Mice treated with Caffeic acid at a dose of 500 mg/kg display a marked reduction in histamine-induced scratching behavior, recording an average of 30.50±10.87 bouts per hour, with a sample size of six. A lower dose of Caffeic acid (100 mg/kg) shows a non-significant reduction in scratching, indicating a possible decreasing trend (49.40±12.35 bouts per hour, n=5). Chloroquine-induced scratching is significantly decreased following pretreatment with 500 mg/kg of Caffeic acid, registering 161.6±31.42 bouts per hour in five subjects^[1].

Additionally, Caffeic acid substantially lowers the expression of 5-LO mRNA in a dose-dependent manner in the hippocampus. Compared to the ischemia-reperfusion (I/R) untreated group, 5-LO protein expression significantly diminishes in the I/R-Caffeic acid-treated group, particularly at 50 mg/kg. Relative to the I/R untreated group, the time taken to locate the platform significantly decreases in both low- and high-dose Caffeic acid-treated groups, with the most notable reduction in the I/R-Caffeic acid 50 mg/kg group (P<0.01). In the low-dose Caffeic acid group, cell injury remains pronounced with a pyknosis ratio of 63.6±2.8%, while in the high-dose group, hippocampal neuron pyknosis significantly decreases, showing a pyknosis ratio of 13.3±3.0%^[2].

Caffeic acid exhibits inhibitory effects on histamine-induced reactions, with its suppressive impact progressively intensifying at concentrations ranging from 0.1 to 1 mM, indicative of a typical dose-dependent response. In HEK293T-TRPV1 cells, a 1 mM pre-incubation with Caffeic acid significantly curtails capsaicin-triggered responses, whereas at lower concentrations, this inhibitory effect on capsaicin-induced reactions is less pronounced. Calcium imaging experiments reveal that Caffeic acid treatment notably reduces activity in histamine-sensitive dorsal root ganglion (DRG) neurons. With a 1 mM Caffeic acid pretreatment, there is a substantial reduction in the proportion of DRG neurons responsive to histamine, decreasing from 12.5% to 2.1%. Additionally, a 1 mM concentration of Caffeic acid effectively obstructs the intracellular calcium increase induced by allylisothiocyanate (AITC) in TRPA1-expressing cells, also preventing AITC-induced TRPA1 activation^[1].