Photoprotective archaeosomes made of lipids extracted with bio-solvents.

Archaea lipids are a source of new biomaterials for pharmaceutical and nanomedical applications; however, their classic extraction method relies on chloroform and methanol, toxic solvents that conflict with green chemistry principles. In this paper we explore the performance of an eco-friendly method for the extraction of total lipids from the haloarchaea Halorubrum tebenquichense. Using the bio-solvents ethyl acetate and ethanol in a two-step procedure, a fraction of total lipids (135 ± 41 mg phospholipids and 1.1 ± 0.4 mg bacterioruberin (BR) / 100 g cell paste) was obtained containing the same composition as that resulting from extraction with the classical solvents as confirmed by Electrospray Ionization Mass Spectrometry, although with lower phospholipid content, thus with a higher proportion of bacterioruberin. The extracted lipids were subsequently utilized for preparation of archaeosomes, which were characterized by uniform size distribution (406 ± 137 nm, 0.63 ± 0.13 polydispersity index), colloidal stability, and negative ζ potential (-38.2 ± 5.4 mV). The photoprotective potential of these archaeosomes was for the first time determined in human keratinocyte (HaCaT) cells exposed to UVB irradiation (270 mJ/cm²). Treatment with archaeosomes significantly (p< 0.05) enhanced cell viability (from ~43 to ~80 %), reduced intracellular ROS generation and proinflammatory cytokine release (TNF-α) and mitigated UVB-induced apoptosis compared to untreated controls, indicating effective cytoprotection. This study demonstrates that ethyl acetate–ethanol-based extraction offers an alternative for archaeal lipid recovery and highlights the potential of archaeosomes as natural photoprotective agents for skincare applications.