Exploring the influence of steric, electronic and lipophilic descriptors of 1,3-diarly propenones on their anti-inflammatory activity

Background and the purpose of the study: Various compounds from natural and synthetic origins containing the 1,3-diarylpropenone structure have been reported to produce a variety of biological activities like anti-microbial, anti-inflammatory, vascular muscle relaxant, etc. A systematic analysis of the structural features responsible for anti-inflammatory activity and a possible mode of their actions were proposed to be evaluated by synthesizing a set of compounds, screening them for anti-inflammatory activity and developing a QSAR model. Two types of 1,3-diarylpropenone derivatives were synthesized employing the Claisen-Schmidt condensation. These compounds were then screened for their in vivo anti-inflammatory activity by the carrageenin induced rat paw edema method and also for in vitro cyclooxygenase-2 (COX-2) inhibition activity using a colorimetric kit for COX (ovine) inhibitor screening assay. These derivatives and their anti-inflammatory activity data were employed for QSAR analysis on Vlife MDS 3.5 software. The molecules were divided into training and test sets based on observed activity and QSAR models were generated for the training set and validated. The activity of the molecules of the test set was predicted according to the QSAR equation fit. Possible correlation between observed anti-inflammatory activity and in vitro cyclooxygenase-2 inhibition was also studied.Results and Insignificant difference between the observed and predicted biological activity revealed that the selected electronic, steric and lipophilic parameters have a significant correlation (r2 = 0.85) with anti-inflammatory activity of the selected class of compounds. On the basis of results it may be suggested that the 1,3-diaryl-2-propen-1-ones framework is an attractive template for structural optimization to achieve better potency of anti-inflammatory activity. Similarly, the relatively low correlation between anti-inflammatory activity and cyclooxygenase-2 inhibition indicates that other modes of actions may also be responsible for the anti-inflammatory activity of the tested compounds.