New oligomeric terpenoids fused with an oxazoline ring linkage from cones of Taxodium ascendens and their biological activities

• Taxodascaloids A-C, three uncommon oligomeric terpenoids , were purified from the cones of Taxodium ascendens . • Compounds 1 and 2 represented the first identified diterpenoid-monoterpenoid adducts linked by an oxazoline ring. • All these three compounds were determined using extensive spectroscopic analysis and X-ray diffraction techniques. Taxodascaloids A-C ( 1–3 ), three uncommon oligomeric terpenoids featuring an oxazoline ring linkage, were purified from the cones of Taxodium ascendens . Compounds 1 and 2 , a unique pair of stereoisomers, represented the first identified diterpenoid-monoterpenoid adducts linked by an oxazoline ring. Compound 3 was an uncommon dimeric diterpenoid and composed of a seco-abietane unit and an abietane unit, also containing an oxazoline ring. The planar structures and absolute configurations of these compounds were determined using extensive spectroscopic analysis and X-ray diffraction techniques. Compounds 1 and 2 demonstrated potent anticancer activity against human colon cancer HCT cells, with the IC 50 values of 25.7 and 40.1 μ M, respectively. Further research indicated that compound 1 could induce both ferroptosis and apoptosis in HCT-116 cells. Additionally, compound 3 showed notable α -glucosidase inhibitory activity in a mixed-type manner with an IC 50 value of 2.9 μ M.