Department of Molecular Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan.
Laboratory of Tumor Microenvironment and Metastasis, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA.
Molecules. 2022 Aug 25;27(17):5459. doi: 10.3390/molecules27175459.
Propolis, a resinous substance produced by honeybees, has been used in folk medicine since ancient times due to its many biological benefits such as antitumor, antioxidant, antimicrobial, anti-inflammatory, and immunomodulatory effects. Propolis contains flavonoids, terpenoids, aromatic aldehydes, and alcohols, which vary with different climate and environmental conditions. In our study, we examined the antiallergic activity of Brazilian green propolis (BGP) and isolated the active compound that can suppress an allergy-sensitive gene, IL-33, expression and eosinophilia. Ethanolic extract of BGP freeze-dried powder was fractionated with several solvent systems, and the active fractions were collected based on activity measurement. The single active compound was found by thin-layer chromatography. Using column chromatography and NMR, the active compound was isolated and identified as 3,5,7-trihydroxy-6,4'-dimethoxyflavone, also known as betuletol. Further, the antiallergic activity of that has been examined in PMA-induced up-regulation of IL-33 gene expression in Swiss 3T3 cells. Our data showed the IL-33 gene suppression both by BGP and the isolated active compound, betuletol. We also found that betuletol suppressed ERK phosphorylation, suggesting it could be effective in suppressing IL-33 mediated eosinophilic chronic inflammation and will provide new insights to develop potent therapeutics against allergic inflammations.
蜂胶是由蜜蜂产生的一种树脂状物质，由于其具有许多生物益处，如抗肿瘤、抗氧化、抗菌、抗炎和免疫调节作用，自古以来就在民间医学中得到应用。蜂胶含有黄酮类、萜类、芳香醛和醇类物质，其种类因不同的气候和环境条件而有所不同。在我们的研究中，我们检查了巴西绿蜂胶 (BGP) 的抗过敏活性，并分离出了可以抑制过敏敏感基因 IL-33 表达和嗜酸性粒细胞增多的活性化合物。BGP 冻干粉末的乙醇提取物用几种溶剂系统进行了分馏，并根据活性测量收集了活性馏分。通过薄层色谱发现了单一的活性化合物。通过柱层析和 NMR，分离并鉴定出该活性化合物为 3,5,7-三羟基-6,4'-二甲氧基黄酮，也称为 betuletol。此外，还在 PMA 诱导的瑞士 3T3 细胞中 IL-33 基因表达上调中检查了该化合物的抗过敏活性。我们的数据显示，BGP 和分离的活性化合物 betuletol 均能抑制 IL-33 基因的表达。我们还发现 betuletol 抑制了 ERK 磷酸化，表明它可能有效抑制 IL-33 介导的嗜酸性粒细胞慢性炎症，并将为开发针对过敏炎症的有效治疗方法提供新的见解。
