Acanthus ebracteatus Vahl. extract-loaded cellulose acetate ultrafine fibers as a topical carrier for controlled-release applications

Acanthus ebracteatus Vahl., also known as sea holly, is a traditional Thai herb used to treat skin diseases. To treat the diseases, the patients are required to take a bath with water boiled with the whole sea holly plants regularly. This makes travel inconvenient for the patients. To solve this problem, a controlled-release system for sea holly extract is required. In this work, the extract of A. ebracteatus Vahl. (5 % w/v) was loaded into electrospun cellulose acetate (CA, 12 % w/v, MW ~3 × 104 g/mol) fibers (460 ± 84 nm). The homogenous fibers were obtained using an applied voltage and fiber collection distance of 12.5 kV and 10 cm, respectively. Fourier transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry revealed that the extract was uniformly dispersed in the CA domains. ~99 % of the loaded extract in the fibers was released in the acetate buffer at 37 °C via a diffusion mechanism, while only ~35 % of it could be done from the corresponding cast films. The 2,2-diphenyl-1-picrylhydrazyl (DPPH·) scavenging assay confirmed an antioxidant activity of the loaded fibers. The incorporation of the extract into the fibers could greatly reduce the cytotoxicity of the extract, and the MTT assay at 37 °C indicated ~52 % of L-929 mouse fibroblast cell viability.