Valorization of <scp> <i>Zingiber officinale</i> </scp> Roscoe leaf biomass: phytotoxic potential and chemical profiling toward sustainable weed management

BACKGROUND: Zingiber officinale Roscoe is widely cultivated as a spice and functional food, generating substantial amounts of aerial biomass that is commonly discarded after harvest. Within a circular-economy framework, this study investigated the phytotoxic potential of Z. officinale leaf biomass and its relevance for sustainable agricultural systems. RESULTS: Leaf powder and aqueous extracts were evaluated under pre- and post-emergence conditions using selected weed species [Echinochloa oryzoides (Ard.) Fritsch, Lolium multiflorum Lam., Sinapis alba L. and Trifolium incarnatum L.] and Oryza sativa L. as a reference crop. Both matrices exerted significant inhibitory effects on seed germination and early seedling development, with marked differences in species sensitivity and lower susceptibility of the crop species across filter paper and soil substrates. Post-emergence assays further confirmed species-dependent responses. Chemical profiling by solid-phase microextraction-gas chromatography/mass spectrometry revealed a volatile fraction dominated by sesquiterpenes, mainly β-caryophyllene, whereas ultra-performance liquid chromatography-high-resolution mass spectrometry and NMR analyses identified C-glycosylated flavones, primarily apigenin derivatives, in the aqueous extract. CONCLUSION: These findings highlight Z. officinale leaves as a promising biologically active by-product for low-impact weed management strategies and agricultural residue valorization. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.