In Vitro and Antioxidant Evaluation of a Nanoemulsion Formulation Containing Kojic Monooleate for Hyperpigmentation Treatment

Abstract

Running Head: Kojic monooleate (KMO) was incorporated into a formulation as the sole active ingredient, and the formulation was analysed for cytotoxicity using EpiDermTM tissue culture and melanin and tyrosinase inhibition using B16-F1 melanoma cells to confirm its capability to treat hyperpigmentation.   Cell damage caused by exposure to UV radiation, as an external stress-inducing factor, may contribute to skin hyperpigmentation. Kojic monooleate (KMO) was used as an active in a nanoemulsion formulation for hyperpigmentation treatment. The objective of this study was to analyse the cytotoxicity and efficacy of a nanoemulsion formulation containing KMO. The formulation was prepared using high and low energy emulsification techniques and analysed for cytotoxicity and melanin and tyrosinase inhibition. Then, it was investigated for total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition, and elastase inhibition. The formulation inhibited tyrosinase and melanin by 74.14% and 36.80%, respectively, at 1 mg/mL concentration. It also contained a substantial amount of phenolic and flavonoid compounds with the values of 8.14 ± 0.03 mg/g eq. to gallic acid and 1.55 ± 0.03 mg/g eq. to rutin, respectively. The formulation also inhibited DPPH free radicals by 12.99% at 100 µg/mL. It also possessed the capability to prevent photodamage, as it inhibited elastase by 27.91% at 1000 µg/mL. The KMO nanoemulsion was also found to be non-irritant. In short, the KMO nanoemulsion formulation could provide good effects if applied to the skin frequently and safe for daily applications.