In Vitro Evaluation of Spirulina platensis Aqueous Extract and C-Phycocyanin on Skin Cell Metabolic Activity, Wound Healing and Antioxidant Activities

Various Spirulina species and their major pigment, Cyano-phycocyanin (C-PC), have been shown to exhibit antioxidant, anti-inflammatory, and anticancer properties, and are used in various skincare products. Spirulina platensis is rich in nutrients, proteins, and antioxidants, with therapeutic potential for skin protection and regeneration. Aqueous Spirulina extracts have gained increasing attention in recent years due to their biocompatibility; however, comparative assessment of aqueous extract and C-PC responses across non-malignant and malignant skin cells remains limited. This study aimed to evaluate the effects of S. platensis aqueous extract and C-PC on the cellular metabolic activity and wound healing of human skin cell lines—melanoma cells, keratinocytes, and fibroblasts—using a 24 h PrestoBlue assay and time-resolved scratch assays. The results demonstrated a concentration- and cell-type-dependent response to both preparations: at selected concentrations, S. platensis aqueous extract and C-PC reduced melanoma cellular metabolic activity while increasing it in keratinocytes and fibroblasts. Notably, both S. platensis aqueous extract and C-PC significantly accelerated wound closure at selected concentrations in keratinocytes and fibroblasts but not in melanoma cell cultures. Additionally, the S. platensis extract exhibited strong antioxidant activity, which correlated with its phenolic and flavonoid content. In conclusion, S. platensis aqueous extract and C-PC exhibit concentration- and cell-type-dependent effects on skin cell metabolic activity and scratch closure, supporting further investigation of their potential for skin-repair applications.