Phytochemical screening and bio-functional assessment of seaweed extract in topical cream formulations

This study evaluated the phytochemical composition, physicochemical properties, antimicrobial activity, irritation potential, and antioxidant capacity of cosmetic creams formulated with varying concentrations of seaweed extract (F1–F4). Phytochemical screening revealed the presence of key secondary metabolites, with flavonoids being most abundant (7.6 mg/g), indicating strong antimicrobial and anti-inflammatory potential. Physicochemical evaluation showed all formulations met standard cosmetic criteria, with increasing seaweed concentration leading to higher moisture content and viscosity, and slightly reduced but acceptable spread ability. Antimicrobial testing revealed no activity in the base cream (F1), while F4 (7.5% seaweed inclusion) demonstrated significant zones of inhibition, particularly against Staphylococcus aureus (8.1 mm), closely matching the standard antibiotic. HET-CAM skin irritation testing confirmed all formulations were non-irritant, including F4 with the highest extract concentration, whereas the positive control (SLS) produced a severe reaction. Antioxidant assays showed concentration-dependent radical scavenging activity, with F4 achieving 25.0%, supported by increased vitamin E content (1.00 mg/g), though still below the ascorbic acid standard. These results indicate that seaweed extract enhances the bifunctional properties of cream formulations without compromising safety, supporting its potential use in natural skincare products.