Chemical composition and antioxidant, enzyme inhibition and cytoprotective activity of two Antarctic lichens of the genus Psoroma (Pannariaceae).

Lichens contain different types of chemical compounds with multiple biological activities that demonstrate their potential pharmacological use. This research aims to report the metabolomic identification of the ethanolic extracts of P. antarcticum and P. hypnorum, their antioxidant, enzyme inhibitory, and their cytoprotection activity. Sixteen metabolites were identified in P. antarcticum and twelve in P. hypnorum; the extracts reported variable antioxidant activity with IC50 >350 µg/mL in DPPH·, values >18 µmol Trolox/g in ORAC and >40 µmol Trolox/g in FRAP and a phenolic compound content >10 mg GAE/g, as well as significant results in cholinesterases, α-glucosidase, pancreatic lipase, α-amylase, and tyrosinase enzyme inhibition activities with IC50 ranging from 18 to 510 µg/mL, and which were complemented by molecular docking experiments. Both extracts showed improved cytoprotection at the concentrations of 0.5 to 1.0 µg/mL. This study contributes to the knowledge of the chemical diversity of Antarctic lichen extracts and their effectiveness in the evaluation of biological activities related to neurodegenerative diseases and metabolic syndrome.

Antioxidant and antidiabetic activity and phytoconstituents of lichen extracts with temperate and polar distribution.

The objective of this research was to characterize the chemical composition of ethanolic extracts of the lichen species Placopsis contortuplicata, Ochrolechia frigida, and Umbilicaria antarctica, their antioxidant activity, and enzymatic inhibition through in vitro and molecular docking analysis. In total phenol content, FRAP, ORAC, and DPPH assays, the extracts showed significant antioxidant activity, and in in vitro assays for the inhibition of pancreatic lipase, α-glucosidase, and α-amylase enzymes, together with in silico studies for the prediction of pharmacokinetic properties, toxicity risks, and intermolecular interactions of compounds, the extracts evidenced inhibitory potential. A total of 13 compounds were identified by UHPLC-ESI-QTOF-MS in P. contortuplicata, 18 compounds in O. frigida, and 12 compounds in U. antarctica. This study contributes to the knowledge of the pool of bioactive compounds present in lichens of temperate and polar distribution and biological characteristics that increase interest in the discovery of natural products that offer alternatives for treatment studies of diseases related to oxidative stress and metabolic syndrome.

Immunomodulatory, Anti-Inflammatory, and Anti-Cancer Properties of Ginseng: A Pharmacological Update.

Ginseng, a medicinal plant of the genus Panax, boasts a rich historical record of usage that dates back to the Paleolithic period. This botanical is extensively acknowledged and consumed in Eastern countries for its therapeutic properties, and, in Western countries, it is becoming increasingly popular as a remedy for fatigue and asthenia. This review provides an update on current research pertaining to ginseng and its isolated compounds, namely, ginsenosides and polysaccharides. The primary focus is on three crucial pharmacological activities, namely, immunomodulation, anti-inflammatory, and anti-cancer effects. The review encompasses studies on both isolated compounds and various ginseng extracts obtained from the root, leaves, and berries.

Phytochemical Characterization and In Vitro and In Silico Biological Studies from Ferns of Genus Blechnum (Blechnaceae, Polypodiales).

The genus Blechnum represents one of the most ecologically and therapeutically important groups of ferns that grow in tropical, subtropical and temperate regions. In this work, the chemical fingerprint of lyophilized extracts of Blechnum chilense, B. hastatum, B. magellanicum and B. penna-marina species, the determination of their antioxidant activity through ORAC, FRAP and DPPH assays and inhibition of cholinesterase enzymes (AChE and BChE), and an in silico analysis of selected majority compounds on cholinesterase enzymes were identified. Nineteen compounds were recorded for B. chilense, nine in B. hastatum, seventeen in B. magellanicum and seventeen in B. penna-marina by liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). The content of phenolic compounds, flavonoids, antioxidant activity and enzyme inhibition were variable among species, with best results for B. penna-marina. Molecular docking evidenced low toxicities, significant pharmacokinetic properties, and significant binding affinities of the tested compounds for the AChE and BChE enzymes. These fern species show high diversity of bioactive compounds and represent a promising resource in phytotherapy, especially for their optimal levels of phenolic compounds that support their antioxidant activity.

