Development of djenkol peel extract-loaded liposome as functional food ingredients: Physicochemical characteristic, antioxidant activities, and cytotoxicity

Djenkol peel is an agricultural by-product containing valuable bioactive compounds. The direct use of its extract faces challenges related to stability and sensory acceptance. This study aimed to investigate the effect of djenkol peel extract (DPE) on the encapsulation efficiency (EE) using liposomes. The physicochemical properties, antioxidant activities, and cytotoxicity of the obtained liposomes were evaluated. DPE (0, 0.25, 0.50, 0.75, and 1.00 %, w/v) was encapsulated using phospholipid/cholesterol as the wall material. The highest EE (66.69 %) was observed in the liposomes loaded with 0.25 % (w/v) DPE (LE-0.25DPE) (P < 0.05). All DPE-loaded liposomes displayed nanometer-scale particle sizes (78.94–135.60 nm) and negative zeta potentials (−52.60 to −57.50 mV). Encapsulation of DPE in liposomes can mask its undesirable color. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) revealed changes in the physicochemical and thermal properties of LE-0.25DPE. Additionally, LE-0.25DPE showed increased DPPH radical-scavenging activity (DPPH-RSA) and ferric reducing antioxidant power (FRAP) in a dose-dependent manner (250–2000 μg/mL). In vitro Caco-2 cell viability test, LE-0.25DPE at 0.1–1 μg/mL exhibited no cytotoxicity compared to the control (P < 0.05). Thus, DPE-loaded liposomes demonstrate potential as a functional food ingredient with high bioactivity.