BB	Berberine
OPCs	Oligomeric proanthocyanidins
SD mice	Sprague Dawley mice
LC–MS/MS	Liquid chromatography–tandem mass spectrometry
P-gp	P-glycoprotein
R123	Rhodamine-123
DM	Diabetes mellitus
T2DM	Type 2 diabetes mellitus
TCM	Traditional Chinese medicine
JTW	Jiaotaiwan
ACC	Acetyl coenzyme A carboxylase
AMPK	AMP-activated protein kinase
GLUT4	Glucose transporter 4
FBG	Fasting blood glucose
OGTT	Oral glucose tolerance test
IPTT	Intraperitoneal insulin tolerance test
TG	Total triglyceride
TC	Total cholesterol
ALT	Alanine transaminase
AST	Aspartate transaminase
AUC	Area under the curve
MTT	Methylthiazolyldiphenyl-tetrazolium bromide
DMEM	Dulbecco’s modified Eagle medium
HBSS	Hank’s balanced salt solution
HPLC	High-performance liquid chromatography
UPLC	Ultrahigh performance liquid chromatograph
ESI	Electrospray ionization
THP	Tetrahydropalmatine
TL	Tube lens voltage
CE	Collision energies
DP	Declustering potential
CEP	Cell exit potential
BL	Basolateral
AP	Apical
ACTB	β-Actin
BCA	Bicinchoninic acid