Design, synthesis and in vitro NO-releasing activities of ocotillol-type furoxans.

A series of novel ocotillol-type furoxan derivatives was synthesized by coupling various furoxans to 3-OH of 6-deoxy ocotillol, and their in vitro nitric oxide (NO) releasing capability was studied. The discharge of NO was examined after 30 min at two different concentrations, the results showed that all of the compounds tested could release NO in a dose-dependent manner. All of the synthesized compounds released similar amounts of NO at 100 μM, whereas at 500 μM these compounds showed more difference, in which compound II1, II3, II4, III2 displayed higher potency in releasing NO at this concentration. Analysis of the in vitro data showed that the derivatives bearing the same furoxan group on different ocotillol cores possessed various NO releasing capacity, suggesting that the structure of carrier of NO releasing groups may affect the NO release. Indeed, except compound II2, 24(S)-6-deoxy ocotillol derivatives from compound 6 with different furoxan substitutions at 3-OH and III2 displayed enhanced NO releasing capacity, compared to other compounds derived from compounds 5 and 9. The results illustrated that the functional group and the stereochemistry on the ocotillol structure may affect the NO release of furoxans.