Fig. 7

Assays of CYP17A1 activity. (a) Representative TLCs illustrating the effect of various treatments on CYP17A1 hydroxylase activity in NCI-H295R cells. Human adrenal NCI-H295R cells were treated with polymer, DMSO, ethanol, abiraterone, abiraterone nanoparticles (ABN), curcumin, piperine (Pip), piperine nanoparticles (PN), curcumin nanoparticles (CN), and curcumin piperine nanoparticles (CPN). Subsequently, cells were incubated with C-14 labelled progesterone, a substrate for CYP17A1-17α-hydroxylase activity. Steroids were then extracted using organic solvents, dried under nitrogen, and separated by TLC. The radioactivity of the steroids was visualized using autoradiography on a phosphorimager and quantitated by densitometric analysis. (b) Curcuminoids inhibited the formation of 17α-hydroxy progesterone in NCI-H295R cells, indicating that Cur & Pip caused significant inhibition of the 17α-hydroxylase. (c) Differential inhibition of various treatments on CYP17A1 17,20 lyase activity. Cells were treated with tritium-labelled 17α-hydroxy pregnenolone, and the tritiated by-product (acetate) was measured using a scintillation counter after DHEA formed in the reaction was precipitated in a charcoal–dextran solution. Ethanol, phosphate buffer-polymer, and DMSO were used as controls at 0.1% of the total reaction volume. (d) Shows the CYP17A1 17α-hydroxylase IC₅₀ curve for the curcumin nanoparticles in NCI-H295R Cells. The statistical analysis was performed using Tukey’s multiple comparisons test. Significant differences are indicated as follows: p < 0.01 (**),p < 0.001 (***), and p < 0.0001 (****), ns, not significant.