Scytonemin

Scytonemin is a hydrophobic alkaloid pigment that can be isolated from the outer sheath of cyanobacteria. Scytonemin has protective function against short-wave solar ultraviolet (UV) radiation, which can reduce the generation of reactive oxygen species (ROS) and the formation of DNA damage. Scytonemin also has anti-inflammatory and anti-proliferative activities, produces concentration-dependent inhibition (IC₅₀=2.0 μM) of polo-like kinase 1 (PLK1)-mediated cdc25C phosphorylation, and plays an important role in regulating the G2/M transition in the cell cycle. It can be used in the research of cancer, acute inflammation and sunscreen cosmetics^{[1][2][3][4][5]}. In Vitro: Scytonemin (3 μM; 24 h) inhibits the proliferation of human T-cell leukemia Jurkat cells (IC₅₀= 7.8 μM) and induces apoptosis^[4].
Scytonemin (100 nM-30 μM) has an inhibitory effect on PDGF-induced RSF and ECGF-induced HUVEC proliferation (IC₅₀=1.5 μM; IC₅₀=5.4 μM) ^[4].
In Vivo: Scytonemin has a highly effective inhibitory effect (ED50=10 mg/kg) on Phorbol 12-myristate 13-acetate (HY-18739) induced ear inflammation in mice when administered parenterally^[3].