Evaluation of Potential Herb-Drug Interactions Between Shengmai Injection and Losartan Potassium in Rat and In Vitro

Abstract

Aim: The present study aimed to explore the potential herb-drug interactions (HDI) between Shengmai injection (SMI) and losartan potassium (LOS) based on the expression profiles of cytochromes P450 (CYP450) and drug transporters in rat and in vitro. Methods: Different concentrations of SMI were used to explore the influence of SMI on the antihypertensive efficacy of LOS in the hypertension rat model established by N (omega)-nitro-L-arginine methyl ester (L-NAME) for 4 weeks. Subsequently, the serum concentration levels of LOS and losartan carboxylic acid (EXP3174) were determined by Liquid Chromatography Mass Spectrometry (LC-MS) and pharmacokinetic analysis. Human liver microsomes, human multidrug resistance protein 1 (MDR1/P-gp), and breast cancer resistance protein (BCRP) vesicles, human embryonic kidney 293 cell line with stable expression of the organic anion transporting polypeptide 1B1 (HEK293-OATP1B1 cells) and mock-transfected HEK293 (HEK293-MOCK) cells were used to verify the effects of SMI on CYP450 enzymes and drug transporters in vitro. Results: Low, medium, and high concentrations of SMI increased the antihypertensive efficacy of LOS to varying degrees. The high dose SMI increased the half-life (t _1/2 ), the maximum plasma concentration (C _max), the area under the plasma concentration-time curve (AUC) from time zero to the time of the last measurable plasma concentration (AUC _0-t ), AUC from time zero to infinity (AUC _0-∞ ), and mean residence time (MRT) values of LOS and decreased its apparent volume of distribution (Vd) and clearance (CL) values. The AUC _0-t , AUC _0-∞ , and MRT of LOS were increased, whereas the CL was decreased by the medium concentration of SMI. In addition, the high, medium, and low doses of SMI increased the relative bioavailability (Frel) of LOS. SMI exhibited no significant effects on the pharmacokinetics of EXP3174. In vitro, SMI exhibited different suppressive effects on the enzyme activity levels of CYP1A2 (6.12%), CYP2B6 (2.72%), CYP2C9 (14.31%), CYP2C19 (12.96%), CYP2D6 (12.26%), CYP3A4 (3.72%), CYP2C8 (10.00-30.00%), MDR1 (0.75%), OATP1B1(2.03%), and BCRP (0.15%). Conclusion: In conclusion, SMI improved the antihypertensive efficacy of LOS in the L-NAME-induced hypertension rat model by increasing the concentration of LOS, while leaving the concentration of EXP3174 intact. SMI affected the pharmacokinetic properties of LOS by decreasing the elimination of LOS. These effects might partly be attributed to the inhibition of the activities of CYP3A4, CYP2C9, and of the drug transporters (P-gp, BCRP, and OATP1B1) by SMI, which need further scrutiny.

Keywords: CYP 450; drug transporters; hypertension; losartan potassium; shengmai injections.

FIGURE 1

The SBP, DBP and MAP of each group were shown after 4 weeks (A–C) and 6 weeks (D–F) treatment. * indicates p < 0.05 compared with the Blank group. # indicates p < 0.05 compared with the model group; Δ indicates p < 0.05 compared with the LOS group; and indicates p < 0.05 compared with the SMI-M + LOS and SMI-L + LOS group. Model group was treated with L-NAME 60 mg/kg·d-1 intragastrically; the SMI high-dose group (SMI-H group) received SMI 6 ml/kg/d in tail vein injection; LOS group was given LOS 10 mg kg⁻¹. d⁻¹ intragastrically; LOS plus SMI high-dose group (SMI-H + LOS group), LOS plus SMI medium-dose group (SMI-M + LOS group) and LOS plus SMI low-dose group (SMI-L + LOS group) were respectively given SMI 6 ml kg⁻¹. d⁻¹, 4 ml kg⁻¹. d⁻¹ and 2 ml kg⁻¹. d⁻¹ in tail vein injection, based on LOS 10 mg kg⁻¹. d⁻¹ intragastrically. SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; L-NAME, N (omega)-nitro-L-arginine methyl ester.

