Quantitative analysis of the five marker compounds in Mori Cortex Radicis and its anti-inflammatory effects

Abstract

Mori Cortex Radicis (MCR, Moraceae), which is root bark of Morus alba L., is used traditionally in the treatment of jaundice, hematemesis, edema, and pollakisuria in Korea. In this study, the anti-inflammatory effects of MCR extract and the five components, neochlorogenic acid (1), chlorogenic acid (2), cryptochlorogenic acid (3), caffeic acid (4), and p-coumaric acid (5) were investigated using RAW 264.7 cells. The simultaneous analysis of the compounds 1 – 5 in MCR extract was performed using high-performance liquid chromatography coupled with photodiode array detector. All analytes were separated on a Gemini C18 column and the column oven temperature was set at 40 ° C with the detection wavelength was set at 320nm. The mobile phase was a gradient comprising 1.0% (v/v) aqueous acetic acid (A) and 1.0% (v/v) acetic acid in acetonitrile (B). The flow rate was 1.0 mL/min and the injection volume was 10 mL. We determined the effects of MCR extract and the compounds 1-5 on the production of nitric oxide (NO), prostaglandin E2 (PGE2), and mRNA expression of cyclooxygenase-2 (COX-2) in RAW 264.7 cells. The HPLC method showed good linearity with a correlation coefficient (r2) ≥0.9999 over the concentration range 0.31 – 20.00 mg/mL. The limit of detection and the quantification of the compounds 1-5 were 12.23 – 61.46 ng/mL and 40.76 – 204.87 ng/mL, respectively. The concentration of the compounds 1-5 was 0.16 – 1.40 mg/g. MCR extract suppressed the production of NO and PGE2 in RAW 264.7 cells in a dose-dependent manner. None of the five components of MCR extract had any influence on the production of NO. However, compounds 4 and 5 were inhibited the production of PGE2 and mRNA expression of COX-2 in RAW 264.7 cells. Our results suggest that MCR extract may offer potential as a therapeutic agent for the treatment of inflammation. The method we have established will help to improve the quality control of MCR extracts.