 Vaccination was associated with significant reductions in total cholesterol, free cholesterol, phospholipids, and triglycerides.The plant alkaloid berberine inhibits the transcription of the PCSK9 gene in immortalized human hepatocytes "in vitro," and lowers serum PCSK9 in mice and hamsters "in vivo".It has been speculated that this action contributes to the ability of berberine to lower serum cholesterol.