Chitosan-based biocomposites enriched with Alstonia boonei stem bark extract exhibit potent immunostimulatory effects in rodent models

Abstract

This study aimed to develop a chitosan-based biocomposite containing Alstonia boonei extract and evaluate its immunostimulatory activity in dexamethasone-induced immunosuppressed rats. Methanol/dichloromethane stem bark extracts were combined to chitosan by ionic gelation using tripolyphosphate as cross-linker. The biocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Entrapment efficiency and acute oral toxicity at 2000 mg/kg were also assessed. Immunomodulatory activity was evaluated following oral administration of 100-500 mg/kg in immunosuppressed rats through delayed-type hypersensitivity and humoral immune response assays. FTIR confirmed successful incorporation of phytochemicals into the chitosan matrix, with an entrapment efficiency of 69%. Structural analyses demonstrated homogeneous and stable biocomposites, while toxicity studies revealed no adverse effects. The formulations significantly reversed dexamethasone-induced immunosuppression in a dose-dependent manner, indicating promising immunostimulatory potential and safety for immune-related therapeutic applications.