Development of a Quantification Method for Procyanidin B1 and B3 in Pine Bark Extracts Using Heart-Cutting HPLC

Pine bark extract (PBE) is a material used as a health food. Its functionality is attributed to the antioxidant effect of its contained procyanidins, and quantification of the procyanidin content is important to monitor its quality. However, conventional single-column High-Performance Liquid Chromatography (HPLC) methods often lack sufficient separation for procyanidins in complex matrices like PBE, leading to inaccurate quantification. In order to improve the accuracy of analysis for procyanidins B1 (PCB1) and B3 (PCB3) contained in PBE, we developed a highly accurate analytical method employing heart-cutting HPLC using columns with multiple properties and performed a detailed validation. The PCB1 and PCB3 contained in commercial health foods ranged from 0.43-2.95 mg/g, with a relative standard deviation of 0.77-6.17%. The spike and recovery tests showed that the recovery of beverages ranged from 98 to 106% at low and high concentrations, and for tablets, the recovery ranged from 95 to 118%. The repeatability relative standard deviation ranged from 1.10 to 3.57%, and the Horwitz Ratio ranged from 0.26-1.89. The intermediate relative standard deviation ranged from 2.62 to 6.83%. Single-laboratory validation of the analytical method employing heart-cutting HPLC showed that it is sufficiently accurate for analyzing PCB1 and PCB3 in commercial health foods containing PBE.