Valorization of residual biomass from essential oil extraction of Ammodaucus leucotrichus: A step towards sustainable cosmetic and pharmaceutical applications

Residual biomass from essential oil extraction is an underutilized resource that can contribute to the circular bioeconomy by recovering valuable bioactive compounds. This study investigates the impact of three extraction methods—Water Distillation (WD), Steam Distillation (SD), and Microwave-Assisted Extraction (MAE)—on the composition and bioactivity of residual biomass from Ammodaucus leucotrichus. The goal is to assess how different methods can support sustainable applications, such as cosmetics, within the circular bioeconomy framework. HPLC analysis revealed that MAE selectively extracted high concentrations of Nobiletin (78.74 mg/g), while WD preserved Neohesperidin (99.91 mg/g). Antioxidant activity, measured by DPPH, FRAP, and ABTS assays, was highest in MAE (DPPH: 80.01 %, FRAP: 87.36 %, ABTS: 82.99 %). Additionally, MAE extracts showed superior enzymatic inhibition, with high activity against tyrosinase (85 %), collagenase (85.71 %), and hyaluronidase (74.93 %), demonstrating their potential for sustainable, anti-aging cosmetic applications. These findings underline the importance of biomass valorization in the circular bioeconomy, where waste-to-value conversion supports sustainable development and climate change mitigation. Cytotoxicity tests on human dermal fibroblasts (HDFa) revealed minimal toxicity for MAE-treated biomass, coupled with significant reductions in reactive oxygen species (ROS) and enhanced collagen and hyaluronic acid production. Principal Component Analysis (PCA) illustrated distinct chemical and biological profiles for each extraction method, with MAE selectively enriching compounds beneficial for skin rejuvenation. These findings highlight the potential of residual biomass in the circular bioeconomy, where waste-to-value conversion supports sustainable development and climate change mitigation.