Atraric Acid Exhibits Anti-Inflammatory Effect in Lipopolysaccharide-Stimulated RAW264.7 Cells and Mouse Models

Employing soil isolated fungi for production of bioactive phenolic compounds: a fermentative approach

An efficient method of solid-state fermentation (SSF) is reported for producing bioactive phenolic compounds using soil-isolated fungi. Antioxidant activity using a rapid DPPH (1,1-diphenyl-2-picryl hydrazyl), was employed to screen the 120 fungal isolates from soil. Aspergillus terreus 1, Aspergillus fumigatus, Aspergillus terreus 2, Penicillium citrinum, Aspergillus wentii1, Aspergillus wentii 2, Penicillium expansum and Penicillium granulatum were chosen, concerning their antioxidant activity and total phenolic content. These fungal strains were applied on agro residues viz. sugarcane bagasse, corn cob, rice straw, pea pod and wheat straw, to evaluate the release of phenolic compounds. The fermented extracts from various agro-residues showed good antioxidant activity against DPPH, ferric ion, and nitric oxide radicals. The highest antioxidant activity was observed in fermented extracts of sugarcane bagasse, followed by pea pod. Additionally, the total phenolic content in the fermented extracts positively correlated with antioxidant potential. This study highlights the significant potential of solid substrate fermentation using soil-isolated fungi and agro-residues to produce bioactive phenolic compounds with potent antioxidant properties. The utilization of SSF for the extraction of bioactive compounds from natural sources not only offers a clean and sustainable approach but also contributes to the valorization of agro-industrial residues.

Structural characterization and anti-inflammatory activity of neutral polysaccharides from American ginseng

American ginseng, a precious classic herbal medicine, is used extensively in China for life prolongation purpose. This study aimed to elucidate the structure and anti-inflammatory activity of a neutral polysaccharide isolated from American ginseng (AGP-A). Nuclear magnetic resonance in conjunction with gas chromatography-mass spectrometry were used to analyze AGP-A's structure, whereas Raw264.7 cell and zebrafish models were employed to assess its anti-inflammatory activity. According to the results, AGP-A has a molecular weight of 5561 Da and is primarily consisted of glucose. Additionally, linear α-(1 → 4)-glucans with α-D-Glcp-(1 → 6)-α-Glcp-(1→ residues linked to the backbone at C-6 formed the backbone of AGP-A. Furthermore, AGP-A significantly decreased pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) in Raw264.7 cell model. AGP-A in zebrafish model significantly lower the massive recruitment of neutrophils to the neuromast of the caudal lateral line. Inflammation may be relieved by the AGP-A component in American ginseng based on these results. In conclusion, our study shows the structural characterization, remarkable anti-inflammatory properties of AGP-A and its potential curative efficacy as a safe, valid natural anti-inflammatory medicine.

Biochemical, Antioxidant Properties and Antimicrobial Activity of Epiphytic Leafy Liverwort Frullania dilatata (L.) Dumort

In this study, the biochemical, antioxidant properties, and antimicrobial activity of the epiphytic leafy liverwort Frullania dilatata (L.) Dumort were investigated. Due to the scarcity and difficulty in obtaining liverworts, research on their bioactivity is limited; thus, this study aimed to uncover the potential of F. dilatata. The antimicrobial activity was evaluated against various microorganisms, including food isolates, clinical isolates, multidrug-resistant strains, and standard strains, using the disk diffusion method and determining the minimum inhibitory concentration (MIC) values. This study represents the first antioxidant investigation on F. dilatata and an antimicrobial study using ethanol extract and the disk diffusion method. Notably, susceptibility was observed in Enterococcus faecalis ATCC 29212, Enterococcus faecium FI, Listeria monocytogenes ATCC 7644, Providencia rustigianii MDR, and Staphylococcus aureus ATCC 25923. The antioxidant capacity was assessed using the DPPH method, emphasizing the high scavenging performance. Gas chromatography-mass spectrometry (GC-MS) analysis identified the primary compounds as frullanolide (19.08%), 2,3-Dimethylanisole (15.21%), linoleic acid (11.11%), palmitic acid (9.83%), and valerenic acid (5.3%). The results demonstrated the significant antimicrobial activity of F. dilatata against the tested microorganisms and its potent antioxidant properties. These findings emphasize the potential of F. dilatata as a promising source of natural antimicrobial and antioxidant agents, underscoring the importance of further investigation into its bioactive compounds and elucidating the mechanisms of action in future studies.

