Cinnamic acid derivatives inhibit hepatitis C virus replication via the induction of oxidative stress.

Several cinnamic acid derivatives have been reported to exhibit antiviral activity. In this study, we prepared 17 synthetic cinnamic acid derivatives and screened them to identify an effective antiviral compound against hepatitis C virus (HCV). Compound 6, one of two hit compounds, suppressed the viral replications of genotypes 1b, 2a, 3a, and 4a with EC50 values of 1.5-8.1 µM and SI values of 16.2-94.2. The effect of compound 6 on the phosphorylation of Tyr705 in signal transducer and activator of transcription 3 (STAT3) was investigated because a cinnamic acid derivative AG490 was reported to suppress HCV replication and the activity of Janus kinase (JAK) 2. Compound 6 potently suppressed HCV replication, but it did not inhibit the JAK1/2-dependent phosphorylation of STAT3 Tyr705 at the same concentration. Furthermore, a pan-JAK inhibitor tofacitinib potently impaired phosphorylation of STAT3 Tyr 705, but it did not inhibit HCV replication in the replicon cells and HCV-infected cells at the same concentration, supporting the notion that the phosphorylated state of STAT3 Tyr705 is not necessarily correlated with HCV replication. The production of reactive oxygen species (ROS) was induced by treatment with compound 6, whereas N-acetyl-cysteine restored HCV replication and impaired ROS production in the replicon cells treated with compound 6. These data suggest that compound 6 inhibits HCV replication via the induction of oxidative stress.

Inhibitory effects of hydroxylated cinnamoyl esters on lipid absorption and accumulation.

Obesity is a risk factor associated with several lifestyle-related diseases, for example, diabetes, high blood pressure, hyperlipidemia and cancer. Caffeic acid 2-phenylethyl ester (CAPE, 1), a naturally-occurring compound found in various plants and propolis, which exhibits anti-inflammatory, immunomodulatory and cytotoxic activities and inhibits 3T3-L1 differentiation to adipocytes. As part of our efforts to moderate lifestyle-related diseases, we synthesized analogs of 1 and studied their effects on pancreatic lipase activities, lipid absorption, and 3T3-L1 differentiation. We found that catechols 1-4 show inhibitory activities against pancreatic lipase in a dose-dependent manner in vitro. Compounds 1-3 proved to be more potent inhibitors of pancreatic lipase than 5, 6, 8, and 9, which have one hydroxyl group, respectively. Compound 7 has three aromatic hydroxyl groups and restrains greater lipase inhibitory activity than the other compounds. In addition, 7 and 3 significantly suppress a rise in blood triglyceride (TG) levels in mice given corn oil orally. Furthermore, 2 and 3 are more potent at preventing 3T3-L1 differentiation (lipid accumulation) than 1, while 7 is more potent than 3, 8, and 9 in these assays. Compounds 2, 3, and 7 inhibit lipid absorption and accumulation, with new compound 7 being the most potent. These results indicate that 7 may have potential benefits as a health agent with anti-obesity properties.