Scavenging activities of the purified compounds of M. paniculata towards DPPH, ABTS and hydroxyl radicals, respectively, are shown in Figure 3, which illustrates that the radical-scavenging effects were found to increase with the increasing concentration of the tested compounds. As shown in Table 1, The IC50 values of DPPH radical scavenging activity decreased as follows: 4 > 1 > 3 > 2. DPPH radical is considered to be a stable free radical and used to evaluate the antioxidant activities of natural products in organic solvents. The DPPH method is based on the color decrease occurring when the odd electron of the nitrogen atom in DPPH radical is reduced by receiving a hydrogen atom from antioxidants.