Abstract
Capsaicin (CAP) and dihydrocapsaicin (DIH) are the main pungent components of capsaicinoids, which account for about 90% of the pungent ingredient in capsicum. These components are known to change immune responses by inducing adrenal hormones, neuropeptides and cytokines. However, the effects of capsaicinoids on the number of immune cells are still unknown. Therefore, the effects of CAP and DIH on the numbers of total white blood cells (WBCs), neutrophil, lymphocytes, monocyte, eosinophil and basophil were studied. The effects of DIH on the numbers of T-lymphocyte, B-lymphocyte and natural killer (NK) cells were also examined. Adult male SD rats were divided into three (CAP, DIH and the control (CON)) groups. CAP and DIH (each dose = 3.0 mg/kg BW) were administered via sc injection. The numbers of total WBCs in CAP and DIH were significantly higher than that in CON. The number of neutrophil in DIH was higher than those in CAP and CON. The numbers of lymphocytes in CAP and DIH were significantly lower than that in CON. The number of B-lymphocyte in DIH markedly decreased. However, the numbers of T-lymphocyte and NK cells were not changed. The numbers of monocyte, eosinophil and basophil showed no significant changes among three groups. In conclusion, the administration of CAP and DIH decreased the numbers of lymphocytes and B-lymphocyte, and increased the numbers of total WBCs and neutrophil without changing the numbers of monocyte, eosinophil and basophil. [J Physiol Sci. 2008;58 Suppl:S103]
