Development and validation of analytical HPLC for phenolics in Pinus densiflora bark extract

Pine (Pinus densiflora) bark, most of which is discarded as a by-product of the timber industry, contains considerable amounts of antioxidant phenolics. We developed and validated a quantitative method of analyzing seven phenolics (protocatechuic acid, procyanidin B1, procyanidin B3, catechin, ferulic acid, taxifolin, and quercetin) in pine bark extract (PBE) using a high-performance liquid chromatography–photodiode array. The simultaneous analytical method for the seven phenolics was validated in terms of specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision. The correlation coefficients of the calibration curves of the seven phenolics were ≥0.9999. The LODs and LOQs of the seven phenolics were 0.01–0.16 and 0.02–0.49 μg/mL, respectively. The ranges of recoveries of the seven phenolics were 97.29–103.59%, and their relative standard deviations were 0.24–3.95%. The described approach to the quantitative analysis of PBE phenolics as marker compounds can be used for standardization in the development of health-functional foods.