological and biological roles, including their effects on other plants, through allelopathy. Usnic acid is one of the most frequent secondary compounds in thalli of lichens forming the layer on the surface of soils, interacting with the seedlings of conifers in the boreal forests. The main aim of this study was to investigate the growth, ploidy level, reactive oxygen species (ROS) production and element content in the Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings cultivated for 14 days using substrates containing addition (10 mg per cultivation tube) of (+) usnic acid (UA). We also investigated UA root content in these plants.The root:shoot ratio (R:S) decreased in stressed pines by over 31%. The average root length diminished by 48% and the shoot length (to the cotyledon base) by 25%. For spruce, the R:S ratio decreased by more than 41%, the root length by 46% while the shoot length by only 9%. The UA treatment particularly increased the number of non-fully developed seedlings during the germination. The seed germination rate did not vary significantly when compared to control. No significant ploidy differences between control and treated seedlings were observed in neither of the species. Ploidy aberration in two P. abies seedlings was discovered. The amount of UA in the roots, including UA bound on their surfaces, in spruce varied from 3.6 to 325.5 μg g−1 DW and in pine roots from 15.6 to 252.3 μg g−1 DW. A significant decrease in total macroelement content in roots of both species was noted, particularly for P, K, Ca, Mg and S contents. Interestingly, the contents of stress markers, e.g. superoxide dismutase and peroxidase were not significantly changed when compared to controls.

Hydrogel Formulation of Usnic Acid and Antibacterial Activity Test Against Propionibacterium acne

Usnic acid is known for its remarkable antimicrobial activity. The aim of this research was to formulate hydrogel of usnic acid and evaluate the antibacterial activity against Propionibacterium acne. Due to low solubility of usnic acid, solid dispersion was prepared using PVP K-30. In this study, intact usnic acid (UA) and usnic acid-solid dispersion (UA-SD) was formulated in hydrogel using several gelling agents: Aqupec HV-505, sodium alginate and HPMC K 100M. Concentration of each gelling agent was optimized for hydrogel base. All of hydrogel base showed homogenous gel, pH at range 5.37–6.33 and viscosity in range 259.07–10,759.00 cps. Hydrogel was prepared by dispersing 1% intact UA and 3% UA-SD in three different gelling agents. The hydrogel was evaluated for pH, viscosity, stability test for two months and microbiology test. The amount of usnic acid in hydrogel was determined by spectrophotometry UV-Vis. Hydrogel UA showed non-homogenous gel, while hydrogel usnic UA-SD was homogenous. The pH of all hydrogel was in range 5.5–6.4 and viscosity was 2,017.03–3,866.52 cps. All the hydrogel was stable and diameter inhibition of hydrogel was in a range 20–32 mm. The amount of usnic acid in hydrogel was in range 96.9–99.23%. In conclusion, hydrogel UA-SD is promising preparation in handling acne.

Elevational Trends in Usnic Acid Concentration of Lichen Parmelia flexilis in Relation to Temperature and Precipitation

Usnic acid contents in acetone extracts of 31 samples of lichen Parmelia flexilis collected from different altitudes were identified using thin layer chromatography (TLC) and determined by high performance liquid chromatography (HPLC). The usnic acid content varied in between highest 5.13% to lowest 1.66% in oven dried (80 °C) lichen samples. The species collected from lower altitudes all show high levels of usnic acid. The negative relationship between usnic acid and altitude was obtained. Statistically, it is revealed that there is a significant difference between average percentages of usnic acid in lichen samples with varying altitudes (p < 0.05). Beside these, the precipitation averages of the regions where the species have been collected were linked with the content of usnic acid. It is clear that lichens from the regions receiving the highest precipitation produced lower amounts of usnic acid. The results suggest that the production of secondary metabolite in lichens is altered due to the climatic variables like temperature and precipitation at different altitude gradients.

Lichen secondary metabolites affect growth of Physcomitrella patens by allelopathy.

Lichen secondary metabolites can function as allelochemicals and affect the development and growth of neighboring bryophytes, fungi, vascular plants, microorganisms, and even other lichens. Lichen overgrowth on bryophytes is frequently observed in nature even though mosses grow faster than lichens, but there is still little information on the interactions between lichens and bryophytes.In the present study, we used extracts from six lichen thalli containing secondary metabolites like usnic acid, protocetraric acid, atranorin, lecanoric acid, nortistic acid, and thamnolic acid. To observe the influence of these metabolites on bryophytes, the moss Physcomitrella patens was cultivated for 5weeks under laboratory conditions and treated with lichen extracts. Toxicity of natural mixtures of secondary metabolites was tested at three selected doses (0.001, 0.01, and 0.1%). When the mixture contained substantial amounts of usnic acid, we observed growth inhibition of protonemata and reduced development of gametophores. Significant differences in cell lengths and widths were also noticed. Furthermore, usnic acid had a strong effect on cell division in protonemata suggesting a strong impact on the early stages of bryophyte development by allelochemicals contained in the lichen secondary metabolites.Biological activities of lichen secondary metabolites were confirmed in several studies such as antiviral, antibacterial, antitumor, antiherbivore, antioxidant, antipyretic, and analgetic action or photoprotection. This work aimed to expand the knowledge on allelopathic effects on bryophyte growth.

Response of the lichen-eating moth Cleorodes lichenaria larvae to varying amounts of usnic acid in the lichens

Lichens are characterized by a great variety of secondary metabolites. The function of these substances remains partly unknown. In this study, we propose that some of these metabolites may expel insect herbivores. To test this hypothesis, we reared larvae of the lichenivorous moth Cleorodes lichenaria on three selected lichens, Cladonia arbuscula subsp. mitis, Usnea hirta, and Usnea dasypoga. In experimental setup, the secondary metabolite usnic acid was removed from the lichens with acetone prior to feeding, whereas a control was left untreated. On all three lichens, removal of usnic acid from the lichens using acetone significantly prolonged survival of larvae and increased their viability. Larvae reared on control lichens contained significantly more usnic acid than those reared on treated lichens, both in their biomass and their faeces. These results support the hypothesis that usnic acid serves as a repellent against insect feeding, besides its well established functions of UV protection and antimicrobial properties.

