Effects of Herbal Formulas Bojungikgi-tang and Palmijihwang-hwan on Inflammation in RAW 264.7 Cells and the Activities of Drug-Metabolizing Enzymes in Human Hepatic Microsomes

In the present study, Bojungikgi-tang (BJIKT: Buzhongyiqi-tang, Hochuekki-to) and Palmijihwang-hwan (PMJHH: Baweidihuang-wan, Hachimijio-gan), traditional herbal formulas, investigated anti-inflammatory efficacies in murine macrophage cell line and the influence on the activities of drug-metabolizing enzymes (DMEs). The anti-inflammatory potentials of the herbal formulas were evaluated to inhibit the production of the inflammatory mediators and cytokines and the protein expression of inducible nitric oxide and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The activities of the major human DMEs, cytochrome P450 (CYP450) and UDP-glucuronosyltransferase (UGT) isozymes, were measured by in vitro enzyme assay systems. BJIKT and PMJHH significantly suppressed the prostaglandin E₂ (PGE₂) production (IC₅₀ = 317.3 and 282.2 μg/mL, respectively) and the protein expression of COX-2 in LPS-treated RAW264.7 cells. On the human microsomal DMEs, BJIKT inhibited the activities of CYP1A2 (IC₅₀ = 535.05 μg/mL), CYP2B6 (IC₅₀ > 1000 μg/mL), CYP2C9 (IC₅₀ = 800.78 μg/mL), CYP2C19 (IC₅₀ = 563.11 μg/mL), CYP2D6 (IC₅₀ > 1000 μg/mL), CYP2E1 (IC₅₀ > 1000 μg/mL), CYP3A4 (IC₅₀ = 879.60 μg/mL), UGT1A1 (IC₅₀ > 1000 μg/mL), and UGT1A4 (IC₅₀ > 1000 μg/mL), but it showed no inhibition of the UGT2B7 activity at doses less than 1000 μg/mL. PMJHH inhibited the CYP2D6 activity (IC₅₀ = 280.89 μg/mL), but IC₅₀ values of PMJHH exceeded 1000 μg/mL on the activities of CYP1A2, CYP2C19, CYP2E1, and CYP3A4. At concentrations less than 1000 μg/mL, PMJHH did not affect the activities of CYP2B6, CYP2C9, UGT1A1, UGT1A4, and UGT2B7. The results indicate that both BJIKT and PMJHH may be potential candidates to prevent and treat PGE₂- and COX-2-mediated inflammatory diseases. In addition, this study will expand current knowledge about herb–drug interactions by BJIKT and PMJHH.