Natural Products as Modulators of Nrf2 Signaling Pathway in Neuroprotection.

Neurodegenerative diseases (NDs) affect the West due to the increase in life expectancy. Nervous cells accumulate oxidative damage, which is one of the factors that triggers and accelerates neurodegeneration. However, cells have mechanisms that scavenge reactive oxygen species (ROS) and alleviate oxidative stress (OS). Many of these endogenous antioxidant systems are regulated at the gene expression level by the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). In the presence of prooxidant conditions, Nrf2 translocates to the nucleus and induces the transcription of genes containing ARE (antioxidant response element). In recent years, there has been an increase in the study of the Nrf2 pathway and the natural products that positively regulate it to reduce oxidative damage to the nervous system, both in in vitro models with neurons and microglia subjected to stress factors and in vivo models using mainly murine models. Quercetin, curcumin, anthocyanins, tea polyphenols, and other less studied phenolic compounds such as kaempferol, hesperetin, and icariin can also modulate Nrf2 by regulating several Nrf2 upstream activators. Another group of phytochemical compounds that upregulate this pathway are terpenoids, including monoterpenes (aucubin, catapol), diterpenes (ginkgolides), triterpenes (ginsenosides), and carotenoids (astaxanthin, lycopene). This review aims to update the knowledge on the influence of secondary metabolites of health interest on the activation of the Nrf2 pathway and their potential as treatments for NDs.

Lichen Depsides and Tridepsides: Progress in Pharmacological Approaches.

Depsides and tridepsides are secondary metabolites found in lichens. In the last 10 years, there has been a growing interest in the pharmacological activity of these compounds. This review aims to discuss the research findings related to the biological effects and mechanisms of action of lichen depsides and tridepsides. The most studied compound is atranorin, followed by gyrophoric acid, diffractaic acid, and lecanoric acid. Antioxidant, cytotoxic, and antimicrobial activities are among the most investigated activities, mainly in in vitro studies, with occasional in silico and in vivo studies. Clinical trials have not been conducted using depsides and tridepsides. Therefore, future research should focus on conducting more in vivo work and clinical trials, as well as on evaluating the other activities. Moreover, despite the significant increase in research work on the pharmacology of depsides and tridepsides, there are many of these compounds which have yet to be investigated (e.g., hiascic acid, lassalic acid, ovoic acid, crustinic acid, and hypothamnolic acid).

Neuropharmacological Effects in Animal Models and HPLC-Phytochemical Profiling of Byrsonima crassifolia (L.) Kunth Bark Extracts.

B. crassifolia is a species that grows in various areas of Latin America. It was known to be useful for the treatment of different human ailments. The present work evaluated the neuropharmacological and analgesic effects of hydroalcoholic and dichloromethane extracts of B. crassifolia. The effect on the central nervous system (CNS) of both extracts obtained from bark, administered by the intraperitoneal route in mice, was evaluated by different tests: spontaneous motor activity, hole-board, motor coordination, pentobarbital induced hypnosis, and rectal temperature. Analgesic activity was evaluated using a hot plate test. Phytochemical analysis was performed by high-performance liquid chromatography (HPLC) using reversed-phase and gradient of elution. The hydroalcoholic extract (dose 0.5 g dry plant/kg weigh) administration caused an important reduction of the head-dipping response in the hole board test. A decrease in spontaneous motor activity test and a disturbance of motor coordination in the rotarod test was observed. The hydroalcoholic extract produced a significant prolongation of pentobarbital induced sleeping time. This extract prevented hot plate test induced nociception. The phytochemical analysis revealed the presence of catechin, epicatechin, and procyanidin B12. Therefore, this study revealed that the hydroalcoholic extract of B. crassifolia possesses analgesic and sedative CNS activity.

