Becker Kathrin, Geisler Simon, Ueberall Florian, Fuchs Dietmar, Gostner Johanna M
Division of Biological Chemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria.
Division of Medical Biochemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria.
Front Pharmacol. 2013 Dec 12;4:154. doi: 10.3389/fphar.2013.00154.
Anti-inflammatory properties of cacao, fruits of Theobroma cacao L. (Sterculiaceae), are well documented, and therapeutic applications are described for gastrointestinal, nervous, and cardiovascular abnormalities. Most, if not all of these disease conditions involve inflammation or immune activation processes. The pro-inflammatory cytokine interferon-γ (IFN-γ) and related biochemical pathways like tryptophan breakdown by indoleamine 2,3-dioxygenase (IDO) and neopterin formation are deeply involved in their pathogenesis. Neopterin concentrations and the kynurenine to tryptophan ratio (Kyn/Trp, an estimate of IDO activity) are elevated in a significant proportion of patients with virus infections, cancer, autoimmune syndrome, neurodegeneration, and coronary artery disease. Moreover, higher neopterin and Kyn/Trp concentrations are indicative for poor prognosis. When investigating the effect of aqueous or ethanolic extracts of cacao on IFN-γ, neopterin and Kyn/Trp concentrations in mitogen-stimulated human peripheral blood mononuclear cells, breakdown of tryptophan by IDO, and formation of neopterin and IFN-γ were dose-dependently suppressed. The effects observed in the cell-based assays are associated with the antioxidant activity of the cacao extracts as determined by the cell-free oxygen radical absorption capacity assay. The influence of cacao extracts on IDO activity could be of particular relevance for some of the beneficial health effects ascribed to cacao: tryptophan breakdown by IDO is strongly involved in immunoregulation, and the diminished availability of tryptophan limits the biosynthesis of neurotransmitter serotonin. The inhibition of tryptophan breakdown by cacao constituents could thus be relevant not only for immune system restoration in patients, but also contribute to mood elevation and thereby improve quality of life. However, the available data thus far are merely in vitro only and future studies need to investigate the influence of cacao on tryptophan metabolism in vivo.
可可（Theobroma cacao L.，梧桐科）果实的抗炎特性已有充分记载，其在胃肠道、神经和心血管异常方面的治疗应用也有相关描述。这些疾病状况中的大多数（即便不是全部）都涉及炎症或免疫激活过程。促炎细胞因子干扰素-γ（IFN-γ）以及相关生化途径，如吲哚胺2,3-双加氧酶（IDO）介导的色氨酸分解和新蝶呤形成，在其发病机制中起着重要作用。在相当一部分病毒感染、癌症、自身免疫综合征、神经退行性疾病和冠状动脉疾病患者中，新蝶呤浓度以及犬尿氨酸与色氨酸的比率（Kyn/Trp，IDO活性的一种估计）会升高。此外，较高的新蝶呤和Kyn/Trp浓度预示着预后不良。在研究可可水提取物或乙醇提取物对丝裂原刺激的人外周血单核细胞中IFN-γ、新蝶呤和Kyn/Trp浓度的影响时，IDO介导的色氨酸分解以及新蝶呤和IFN-γ的形成受到剂量依赖性抑制。基于细胞的实验中观察到的这些效应与通过无细胞氧自由基吸收能力测定法所确定的可可提取物的抗氧化活性相关。可可提取物对IDO活性的影响可能与归因于可可的一些有益健康效应特别相关：IDO介导的色氨酸分解在免疫调节中起着重要作用，色氨酸可用性的降低会限制神经递质血清素的生物合成。因此，可可成分对色氨酸分解的抑制不仅可能与患者免疫系统的恢复有关，还可能有助于改善情绪，从而提高生活质量。然而，目前可用的数据仅来自体外实验，未来的研究需要调查可可对体内色氨酸代谢的影响。
