Collagenase and Tyrosinase Inhibitory Compounds from Fish Gut Bacteria and .

and are fish gut bacteria that have been isolated from the guts of and , respectively. A total of 22 compounds (-) were isolated from these two bacteria; 16 compounds (-) from and 6 compounds (-) from . Their chemical structures were elucidated by spectroscopic and spectrometric data analysis and chemical synthesis. Compounds and showed strong collagenase inhibitory activity, with 31.91% and 36.43% at 20 μM, respectively, comparable to or surpassing that of the positive control epigallocatechin gallate (EGCG, 34.66%). Also, compounds and exhibited a mild tyrosinase inhibitory effect of 6.73% and 13.68%, respectively. All of the tested compounds displayed no significant antibacterial activity against and up to 100 μM. The collagenase- and tyrosinase-inhibitory compound , cyclo(l-Pro-d-Leu), was found to be stable under heat (50 °C) and UV light (254 and 365 nm) for up to 6 days. These results indicate that compound could be developed into a cosmeceutical with antiaging effects.