Siamycin I is a tricyclic peptide originally isolated from Streptomyces and has antiviral and antibacterial activities. It is active against laboratory strains and clinical isolates of HIV-1 (ED50s = 0.05-0.45 and 0.89-5.7 μM, respectively), as well as the CBL-20 strain of HIV-2 (ED50 = 0.45 μM), in vitro. Siamycin I inhibits HIV-induced fusion of C8166 T cells with HIV-1-infected CEM-SS cells with an ED50 value of 0.08 μM. It is also active against B. subtilis, M. luteus, and S. aureus (MICs = 1.6-6.3 μg/ml). Siamycin I inhibits autophosphorylation of the E. faecalis quorum sensing kinase FsrC induced by gelatinase biosynthesis-activating pheromone (GBAP).
Lancifodilactone F exerts minimal cytotoxicity against C8166 cells (CC50 > 200 microg mL) and shows anti-HIV activity with EC50 = 20.69 + - 3.31 microg mL and a selectivity index > 6.62.
Shizukaol B exerts anti-inflammatory effects in LPS-activated microglia partly by modulating JNK-AP-1 signaling pathway; it also shows significant anti-neuroinflammatory effects by inhibiting nitric-oxide (NO) production in lipopolysaccharide (LPS)-stimul
1. Shizukaol C shows anti-HIV-1 replication activities in both wild-type HIV-1 and two NNRTIs-resistant strains. 2. Shizukaol C has significant cytotoxicities against C8166 cells.