Cassia alata Linn is an Indonesian tropical plant that are well spread in tropical regions such as in the countries of Asia, America and Africa. This plant has traditionally been used as an anthelmintic, thrush. laxative, anti-parasitic, herpes, syphilis, scabies and other skin diseases. The objective of this research was to isolate the anthraquinone compound from the leaves of the plant. Extraction was done by soxletation method, while purification was done by vacuum liquid chromatography with silica gel as stationary phase and gradually eluted using Step Gradient Polarity (SGP) method by using the solvent n-hexane, ethyl acetate and methanol. Structure elucidation done by ultraviolet, infrared and 1H-NMR spectroscopy. Compound was isolated from ethyl acetate fraction as an orange powder as much as 8 mg. The isolated compounds were anthraquinone derivate. Testing the antioxidant activity of the ethyl acetate fraction shown IC50 = 310 μg/ mL and classified as active antioxidants.