Penicitrinine　A,　a　novel　alkaloid　with　a　unique　spiro　skeleton,　was　isolated　from　a　marine-derived　fungus　Penicillium　citrinum.　In　this　study,　the　isolation,　structure　and　biosynthetic　pathway　elucidation　of　the　new　compound　were　described.　This　new　compound　showed　anti-proliferative　activity　on　multiple　tumor　types.　Among　them,　the　human　malignant　melanoma　cell　A-375　was　confirmed　to　be　the　most　sensitive.　Morphologic　evaluation,　apoptosis　rate　analysis,　Western　blot　and　real-time　quantitative　PCR　(RT-qPCR)　results　showed　penicitrinine　A　could　significantly　induce　A-375　cell　apoptosis　by　decreasing　the　expression　of　Bcl-2　and　increasing　the　expression　of　Bax.　Moreover,　we　investigated　the　anti-metastatic　effects　of　penicitrinine　A　in　A-375　cells　by　wound　healing　assay,　trans-well　assay,　Western　blot　and　RT-qPCR.　The　results　showed　penicitrinine　A　significantly　suppressed　metastatic　activity　of　A-375　cells　by　regulating　the　expression　of　MMP-9　and　its　specific　inhibitor　TIMP-1.　These　findings　suggested　that　penicitrinine　A　might　serve　as　a　potential　antitumor　agent,　which　could　inhibit　the　proliferation　and　metastasis　of　tumor　cells.