Cyclo(Phe-Pro)

Cyclo(Phe-Pro) (Cyclo(phenylalanylprolyl)) is a quorum-sensing molecule of Vibrio vulnificus that specifically interacts with RIG-I, inhibiting RIG-I polyubiquitination, suppressing IRF-3 activation, and reducing type I interferon production. Cyclo(Phe-Pro) enhances susceptibility to HCV and influenza virus and also alleviates plant aluminum toxicity stress. The mechanism of Cyclo(Phe-Pro) involves the regulation of host immune signaling pathways, bacterial virulence gene expression, and plant antioxidant systems, making it a promising candidate for research in viral infections, bacterial virulence regulation, and agricultural stress resistance^[1][2][3]. In Vitro: Cyclo(Phe-Pro) (2.5 mM, 24 h) promotes HCV replication by suppressing IFN-β and IRF-3 activation in Huh7 cells^[1].
Cyclo(Phe-Pro) (0.5-1.0 mM, 5 h) inhibited the expression of virulence factors cholera toxin (CT) and toxin-coregulated pilus (TCP) in Vibrio cholerae O1 El Tor N16961 and regulated virulence factor expression by downregulating tcpPH transcription, while overexpression of tcpPH alleviated the inhibitory effect of Cyclo(Phe-Pro)^[2].
Cyclo(Phe-Pro) (50 μM, 24 h) promotes root growth, reduces aluminum accumulation, alleviates oxidative damage, and enhances antioxidant capacity in the aluminum toxicity wheat root model^[3].
In Vivo: Cyclo(Phe-Pro) (50 mg/kg, i.v., once daily for 3 days) promoted HCV replication and suppressed poly(I:C)-induced antiviral response in the HCV-infected Huh7 subcutaneous xenograft NOD/SCID mouse model^[1].