Abstract
Thymoquinone (TQ), obtained from black cumin (Nigella sativa), is a natural product with antioxidant, anti-inflammatory, and hepatoprotective effects but unfortunately with poor bioavailability. Aiming to improve its poor oral bioavailability, TQ-loaded nanostructured lipid carriers (NLCs) were prepared by high-speed homogenization followed by ultrasonication and evaluated in vitro. Bioavailability and pharmacodynamic studies were also performed. The resultant NLCs showed poor physical homogeneity in Compritol 888 ATO Pluronic F127 system which consequently produced larger particle size and polydispersity index, smaller zeta potential values, and lower short-term (30 days) physical stability than other systems. Encapsulation efficiency percentage (EE%) lied between 84.6 +/- 5% and 96.2 +/- 1.6%. TQ AUC(0-t) values were higher in animals treated with NLCs, with a relative bioavailability of 2.03- and 3.97-fold (for F9 and F12, respectively) higher than TQ suspension, indicating bioavailability enhancement by NLC formulation. Hepatoprotective effects of F12 showed significant (P<0.05) decrease in both serum alanine amino transferase and aspartate amino transferase to reach 305.0 +/- 24.88 and 304.7 +/- 23.55 U/ml, respectively, when compared with untreated toxic group. Anti-oxidant efficacy of F12 showed significant (P<0.05) decline of malondialdehyde and elevation of reduced glutatione. This improvement was also confirmed histopathologically.