A simple and reliable analytical method based on HPLC-UV to determine oleanonic acid content in Chios gum mastic for...

A reliable analytical method based on high-performance liquid chromatography-ultraviolet detection was established for the determination of oleanonic acid (OA) content in Chios gum mastic (CGM). A simple method involving methanol extraction of CGM powder followed by basification and ether extraction was developed to isolate the triterpenic fraction including OA. The triterpenic fraction was chromatographed on a Phenomenex Gemini C₁₈ column (150 × 4.6 mm, 5 µm) under a simple gradient elution of a mobile phase containing acetonitrile and water at a flow rate of 1.0 mL min^-1. The detection wavelength was set at 210 nm. Good linearity was achieved in the range of 100.0-1000.0 μg mL^-1 with r² > 0.9993, and the limit of quantification was 32.22 μg mL^-1. Accuracy measured at three concentration levels was in the range of 93.72-99.56%, while intra-day and inter-day precisions estimated using both OA standard and CGM samples were no more than 2.83 and 4.57% RSD, respectively. Finally, this method was applied to real CGM samples from various batches, revealing that the OA contents were between 88.13 and 100.83 μg mg^-1. These results suggest that the current method can be applied as an efficient analytical method for quality control of CGM.