Simultaneous Determination and Stability Test of Two Phthalic Anhydride Derivatives, Senkyunolide A and Z-Ligustilide, in the Water Extract of Cnidium Rhizome from Different Geographical Regions and Species Using HPLC-UVD Analysis

Cnidium rhizome from Cnidium officinale Makino and Ligusticum chuanxiong Hort (Umbelliferae) is traditionally used to treat pain in East Asian countries. Senkyunolide A and Z-ligustilide are phthalic anhydride derivatives that are the bioactive components of cnidium rhizome and chemical markers of the two species; they are also susceptible to external stimuli. In this study, we developed a method to identify two chemical markers using high-performance liquid chromatography (HPLC) with an ultraviolet detector (UVD); the contents of senkyunolide A and Z-ligustilide in cnidium rhizome from different regions were quantified. The stabilities of the compounds were tested at two different temperatures over 12 months. An HPLC-UVD system was used to identify and quantify senkyunolide A and Z-ligustilide in 10 C. officinale samples and 6 L. chuanxiong samples from China and Korea. The long-term stability of the C. officinale samples in dark conditions at 4 and 25 °C was also tested. The calibration curves for the two chemical markers showed high linearity (R2 = 1.0000), the precision was high (relative standard deviation (RSD) <4.17%), and the recoveries were within the range of 95–105%. The contents were mostly independent of the geographical origin and species, and >10% of the compounds degraded after storage at 4 and 25 °C for 6 months. A method was developed to rapidly identify two chemical markers in cnidium rhizome with good linearity, precision, and accuracy using HPLC-UVD. These markers will be utilized for the quality control or evaluation of herbal preparations containing cnidium rhizome.