The antimicrobial peptides (AMPs) are important components of the innate defense of plants and other organisms. The synthesis of those molecules corresponds to an old, flexible and economical-defense strategy for plants. In general, they present wide spectrum of antimicrobial action. Some varieties of eggplant are not much susceptible to some plant-pathogens, possibly for their expression of natural defense compounds, as AMPs. This work aimed to compare the in vitro antimicrobial potential of eggplant-cationic and anionic peptide-enriched extracts, obtained from young plants (5, 10 or 15-cm) or fully-expanded leaves on Ralstonia solanacearum and Clavibacter michiganensis subsp. michiganensis growth. Leaves (60-days plants) or the whole-seedlings (5, 10 or 15-cm) of eggplant were powdered, macerated (Tris-HCl, EDTA, PMSF, benzamidine, thioureia), the extract was centrifuged and the supernatant corresponded to the Soluble Extract (SE). The precipitate was washed (water), extracted with LiCl (EDTA, PMSF, benzamidine, thioureia), the homogenate was centrifuged and the supernatant was named Cell-Wall Extract (CWE). CWE and SE obtained from the four different plant developmental stages (eight extracts) were fractionated (ammonium sulfate and heating), dialyzed, lyophilized and separate by anionic-exchange chromatography (FPLC, DEAE-Sepharose). Two cationic (CP1 and CP2) and one anionic (AP) peaks were obtained from each analyzed stage, that were submitted to inhibition tests against the two plant-pathogenic bacteria. For R. solanacearum, the best inhibition rates were: 5-cm, CP2-CWE (91%) and AP-SE (23,9%); 15-cm, CP2-CWE (80.0%) and CP1-SE (92.2%); expanded-leaves, AP-CWE (69%) and CP2-SE (100%). Similar behavior was observed for C. michiganensis subsp. michiganensis, since 5-cm-CWE was more effective than 5-cm-SE, while 15-cm- and leaf-SE produced best inhibition than 15-cm- and leaf-CWE, indicating a larger bacterial inhibition by CWE obtained from the younger plants. Possibly, youthful plants express innate defense compounds in the cell-wall, as AMPs, to avoid the antimicrobial invasion, while in old-plants the induced defense would prevail in relation to the innate defense, starting from the moment in that plants can answer to the invaders. Supported by FAPEMIG.