As　of　February　2017,　approximately　7639　amphibian　species　have　been　described　in　the　AmphibiaWeb　database.　However,　only　20　cathelicidin-like　antimicrobial　peptides　have　been　identified　to　date　from　10　amphibian　species.　Half　of　these　peptides　were　identified　from　genome　sequences　and　have　not　yet　been　functionally　characterized.　In　this　study,　a　novel　cathelicidin-like　peptide　designated　cathelicidin-PP　was　purified　from　the　skin　of　tree　frog　Polypedates　puerensis.　Cathelicidin-PP　is　a　32　residue　peptide　of　sequence　ASENGKCNLLCLVKKKLRAVGNVIKTVVGKIA.　Circular　dichroism　spectroscopy　indicated　that　cathelicidin-PP　mainly　adopts　a　beta-sheet　structure　in　membrane-mimetic　solutions.　Cathelicidin-PP　exhibits　potent　antimicrobial　activity　against　bacteria　and　fungi,　especially　Gram-negative　bacteria.　Meanwhile,　it　shows　low　cytotoxicity　toward　mammalian　cells.　Scanning　electron　microscopy　analysis　indicated　that　cathelicidin-PP　kills　bacteria　through　the　disruption　of　the　bacterial　cell　membrane　integrity.　Furthermore,　cathelicidin-PP　exerts　significant　anti-inflammatory　functions　by　inhibiting　the　lipopolysaccharide　(LPS)-mediated　generation　of　nitric　oxide　and　pro-inflammatory　cytokines,　tumor　necrosis　factor-alpha,　interleukin-1　beta,　and　interleukin-6.　The　MAPKs　(ERK,　JNK,　and　p38)　and　NF-kappa　B　signaling　pathways　are　involved　in　the　anti-inflammatory　effect.　Cathelicidin-PP　caused　partial　neutralization　of　LPS　in　a　dose-dependent　manner.　Quantitative　PCR　indicated　that　infection　of　tree　frogs　with　bacteria　causes　increased　expression　of　cathelicidin-PP　in　immune-related　tissues.　Taken　together,　cathelicidin-PP　is　the　first　identified　cathelicidin-like　peptide　from　tree　frogs.　Our　findings　demonstrate　that　in　addition　to　direct　bactericidal　capacity,　cathelicidin-PP　also　possesses　immunomodulatory　properties,　including　partial　neutralization　of　LPS,　and　inhibiting　the　production　of　inflammatory　cytokines.