Metabolomic Profiling, Antioxidant and Enzyme Inhibition Properties and Molecular Docking Analysis of Antarctic Lichens.

The lichen species Lecania brialmontii, Pseudephebe pubescens, and Sphaerophorus globosus are part of the prominent lichenoflora of the Antarctic territory. In this work, we report the metabolomic identification of ethanolic extracts of these species, their antioxidant and cholinesterase enzyme inhibitory activity, and conduct a molecular docking analysis with typical compounds. Eighteen compounds were identified by UHPLC-ESI-QTOF-MS in L. brialmontii, 18 compounds in P. pubescens, and 14 compounds in S. globosus. The content of phenolic compounds was variable among the species, ranging from 0.279 to 2.821 mg AG/g, and all three species showed high inhibition potential on the cholinesterase enzymes. Molecular docking showed important interactions between AChE and BChE with the selected compounds. This study evidences the chemical fingerprint of three species of the order Lecanorales that support the continuation of the study of other biological activities and their potential for medical research.

Lichen Extracts from Cetrarioid Clade Provide Neuroprotection against Hydrogen Peroxide-Induced Oxidative Stress.

Oxidative stress is involved in the pathophysiology of many neurodegenerative diseases. Lichens have antioxidant properties attributed to their own secondary metabolites with phenol groups. Very few studies delve into the protective capacity of lichens based on their antioxidant properties and their action mechanism. The present study evaluates the neuroprotective role of Dactylina arctica, Nephromopsis stracheyi, Tuckermannopsis americana and Vulpicida pinastri methanol extracts in a hydrogen peroxide (H2O2) oxidative stress model in neuroblastoma cell line "SH-SY5Y cells". Cells were pretreated with different concentrations of lichen extracts (24 h) before H2O2 (250 µM, 1 h). Our results showed that D. arctica (10 µg/mL), N. stracheyi (25 µg/mL), T. americana (50 µg/mL) and V. pinastri (5 µg/mL) prevented cell death and morphological changes. Moreover, these lichens significantly inhibited reactive oxygen species (ROS) production and lipid peroxidation and increased superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) levels. Furthermore, they attenuated mitochondrial membrane potential decline and calcium homeostasis disruption. Finally, high-performance liquid chromatography (HPLC) analysis revealed that the secondary metabolites were gyrophoric acid and lecanoric acid in D. artica, usnic acid, pinastric acid and vulpinic acid in V. pinastri, and alectoronic acid in T. americana. In conclusion, D. arctica and V. pinastri are the most promising lichens to prevent and to treat oxidative stress-related neurodegenerative diseases.

The Genus Cetraria s. str.-A Review of Its Botany, Phytochemistry, Traditional Uses and Pharmacology.

The genus Cetraria s. str. (Parmeliaceae family, Cetrarioid clade) consists of 15 species of mostly erect brown or greenish yellow fruticose or subfoliose thallus. These Cetraria species have a cosmopolitan distribution, being primarily located in the Northern Hemisphere, in North America and in the Eurasia area. Phytochemical analysis has demonstrated the presence of dibenzofuran derivatives (usnic acid), depsidones (fumarprotocetraric and protocetraric acids) and fatty acids (lichesterinic and protolichesterinic acids). The species of Cetraria, and more particularly Cetraria islandica, has been widely employed in folk medicine for the treatment of digestive and respiratory diseases as decoctions, tinctures, aqueous extract, and infusions. Moreover, Cetraria islandica has had an important nutritional and cosmetic value. These traditional uses have been validated in in vitro and in vivo pharmacological studies. Additionally, new therapeutic activities are being investigated, such as antioxidant, immunomodulatory, cytotoxic, genotoxic and antigenotoxic. Among all Cetraria species, the most investigated by far has been Cetraria islandica, followed by Cetraria pinastri and Cetraria aculeata. The aim of the current review is to update all the knowledge about the genus Cetraria covering aspects that include taxonomy and phylogeny, morphology and distribution, ecological and environmental interest, phytochemistry, traditional uses and pharmacological properties.

