Isolation of a Unique Monoterpene Diperoxy Dimer From Ziziphora clinopodioides subsp. bungeana Together With Triterpenes With Antidiabetic Properties.

INTRODUCTION: Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. is used in traditional medicine for various purposes. Previous phytochemical studies focused on phenolic compounds, but triterpenoids were almost overlooked. OBJECTIVE: The study focused on the isolation of compounds with dual antidiabetic activity from the aerial parts of Z. clinopodioides subsp. bungeana. MATERIALS AND METHODS: Separation of CHCl(3)-soluble fraction by silica gel column chromatography using different mobile phases and purification of compounds by semi-preparative HPLC or preparative TLC. The structures of pure compounds were elucidated by 1D and 2D NMR experiments along with HRMS. Compound 1 was additionally identified by the single crystal X-ray diffraction method. α-Glucosidase inhibitory assay and GLUT4 expression and translocation in C2C12 myotubes were conducted to evaluate antidiabetic potential of isolated compounds. RESULTS: This phytochemical study led to the isolation of 20 compounds, including a unique monoterpene diperoxy dimer (1). Compounds 7 and 9-11 displayed more potent α-glucosidase inhibitory activity (IC(50) 45.3-135.3 μM) than acarbose used as a positive control (IC(50) 264.7 μM), while only pomolic acid (5) increased GLUT4 translocation in C2C12 myotubes in a significant manner. CONCLUSION: Extensive chromatographic separation led to the isolation and identification of a unique monoterpene diperoxy dimer (1) from aerial parts of Z. clinopodioides subsp. bungeana. Some triterpenes inhibited α-glucosidase, another increased GLUT4 translocation. Although none of the isolated compounds demonstrated dual antidiabetic activity, selected triterpenes proved to be potent antidiabetic agents in vitro.