Bioactivity and physicochemical characterization of Centella asiatica and Marigold extract serums: Antioxidant, anti-inflammatory, anti-tyrosinase and skin barrier function insights.

Abstract

Centella asiatica extract (CAE) and Marigold extract (ME) have been renowned for centuries in traditional medicine, particularly in Asia, for their wound-healing, anti-inflammatory and skin-regenerative properties. This study presents the formulation and comprehensive evaluation of serums enhanced with these extracts, aiming to harness their bioactive properties for skin health. Serums were selected over creams due to their lightweight, water-based nature, which ensures faster absorption and enhanced skin penetration of active ingredients. The serums, developed in varying concentrations (0.2%, 0.5% and 1.0%), were assessed for physicochemical properties, stability, bioactivity and skin barrier enhancement. Stability tests confirmed the serums' robustness, maintaining consistent pH (5.0-6.5), viscosity and organoleptic properties over 60 days. The MTT assay revealed that both extracts were non-cytotoxic, maintaining cell viability above 100%, with formulations containing CAE, demonstrating a concentration-dependent proliferative effect, reaching nearly 120%. Antibacterial evaluation using the agar well diffusion assay showed that both extracts exhibited considerable activity, with CAE achieving greater inhibition zones, particularly against S. aureus. Antioxidant, anti-inflammatory and anti-tyrosinase activities confirmed the strong bioactive potential of both extracts in combating oxidative stress, reducing inflammation, and regulating pigmentation. Skin barrier and permeability studies demonstrated the serums' ability to improve barrier integrity and facilitate active compound delivery. These findings demonstrate the potential of Centella asiatica and Marigold extracts for multifunctional skincare formulations, combining regeneration, hydration, antioxidant and antibacterial benefits.