Modulation of Cellular Circadian Rhythms by Secondary Metabolites of Lichens.

Background: Most mammalian cells harbor molecular circadian clocks that synchronize physiological functions with the 24-h day-night cycle. Disruption of circadian rhythms, through genetic or environmental changes, promotes the development of disorders like obesity, cardiovascular diseases, and cancer. At the cellular level, circadian, mitotic, and redox cycles are functionally coupled. Evernic (EA) and usnic acid (UA), two lichen secondary metabolites, show various pharmacological activities including anti-oxidative, anti-inflammatory, and neuroprotective action. All these effects have likewise been associated with a functional circadian clock. Hypothesis/Purpose: To test, if the lichen compounds EA and UA modulate circadian clock function at the cellular level. Methods: We used three different cell lines and two circadian luminescence reporter systems for evaluating dose- and time-dependent effects of EA/UA treatment on cellular clock regulation at high temporal resolution. Output parameters studied were circadian luminescence rhythm period, amplitude, phase, and dampening rate. Results: Both compounds had marked effects on clock rhythm amplitudes and dampening independent of cell type, with UA generally showing a higher efficiency than EA. Only in fibroblast cells, significant effects on clock period were observed for UA treated cells showing shorter and EA treated cells showing longer period lengths. Transient treatment of mouse embryonic fibroblasts at different phases had only minor clock resetting effects for both compounds. Conclusion: Secondary metabolites of lichen alter cellular circadian clocks through amplitude reduction and increased rhythm dampening.

UHPLC-MS Chemical Fingerprinting and Antioxidant, Enzyme Inhibition, Anti-Inflammatory In Silico and Cytoprotective Activities of Cladonia chlorophaea and C. gracilis (Cladoniaceae) from Antarctica.

The lichen species Cladonia chlorophaea and C. gracilis (Cladoniaceae) are widely distributed in the island archipelago of maritime Antarctica and represent a natural resource of scientific interest. In this work, the metabolomic characterization of the ethanolic extracts of these species and the determination of the antioxidant activity, enzymatic inhibition and anti-inflammatory potential of selected compounds on the 5-lipoxygenase enzyme by molecular docking and cytoprotective activity in the SH-SY5Y cell line were carried out. Nineteen compounds were identified by liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS) in each of the species. The contents of phenolic compounds, antioxidant activity, the inhibition of cholinesterases (acetylcholinesterase and butyrylcholinesterase) and digestive enzymes (α-glucosidase and pancreatic lipase) were variable among species, with better results in C. chlorophaea. Molecular docking evidenced significant binding affinities of some compounds for the 5-lipoxygenase enzyme, together with outstanding pharmacokinetic properties. Both extracts were shown to promote cell viability and a reduction in reactive oxygen species production in an H2O2-induced oxidative stress model. This study contributes to the chemical knowledge of the Cladonia species and demonstrates the biological potential for the prevention and promising treatment of central nervous system pathologies, inflammatory disorders and metabolic alterations.

Dibenzofurans from Lichens - A Pharmacological Overview.

Lichens are a symbiotic association between a fungus (mycobiont) and a green algae/- cyanobacterium (photobiont). Lichens are a source of secondary metabolites, most of them being exclusively for these species, among which dibenzofurans are found. Dibenzofurans are a small group (over 35 different identified compounds), being usnic acid the most studied. In the last 10 years, there has been a growing interest in the pharmacological activity of dibenzofurans. In this work, dibenzofurans isolated from lichens (alectosarmentin, condidymic acid, didymic acid, isousnic acid, isostrepsilic acid, usimines A-C and usnic acid) were reviewed, most of which showed antibacterial, antifungal, and cytotoxic activities. These findings provide future guidance for research on pharmacological activity of dibenzofurans.