Bioproduction of usnic acid from acetate by kaolinite immobilized cells of Cladonia substellata Vain.

Cells of the lichen <i>Cladonia substellata</i>, immobilized in kaolinite and supplied with acetate, produce at room temperature large amounts of usnic acid which can be recovered from the washing solution.

Quantitative determination of secondary metabolites in Cladina stellaris and other lichens by micellar electrokinetic chromatography

The quantitative determination of usnic acid (UA), perlatolic acid (PA), and atranorin (AT) in Alaska lichens by micellar electrokinetic chromatography (MEKC) is reported. The background electrolyte (BGE) included sodium docecyl sulfate (SDS), and β-cyclodextrin (β-CD) in a high-pH borate buffer. The presence of β-CD in the buffer significantly decreases peak width, especially for UA, as it decreases migration time for both UA and PA. Linear calibration curves for UA, PA, and AT were established using an internal standard of benzoic acid (BA). Concentration limits of detection (cLODs) are 2.5, 2.2 and 2.0 μg/mL (S/N 3) for UA, PA, and AT, respectively. Dry samples of lichen were extracted at room temperature with acetone for 24 h in the presence of BA as internal standard. Recoveries of UA from spiked samples ranged from 92 to 98%. Amounts of UA and PA in the lichen samples ranged from 0.28 to 1.7% dry weight and 0.02 to 0.23%, respectively.

Identification and Quantitation of Usnic Acid from the Lichen Usnea Species of Anatolia and Antimicrobial Activity

Six species of lichens, such as Usnea florida, Usnea barbata, Usnea longissima, Usnea rigida, Usnea hirta and Usnea subflorida, were collected from different areas of Anatolia (district of Antalya, Karabük, Qankiri, Giresun and Trabzon) in Turkey. Their usnic acid amounts in acetone extracts were determined by HPLC. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis and Bacillus megaterium. It was shown that with increasing amount of usnic acid, the antimicrobial activity increased. Usnic acid contents of Usnea species varied between 0.22-6.49% of dry weight.

Effects of UV Radiation on Usnic Acid in Xanthoparmelia microspora (Müll. Arg. Hale)

An important decrease in the level of stratospheric ozone has been observed during the past decade (1), with accompanying increases in UV-B radiation (2) and some UV-A radiation (3), thus leading to probable damage to aquatic and terrestrial ecosystems (4–7). Inhabitants of terrestrial and aquatic ecosystems have developed strategies to cope with the potential stress induced by UV radiation. One of these strategies is the synthesis of photoprotector compounds derived mainly from the biosynthetic route of the polymalonate acetate (8–13). As levels of UV radiation increase, accumulation rates of some photoprotective compounds in lichen species from the Chilean Alpine zones also increase (14). Photodegradation of depsides may have accounted for the low levels of phenolics in lichens at higher elevations (15). It was observed that, in Xanthoparmelia lichens from the Alpine regions of Chile, the higher the altitude where the lichen was found, the greater amount of usnic acid it produced (16). This increase of usnic acid is the result of the lichen’s ability to adapt to radiation, which ensures its survival in extreme environmental conditions. In thalli from Xanthoparmelia oleosa collected at 4690 m no usnic acid was detected, which could be proof of the presence of a photodegradation product of usnic acid (17) but which has not been identified to date. In growth-chamber experiments lasting 1 week, thalli of Umbilicaria americana always produced smaller amounts of phenolic residue when exposed to both UV-B and UV-A radiation, compared with exposure to UV-A alone. In one field experiment exclusion of UV-B by light filtration produced significant increases in phenolic compounds. This increase occurs only during spring and autumn, when lichens are metabolically more active (18). In this article we evaluated the accumulation rates of usnic acid in Xanthoparmelia microspora (Mull. Arg. Hale) exposed to doses of solar radiation and to additional doses of UV-A and UV-B radiation. Furthermore, we report on the photolysis of usnic acid in nonnucleofilic solvents during exposure to higher doses of UV-A and UV-B radiation.

Physiological attributes of the lichen Cladonia pleurota in heavy metal-rich and control sites near Sudbury (Ont., Canada)

The recovery of lichen communities on metal-rich historical ore-roasting beds west of Sudbury has been slow, and our objective was to locate and measure metals in Cladonia pleurota, the most frequently encountered roast bed lichen species. Particulates incorporated into the thallus on or near the roast bed contained high Fe, Al, Cu and Ni, and inductively coupled plasma-atomic emission spectroscopy showed lower concentrations of heavy metals in the control site 60 km upwind than in the roast bed or an immediately adjacent forest. Wavelength-dispersive X-ray spectrometry indicated potentially toxic levels of Cu, Ni, Fe and Al in both the mycobiont and photobiont in the roast bed. The physiology of roast bed lichens was consistent with damage found in metal-treated photobionts in culture: lower concentrations of chlorophyll a, chlorophyll b and total carotenoids on or near the roast bed than in the control site. In addition chlorophyll a on the roast bed was more subject to phaeophytinization and the yield of photosystem II, as measured by F v/ F m, was significantly less in both of the metal-rich sites than in the control. Thin-layer densitometry and UV spectrophotometry showed no significant difference in the amount of usnic acid between metal-rich and control sites, but heavy metals were associated with crystals of usnic acid, possibly forming complexes.