New pseudopterosin and seco-pseudopterosin diterpene glycosides from two Colombian isolates of Pseudopterogorgia elisabethae and their diverse biological activities

As part of an ongoing program to explore the chemical constituents of Caribbean marine invertebrates, a family of 13 new diterpene glycosides, pseudopterosins P-Z (1-11) and seco-pseudopterosins H (12) and I (13), have been isolated from the organic extracts of two collections of the sea whip Pseudopterogorgia elisabethae procured near the Colombian Southwestern Caribbean Sea. The structures of compounds 1-13, including absolute stereochemistry, have been proposed on the basis of comprehensive spectral analyses, chemical transformations, specific rotation, and TLC chromatographic analyses. Pseudopterosin Q (2) inhibited thromboxane B-2 (TXB2) (IC50 = 4.7 muM) and superoxide anion (O-2(-)) (IC50 = 11.2 muM) generation from E. coli lipopolysaccharide (LPS) activated rat neonatal microglia in vitro. In contrast, pseudopterosins P (1), U (6), V (7), W (8), and X (9) as well as seco-pseudopterosins H (12) and I (13) demonstrated minimal effects on both TXB2 and O-2(-) release. In addition, some of the new compounds displayed strong antituberculosis, antiviral, antimalarial, and anticancer activity.