This study aims to conduct the antioxidant activity test of grapefruit peel ethanolic extracts and gel formulation. Grapefruit (Citrus maxima Merr.) is a plant of the Rutaceae family, which has been known to contain phenolic compounds (flavonoids and tannins). Grapefruit skin was very thick (>30% of the total weight of the fruit) and always considered as waste that has not been utilized properly. Phytochemical screening and water content assay was conducted on the simplicia powder. The simplicia powder was extracted by the maceration method with ethanol as the solvent. Dried extract was obtained by evaporating the solvent with a rotary evaporator, then freeze drying. Antioxidant activity test of grapefruit peel ethanolic extracts using free radical trapping DPPH (1,1-diphenyl-2- picrylhydrazil) was measured at a wavelength of 516 nm after 60 minutes at room temperature with vitamin C as a comparison. Preparation of ethanol extract gel formulations skin grapefruit gel base with CMC-Na and was conducted the evaluation of the material of the gel and the activity of anti aging. Results of phytochemical screening showed simplicia powder contains alkaloids, flavonoids, glycosides, saponins, tannins, and steroids. Water content assay results obtained 7.32%. The test results of antioxidant activity in the DPPH free radical trapping obtained the inhibitory concentration 50 (IC50) values 60.182 ppm and vitamin C 2.679 ppm. Preparation of ethanol extract gel grapefruit skin preparation gels that is meets the requirements of its homogeneity, pH, stability, irritation, and testing activities, namely anti-aging moisture, smoothness, large pores, blemishes, wrinkles, wrinkle depth. Grapefruit peel ethanolic extract had a strong category antioxidant activity and can be formulated as material of topical anti-aging gel.
