Identification, antioxidant and acetylcholinesterase inhibitory activities of soluble and insoluble-bioactive components from Cinnamomum camphora seed kernel residue.

Cinnamomum camphora seed kernel (CCSK) is a rich source of phytochemicals (e.g., phenolic compounds and alkaloids), but has not been comprehensively explored yet. In this study, both the SBC and IBC were prepared for the first time from the solid fraction obtained during the aqueous extraction of CCSK oil, and their composition, antioxidant activity, and acetylcholinesterase (AChE) inhibitory capacity were investigated. The SBC was extracted directly by 80 % ethanol aqueous solution; the IBC extraction conditions were optimized to yield the following parameters: cellulase to acidic protease ratio of 2:1 (w/w), extraction temperature of 60 °C, enzyme dosage of 940 U/g, extraction time of 4 h, liquid-to-solid ratio of 43 mL/g, and pH value of 5.0. Under the optimized conditions, the TPC and lindoldhamine yield in the IBC were determined to be 142.39 ± 5.30 mg GAE/10 g dw and 240.78 ± 1.91 mg/10 g dw, respectively. A total of 21 phenolic compounds and 16 alkaloids were identified in the SBC, while 14 phenolic compounds and 14 alkaloids were identified in the IBC by HPLC-ESI-QTOF-MS2. Furthermore, the IBC exhibited significantly stronger antioxidant activities and AChE inhibitory capacity than SBC, attributing to its higher lindoldhamine content. These findings highlight the considerable potential of SBC and IBC for application in antioxidant formulations and the prevention of Alzheimer's disease.