Determination of Total Phenolic Content and Antioxidant Activity of Ethanol Extract of Green Tea Leaves (Camellia sinensis L.) Based on IC₅₀ Values Using the DPPH Method

Normal metabolic processes in the human body can generate free radicals as by-products. The accumulation of free radicals may also be influenced by various external factors, including ultraviolet radiation exposure, air pollution, and cigarette smoke. Therefore, antioxidants play an essential role in controlling and neutralizing oxidative effects caused by excessive free radicals. Green tea leaves (Camellia sinensis L.) contain secondary metabolites, particularly phenolic compounds, which have potential as natural antioxidants. This study aimed to determine the total phenolic content and antioxidant activity of green tea leaf ethanol extract based on IC₅₀ values using the DPPH method. The extraction process was carried out using the maceration method with 96% ethanol, followed by phytochemical screening, determination of total phenolic content using the Folin–Ciocalteu method with gallic acid as a standard solution at concentrations of 4, 6, 8, 10, and 12 ppm, and antioxidant activity evaluation using the DPPH assay. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, and steroids. The total phenolic content of the extract was 113.034 mg GAE/g extract, with an IC₅₀ value of 9.9874 ppm, indicating very strong antioxidant activity. Therefore, green tea leaf ethanol extract has potential as a natural antioxidant source. Further studies are recommended to identify the active compounds responsible for the antioxidant activity of green tea leaf ethanol extract.