Optimization and Validation of a New HPLC Method for the Determination of Asparagine Active Ingredient in Asparagus lycicus and Phytochemical Characterization of Endemic Asparagus lycicus Specie

A new HPLC method was optimized and validated for the determination of asparagine in Asparagus lycicus plant, an endemic specie found in Turkey, and the phytochemical analysis of this plant was carried out. For asparagine analysis, optimum separation was obtained with water:methanol mixture (95:5, v/v) in the presence of formic acid (FA):ammonium formate (AF) buffer as mobile phase by using a C18 reversed phase column. In this new method, retention time (0.61 min) of asparagine was very short. The linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), and selectivity parameters were studied for the validation of optimized method. By this method, satisfactory recovery (100.10 ± 2.86%) was obtained for asparagine analysis and LOD and LOQ values were determined to be 0.28 mg L⁻¹ and 0.92 mg L⁻¹, respectively. Freeze-thaw stability of the method is quite high. The results of matrix effect experiments showed that the matrix of Asparagus lycicus plant does not significantly affect the quantification analysis of asparagine. In the phytochemical characterization of endemic Asparagus lycicus plant, asparagine content (6.14 mg g⁻¹ plant), total phenolic (13.22 mg GAE g⁻¹ plant) and flavonoid (3.24 mg CE g⁻¹ plant) contents, phenolic and flavonoid components (28.8 mg rosmarinic acid, 109.2 mg ferulic acid, 531.2 mg chlorogenic acid, 2.8 mg o-coumaric acid, 17.6 mg p-coumaric acid and 6.0 mg sinapic acid per kg plant), total antioxidant activity (13.2 mg mg⁻¹ DPPH), vitamin C content (234.6 mg kg⁻¹ plant), organic acid content as malic acid (2.9 mg kg⁻¹ plant), sugar components (25.15 g fructose and 18.25 g glucose per kg plant), total anthocyanin content (5.15 mg kg⁻¹ plant), total oil content (9.65%) and fatty acid components (oleic acid (55.36%), and linoleic acid (32.01%) and palmitic acid (7.61%)) were determined. The results of this study exhibited that endemic Asparagus lycicus plant might be considered as a promising natural source with antioxidant and bioactive constituents in the potential applications of pharmaceutical and food industries. Graphical abstract