Encapsulation of ethanolic mangosteen ( <i>Garcinia mangostana</i> L.) rind extract in solid lipid nanoparticles (SLNs) based on palm stearin: study the effect of lipid composition and extract concentration on physicochemical properties

Mangosteen (Garcinia mangostana L.) rind is a source of antioxidants derived from its bioactive compounds, primarily phenolic, flavonoids, and xanthones, but are unstable and have a bitter taste. Nanoencapsulation by solid lipid nanoparticles (SLNs) improved the stability and effectiveness as a delivery system. This study aimed to obtain SLN-mangosteen rind extract with the best entrapment efficiency and physicochemical properties by modifying the lipid composition using palm stearin and monoacylglycerol (MAG) and diacylglycerol (DAG)-rich fats and extract concentration. The results showed that MAG-DAG-rich fat improved the entrapment efficiency and physicochemical properties. Furthermore, SLN-mangosteen rind extract, using MAG DAG-rich fat of (40%) and mangosteen rind (15%), produced the best characteristics with an entrapment efficiency, loading capacity, z-average, and polydispersity index of 94.25 ± 0.74%, 0.02%, 235.6 nm, and 0.787, respectively. SLN-mangosteen rind extract was spherical and had an amorphous structure. This extract also had a total phenolic content, flavonoids, and antioxidant activity (IC50) of 14.46 mg GAE/g, 2.25 mg QE/g, and 252.71 ppm, respectively. Consequently, the ethanolic extract of mangosteen rind was effectively encapsulated in the SLN based on palm stearin and MAG-DAG-rich fat from coconut stearin and had the potential to be a good delivery system.