Current uses and knowledge of medicinal plants in the Autonomous Community of Madrid (Spain): a descriptive cross-sectional study.

BACKGROUND: The usage of medicinal plants as a key component of complementary and alternative medicine, has acquired renewed interest in developed countries. The current situation of medicinal plants in Spain is very limited. This paper provides new insights and greater knowledge about current trends and consumption patterns of medicinal plants in the Autonomous Community of Madrid (Spain) for health benefits. METHODS: A descriptive cross-sectional study was designed for a population-based survey on medicinal plants. The data were collected (May 2018 to May 2019) using semi-structured face-to-face interviews in independent pharmacies, hospital centers and primary care health centers in the Autonomous Community of Madrid. The survey had 18 multiple choice and open-ended questions. Quantitative indices were calculated: Fidelity Level (FL), Use Value (UV) and Informants Consensus Factor (ICF). Chi-square test was used for data analysis. RESULTS: Five hundred forty-three people were interviewed. The majority of the participants (89.6%) have used medicinal plants to treat health disorders in the past 12 months, mainly for digestive problems, sleep disorders and central nervous system diseases. A total of 78 plants were recorded, being Matricaria recutita, Valeriana officinalis, Tilia spp. and Aloe vera the most used. The highest UV was found for Mentha pulegium (UV 0.130) followed by Aloe vera (UV 0.097) and Vaccinium macrocarpon. (UV 0.080). The highest FL values were for Eucalyptus spp. (FL 90.47%) for respiratory conditions and, Matricaria recutita (85.55%) and Mentha pulegium (84.09%) for digestive problems. The highest ICF corresponded to metabolism and depression (ICF = 1), pain (ICF = 0.97), insomnia (ICF = 0.96) and anxiety (ICF = 0.95). Participants mostly acquired herbal medicines from pharmacies, herbal shops and supermarkets. Some side effects (tachycardia, dizziness and gastrointestinal symptoms) and potential interactions medicinal plants-drugs (V. officinalis and benzodiazepines) were reported. CONCLUSION: Many inhabitants of the Autonomous Community of Madrid currently use herbal products to treat minor health problems. The most common consumer pattern are young women between 18 and 44 years of age with higher education. In order to confirm the pattern, further research should be focused to investigate current uses of medicinal plants in other Spanish regions.

Lichens of Parmelioid Clade as Promising Multitarget Neuroprotective Agents.

Neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease are multifactorial disorders which are increasing in incidence and prevalence over the world without existing effective therapies. The search for new multitarget compounds is the latter therapeutic strategy to address these pathological conditions. Lichens have an important and unknown therapeutic value attributed to their unique secondary metabolites. The aim of this study is to evaluate for the first time the in vitro neuroprotective activities and molecular mechanisms underlying methanol extracts of lichens of the parmelioid clade and to characterize major bioactive secondary metabolites responsible for their pharmacological actions. Of the 15 parmelioid lichen species, our results showed that Parmotrema perlatum and Hypotrachyna formosana methanol extracts exhibited high antioxidant activity as evidenced in ORAC, DPPH, and FRAP assays. Then, SH-SY5Y cells were pretreated with methanol extracts (24 h) followed by Fenton reagent exposure (2 h). Pretreatments with these two more antioxidant methanol lichen extracts increased cell viability, reduced intracellular ROS, prevented oxidative stress biomarkers accumulation, and upregulated antioxidant enzyme (CAT, SOD, GR, and GPx) activity compared to Fenton reagent cells. The neuroprotective activity was much higher for H. formosana than for P. perlatum, even equal to or higher than Trolox (reference compound). Moreover, H. formosana extracts inhibited both AChE and BuChE activities in a concentration dependent manner, and P. perlatum only showed concentration dependent activity against AChE. Finally, chemical composition analysis using TLC and HPLC methods revealed that physodic acid, lividic acid, and lichexanthone are major secondary metabolites in H. formosana and stictic acid and constictic acid are in P. perlatum. These results demonstrated that P. perlatum and, specially, H. formosana are promising multitargeted neuroprotective agents due to their antioxidant and AChE and BuChE inhibition activities.

