Anti‐Inflammatory Potential of Compounds Isolated from Tunisian Lichens Species

Abstract

The lichen's special symbiotic structure enables it to produce bioactive substances. They have historically been recognized for their aesthetic and medicinal benefits. Furthermore, in recent years, they have performed in various fields, including perfumery, dyeing, and pharmacology due to their rich secondary metabolites. From our study, four compounds were isolated from organic extracts of Parmotrema hypoleucinum, Roccella phycopsis, and Xanthoria parietina and identified by spectroscopic investigation as atranorin, (+)-iso-usnic acid, methyl orsellinate, and parietin, respectively. The anti-inflammatory effects of lichens extracts, and pure compounds were evaluated on RAW 264.7 macrophages cells at different concentrations. At 25 μg/mL all treated samples did not show any effect on cell viability. Atranorin and (+)-iso-usnic acid showed an inhibitory effect on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated macrophages. Nitric oxide (NO) production was measured using Griess reagent, atranorin and (+)-iso-usnic acid showed a high anti-inflammatory potential (75.99 % and 57.27 % at 25 μg/mL). On the other hand, methyl orsellinate and the organic extracts of three lichens showed good anti-inflammatory activity ranging from 29.16 % at 25 μg/mL to 86.91 % at 100 μg/mL.

Parietin, the Vibrant Natural Dye in Xanthoria parietina

“…[5] Several studies have demonstrated the medicinal potential of bioactive chemicals found in lichens, such as cytotoxins, analgesics, insecticides, antioxidants, and antimicrobials. [6][7][8][9][10][11] Several genera of lichens, including Xanthoria, Roccella, Cladonia, Evernia, Lobaria, Parmelia, and Usnea, exhibit rich repositories of beneficial chemicals that can be used for a variety of medicinal purposes. [11] They have long been used as ecological indicators, cosmetics dyes, [12] and traditional medicine.…”

Small Molecules as Anti‐inflammatory Agents: Molecular Mechanisms and Heterocycles as Inhibitors of Signaling Pathways

“…Compound (16) displayed moderate activity (Figure 11). [102] More recently, many researchers have reported natural products as anti-inflammatory agents targeting different inflammatory pathways. [103][104][105][106]…”

“…Also, methyl orsellinate ( 15 ) and the organic extracts of three lichens exhibited good strong inhibition at 100 μg/mL. Compound ( 16 ) displayed moderate activity (Figure 11 ) [102] …”

Mycotoxin Contamination in Hazelnut: Current Status, Analytical Strategies, and Future Prospects

“…Three anthraquinones were detected in Turkish hazelnut samples by Varga et al [ 12 ], namely physcion (= parietin, PHY), macrosporin (MCP), and emodin (EMO) ( Figure 8 ). Anthraquinones are a valuable class of natural and synthetic compounds with a broad pharmacological function, including anti-bacterial, antioxidant, anti-tumor, and other activities, which are produced by many fungal species [ 44 , 45 ]. A growing number of toxicological data highlight the potential toxicity of compounds belonging this class [ 46 ].…”