Protective effects of avocado peel and seed extracts against UVB-damaged fibroblasts for the development of an anti-photoaging nanoemulgel

This study investigates the anti-photoaging potential of ethanolic extracts from avocado peel and seed and their application in a nanoemulgel formulation. Both extracts demonstrated high phenolic content and strong antioxidant activity, with DPPH IC 50 values of 57.05 ± 1.65 µg/ml (peel) and 52.44 ± 0.32 µg/ml (seed). In UVB-irradiated human dermal fibroblasts (BJ cells), the extracts (12.5–50 µg/ml) significantly reduced intracellular ROS, decreased MMP-1 and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), and restored collagen levels. A nanoemulgel was developed using the phase inversion composition (PIC) method, with avocado oil, isononyl isononanoate, Tween 60, and polyglyceryl-3 diisostearate, which resulted in nanoemulsions (NEs) with an average droplet size of 84.45 ± 5.45 nm and a zeta potential of −69.94 ± 5.66 mV. Incorporation of 0.5% Aqupec HV-505E and avocado extracts produced stable, light green gel. The resulting avocado extract-loaded nanoemulgel (ANE) demonstrated antioxidant activity, cytocompatibility with BJ cells, and stability in terms of color, pH, and viscosity. These findings reveal the anti-aging potential of avocado peel and seed extracts in preserving effectiveness within nanoemulgel for skin applications.