Regulation of redox status in neuronal SH-SY5Y cells by blueberry (Vaccinium myrtillus L.) juice, cranberry (Vaccinium macrocarpon A.) juice and cyanidin.

Blueberry and cranberry are fruits with high polyphenol content, particularly anthocyanins. As cyanidin derivatives have been identified as one of the most representative polyphenols in berry juices, cyanidin has been designated for a better comparison and understanding of the potential neuroprotection of juices obtained from two Vaccinium species. Neuroblastoma SH-SY5Y cells were previously treated with different concentrations of lyophilized blueberry juice, cranberry juice or cyanidin for 24 h and oxidative stress was then generated with hydrogen peroxide (100 µM) for 30 min. Cytoprotective properties of cranberry juice, blueberry juice or cyanidin were evaluated using different methodologies such as mitochondrial activity (MTT), TBARS and ROS production, antioxidant enzymes (CAT, SOD) and antioxidant properties (ORAC, FRAP). Results indicated that blueberry and cranberry juices as well as cyanidin increased mitochondrial activity and reduced intracellular ROS production and lipid peroxidation induced by hydrogen peroxide. Furthermore, these berry juices and cyanidin upregulated the activity of the antioxidant enzymes catalase and superoxide dismutase. Finally, in vitro antioxidant capacities were confirmed by ORAC and FRAP assays demonstrating the potential of cyanidin and cyanidin-containing products for pharmaceutical or nutritional applications to prevent oxidative stress in neuronal cells.

Anthocyanin profile, antioxidant activity and enzyme inhibiting properties of blueberry and cranberry juices: a comparative study.

Cranberry (Vaccinium macrocarpon) and blueberry (Vaccinium myrtillus) juices are commonly consumed as a source of antioxidants. The aim of this study was to compare bioactivities as well as the differences in the polyphenol content and anthocyanin profile of both juices. Polyphenol and anthocyanin contents were quantified using spectrophotometric and chromatographic methods. Bioassays were carried out in terms of antioxidant properties in cell and cell free systems as well as inhibition of physiological enzymes that are targets involved in the prevention of chronic diseases (monoamine oxidase A, tyrosinase, acetylcholinesterase, α-glucosidase and dipeptidyl peptidase-4). Both juices contained a significant amount of anthocyanins (3.909 mg anthocyanins per mg extract for blueberry juice and 0.398 for cranberry juice) and also exhibited antioxidant properties against DPPH, superoxide radicals and hydrogen peroxide. These juices showed inhibitory effects on the enzymes, showing substantial potential as antioxidant, neuroprotective and anti-hyperglycaemic agents. The total anthocyanin and polyphenol content was higher in blueberry juice, which is indicative of a higher antioxidant activity. Both juices were also able to inhibit monoamine oxidase A, tyrosinase, α-glucosidase and dipeptidyl peptidase-4 in a dose-dependent manner. However, cranberry juice had a greater capacity than blueberry juice as an α-glucosidase inhibitor, revealing a similar activity to acarbose.

Methanol extract of Nigella sativa seed induces changes in the levels of neurotransmitter amino acids in male rat brain regions.

