Encapsulation of Aloe vera leaf skin extract in solid lipid nanoparticles and liposomes: cytotoxic assessment in HepG2 cells

Aloe vera L. is well known for its soothing and wound-healing effects, yet its leaf skin also contains bioactive compounds such as aloin derivatives and aloe-emodin, which have been associated with anticancer activity. In this study, A. vera leaf skin extract (AvE) was prepared using ultrasonic-assisted extraction and evaluated for cytotoxicity against HepG2 liver cancer cells using the MTT assay. The crude extract demonstrated an IC₅₀ value of 144.17 µg/mL after 48 h of treatment. To improve cytotoxicity and address solubility and stability concerns, the extract was loaded into two nanocarrier systems: solid lipid nanoparticles (SLNs) and liposomes. The SLNs showed a mean particle size of 86.6 ± 2.6 nm and an IC₅₀ of 105.88 ± 2.38 µg/mL, while liposomes exhibited a larger particle size of 185.2 ± 14.4 nm with a lower IC₅₀ of 94.58 ± 6.22 µg/mL. The encapsulation efficiency (EE%) of SLNs reached 92.6% for aloin and 97.1% for aloe-emodin, while the corresponding values for liposomes were 74.2% and 79.0%, respectively. Marker-specific drug loading was also determined based on the quantified content of these compounds in the extract. Characterization by dynamic light scattering (DLS), zeta potential, and FE-SEM confirmed the nanoscale size, surface charge, and spherical morphology of the formulations, while long-term stability assessment demonstrated their physical stability during storage. Moreover, total phenolic and flavonoid analyses indicated that sonication and encapsulation retained the major phytochemical constituents. Overall, both SLNs and liposomes enhanced the cytotoxic effect of AvE on HepG2 cells, with liposomes showing a numerically lower IC₅₀ than SLNs, although the difference was not statistically significant ( p > 0.05). These findings demonstrate that lipid-based nanocarriers enhanced the in vitro cytotoxic activity of AvE against HepG2 cells and provide a promising platform for further investigation.