Bioactive abietenolide diterpenes from Suregada procera

The phytochemical investigation of the leaves and the roots of Suregada procera afforded the new ent-abietane diterpenoid sureproceriolide A (1) along with the known secondary metabolites 8,14β:11,12α-diepoxy-13(15)-abietane-16,12-olid (2), jolkinolide A (3), jolkinolide E (4), ent-pimara-8(14),15-dien-19-oic acid (5), sitosterol (6), oleana-9(11):12-dien-3β-ol (7), and oleic acid (8). Their structures were elucidated by NMR spectroscopic and mass spectrometric analyses, and the structure of jolkinolide A (3) was confirmed by single-crystal X-ray diffraction analysis. Sureproceriolide A (1) showed modest activity against the Gram-positive bacterium Staphylococcus lugdunensis (MIC = 31.44 μM), and sitosterol (6) against the Gram-negative bacterium Porphyromonas gingivalis (IC₅₀ = 45.37 μM). Jolkinolide A (3) and E (4) as well as sitosterol (6) inhibited the release of NOS (IMR-90 cells), TNF-α (HaCaT cells) and NF-κB (HaCaT cells), with IC₅₀ values of 0.43, 3.21, and 10.32 μM, respectively. Compound 6 showed antitumoral activity against SK-MEL-28 (IC₅₀ = 20.66 μM) and CCD-13Lu (IC₅₀ = 24.70 μM) cell lines, with no cytotoxic effect against the prostate cells PrEC (CC₅₀ > 300 μM).