CONTEXT: Nigella sativa L. (Ranunculaceae) (NS) has been used for medicinal and culinary purposes. Different parts of the plant are used to treat many disorders. OBJECTIVE: This study investigates the effects of NS methanol extract on brain neurotransmitter amino acid levels. MATERIALS AND METHODS: We measured the changes in aspartate, glutamate, glycine and γ-aminobutyric acid in five brain regions of male Wistar rats after methanol extract treatment. Animals were injected intraperitoneally with saline solution (controls) or NS methanol extract (equivalent of 2.5 g/kg body weight) and sacrificed 1 h later or after administering 1 daily dose for 8 days. The neurotransmitters were measured in the hypothalamus, cortex, striatum, hippocampus and thalamus by HPLC. RESULTS AND DISCUSSION: Results showed significant changes in amino acids compared to basal values. Glutamate increased significantly (16-36%) in the regions analyzed except the striatum. Aspartate in the hypothalamus (50 and 76%) and glycine in hippocampus (32 and 25%), thalamus (66 and 29%) and striatum (75 and 48%) also increased with the two treatment intervals. γ-Aminobutyric acid significantly increased in the hippocampus (38 and 32%) and thalamus (22 and 40%) but decreased in the cortex and hypothalamus although in striatum only after eight days of treatment (24%). CONCLUSION: Our results suggest that injected methanol extract modifies amino acid levels in the rat brain regions. These results could be of interest since some neurodegenerative diseases are related to amino acid level imbalances in the central nervous system, suggesting the prospect for therapeutic use of NS against these disorders.

Bioactive and functional properties of sour cherry juice (Prunus cerasus).

Sour cherry juice (Prunus cerasus) is consumed as a nutritional supplement claiming health effects. The aim of the study was to evaluate the different properties of sour cherry juice in terms of antioxidant activity and inhibition of target enzymes in the central nervous system and diabetes. The content of polyphenols and anthocyanins was quantified. Different experiments were carried out to determine the radical scavenging properties of the juice. The activity of sour cherry juice was also tested in physiological relevant enzymes of the central nervous system (acetylcholinesterase, monoamine oxidase A, tyrosinase) and others involved in type 2 diabetes (α-glucosidase, dipeptidyl peptidase-4). Sour cherry juice showed significant antioxidant effects but the activity of the lyophilized juice was not superior to compounds such as ascorbic, gallic or chlorogenic acid. Furthermore, sour cherry juice and one of its main polyphenols known as chlorogenic acid were also able to inhibit monoamine oxidase A and tyrosinase as well as enzymes involved in diabetes. This is the first time that sour cherry juice is reported to inhibit monoamine oxidase A, α-glucosidase and dipeptidyl peptidase-4 in a dose dependent manner, which may be of interest for human health and the prevention of certain diseases.

Antioxidant potential of lichen species and their secondary metabolites. A systematic review.

CONTEXT: Pharmacological interest of lichens lies in their capacity to produce bioactive secondary metabolites, being most of them phenolic compounds with reactive hydroxyl groups that confer antioxidant potential through various mechanisms. Increasing incidence and impact of oxidative stress-related diseases (i.e., neurodegenerative disorders) has encouraged the search of new pharmacological strategies to face them. Lichens appear to be a promising source of phenolic compounds in the discovery of natural products exerting antioxidant activity. OBJECTIVE: The present review thoroughly discusses the available knowledge on antioxidant properties of lichens, including both in vitro and in vivo studies and the parameters assessed so far on lichen constituents. METHODS: Literature survey was performed by using as main databases PubMed, Google Scholar, Scopus, Science Direct, and Recent Literature on Lichens. We reviewed 98 highlighted research articles without date restriction. RESULTS: Current report collects data related to antioxidant activities of more than 75 lichen species (from 18 botanical families) and 65 isolated metabolites. Much information comes from in vitro investigations, such as chemical assays evaluating radical scavenging properties, lipid peroxidation inhibition, and reducing power of lichen species and compounds; similarly, research on cellular substrates and animal models generally measures antioxidant enzymes levels and other antioxidant markers, such as glutathione levels or tissue peroxidation. CONCLUSION: Since consistent evidence demonstrated the contribution of oxidative stress on the development and progression of several human diseases, reviewed data suggest that some lichen compounds are worthy of further investigation and better understanding of their antioxidant and neuroprotective potentials.