Isolation of Bioactive Metabolites from Soil Derived Fungus-Aspergillus fumigatus

Fungi produce numerous secondary metabolites with intriguing biological properties for the health, industrial, and agricultural sectors. Herein, we report the high-yield isolation of phenolic natural products, N-formyl-4-hydroxyphenyl-acetamide 1 (~117 mg/L) and atraric acid 2 (~18 mg/L), from the ethyl acetate extract of the soil-derived fungus, Aspergillus fumigatus. The structures of compounds 1 and 2 were elucidated through the detailed spectroscopic analysis of NMR and LCMS data. These compounds were assayed for their antimicrobial activities. It was observed that compounds 1 and 2 exhibited strong inhibition against a series of fungal strains but only weak antibacterial properties against multi-drug-resistant strains. More significantly, this is the first known instance of the isolation of atraric acid 2 from a non-lichen fungal strain. We suggest the optimization of this fungal strain may exhibit elevated production of compounds 1 and 2, potentially rendering it a valuable source for the industrial-scale production of these natural antimicrobial compounds. Further investigation is necessary to establish the veracity of this hypothesis.

Topical Delivery of Atraric Acid Derived from Stereocaulon japonicum with Enhanced Skin Permeation and Hair Regrowth Activity for Androgenic Alopecia

Atraric acid (AA) is a phenolic compound isolated from Stereocaulon japonicum that has demonstrated anti-androgen properties and was used to design an alternative formulation for the treatment of alopecia. This new topical formulation was designed using a solvent mixture system composed of ethanol as a volatile vehicle, oleic acid as a permeation enhancer, and water for skin hydration. The ideal topical AA formulation (AA-TF#15) exhibited an 8.77-fold higher human skin flux and a 570% increase in dermal drug deposition, compared to 1% (w/w) AA in ethanol. In addition, compared to other formulations, AA-TF#15 (1% [w/w] AA) activated keratinocytes and human dermal papilla cell proliferation at a concentration of 50 µM AA, which is equivalent to 50 µM minoxidil. Moreover, AA-TF#15 treatment produced a significant increase in hair regrowth by 58.0% and 41.9% compared to the 1% (w/w) minoxidil and oral finasteride (1 mg/kg)-treated mice. In addition, AA-TF#15 showed a higher expression level of aldehyde dehydrogenase 1, β-catenin, cyclin D1, and pyruvate kinase M2 proteins in the skin of AA-TF#15-treated mice compared to that of those treated with minoxidil and oral finasteride. These findings suggest AA-TF#15 is an effective formulation for the treatment of scalp androgenic alopecia.

Atraric Acid Ameliorates Hyperpigmentation through the Downregulation of the PKA/CREB/MITF Signaling Pathway

Atraric acid (AA) is derived from lichens and is widely used in perfumes for its desirable scent. It has been reported as having anti-inflammatory and antioxidant activity. Hyperpigmentation is the underlying cause of a variety of dermatological diseases that have a significant impact on patients' quality of life and are frequently difficult to treat. This study aimed to explore the inhibitory effects of AA on hyperpigmentation in vitro and in vivo and its potential molecular mechanisms. The cytological results revealed that at a dose of 250 μM, AA may reduce melanin content and tyrosinase levels without causing cytotoxicity. Furthermore, the expression of melanocortin-1 receptor (MC1R), phosphorylated protein kinase A (pPKA) and phosphorylated cAMP response element binding protein (pCREB) were downregulated in AA-administrated cells. In vivo, histological analysis showed that AA could inhibit melanin production and tyrosinase activity, and 3% AA had the best activity, with almost no side effects. Furthermore, the results of Western blot analysis and RT-PCR suggested that AA may suppress the mRNA transcription of microphthalmia-associated transcription factor (MITF) protein and tyrosine protease by decreasing the expression of MC1R, consequently decreasing the phosphorylation of PKA and CREB. Finally, the MC1R inhibitor MSG606 verified the hypothesis that AA suppresses melanin formation by downregulating the PKA/CREB/MITF signaling pathway. Taken together, our study offers valuable information for the development of AA as a possible ingredient in skin-lightening cosmeceuticals and hyperpigmentation inhibitors.

