Developing an antioxidant and anti-aging face serum containing spirulina extract, and evaluating its physical, chemical, and biological properties.

Abstract

This study falls within the scope of enhancing natural resources and their use in the cosmetic industry. The main objective of this work is to prepare a natural serum based on spirulina (Arthrospira platensis) extract and to evaluate its topical efficacy on the skin. For this purpose, the extract was obtained through several stages (defatting, protein extraction, and processing to obtain bioactive compounds), and two serum formulations were developed (one for dry skin and the other for oily skin). These formulations were subjected to physicochemical tests (pH measurement and stability testing). Regarding the in vivo study, 50 µL of each formulation were topically applied to 24 Wistar rats, divided into 6 groups (4 rats per group), in order to assess the serum's effects on the skin through hematological, biochemical, bacteriological, and histological analyses. Physicochemical analyses revealed that the prepared serum exhibits suitable properties for topical application, with good stability and remarkable skin compatibility. Hematological parameters (Table 05) for the treated group (G2/g4) showed the following values: white blood cells (5.4 × 10³/µL) within the reference range, red blood cells (6.56 × 10⁶/µL) slightly above the reference, hemoglobin (13.2 g/dL), platelets (734 × 10³/µL) elevated compared to the norm, and hematocrit (41.2 %) within normal limits. Furthermore, biochemical parameters (Table 06) recorded blood glucose levels ranging between 0.58 and 0.76 g/L, urea between 0.30 and 0.37 g/L, and creatinine between 5.90 and 7.10 mg/L, with a low coefficient of determination (R² = 0.08) for creatinine, indicating low variability among groups. The in vivo results demonstrated a significant improvement in biological and tissue indicators compared to the control group, with a marked reduction in signs of dryness and inflammation at the skin level. Histological examination confirmed the good tolerance and beneficial effect of the formulations on the structure of the epidermal tissue. In conclusion, this study confirms the promising potential of spirulina as a viable natural ingredient in cosmetic and dermatological formulations. The demonstrated stabilizing properties, safety profile, and biological efficacy open new perspectives for the application of this cyanobacterium in skincare products.