Amaranth Oil for Dermatologic Conditions: Inflammation Control and Cytotoxicity Assessment in Skin-Related Cell Models—Preliminary Study

Amaranth oil (AMO) and its topical formulation enriched with rose oil (AMOR) were evaluated for anti-inflammatory and cytotoxic properties in skin-relevant models. Two complementary inflammation models were used to assess immunomodulatory potential, (i) LPS-stimulated macrophages and (ii) TNF-α/IFN-γ-stimulated immortalized HaCaT keratinocytes, while cytotoxicity and selectivity were tested on human HaCaT keratinocytes and melanoma cell lines (A375, HTB140). GC-MS and FTIR analyses were performed to confirm the presence of key bioactive compounds (squalene, fatty acids, phenolics). AMOR showed significantly higher polyphenol and palmitic acid content than AMO. In both inflammation models, AMOR more effectively reduced IL-6, IL-1β, and TNF-α release. Cytotoxicity assays revealed that both oils were safe for normal keratinocytes, while selectively cytotoxic to melanoma cells, with AMOR demonstrating greater potency (IC₅₀ A375 = 3.8 μg/mL and HTB140 = 18.9 μg/mL). Albumin-binding studies showed that AMOR had stronger interactions with these proteins, which may enhance delivery and tissue retention. In conclusion, both oils exhibit promising topical safety, but AMOR provides enhanced anti-inflammatory and cytotoxic effects due to its enriched composition. This study supports the therapeutic potential of amaranth oil in different skin diseases, especially when combined with essential oils of complementary bioactivity.