Taxadendins A-P, previously undescribed abietane diterpenoids with diverse structures from the bark of Taxodium...

Taxadendins A-P, sixteen unprecedented abietane diterpenoids, featured extensively rearranged, and highly oxidized structures, were isolated from the bark of Taxodium ascendens, Taxadendin A (1) is a rearranged tetracyclic diterpenoid, possessing an unprecedented 6/6/6/6 ring system derived from normal abietane skeleton. Taxadendin B (2), a highly oxidized rearranged tricyclic diterpenoid, have a different A-ring structure and lacked the D ring present in 1. Their structures were unambiguously determined through spectroscopic analysis and calculated electronic circular dichroism. All compounds were tested for their antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella enterica, and Pseudomonas aeruginosa. Compounds 9-11, 13, and 16 exhibited potent inhibitory activities against S. aureus, with MIC₅₀ values of 41.97 ± 0.16, 10.11 ± 0.11, 34.53 ± 0.24, 14.57 ± 0.05 and 4.33 ± 0.05 μM, respectively.