Anti-Inflammatory Potential of Green Synthesized Silver Nanoparticles of the Soft Coral Nephthea Sp. Supported by Metabolomics Analysis and Docking Studies

Soft corals have been endorsed as a plentiful source of bioactive compounds with promising anti-inflammatory activities; therefore, exploring their potential as source of anti-inflammatory metabolites has stimulated a growing research interest. To investigate the anti-inflammatory potential of the soft coral, sp., in its bulk and silver nanostructure. Metabolomics analysis of sp., followed by molecular docking studies, was also conducted in order to explore and predict the secondary metabolites that might provide its inhibitory actions on inflammation. The petroleum ether and ethyl acetate fractions were used to synthesize silver nanoparticles. The prepared silver nanoparticles were characterized through UV-vis spectrophotometric, transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) analyses. Testing for the anti-inflammatory activity was performed against COX-1 and COX-2. Furthermore, liquid chromatography-mass spectrometry (LC-MS) based metabolomics analysis and molecular docking were also applied. A variety of secondary metabolites were identified, among them, sesquiterpenes were found to prevail. The petroleum ether and acetone fractions of sp. showed the highest COX-2 inhibitory activities, possibly attributable to their substantial contents of terpenoids. Additionally, the green synthesized silver nanoparticles of both the petroleum ether and ethyl acetate fractions of sp. demonstrated higher anti-COX-2 properties. The obtained results showed the effectiveness of non-targeted metabolomics technique in metabolic profiling of sp., helping the search for new bioactive metabolites in future chemical studies on this soft coral. The interesting anti-inflammatory potential of the tested extracts and their nanoparticles could also be relevant to the development of new, effective anti-inflammatory agents.