Salvianolic acid B as a substrate and weak catechol-O-methyltransferase inhibitor in rats

Extra virgin olive oil-based phospholipid complex/self-microemulsion enhances oral absorption of salvianolic acid B through inhibition of catechol-O-methyltransferase-mediated metabolism

The oral bioavailability of many phenolic acid drugs is severely limited due to the high hydrophilicity and extensive first-pass effect induced by catechol-O-methyltransferase (COMT) metabolism. The present study investigated the inhibitory activity of the pharmaceutical excipients of extra virgin olive oil (EVOO) against COMT and evaluated the potential of a self-microemulsion loaded with a phospholipid complex containing EVOO for oral absorption enhancement of salvianolic acid B (SAB), a model phenolic acid. In vitro COMT assay showed that EVOO could effectively inhibit enzyme activity in the rat liver cytosol. Next, the SAB phospholipid complex/self-microemulsion containing EVOO (named SP-SME1) was prepared and characterized (particle size, 243.60 ± 6.96 nm and zeta potential, -23.67 ± -1.36 mV). The phospholipid complex/self-microemulsion containing ethyl oleate (EO) (named SP-SME2) was taken as the control group. Compared with free SAB, the apparent permeability coefficient (P_app value) of the two SP-SMEs significantly increased (12.0-fold and 10.90-fold). Pharmacokinetic study demonstrated that the AUC_0-∞ value of SAB for the SP-SME1 group significantly increased by 4.72 and 2.82 times compared to those for free SAB (p < 0.001) and SP-SME2 (p < 0.01), respectively. Moreover, the AUC_0-∞ value of monomethyl-SAB (metabolite of SAB, MMS) for the SP-SME1 group decreased by 0.83 times compared to that for SP-SME2. In conclusion, the EVOO-based phospholipid complex/self-microemulsion greatly enhanced the oral absorption of SAB, which was mainly attributed to the inhibition of COMT activity induced by EVOO.

Drug-drug interactions between salvianolate injection and aspirin based on their metabolic enzymes

BACKGROUND

It is unclear whether the combination of traditional Chinese medicine and Western medicine leads to interactions in pharmacokinetics (PKs) and pharmacodynamics (PDs). In this study, the influence of salvianolate and aspirin on metabolic enzymes, and the relationship between the blood concentration and pharmacodynamic indexes, were determined.

METHOD

In this, randomized, parallel-grouped, single-center clinical trial, 18 patients with coronary heart disease were randomly allocated into three groups: aspirin (AP) group, salvianolate (SV) group, and combination (A + S) group. All treatment courses lasted for 10 days, and blood samples were acquired before and after administration at different timepoints. The expression of catechol-O-methyltransferase (COMT), CD62p, procaspase-activating compound 1 (PAC-1), P2Y12, phosphodiesterase, and mitogen-activated protein kinase 8 (MAPK8) were compared with variance analysis The blood concentrations were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

Sixteen subjects completed the study. No significant difference in COMT was found among groups, although there was a decrease in the SV group. The PK results indicated that the absorption time of salicylic acid was shortened and the AUC_0-∞ decreased and the elimination time of salvianolic acid B was prolonged and the AUC_0-∞ decreased. The PD results declined after administration. A significant difference was found in MAPK8, CD62p, and P2Y12 expression. Compared with the SV group, a significant difference in P2Y12 in the A + S group was found.

CONCLUSION

A pharmacokinetic drug-drug interaction was found in the aspirin and salvianolate combination. Pharmacodynamically, there was no difference between the A + S and AP groups. However, P2Y12 expression in the combination group was superior to that in the SV group.

TRIAL REGISTRATION NUMBERS

The trial was registered on October 9, 2017, ClinicalTrials.gov, NCT03306550. https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0007D8H&selectaction=Edit&uid=U0003QY8&ts=2&cx=oiuc9g.

Transport of salvianolic acid B via the human organic anion transporter 1B1 in the liver

Salvianolic acid B (SAB) has a high concentration in the liver, but the mechanism of its distribution in the liver is unclear. The aim of this study was to investigate the mechanisms of hepatic uptake of SAB. In this study, we first explored the uptake features of SAB in HepG2 cells and the effect of rifampicin on uptake. Then, we explored the effects of SAB on the uptake of pitavastatin in HepG2 cells. Finally, we established an HEK239T-OATP1B1 cell model to confirm whether OATP1B1 mediated the transport of SAB. Results showed that the uptake kinetic parameters Vmax and Km for SAB in HepG2 cells were 21.28 ± 2.06 pmol mg^-1 per protein min^-1 and 28.47 ± 7.36 μM, respectively. Rifampicin inhibited the uptake of SAB in HepG2 cells (IC50 was 5.85 ± 1.70 μM), and SAB affected the uptake of pitavastatin in HepG2 cells (IC50 was 27.67 ± 1.90 μM). The uptake kinetic parameters Vmax and Km for SAB in HEK239T-OATP1B1 were 60.03 ± 6.16 pmol mg^-1 per protein min^-1 and 87.24 ± 15.28 μM, respectively, whereas in EGFP-HEK293 cells were 14.04 ± 2.53 pmol mg^-1 per protein min^-1 and 56.53 ± 15.50 μM. The SAB had no effect of on the expression of OATP1B1 in HEK239T-OATP1B1 cells. In conclusion, this study demonstrated that OATP1B1 contributes to the transport and accumulation of SAB in the liver.