FIGURE 2

The concentration-time curves of LOS and EXP3174 with (A,B) and without (C,D) L-NAME treatment. Model group was treated with L-NAME 60 mg kg⁻¹. d⁻¹ intragastrically; SMI high-dose group (SMI-H group) received SMI 6 ml kg⁻¹. d⁻¹ in tail vein injection; LOS group was given LOS 10 mg kg⁻¹. d⁻¹ intragastrically; LOS plus SMI high-dose group (SMI-H + LOS group), LOS plus SMI medium-dose group (SMI-M + LOS group) and LOS plus SMI low-dose group (SMI-L + LOS group) were respectively given SMI 6 ml kg⁻¹. d⁻¹, 4 ml kg⁻¹. d⁻¹, 2 ml kg⁻¹. d⁻¹ in tail vein injection, based on LOS 10 mg kg⁻¹. d⁻¹ intragastrically. Blank + LOS received LOS 10 mg kg⁻¹. d⁻¹ by intragastric administration without L-NAME treatment; Blank + LOS + SMI-H group received SMI 6 ml/kg/d in tail vein injection and LOS 10 mg kg⁻¹. d⁻¹ by intragastrically administration without L-NAME treatment. LOS, losartan potassium; EXP3174, losartan carboxylic acid; L-NAME, N (omega)-nitro-L-arginine methyl ester.

FIGURE 3

The relative protein expression levels of CYP3A4 (A), CYP2C9 (B) and P-gp (C) and protein bands of these (D) in each group with L-NAME treatment. * indicates p < 0.05 compared with Blank group; # indicates p < 0.05 compared with Model group; and indicates p < 0.05 compared with LOS group. Model group was treated with L-NAME 60 mg kg⁻¹. d⁻¹ intragastrically; SMI high-dose group (SMI-H group) received SMI 6 ml kg⁻¹. d⁻¹ in tail vein injection; LOS group was given LOS 10 mg kg⁻¹. d⁻¹ by intragastric administration; LOS plus SMI high-dose group (SMI-H + LOS group), LOS plus SMI medium-dose group (SMI-M + LOS group) and LOS plus SMI low-dose group (SMI-L + LOS group) were respectively given SMI 6 ml kg⁻¹. d⁻¹, 4 ml kg⁻¹. d⁻¹, 2 ml kg⁻¹. d⁻¹ in tail vein injection, based on LOS 10 mg kg⁻¹. d⁻¹ intragastrically.

FIGURE 4

After different concentrations of SMI treatment, the CYP450 enzyme (A–G) and drug transporters (H–J) activities were shown. * indicates p < 0.05 compared with NC group. Comparison of enzyme activities after different concentrations of SMI treatment, in figure (A–G), 0.1% vs. 0.5%, #p < 0.05; 0.1% vs. 3%, $p < 0.05; 0.1% vs. 10%, &p < 0.05; 0.1% vs. 30%, αp<0.05; 0.5 vs. 3%, βp<0.05; 0.5 vs. 10%, γp<0.05; 0.5 vs. 30%. δp<0.05; 3 vs. 10%, εp<0.05; 3–30%, ηp<0.05; 10–30%, θp<0.05. In figure (H–J), 0.1 vs. 0.5%, #p < 0.05; 0.1 vs. 2%, $p < 0.05; 0.1 vs. 5%, &p < 0.05; 0.1 vs. 20%, αP<0.05; 0.5 vs. 2%, βP<0.05; 0.5 vs. 5%, γP<0.05; 0.5 vs. 20%, δP<0.05; 2 vs. 5%, εP<0.05; 2 vs. 20%, ηP<0.05; 5 vs. 20%, θP<0.05. NC, negative control group; PC, positive control group.

FIGURE 5

Different concentrations of SMI correspond to different CYP450 enzyme activities and the IC50 curve. X is the logarithm of SMI concentration; Y is the corresponding percentage of NC. The nonlinear formula, “Y = 100/(1 + 10^((X-logic50))" (Y starts at Bottom and goes to Top with a sigmoid shape). The results showed that SMI had different inhibitory effects on CYP1A2 (A), 2B6 (B), 2C9 (C), 2C19 (D), 2D6 (E), 3A4 (F), MDR1 (G), BCRP (H), OATP1B1(I). As for CYP2C8, since SMI increased CYP2C8 metabolism in the no/weak inhibition interval, inhibition was only observed at high concentrations. When it is not clear why SMI increases CYP2C8 metabolism in the no/weak inhibition interval, the current test system cannot determine a more accurate IC50. Therefore, the data cannot fit the IC50 curve. We can only be sure that the IC50 value is between 10 and 30%.