LAUSR

Crassostrea sikamea (C.sikamea) is an important edible and medicinal seafood in China. In the present study, a compound named flazin was separated and identified from the ethyl acetate extract of C.sikamea (EAECs) for the first time. The preliminary characteristics of flazin were analyzed through physical and spectroscopic methods. In addition, the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphen yl)-2- (4-sulfophenyl)-2H-tetra zolium (MTS) assay revealed that EAECs and flazin could inhibit the transformation of splenic lymphocytes in vitro. Moreover, flazin (20 μg/mL) altered the populations of splenic lymphocyte subtypes. Real-time quantitative PCR (RT-qPCR) analysis and enzyme-linked immunosorbent assay (ELISA) showed that flazin suppressed the mRNA expression and secretion of TNF-α and IL-2, and reversed Concanavalin A (ConA)-induced mRNA upregulation and protein secretion of TNF-α and IL-2. Western blot results showed that flazin reversed the ConA-induced increase in p-ERK1/2 and p-p38 in splenocytes. In conclusion, flazin showed effective immunomodulation and may be useful for treating immune-related disorders, which indicates the application potential of C.sikamea as a functional food or immunomodulator.