Antioxidant activity and physicochemical stability of phytocosmetic formulations containing Phyllanthus niruri extract

Abstract

Antioxidants are an appreciable strategy to prevent skin photoaging as they inhibit reactive oxygen species formation under UV exposure. Phyllanthus niruri L. (Euphorbiaceae) is a medicinal plant utilized in treating urolithiasis and contains high amounts of secondary metabolites with antioxidant activity. The potential cosmetic usage of the dry extract of P. niruri in three cosmetic base formulations (non-ionic emulsion, anionic gel, and gel cream were assessed by evaluating antioxidant activity and thermal stability. Antioxidant activity was assessed by the DPPH method and the preliminary stability test was performed in different storage temperature conditions (40.0±2.0, 20.0±5.0, 5.0±2.0 °C). Organoleptic (appearance, color, odor), sensory (consistency) and physical-chemical characteristics (pH) were evaluated after 30 days. Formulations containing the plant extract presented high antioxidant activity, whereas the non-ionic emulsion had the best performance. All formulations exhibited antioxidant activity stability when stored at low temperatures, however, medium and high temperatures caused a reduction of this parameter. Therefore, non-ionic emulsion was considered the ideal base formulation for antiaging purposes as long as stored at low temperature.