Oroxylum indicum seeds - Analysis of flavonoids by HPLC-MS

The seeds of Oroxylum indicum Vent, play an important role in Traditional Chinese Medicine to treat infectious diseases of the respiratory tract. In this manuscript the first HPLC-MS assay for the separation of all major flavonoids as well as their isolation and quantification is reported. The developed method was fully validated and showed to be accurate (recovery rates >= 96.2%), precise (intra-day sigma(rel) <= 4.83%, inter-day sigma(rel) <= 5.23%), repeatable (sigma(rel) <= 2.57), sensitive (LOD: 0.05-0.34 mu g/ml) and linear (R-2 >= 0.999). Four samples of Oroxyli semen from different origins were separated with this optimized HPLC procedure on a Phenomenex Luna 5 mu C8 (2) 100 angstrom column using acetonitrile and water/0.1% formic acid as mobile phase. Temperature, flow rate and injection volume were set to 25 degrees C, 0.5 ml/min and 10 mu l, respectively. The most dominant flavonoid showed to be Baicalein-7-O-beta-D-gentiobiosid, occurring in the specimens in percentages ranging from 0.92 to 4.08%. (C) 2012 Elsevier B.V. All rights reserved.