Formulation of curcumin- and quercetin-loaded nanoethosomes and evaluation of their antioxidant, antibacterial, and anti-inflammatory potential with dermal irritation assessment in chickens

Biological activities and dermal safety of nanoethosomes

Abstract

Quercetin and curcumin are strong natural antibacterial and antioxidant compounds. However, their topical use is restricted due to their low stability, poor solubility, and insufficient skin penetration. The purpose of this study was to develop nanoethosomes loaded with curcumin and quercetin and assess their antibacterial efficacy, antioxidant activity, and physicochemical characteristics for topical administration. The ethanolic injection method was used to create the nanoethosomes, which were then characterized for entrapment efficiency, zeta potential, particle size, and polydispersity index (PDI). The DPPH assay was used to measure antioxidant activity, while zone of inhibition, MIC, and MBC studies were used to measure antibacterial efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The findings indicated that the nanoethosomes loaded with quercetin had particle size of 128.7 ± 16.4 nm, PDI of 0.545 ± 0.05, and zeta potential of −34.8 ± 0.6 mV, whereas those loaded with curcumin measured 155.3 ± 1.2 nm, PDI 0.186 ± 0.07, and zeta potential −42.2 ± 0.3 mV. Curcumin's entrapment efficiency was 92.1 ± 2.1%, whereas quercetin's was 84.6 ± 1.8%. The curcumin-loaded nanoethosomes exhibited antibacterial activity against S. aureus, P. aeruginosa, and E. coli, with inhibition zones of 21.5 ± 1.1, 20.1 ± 0.9, and 22.3 ± 0.8 mm, respectively. Similarly, at 50 µg/mL, both formulations showed 65 and 54% inhibition of BSA protein denaturation, respectively. These results demonstrated strong antioxidant activity, high stability, excellent drug loading, and broad-spectrum antibacterial activity, underscoring their promise as secure and efficient topical delivery methods for natural medicines.