Antiproliferative, Antibacterial and Antifungal Activity of the Lichen Xanthoria parietina and Its Secondary Metabolite Parietin

Abstract

Lichens are valuable natural resources used for centuries throughout the world as medicine, food, fodder, perfume, spices and dyes, as well as for other miscellaneous purposes. This study investigates the antiproliferative, antibacterial and antifungal activity of the acetone extract of the lichen Xanthoria parietina (Linnaeus) Theodor Fries and its major secondary metabolite, parietin. The extract and parietin were tested for antimicrobial activity against nine American Type Culture Collection standard and clinically isolated bacterial strains, and three fungal strains. Both showed strong antibacterial activity against all bacterial strains and matched clinical isolates, particularly against Staphylococcus aureus from standard and clinical sources. Among the fungi tested, Rhizoctonia solani was the most sensitive. The antiproliferative effects of the extract and parietin were also investigated in human breast cancer cells. The extract inhibited proliferation and induced apoptosis, both effects being accompanied by modulation of expression of cell cycle regulating genes such as p16, p27, cyclin D1 and cyclin A. It also mediated apoptosis by activating extrinsic and intrinsic cell death pathways, modulating Tumor Necrosis Factor-related apoptosis-inducing ligand (TRAIL) and B-cell lymphoma 2 (Bcl-2), and inducing Bcl-2-associated agonist of cell death (BAD) phosphorylation. Our results indicate that Xanthoria parietina is a major potential source of antimicrobial and anticancer substances.

HPLC Fingerprint Analysis with the Antioxidant and Cytotoxic Activities of Selected Lichens Combined with the Chemometric Calculations

“…Fr. at a concentration of 1.5–3.0 mg∙mL −1 inhibits proliferation and induces apoptosis of MCF-7 and MDA-MB231 breast cancer cells [ 60 ].…”

Endolichenic fungi: the lesser known fungal associates of lichens

“…Many lichens elaborate antifungal metabolites (Basile et al 2015) and hence a lichen’s endolichenic fungal community should be insensitive to these metabolites or be able to detoxify them. It could be assumed that only such fungi would constitute the endolichenic fungal assemblage of a given lichen.…”

Anticancer Potential of Lichens’ Secondary Metabolites

“…X. parietina extract inhibited the proliferation of MCF-7 and MDA-MB-231 cells with the maximum effect observed at the concentration of 1.5-3 mg/mL. This extract induced the G1 cell cycle inhibition with the upregulation of p27 and p16 and downregulation of cyclin D1 and cyclin A. Interestingly, therapy of MCF-7 and MDA-MB-231 cells with X. parietina decreased the expression of anti-apoptotic Bcl-2 and increased the expression of pro-apoptotic TRAIL and pBAD proteins [103]. In addition, a metanol extract of Parmelia sulcata had a cytotoxic effect on both MCF-7 and MDA-MB-231 cells.…”