Preparation, characterization and cytotoxic activity of rhein argininate

Abstract

Rhein is a natural anthraquinone, which can be isolated from the rhizomes of rhubarb, a traditional Chinese medicine herb showing antitumor activity. The poor aqueous solubility of rhein hampers its broader applications. Rhein argininate was prepared as a potential cytotoxicity formulation by co-grinding together a 1 : 1 molar mixture of rhein and L-arginine for 8 hours. Characterization of rhein argininate was achieved by nuclear magnetic resonance, mass spectrometry, X-ray powder diffraction, infrared spectroscopy, and differential scanning calorimetry techniques. The HPLC method was used to study the solubilization of rhein argininate. The MTT method was used to assay the cytotoxic activity of rhein argininate. Rhein argininate could enhance the solubility of rhein by 8 fold as compared to that in water. The cytotoxicity of rhein argininate on cancer cell line activity was 4 times that of rhein. The satisfactory water solubility and cytotoxicity of rhein argininate on cancer cell line activity will be potentially useful for its application as a new pharmaceutical formulation in cancer treatment in the future.