Nadegger Christian, Frei Patricia, Elvert Christian A, Karg Cornelia A, Gostner Johanna M, Lindsey Jonathan S, Kreutz Christoph R, Schwaiger Stefan, Müller Thomas, Moser Simone
Institute of Organic Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
Center for Molecular Biosciences, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
J Agric Food Chem. 2025 Jul 16;73(28):17637-17645. doi: 10.1021/acs.jafc.5c03549. Epub 2025 Jul 7.
Hops is of high relevance to the food sector, and increasingly valued as medicinal plant. Its complex phytochemistry includes phenolic compounds and bitter prenylated polyketides, but phyllobilins─bioactive linear tetrapyrroles from chlorophyll catabolism─remain underexplored. In this work, several dioxobilin-type phylloleucobilins (DPleBs) and phylloxanthobilins (DPxBs) were identified in yellowish leaves of common hops (). Isolation from 107 g of leaves yielded 0.24 mg of -DPleB-28 and 0.80 mg of -DPxB-31. Structural elucidation via UV/vis, HR-MS, and NMR confirmed those as new phyllobilins, featuring an unusual hydroxylation motif, indicating an uncharacterized metabolic pathway. -DPxB constituted about 40% of HPLC peak areas at 420 nm in yellow leaves, suggesting its significant role in the visual senescence of hops. -DPxB-31 possessed high antioxidative activity, comparable to quercetin. A virtual tool predicted over 60% bitterness probability. These findings expand the phytochemical profile of hops and highlight potential for upcycling leaf waste.
啤酒花与食品行业高度相关，并且越来越被视为药用植物。其复杂的植物化学物质包括酚类化合物和苦味的异戊烯基化聚酮化合物，但叶胆素（来自叶绿素分解代谢的生物活性线性四吡咯）仍未得到充分研究。在这项工作中，在啤酒花的淡黄色叶子中鉴定出了几种二氧胆素型叶亮胆素（DPleBs）和叶黄胆素（DPxBs）。从107克叶子中分离得到0.24毫克的 -DPleB-28和0.80毫克的 -DPxB-31。通过紫外/可见光谱、高分辨质谱和核磁共振进行的结构解析证实这些是新的叶胆素，具有不寻常的羟基化基序，表明存在一条未被表征的代谢途径。在黄叶中，-DPxB在420纳米处约占高效液相色谱峰面积的40%，表明其在啤酒花视觉衰老中起重要作用。-DPxB-31具有较高的抗氧化活性，与槲皮素相当。一个虚拟工具预测其苦味概率超过60%。这些发现扩展了啤酒花的植物化学特征，并突出了将叶废料升级利用的潜力。
