Diploschistes ocellatus (Fr.) Norman is a medicinally important lichen with reported biological activities and a history of traditional use by indigenous populations in southwestern Iran for treating various ailments. The present study aimed to assess the cytotoxic effects of different solvent fractions of D. ocellatus on breast cancer cell lines using the MTT assay, to perform lichenochemical characterization of the most active fraction, and to investigate interactions between isolated compounds and target proteins through molecular docking analysis. Aqueous, acetone, chloroform, ethyl acetate, and methanolic fractions of D. ocellatus were prepared and evaluated for cytotoxic activity against three human breast cancer cell lines (MCF-7, T-47D, and MDA-MB-231) using the MTT method. Molecular docking studies were conducted employing AutoDock 4.2 software with standard protocols and default parameters. Among the tested fractions, the acetone extract exhibited the strongest cytotoxic activity and was therefore selected for further phytochemical investigation. Lichenochemical analysis of this fraction resulted in the isolation and identification of stictic acid and 2-(7′-hydroxy-3,5,6,8-tetramethyl-9-oxooxonan-2-yl) propanoic acid. Molecular docking simulations targeting survivin demonstrated favorable binding interactions between the isolated compounds and key amino acid residues of the protein. The findings suggest that D. ocellatus represents a promising natural source of bioactive compounds with potential anticancer properties. Further pharmacological and mechanistic studies are warranted to validate and expand upon these results.
