UHPLC-assay determining total content of flavonoids in Passion Flower herb and Passion Flower dry extract considering different Passion Flower chemotypes

In commercial Passion flower herbal drug, the occurrence of different chemotypes with respect to the contained C-glycosyl flavonoid pattern is observed. In addition to varieties containing isovitexin as major flavonoid, increasingly also those in which swertisin as the main component are found. By means of a UHPLC-DAD fingerprint, achieved on an acquity HSS T3 1.8 µm (100 × 2.1 mm) column, the chemotypes can be clearly distinguished. Regardless of the present variety the total flavonoids in passion flower herb and passion flower dry extract can be quantified by using UHPLC-DAD. All peaks in a certain retention time window can be identified as flavonoids by UV-spectra. The sum of all flavonoid peaks is calculated as isovitexin. The validation shows a very good linearity, accuracy and robustness of the method. One-point calibration is possible. In comparison with the photometric assay according to PharmEur the UHPLC-assay indicates a 0.77-fold lower content of flavonoids.

Keywords: Passiflora, Passion flower, C-glycosyl flavonoids, isovitexin, swertisin, UHPLC-Assay, HSS T3