Synthesis and Biological Properties of Formulated Skin Serum Containing Coelomic Fluid of Earthworm Eisenia fetida/andrei

Background and Objectives: In this study, the coelomic fluid of Eisenia fetida/ andrei species was used for the first time to prepare an anti-aging serum, and its antioxidant and antibacterial properties were investigated. In addition, its cytotoxicity on mouse fibroblast cells was measured as material for the production of natural anti-aging products. Material and Methods: This study investigates the antibacterial, antioxidant, and cytotoxic properties of coelomic fluid extracted from Eisenia fetida/andrei. Earthworms were cultured for a year, and their coelomic fluid was extracted using an electroshock method, sterilized, and lyophilized into powder. Antibacterial activity was tested against Escherichia coli and Staphylococcus aureus using MIC assays. Antioxidant properties were evaluated using the DPPH radical scavenging assay. Cytotoxicity effects on L929 and NHEK cell lines were assessed using MTT assays. Oxidative stress and enzymatic activities were analyzed by measuring malondialdehyde (MDA) levels and catalase activity in NHEK cells treated with coelomic fluid. A serum formulation incorporating coelomic fluid was prepared and subjected to stability tests, including pH, temperature, mechanical, and heavy metal residue analysis. Antibacterial and antioxidant properties of the serum were also evaluated. Statistical analyses were conducted using SPSS software (version 0.26). Results highlight the multifunctional potential of coelomic fluid for biomedical and cosmetic applications. Results: Coelomic fluid exhibited antibacterial activity with MICs of 0.15 mg/mL for both E. coli and S. aureus, showing significant inhibition at higher concentrations. Ciprofloxacin and penicillin demonstrated stronger effects compared to the coelomic fluid. Antioxidant activity increased with concentration, achieving 77% inhibition at 10 mg/mL, with an IC50 of 10.67 mg/mL. Cytotoxicity analysis revealed no significant toxicity below 20 mg/mL, with enhanced cell viability at 2.5–5 mg/mL and restorative effects on fibroblasts at 10 mg/mL. Oxidative stress assays indicated reduced lipid peroxidation and increased catalase activity without inducing significant oxidative stress. Measurement of residues of mercury and lead in the sera showed that they were less than 0.01 ppm for mercury and less than 0.03 and 0.05 ppm for lead, respectively. These levels are below the U.S. Food and Drug Administration's approved limits for these metals. Aqueous serum containing coelomic fluid showed similar antibacterial and antioxidant properties, emphasizing its potential for cosmetic and pharmaceutical applications. Conclusions: These results show that the use of earthworm coelomic fluid in skin care serum slows the aging process and restores damaged cells.