Evaluation of μ-calpain inhibitory activity of Korean indigenous marine organism extracts

Marine organism extracts were prepared from 26 species of Korean indigenous marine organisms, including 25 species belonging in class Anthozoa of phylum Cnidaria and a species belonging to subphylum Urochordata of phylum Chordata, and screened their inhibitory effects against μ-calpain. As a result, the thirteen extracts were found to be active in the criteria of IC₅₀ << 100 μg/mL. Among them, the MeOH extracts of Plexauroides praelonga and Alveopora japonica showed remarkable μ-calpain inhibitory activity with IC₅₀ values of 4.62 ± 0.22 and 4.82 ± 0.07 μg/mL, respectively. In addition, chemical investigation of A. japonica led to the isolation of an active compound, hexadecyl tetradecanoate, as a selective cathepsin B inhibitor (IC_5o = 9.05 ± 2.45 μM). This compound was isolated as constituent of A. japonica for the first time in the present study.