FORMULASI DAN UJI ANTIOKSIDAN GEL MOISTURIZER EKSTRAK BIJI KOPI HIJAU ROBUSTA (Coffea canephora Pierre ex A. Froehner) DENGAN METODE DPPH

Abstract

Introduction: Robusta green coffee beans (Coffea canephora) are recognized for their abundant chlorogenic acid content, a bioactive compound with significant antioxidant capacity capable of neutralizing free radicals that contribute to dermal damage. The gel dosage form was selected owing to its lightweight consistency, rapid dermal absorption, and combined moisturizing and protective properties. This study aimed to produce a physically and organoleptically stable gel formulation derived from robusta green coffee bean extract, with emphasis on optimizing antioxidant activity as assessed by the DPPH method through IC₅₀ determination. Method: An experimental laboratory approach was employed, utilizing beans obtained from Parapat, Toba region. The study encompassed three sequential stages: plant material extraction, gel preparation, and comprehensive physicochemical stability assessment. Results: Extraction produced an 11.15% yield. Characterization of the crude extract met established quality parameters, with moisture content at 2.5%, water-soluble extract at 13.3%, ethanol-soluble extract at 13.6%, total ash at 3.33%, and acid-insoluble ash at 0.5%. All three gel formulations (F1, F2, F3) exhibited characteristic coffee organoleptic profiles, maintained homogeneity, demonstrated stable pH values ranging from 6.2 to 6.7, displayed satisfactory spreadability, and caused no skin irritation. Moisturization parameters including skin hydration, wrinkle reduction, and pore appearance were improved across all formulations. Formulation F3, containing 9% extract, delivered the highest antioxidant efficacy with an IC₅₀ of 53.157 ppm, placing it in the strong antioxidant category. Conclusion: Robusta green coffee bean extract was successfully incorporated into a stable and safe gel moisturizer with strong antioxidant activity. A direct relationship was observed between extract concentration and both moisturizing performance and free radical scavenging capability.