Anti-Inflammatory Activity of Chlorogenic Acid on Macrophages: A Simplified Simulation of Pharmacokinetics Following Ingestion Using a Windup Syringe Pump

Cell-culture-based drug tests are usually performed in an instantaneous delivery manner. However, in vivo pharmacokinetic studies have shown a steady increase in the concentration of bioactive compounds in the plasma following oral administration, with the maximum concentration observed after several hours. Here, a novel palm-sized syringe pump powered by the manual winding of a spring was utilized for sustained delivery of chlorogenic acid (CHA) to lipopolysaccharide (LPS)-challenged RAW 264.7 macrophages over 2 h. When delivered in a sustained manner and simulating the in vivo pharmacokinetics following oral administration, CHA showed a stronger inhibitory effect on LPS-induced expression of inducible nitric oxide synthase and the transcription and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-α. It also enhanced the mRNA expression of the gene encoding heme oxygenase 1. The suppression of phosphorylation of p38 but not the nuclear translocation of nuclear factor-κB was affected by the sustained delivery of CHA. High-performance liquid chromatography analysis indicated that the sustained delivery model showed a higher concentration of CHA in the conditioned medium two hours after starting the delivery. A stronger anti-inflammatory effect of CHA was observed upon sustained delivery to the cell medium, simulating an in vivo pharmacokinetic release profile following oral administration.