TY - JOUR
T1 - Molecular docking and enzyme kinetic studies of dihydrotanshinone on metabolism of a model CYP2D6 probe substrate in human liver microsomes
AU - Zhou, Xuelin
AU - Wang, Yan
AU - Or, Penelope M Y
AU - Wan, David C C
AU - Kwan, Yiu Wa
AU - Yeung, John H K
PY - 2012/5/15
Y1 - 2012/5/15
N2 - The effects of Danshen and its active components (tanshinone I, tanshinone IIA, dihydrotanshinone and cryptotanshinone) on CYP2D6 activity was investigated by measuring the metabolism of a model CYP2D6 probe substrate, dextromethorphan to dextrorphan in human pooled liver microsomes. The ethanolic extract of crude Danshen (6.25-100 μg/ml) decreased dextromethorphan O-demethylation in vitro (IC 50 = 23.3 μg/ml) and the water extract of crude Danshen (0.0625-1 mg/ml) showed no inhibition. A commercially available Danshen pill (31.25-500 μg/ml) also decreased CYP2D6 activity (IC 50 = 265.8 μg/ml). Among the tanshinones, only dihydrotanshinone significantly inhibited CYP2D6 activity (IC 50 = 35.4 μM), compared to quinidine, a specific CYP2D6 inhibitor (IC 50 = 0.9 μM). Crytotanshinone, tanshinone I and tanshinone IIA produced weak inhibition, with IC 20 of 40.8 μM, 16.5 μM and 61.4 μM, respectively. Water soluble components such as salvianolic acid B and danshensu did not affect CYP2D6-mediated metabolism. Enzyme kinetics studies showed that inhibition of CYP2D6 activity by the ethanolic extract of crude Danshen and dihydrotanshinone was concentration-dependent, with K i values of 4.23 μg/ml and 2.53 μM, respectively, compared to quinidine, K i = 0.41 μM. Molecular docking study confirmed that dihydrotanshinone and tanshinone I interacted with the Phe120 amino acid residue in the active cavity of CYP2D6 through Pi-Pi interaction, but did not interact with Glu216 and Asp301, the key residues for substrate binding. The logarithm of free binding energy of dihydrotanshinone (-7.6 kcal/mol) to Phe120 was comparable to quinidine (-7.0 kcal/mol) but greater than tanshinone I (-5.4 kcal/mol), indicating dihydrotanshinone has similar affinity to quinidine in binding to the catalytic site on CYP2D6.
AB - The effects of Danshen and its active components (tanshinone I, tanshinone IIA, dihydrotanshinone and cryptotanshinone) on CYP2D6 activity was investigated by measuring the metabolism of a model CYP2D6 probe substrate, dextromethorphan to dextrorphan in human pooled liver microsomes. The ethanolic extract of crude Danshen (6.25-100 μg/ml) decreased dextromethorphan O-demethylation in vitro (IC 50 = 23.3 μg/ml) and the water extract of crude Danshen (0.0625-1 mg/ml) showed no inhibition. A commercially available Danshen pill (31.25-500 μg/ml) also decreased CYP2D6 activity (IC 50 = 265.8 μg/ml). Among the tanshinones, only dihydrotanshinone significantly inhibited CYP2D6 activity (IC 50 = 35.4 μM), compared to quinidine, a specific CYP2D6 inhibitor (IC 50 = 0.9 μM). Crytotanshinone, tanshinone I and tanshinone IIA produced weak inhibition, with IC 20 of 40.8 μM, 16.5 μM and 61.4 μM, respectively. Water soluble components such as salvianolic acid B and danshensu did not affect CYP2D6-mediated metabolism. Enzyme kinetics studies showed that inhibition of CYP2D6 activity by the ethanolic extract of crude Danshen and dihydrotanshinone was concentration-dependent, with K i values of 4.23 μg/ml and 2.53 μM, respectively, compared to quinidine, K i = 0.41 μM. Molecular docking study confirmed that dihydrotanshinone and tanshinone I interacted with the Phe120 amino acid residue in the active cavity of CYP2D6 through Pi-Pi interaction, but did not interact with Glu216 and Asp301, the key residues for substrate binding. The logarithm of free binding energy of dihydrotanshinone (-7.6 kcal/mol) to Phe120 was comparable to quinidine (-7.0 kcal/mol) but greater than tanshinone I (-5.4 kcal/mol), indicating dihydrotanshinone has similar affinity to quinidine in binding to the catalytic site on CYP2D6.
KW - CYP2D6 activity
KW - Danshen (Salvia miltiorrhiza)
KW - Dextromethorphan metabolism
KW - Dihydrotanshinone
KW - Human liver microsomes
KW - Molecular docking
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UR - http://www.scopus.com/inward/citedby.url?scp=84860638612&partnerID=8YFLogxK
U2 - 10.1016/j.phymed.2012.01.005
DO - 10.1016/j.phymed.2012.01.005
M3 - Article
C2 - 22541637
AN - SCOPUS:84860638612
VL - 19
SP - 648
EP - 657
JO - Phytomedicine
JF - Phytomedicine
SN - 0944-7113
IS - 7
ER -