Preliminary structure-activity relationship on theonellasterol, a new chemotype of FXR antagonist, from the marine sponge Theonella swinhoei.

Using theonellasterol as a novel FXR antagonist hit, we prepared a series of semi-synthetic derivatives in order to gain insight into the structural requirements for exhibiting antagonistic activity. These derivatives are characterized by modification at the exocyclic carbon-carbon double bond at C-4 and at the hydroxyl group at C-3 and were prepared from theonellasterol using simple reactions. Pharmacological investigation showed that the introduction of a hydroxyl group at C-4 as well as the oxidation at C-3 with or without concomitant modification at the exomethylene functionality preserve the ability of theonellasterol to inhibit FXR transactivation caused by CDCA. Docking analysis showed that the placement of these molecules in the FXR-LBD is well stabilized when on ring A functional groups, able to form hydrogen bonds and π interactions, are present.

Swinholide J, a potent cytotoxin from the marine sponge Theonella swinhoei.

In our ongoing search for new pharmacologically active leads from Solomon organisms, we have examined the sponge Theonella swinhoei. Herein we report the isolation and structure elucidation of swinholide A (1) and one new macrolide, swinholide J (2). Swinholide J is an unprecedented asymmetric 44-membered dilactone with an epoxide functionality in half of the molecule. The structural determination was based on extensive interpretation of high-field NMR spectra and HRESIMS data. Swinholide J displayed potent in vitro cytotoxicity against KB cells (human nasopharynx cancer) with an IC(50) value of 6 nM.

GPBAR1 Activation by C6-Substituted Hyodeoxycholane Analogues Protect against Colitis.

GPBAR1 agonists have been identified as potential leads for the treatment of diseases related to colon inflammation such as Crohn's and ulcerative colitis. In this paper, we report the discovery of a small library of hyodeoxycholane analogues, decorated at C-6 with different substituents, as potent and selective GPBAR1 agonists. In vitro pharmacological assays showed that compound 6 selectively activates GPBAR1 (EC50 = 0.3 µM) and reduces the production of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) in THP1 cells. The binding mode of compound 6 in GPBAR1 was elucidated by docking calculations. Moreover, compound 6 protects against TNBS-induced colitis in Gpbar1+/+ rodent model, representing an intriguing lead for the treatment of these inflammatory disorders.

Identification of a new sesquiterpene polyol ester from Celastrus paniculatus.

A new sesquiterpene polyol ester characterized as 1alpha,6beta,8beta-triacetoxy-9beta-benzoyloxydihydro-beta-agarofuran (1), along with the three known compounds: 1alpha,6beta,8alpha-triacetoxy-9alpha-benzoyloxydihydro-beta-agarofuran (2), angulatueoid C (3), and 1alpha,6beta,8beta,14-tetraacetoxy-9alpha-benzoyloxydihydro-beta-agarofuran (4), was isolated from the CCl (4)-soluble fraction of Celastrus paniculatus methanolic seed extract. All four compounds produce at a concentration of 1 microg/mL a relaxant effect on the isolated rat ileum of 31.4 +/- 7.5, 24.3 +/- 9.6, 24.4 +/- 4.9, and 16.2 +/- 7.2 %, respectively.