Lichens in Pharmacological Action: What Happened in the Last Decade?

Lichens are a unique group of organisms, which can produce compounds that are named secondary metabolites and rarely or are not produced in other organisms. Lichens possess pharmacological actions related to their secondary metabolites. Our knowledge of lichens and their pharmacological actions rapidly increases as new technologies and devices, which facilitate the investigation of the chemical profile and biological activities of lichens, are introduced and become more readily available. In addition, new methods and perspectives, as well as suggestions for pharmacological mechanisms, accumulate daily. Furthermore, lichen substances stand as a relatively untapped source of natural products. Accordingly, researchers investigate the pharmacological actions of lichen-derived material more frequently than it was in the past. This review focused on the pharmacological activities of lichens published in the last 11 years (2012-2022). Literature data obtained from WebOfScience and PubMed databases using related search keywords revealed that anti-genotoxicity, anticancer, and anti-microbial activity studies have constantly been conducted. More recently, immunomodulatory and inflammation-related studies took to the stage. Enzyme inhibition actions were popular as well. Our selection was based on the novelty and mechanistic insight that papers presented.

Lichens: An update on their ethnopharmacological uses and potential as sources of drug leads

ETHNOPHARMACOLOGICAL RELEVANCE

Lichens, a unique symbiotic association between an alga/cyanobacterium and a fungus, produce secondary metabolites that are a promising source of novel drug leads. The beauty and importance of lichens have not been adequately explored despite their manifold biological activities such as anticancer, antimicrobial, antioxidant, anti-inflammatory, analgesic, antipyretic and antiparasitic.

AIM OF THE STUDY

The present review collates and discusses the available knowledge on secondary metabolites and biological activities of lichens (in vitro and in vivo).

MATERIALS AND METHODS

Using relevant keywords (lichens, secondary metabolites, bioactivity, pharmacological activities), five electronic databases, namely ScienceDirect, PubMed, Google Scholar, Scopus and Recent Literature on Lichens, were searched for past and current scientific contributions up until May 2022. Literature focusing broadly on the bioactivity of lichens including their secondary metabolites were identified and summarized.

RESULTS

A total of 50 review articles and 189 research articles were searched. Information related to antioxidant, antimicrobial, anti-inflammatory, anticancer and insecticidal activities of 90 lichen species (from 13 families) and 12 isolated metabolites are reported. Over 90% of the studies comprised in vitro investigations, such as bioassays evaluating radical scavenging properties, lipid peroxidation inhibition and reducing power, cytotoxicity and antimicrobial bioassays of lichen species and constituents. In vivo studies were scarce and available only in fish and rats. Most of the studies were done by research groups in Brazil, France, Serbia, India and Turkey. There were relatively few reports from Asia and Africa despite the ubiquitous nature of lichens and the high occurrence in these continents.

CONCLUSION

Secondary metabolites from lichens are worthy of further investigation in terms of their potential therapeutic applicability, including better understanding of their mechanism(s) of action. This would be of great importance in the search for novel drugs.

Anti-Inflammatory Effects of Phlebia sp. Extract in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

Lichens are a life form in which algae and fungi have a symbiotic relationship and have various biological activities, including anti-inflammatory and antiproliferative activities. This is the first study to investigate the anti-inflammatory activity of a Phlebia sp. fungal extract (PSE) isolated from Peltigera neopolydactyla in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophage. PSE reduced the production of the proinflammatory cytokine (tumor necrosis factor-α, interleukin-6, and interleukin-1β), chemokine (granulocyte-macrophage colony-stimulating factor), nitric oxide, and prostaglandin E2 in the LPS-stimulated RAW264.7 macrophages. Especially, PSE inhibits the phosphorylation of activator protein-1 (AP-1) signaling (c-Fos and c-Jun) and their upstream mitogen-activated protein kinase kinases/mitogen-activated protein kinases (MKK/MAPKs: MKK4, MKK7, and JNK) and finally reduced the production of the inflammatory cytokines. The inhibitory effects mainly act via suppressing JNK-mediated AP-1 rather than the NF-κB pathway. Furthermore, PSE inhibited the production of final inflammatory effector molecules involved in AP-1 signaling, including nitric oxide (NO) and prostaglandin E2 (PGE2). Here, we report that PSE has the potential to be developed as an anti-inflammatory agent.

