Analysis of arglabin and its derivatives using high-performance liquid chromatography.

Introduction: The chemical modification of arglabin, a natural sesquiterpene lactone, has garnered significant attention because it comprises a guaianolide structure that exhibits antitumour and immunomodulating properties. Its primarily derived from Artemisia glabella Kar. et Kir. Physicochemical characterisation of commercial anititumour drugs based on arglabin can be time-consuming and expensive; thus, high-performance liquid chromatography (HPLC) is an optimal method to identify arglabin and its derivatives.

Aim: This study has a two-fold objective: to develop a unified HPLC method for quality control of arglabin and its new hybrid molecules with alkaloids (cytisine, anabasine), and to study the relationship between their structures and chromatographic behaviours.

Materials And Methods: To develop a selective method that ensures the quality of arglabin and its derivatives, HPLC was used with the Zorbax SB-C18 analytical column. Dipole moments were calculated via the restricted Hartree-Fock method (RHF/6-31G(d, p)) and the B3LYР density functional theory with full geometry optimisation by using the GAUSSIAN 03 W program.

Results: A novel analytical method has been developed using reversed-phase (RP) HPLC, which is selective and allows reliable as well as quantitative determination of arglabin and its derivatives. To confirm the selectivity of the developed method, the chromatographic capacity factors and column selectivity were calculated. The relationship between retention time and structure (particularly, the nature of the substituent) was studied for the first time for arglabin and its derivatives using the B3LYP/6-31G(d) quantum chemical method. The influence of the dipole moment on the retention time of arglabin and its derivatives was confirmed.

Conclusion: A novel unified quality control method using HPLC was developed to analyse arglabin, and its new hybrid molecules with alkaloids (cytisine and anabasine). For the first time, the relationship between the chromatographic behaviour in RP-HPLC and the dipole moment for arglabin and its derivatives was revealed.