A New Abietane-Type Diterpenoid Glycoside Isolated from the Ethyl Acetate Extract of Ajuga decumbens Thunb. and its Preliminary In Vitro Anticancer Activities.

INTRODUCTION: Ajuga decumbens Thunb. is a Chinese medicinal plant used in folk medicine for the treatment of various ailments. It contains various active components, which contribute to a wide range of biological activities, especially anticancer activity. Based on our previous findings, we continue to study the chemical components of Ajuga decumbens Thunb. to identify new secondary metabolites that could be used as anticancer drug candidates or lead compounds. METHODS: The ethyl acetate extract of Ajuga decumbens Thunb. was isolated by silica gel column chromatography to obtain different fractions, and similar fractions and subfractions were combined based on TLC or HPLC analysis. The pure compounds were obtained by reversed-phase preparative HPLC, and their purity was confirmed by HPLC, while their chemical structures were characterized by NMR, HRESIMS, and SC-XRD. Then, the cytotoxicity against four cancer cell lines [pancreatic cancer cells (PANC1), cervical cancer cells (HeLa), ovarian cancer cells (A2780), and lung cancer cells (A549)] was evaluated using the CCK8 assay. RESULTS: Here, we isolated a new abietane-type diterpenoid glycoside (1) along with four known compounds (2- 5) from Ajuga decumbens Thunb. Notably, compound 2 was first isolated and confirmed from Ajuga species. The anticancer evaluation revealed that compound 1 showed good cytotoxicity against A2780 cells, with an IC50 value of 46.9 μM. DISCUSSION: In this work, we discovered a new abietane-type diterpenoid glycoside from Ajuga decumbens Thunb., and elucidated its structure using NMR, HRESIMS, and SC-XRD. The anticancer evaluation revealed that it exhibited good cytotoxicity against A2780 cells, with an IC50 value of 46.9 μM. CONCLUSION: This work provides the material basis for Ajuga decumbens Thunb., as documented in pharmacopoeias and historical records. Based on this finding, further studies are being carried out for discover more new compounds from Ajuga decumbens Thunb.