<![CDATA[Metal nanoparticles are widely used in various applications, such as drug sensors and catalytic. The principle of the green metal nanoparticle preparation method (green synthesis method) is that microorganisms or plants function as reducing agents. In the synthesis process, plants utilize organic compounds contained in living things, mainly containing secondary metabolites such as flavonoids, terpenoids, alkaloids, steroids, and tannins which have antioxidant properties. One of the plants that can synthesize metal nanoparticles is the jamblang plant. One of them is the flavonoid compound, flavonoids are one of the secondary metabolites found in plants. This compound can be used as an antimicrobial, wound infection medicine, antifungal, antiviral, anticancer, and antitumor. Previous studies have shown that methanol extract of jamblang leaves has antioxidant activity (IC50 12.53 ppm). This research method is an experimental method that includes sample collection and processing, characteristics of simple drugs, phytochemical screening, making aquadest liquid extract, synthesis of copper nanoparticles using jamblang leaf extract, characterization of nanoparticles using Particle Size Analyzer (PSA), and antioxidant activity test of copper nanoparticles, jamblang leaf extract and Vitamin C comparator using the DPPH method. The results of phytochemical screening on simple drugs and extracts contain alkaloids, flavonoids, tannins, saponins, steroids and glycosides. The results of copper nanoparticles are formed with a change in color, there is sediment, and the concentration of CuNO3 decreases, the results of the nanoparticle test using PSA on the extract alone are 2504.59 nm, at 1: 1 it is 2552.06 nm, 1: 2 it is 312.50 nm, 1: 3 it is 1299.50 nm, 1: 4 it is 175.41 nm. The results of the antioxidant test showed that the copper extract was greater than the extract alone, both were categorized as very strong, namely in the copper extract 44.59 ppm and in the extract alone 26.74 ppm.]]>
