title: Anti-allergic effect of the naturally-occurring conjugated linolenic acid isomer, jacaric acid, on the activated human mast cell line-1.
abstract: The present study aimed to investigate the immunomodulatory effect of jacaric acid, a naturally-occurring conjugated linolenic acid isomer that can be found in jacaranda seed oil, on the activated human mast cell line-1 (HMC-1). Our previous studies have demonstrated that jacaric acid only exerted minimal, if any, cytotoxicity on normal murine cells. In the present study, jacaric acid at concentrations ≤100 µM did not exhibit direct cytotoxicity on human peripheral blood mononuclear cells after 72 h of incubation, as determined by the MTT reduction assay. By contrast, jacaric acid could alleviate the calcium ionophore A23187 and phorbol 12-myristate 13-acetate-triggered allergic response in the HMC-1 cells at concentrations that were non-cytotoxic to the HMC-1 cells. Following pre-treatment with jacaric acid, the secretion of two inflammatory mediators, β-N-acetylglucosaminidase and tryptase, as well as the T helper 2 cytokines [interleukin (IL)-4 and IL-13] was significantly reduced in HMC-1 cells. The alleviation of allergic response was accompanied by downregulation of the matrix metalloproteinase-2 and -9 proteins and upregulation of the tissue inhibitor of metalloproteinase-1 protein. Collectively, the results indicated that the naturally-occurring jacaric acid exhibits a suppressive effect on the allergic response in activated human mast cellsin vitro, and this could not be attributed to the direct cytotoxicity of jacaric acid on the treated cells.
authors.affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors.forename: Wai Nam
authors.initials: WN
authors.lastname: Liu
authors.affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors.forename: Kwok Nam
authors.initials: KN
authors.lastname: Leung
keywords: anti-allergic effect; conjugated linolenic acids; interleukins; jacaric acid; mast cells; matrix metalloproteinases; tryptases; β-N-acetylglucosaminidase