Aryl benzofuran derivatives from the stem bark of Calpocalyx dinklagei attenuate inflammation.

Calpocalyx dinklagei Harms (Fabaceae) is a tropical medicinal tree, which is indigenous to Western Africa. A phytochemical study of this local plant species from its stem bark has led to the isolation of two previously undescribed aryl benzofuran derivatives, named dinklagein A and B, together with eight known compounds. Their chemical structures were elucidated by use of extensive spectroscopic methods (IR, HREI-MS and 1D and 2D NMR). Among all isolates, dinklagein A displayed remarkably potent inhibitory activity against the production of nitric oxide (NO) in the lipopolysaccharide (LPS) induced RAW264.7 macrophages. SAR and molecular docking investigations on iNOS and previously undescribed compounds (dinklagein A and B) supported experimental data. Furthermore, dinklagein A dose dependently suppressed the LPS-stimulated iNOS expression at both mRNA and protein level. It also attenuated IL-1ß release, mRNA expressions of IL-1ß and COX-2 at low doses. These results suggest that dinklagein A can be developed as natural, multi-target agent against several inflammatory diseases.

Biological evaluation and molecular docking studies of nitro benzamide derivatives with respect to in vitro anti-inflammatory activity.

A series of nitro substituted benzamide derivatives were synthesized and evaluated for their potential anti-inflammatory activities in vitro. Firstly, all compounds (1-6) were screened for their inhibitory capacity on LPS induced nitric oxide (NO) production in RAW264.7 macrophages. Compounds 5 and 6 demonstrated significantly high inhibition capacities in a dose-dependent manner with IC50 values of 3.7 and 5.3µM, respectively. These two compounds were also accompanied by no cytotoxicity at the studied concentrations (max 50µM) in macrophages. Molecular docking analysis on iNOS revealed that compounds 5 and 6 bind to the enzyme more efficiently compared to other compounds due to having optimum number of nitro groups, orientations and polarizabilities. In addition, 5 and 6 demonstrated distinct regulatory mechanisms for the expression of the iNOS enzyme at the mRNA and protein levels. Specifically, both suppressed expressions of COX-2, IL-1ß and TNF-α significantly, at 10 and 20µM. However, only compound 6 significantly and considerably decreased LPS-induced secretion of IL-1ß and TNF-α. These results suggest that compound 6 may be a multi-potent promising lead compound for further optimization in structure and as well as for in vivo validation studies.