galaxamide

**Galaxamide** is a novel cyclic pentapeptide, specifically a cyclo-(Leu)₅ structure, isolated from the marine red alga *Galaxaura filamentosa* found in the South China Sea. It contains five leucine residues and has a molecular weight of approximately 593.4 g/mol[1][2][4]. Galaxamide exhibits significant anticancer cytotoxicity against various human cancer cell lines (including HepG2, MCF-7, SW480, U87, SMMC-7721, and HeLa) with notably low cytotoxicity toward normal liver cells[1][4][5]. Its primary mechanism of action involves induction of apoptosis through a mitochondria-mediated, caspase-dependent pathway (including increased activation of caspase-3, caspase-9, and PARP)[1][5]. Galaxamide also induces cell cycle arrest at the G0/G1 phase and increases reactive oxygen species (ROS), contributing to cancer cell death[4][5]. In cervical cancer cells (HeLa), galaxamide additionally inhibits the Wnt signaling pathway, specifically downregulating Wnt6, thereby suppressing stemness, colony formation, migration, and invasion[2]. Galaxamide and its analogues have been investigated as lead compounds for novel anticancer drug development due to their potent and broad-spectrum antitumor activity[1][2][4][5].