Integrated Valorisation of Spartium junceum into a Bioactive Cellulose Acetate/Halloysite Nanofibrous Wound Dressing with Sustained Antioxidant Availability and Enhanced Fibroblast Migration

An integrated cascade-valorisation strategy was developed to convert Spartium junceum (Spanish broom) flower biomass into a cellulose acetate/halloysite nanotube (CA/HNT) nanofibrous wound-dressing platform. Volatile constituents were first recovered by steam distillation, and the residual aqueous phase was then partitioned sequentially with hexane and chloroform; the exhausted lignocellulosic biomass was subsequently converted to cellulose and then to cellulose acetate. The synthesised cellulose acetate had a degree of substitution of 2.66 ± 0.04 (n = 3). GC–MS identified chemically distinct major constituents in each fraction, with linoleic acid methyl ester (51.02%) dominant in the hexane fraction and 1,4-benzenedicarboxylic acid dimethyl ester (29.37%) and palmitic acid methyl ester (25.10%) dominant in the chloroform fraction. A 12% (w/v) CA formulation containing 3 wt% extract-loaded HNT produced homogeneous, bead-free nanofibers with diameters of approximately 130–200 nm (mean ≈ 173 nm, measured from SEM micrographs). FTIR, XRD, and DSC confirmed successful acetylation and formation of the composite nanofibrous matrix. The dressing showed balanced water-management behaviour, was non-cytotoxic to L929 fibroblasts by ISO 10993-5, and increased scratch closure to 97.2% at 48 h versus 64.8% for untreated controls. CUPRAC measurements showed antioxidant activity in the release medium for up to 48 h, peaking at 0.055 mM Trolox equivalents at 2 h. Together, these findings demonstrate the feasibility of coupling renewable cellulose-acetate production with phytochemical recovery and nanofiber fabrication in a single biomass-valorisation platform.