Application of Quantitative Proton Nuclear Magnetic Resonance Spectroscopy for Determination of the Content of Geniposide in Gardeniae fructus

Abstract

Background: Gardeniae fructus (Zhi-Zi) is the dry ripe fruit of the plant Gardenia jasminoides Ellis (Rubiaceae), which can be used as both food and medicine. Geniposide, a key constituent of Gardeniae fructus, serves as an indicator component for evaluating the quality of Gardeniae fructus. Traditionally, the quantification of geniposide in Gardeniae fructus is achieved through High-performance Liquid Chromatography (HPLC)-based methods. Objective: The present study aimed to introduce a rapid approach to quantifying geniposide content in Gardeniae fructus along with validating its effectiveness. Methods: The experiments involved finding a suitable deuterium solvent, Internal Standard (IS), specific peak, and Nuclear Magnetic Resonance (NMR) parameters for quantitation, and validating specificity, accuracy, precision, and stability. Results: The results have indicated that methanol-d4 as a solvent has facilitated excellent signal separation in the proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, with trimethyl 1,3,5- benzenetricarboxylate emerging as the ideal IS. The specific signal at δ 7.45, corresponding to H-3 in geniposide, has been identified as the optimal peak for integration. The application of distinctive signals from the 1H NMR spectroscopy has allowed for the precise quantification of geniposide in Gardeniae fructus. Conclusion: This study has suggested using 1H NMR to quantify geniposide in Gardeniae fructus to be a viable alternative to HPLC-based methods, providing a suitable approach for quality control of Gardeniae fructus.