Extraction and Purification of 9-Methoxycanthin-6-One from Radix Eurycomae Longifoliae for Reference Standard Establishment

Abstract

9-methoxycanthin-6-one (9MC6) is a canthin-6-one alkaloid isolated from Radix Eurycomae longifoliae with relatively large content. 9MC6 has been shown several important biological activities of this herbal material, including the ability to resist many different cancer cell lines such as breast, lung, colorectal, uterine, prostate, and ovarian cancer, and exhibit strong anti-inflammatory properties. Therefore, 9MC6 is a potential chemical marker for controlling the quality of this herbal material. This study presents the development of a procedure for the extraction and purification of 9MC6 to establish a reference standard. In this procedure, the Radix Eurycomae longifoliae powder was ultrasonically extracted with ethanol 50% (v/v), and then ethanol was evaporated in vacuo to give water suspension. The suspension was successfully partitioned with dichloromethane, eluted on a silica column, and crystallized by using the combination of dichloromethane, methanol, acetone, and water at suitable ratios to obtain the crystal. Finally, the crystal was purified on the C18 column to get 9MC6 material. The 9MC6 material, which was identified by MS spectrometry, NMR, UV-VIS, and IR spectroscopy, contained 99.21% of 9-methoxycanthin-6-one (C₁₅H₁₀N₂O₂), which was calculated from volatile impurities (0.0014%), residue on ignition (0.012%) and of related substances (0.78%). It was concluded that the established procedure was suitable for producing 9MC6 material for standard reference establishment.