Danshen, a well-known traditional Chinese medicine (TCM), has gained increasing
attention due to the protective effects on nonalcoholic fatty liver disease (NAFLD). However, the
molecular basis and working mechanism remain to be elucidated. Niemann-Pick C1-like 1 (NPC1L1)
is the crucial target mediating intestinal cholesterol absorption and its inactivation has been shown
to alleviate NAFLD. Thus, this study aimed to screen NPC1L1 inhibitors in Danshen and investigate
the therapeutic effects on NAFLD. A high-throughput screening platform based on the stable Caco2
cell lines expressing human-NPC1L1 (hL1-Caco2) was developed, and we found that tanshinones
(Tans), the liposoluble components in Danshen, inhibited NPC1L1-mediated cholesterol absorption
in hL1-Caco2 cells. The hepatic steatosis in high-fat diet (HFD)-fed mice was also reduced by Tans
treatment. To find the active compounds in Tans, activity-oriented separation was performed by
combining the high-throughput screening platform and two-dimensional chromatographic
techniques. Ultimately, cryptotanshinone (CTS) was identified as a novel NPC1L1 inhibitor and
profoundly decreased hepatic steatosis in HFD-fed mice. The binding modes and stability between
CTS and NPC1L1 were confirmed by molecular docking and dynamics simulation. Taken together,
our findings demonstrate for the first time that CTS, the liposoluble compound in Danshen, alleviates
NAFLD by inhibiting NPC1L1-mediated intestinal cholesterol absorption, suggesting that inhibition
of NPC1L1 with CTS may be a potential strategy for the treatment of NAFLD.