Xylosma G. Forst. Genus: Medicinal and Veterinary Use, Phytochemical Composition, and Biological Activity

Xylosma G. Forst. is a genus of plants belonging to the Salicaceae family with intertropical distribution in America, Asia, and Oceania. Of the 100 accepted species, 22 are under some level of conservation risk. In this review, around 13 species of the genus used as medicinal plants were found, mainly in Central and South America, with a variety of uses, among which antimicrobial is the most common. There is published research in chemistry and pharmacological activity on around 15 of the genus species, centering in their antibacterial and fungicidal activity. Additionally, a variety of active phytochemicals have been isolated, the most representative of which are atraric acid, xylosmine and its derivatives, and velutinic acid. There is still ample field for the validation and evaluation of the activity of Xylosma extracts, particularly in species not yet studied, and concerning uses other than antimicrobial and for the identification and evaluation of their active compounds.

Polyphenols Extracted from Shanxi-Aged Vinegar Inhibit Inflammation in LPS-Induced RAW264.7 Macrophages and ICR Mice via the Suppression of MAPK/NF-κB Pathway Activation

Shanxi-aged vinegar, a traditional Chinese grain-fermented food that is rich in polyphenols, has been shown to have therapeutic effects on a variety of diseases. However, there has been no comprehensive evaluation of the anti-inflammatory activity of polyphenols extracted from Shanxi-aged vinegar (SAVEP) to date. The anti-inflammatory activities of SAVEP, both in RAW 264.7 macrophages and mice, were extensively investigated for the potential application of SAVEP as a novel anti-inflammatory agent. In order to confirm the notion that polyphenols could improve inflammatory symptoms, SAVEP was firstly detected by gas chromatography mass spectrometry (GC-MS). In total, 19 polyphenols were detected, including 12 phenolic acids. The study further investigated the protective effect of SAVEP on lipopolysaccharide-induced inflammation in RAW264.7 macrophages and ICR mice. The results showed that compared with those of the model group, SAVEP could remarkably recover the inflammation of macrophage RAW264.7 and ICR mice. SAVEP can normalise the expression of related proteins via the suppression of MAPK/NF-κB pathway activation, inhibiting the expression of iNOS and COX-2 proteins, and consequently the production of inflammatory factors, thus alleviating inflammatory stress. These results suggest that SAVEP may have a potential function against inflammation.

Establishment of Agrobacterium tumefaciens-Mediated Transformation of Cladonia macilenta, a Model Lichen-Forming Fungus

Despite the fascinating biology of lichens, such as the symbiotic association of lichen-forming fungi (mycobiont) with their photosynthetic partners and their ability to grow in harsh habitats, lack of genetic tools manipulating mycobiont has hindered studies on genetic mechanisms underpinning lichen biology. Thus, we established an Agrobacterium tumefaciens-mediated transformation (ATMT) system for genetic transformation of a mycobiont isolated from Cladonia macilenta. A set of combinations of ATMT conditions, such as input biomass of mycobiont, co-cultivation period with Agrobacterium cells, and incubation temperature, were tested to identify an optimized ATMT condition for the C. macilenta mycobiont. As a result, more than 10 days of co-cultivation period and at least 2 mg of input biomass of the mycobiont were recommended for an efficient ATMT, owing to extremely slow growth rate of mycobionts in general. Moreover, we examined T-DNA copy number variation in a total of 180 transformants and found that 88% of the transformants had a single copy T-DNA insertion. To identify precise T-DNA insertion sites that interrupt gene function in C. macilenta, we performed TAIL-PCR analyses for selected transformants. A hypothetical gene encoding ankyrin repeats at its C-terminus was interrupted by T-DNA insertion in a transformant producing dark-brown colored pigment. Although the identification of the pigment awaits further investigation, this proof-of-concept study demonstrated the feasibility of use of ATMT in construction of a random T-DNA insertion mutant library in mycobionts for studying genetic mechanisms behind the lichen symbiosis, stress tolerance, and secondary metabolite biosynthesis.