Structure, Absolute Configuration, Antiproliferative and Phytotoxic Activities of Icetexane and Abietane Diterpenoids from and Chemotaxonomic Implications.

From the aerial parts of Zamudio and Bedolla, three new icetexane-type diterpenoids were isolated. Their structures were established through spectroscopic methods and named the following: salvicarranzanolide (), 19-deoxo-salvicarranzanolide () and 19-deoxo-20-deoxy-salvicarranzanolide (). In addition, the known icetexane-type diterpenoids, 6,7,11,14-tetrahydro-7-oxo-icetexone (), -icetexone (), 19-deoxo--icetexone (), icetexone (), 19-deoxo-icetexone () and 7α-acetoxy-6,7-dihydroicetexone (), were also isolated, along with the abietanes sessein () and ferruginol (). α-Tocopherol was also identified. Compounds , and were tested for their antiproliferative activity using the sulforhodamine B assay on six cancer and one normal human cell lines. Diterpenoids and showed noteworthy antiproliferative activity, exhibiting an IC (μM) = 0.43 ± 0.01 and 1.34 ± 0.04, respectively, for U251 (glioblastoma), an IC (μM) = 0.45 ± 0.01 and 1.29 ± 0.06 for K5621 (myelogenous leukemia), 0.84 ± 0.07 and 1.03 ± 0.10 for HCT-15 (colon cancer), and 0.73 ± 0.06 and 0.95 ± 0.09 for SKLU-1 (lung adenocarcinoma) cell lines. On the other hand, the phytotoxicity of compounds - and - was evaluated on seed germination and root growth in some weeds such as , , and as models. While compounds and exhibited a moderate inhibitory effect on the root growth of and at 100 ppm, the diterpenoids , and were ineffective in all the plant models. Taxonomic positions based on the chemical profiles found are also discussed.