Knockdown of CPT1A influenced the lipid-lowering effect of Ginkgo biloba extract (GBE) and its ingredients in HepG2 cells. (A) CPT1A expression regulated by GBE and its flavonoids in NC- and shRNA- cells. The mRNA expression of CPT1A was normalized to β-actin. **P < 0.01 versus DMSO treatment in NC group. (B) CPT1A protein expression in NC- and shRNA- cells. Vectors without influence on the expression of CPT1A were negative controls (NC). (C) Cellular triglyceride content regulated by GBE and its flavonoids in NC- and shRNA- cells. The cellular triglyceride content in NC group with DMSO treatment was set at 100%, and values in other groups were compared to it. *P < 0.05 versus DMSO treatment in NC group. #P < 0.05 versus DMSO treatment in shRNA group. D, G200, Q20, K20, I8 represented HepG2 cells incubated with 0.1% DMSO, 200 μg/ml GBE, 20 μg/ml quercetin, 20 μg/ml kaempferol, and 8 μg/ml isorhamnetin, respectively.