Formulation, characterization and sunscreen potential evaluation of lemongrass (Cymbopogon citratus) oil nanoemulsion

Abstract

Lemongrass (Cymbopogon citratus) oil is one of the natural resources with antioxidant activity and has the potential to be applied as a sunscreen to prevent free-radical reactions caused by UV light. This research aimed to formulate lemongrass oil nanoemulsion, characterize, and examine its potency as a sunscreen. Lemongrass oil nanoemulsion was formulated with 1, 3, 5, and 7% of oil concentrations. The characterization included organoleptic tests, pH tests, viscosity tests, transmittance percentage (%T) tests, nanoemulsion type tests, droplet size tests, and thermodynamic stability tests. Based on the organoleptic test, nanoemulsions with oil concentrations of 1, 3, and 5% showed clear visual and good stability, while the nanoemulsion 7% exhibited turbid visual and instability. The pH tests revealed that the prepared formulas were safe to be used on the skin. The viscosity tests displayed the viscosity values were <200 mPas, while the %T tests of the formulas were near 100%. In addition, the nanoemulsion types of the prepared lemongrass oil nanoemulsions were found to be o/w, with a droplet size of <10 nm. Evaluation of the potential of nanoemulsion as sunscreen was conducted using a spectrophotometer UV-Vis (290-400 nm) with ethanol as a blank solution and non-nano-emulsified lemongrass oil as a comparison. Based on the test, sunscreen activities of lemongrass oil nanoemulsions 1, 3, and 5% were higher than sunscreen activities of non-nano-emulsified lemongrass oil with the same oil concentrations. The nanoemulsion formula with the highest sunscreen activity was nanoemulsion with a concentration of 5%. This formulation showed an SPF value of 2.59, a percentage transmission of erythemal (%Te) value of 11.27%, and a percentage transmission of pigmentation (%Tp) value of 45.54%. Furthermore, the sunscreen activity of the lemongrass oil nanoemulsion 5% was categorized as a regular suntan.