The fate of chlorophyll in hops: Profiling phyllobilins in senescent leaves of Humulus lupulus L.

Hops ( Humulus lupulus L., Cannabaceae) have long been valued for their role in brewing and traditional medicine, primarily due to their content of bitter acids and volatile compounds [ 1 ] [ 2 ]. Large portions of hop biomass, however, particularly senescent leaves, remain underutilized despite their potential as sources of phytochemicals. This study aimed to investigate bilin-type chlorophyll metabolites — phyllobilins (PBs) — in hop leaves. PBs are increasingly recognized as bioactive molecules with antioxidant, anti-inflammatory, and anti-cancer properties [ 3 ]. In our study, we profiled senescent hop leaves using chromatographic and spectroscopic techniques, revealing the presence of diverse PBs including dioxobilin-type phylloleucobilins (DPleBs) and phylloxanthobilins (DPxBs). DPxBs are yellow pigments, which we show to contribute to the coloration of hop leaves in autumn. The identified DPleBs and DPxBs from hops displayed a characteristic structural feature that could hint towards a diversified chlorophyll catabolism. Our findings suggest that hop leaves, typically discarded post-harvest, constitute a promising and sustainable source of bioactive PBs. This work expands the phytochemical profile of H. lupulus and underscores its potential for nutraceutical and phytotherapeutic applications beyond traditional uses. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany