Humulus lupulus L. and its potential application in dermocosmetics

Humulus lupulus L . is traditionally exploited for brewing, however, its vegetative tissues and industrial residues remain largely underexplored. This study provides the first comprehensive and integrated comparison of cones, leaves, stems, seeds, bracts, and brewery by-products from three commercial cultivars (Nugget, Cascade, Chinook) and spontaneous wild hops collected in northeast Portugal, targeting their suitability as multifunctional dermocosmetic ingredients. Hydromethanolic extracts were characterised by UV–Vis and HPLC-DAD, revealing abundant flavonols/flavones, with isoquercetin reaching 6.14 g kg⁻¹ dry weight in Chinook cones. The amino acid profile of asparagine dominated the profile of all cone extracts, reaching 366 mg kg⁻¹ of dry weight in Cascade. Photoprotective evaluation demonstrated SPF values up to 19.83. Enzyme inhibition assays revealed marked anti-ageing potential, with elastase inhibition reaching 100%. The cone showed remarkable antibacterial activity against Cutibacterium acnes (MIC ≤ 250 µg mL⁻¹). Extracts also reduced nitric oxide production in LPS/IFN-γ-stimulated RAW 264.7 macrophages (IC₅₀ down to 9.66 µg mL⁻¹), indicating modulation of a key pro-inflammatory mediator. HaCaT keratinocyte and HFF-1 fibroblasts maintained ≥ 90% viability at concentrations up to 1 mg mL⁻¹. Collectively, these results demonstrate that not only hop cones but also vegetative parts and industrial by-products represent sustainable and safe sources of bioactive compounds with antimicrobial, photoprotective, enzyme-inhibitory, nitric oxide-modulating activities and cytotoxicity. The valorisation of such materials aligns with circular-economy principles and offers a feasible pathway for the development of plant-based actives in next generation skincare formulations.