Quantification of catalpol in root of Rehmannia glutinosa varieties 19 collected in Phu Tho province by high-performance liquid chromatography

The active ingredient catalpol in the Rehmannia glutinosavariety 19 roots is an important chemical component. Catalpol has hypoglycemia, diuretic, and laxative effects; it is used to support the treatment of diabetes, ischemic cerebral, and dementia, and it is regulated by Vietnamese Pharmacopoeia V (2017) as a marker to check the quality of medicinal herbs. This study aimed to develop a procedure for quantifying catalpol in the root of Rehmannia glutinosa varieties 19 by high-performance liquid chromatography (HPLC) to evaluate the quality of medicinal herbs. The research results have selected suitable chromatographic conditions using the Gemini C18 column (250x4.6 mm, 5 μm), detector at 210 nm, mobile phase acetonitrile - phosphoric acid 0.1%, and flow rate at 0.6 ml/min. The peak area and catalpol concentration have a strong linear correlation with r=0.9999, Y = 21887X + 26213. The procedure has good accuracy and repeatability with a relative standard deviation (RSD) <2%. Quantitative results of catalpol in the root of the R. glutinosa varieties 19 reached 1.25%. The HPLC method is suitable for quantifying catalpol in the root of R. glutinosa varieties 19.