A new aporphine glycoside (1), named 'angkorwatine', and eight known alkaloids: oblongine (2), stepharine (3), asimilobine-β-d-glucopyranoside (4), isocorydine (5), tetrahydropalmatine (THP) (6), jatrorrhizine (7), palmatine (PAL) (8), and roemerine (ROE) (9) were simultaneously isolated from the tuber of Stephania cambodica. The development and validation of UHPLC-DAD method was carried out for the quantification of marker compounds (PAL, ROE, THP) of S. cambodica. In addition to good selectivity and linearity (r2 > 0.997), trueness, precision, and accuracy of the method did not exceed the acceptance limit of ±10% for ROE, THP and ±20% for PAL. Consequently, this method is able to provide accurate results between 1.39-4.18 μg/mL, 2.01-30.72 μg/mL, and 4.29-64.42 μg/mL for PAL, ROE, and THP, respectively. This study shows that the validated UHPLC method is a rapid, innovative and effective analytical approach to control quality of tubers of S. cambodica and to regulate the usage of this plant in traditional medicine.
Keywords: Accuracy profile; alkaloid; method validation; palmatine; quantification; roemerine; tetrahydropalmatine.