Fast inverted, oil-in-water (o/w) emulsions, also known as SWitch-Oil-Phase (SWOP) emulsions, express the performances of both o/w and water-in-oil (w/o) emulsions during application to the skin, favoring their use as cosmetic carriers in sunscreen products. The objective of this study was to investigate the antioxidant potential (by 2 different methods) and the ultraviolet (UV) absorption ability of SWOP emulsion (S) with incorporated plant-based antioxidants dihydroquercetin (DHQ) and β-carotene (βC), using quercetin (Q) in a reference emulsion, in addition to the evaluation of their physicochemical properties and stability. A new biochemical extracellular model for in vitro assessment of antioxidative properties for the SWOP emulsions (S, SQ, SDHQ, and SDHQβC) was developed and compared with the results of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. The analyses were performed at 20 °C and 37 °C, and oxidative stress parameters were monitored and statistically analyzed. The sun protection factor (SPF) of the samples was determined in vitro. Q and DHQ incorporated into the SWOP emulsion exhibited a strong DPPH radical scavenging ability. Neither incorporated nor pure βC showed DPPH radical scavenging ability at the tested concentrations. Contrary to that, in the bioenvironment conditions, SDHQβC showed minor antioxidative effects increase and also a significant decrease in exogenous pro-oxidative effects, caused by pro-oxidant, when compared to SDHQ. The obtained SPFs of SDHQβC, SDHQ, and SQ were 5.19, 4.65, and 3.35, respectively. The physicochemical stability of the emulsions was satisfactory during 1 month storage. The presented results demonstrated that the SWOP emulsion is a suitable carrier for antioxidants with a photoprotective ability. The novel biochemical approach could be used in addition to DPPH assay with several advantages, relevant for the testing of antioxidant activity of potential active ingredients in cosmetic products.

Poznato je da produženo izlaganje kože ultravioletnom (UV) zračenju dovodi do pojave crvenila, solarnog еritеmа ili оpеkоtinа, da utiče na strukturu vezivnog tkiva kože, proizvodnju slobodnih radikala, stimuliše proizvodnju matriks metaloproteinaza i da može dovesti do razvoja kаncеrа kоžе. Svetska zdravstvena organizacija predlaže niz preventivnih mera za zaštitu kože od negativnih efekata UV zračenja, među kojima je i primena na kožu proizvoda za zaštitu od UV zračenja. Jedna od strategija za poboljšanje kvaliteta i efikasnosti proizvoda za zaštitu od UV zračenja je korišćenje novih, efikasnijih i bezbednijih aktivnih molekula koji apsorbuju, reflektuju ili rasipaju UV fotone, kao i uvođenje supstanci/materijala koji mogu da spreče, neutrališu i čak poprave oštećenja kože nastala delovanjem UV zračenja. Značajan potencijal za zaštitu kože od UV zračenja prepoznat je u supstancama/sastojcima biljnog porekla, koje primarno ispoljavaju antioksidantni efekat, a dodatno, poseduju i druge fotozaštitne osobine, što ih čini interesantnim za detaljnija istraživanja. U ovom radu je dat pregled fizičkohemijskih karakteristika antioksidanasa biljnog porekla, koje su značajne za formulaciju finalnog kozmetičkog proizvoda i potencijalnih efekata ovih sirovina/materijala u zaštiti kože od UV zračenja.