GABRIELA STANCIU, FLORIN AONOFRIESEI, NICOLETA CRISTACHE, SIMONA LUPSOR QUANTITATIVE ANALYSIS AND ANTIBACTERIAL ACTIVITY OF SOME COUMARINS EXTRACTS Extracts of melilot, cinnamon and ash were analyzed with TLC and molecular absorption spectrometry. With TLC method coumarin and coumarins derivatives (fraxetin, psoralen and scopoletin) contained in the studied plants were identified. The coumarin concentrations in melilot (637.84 mg/100g d.w) and cinnamon (58.594 mg/100g d.w.) were the highest. Melilot and cinnamon extracts have been tested against two reference bacterial strains and against two clinical bacterial strains in order to preliminary evaluate their antimicrobial profile. Our results showed a significant response of bacterial growth on culture media when exposed to coumarin derivatives found in melilot and cinnamon extracts. Overall, the inhibitory activity of extracts was higher on Gram positive bacteria on one hand and on clinical strains on the other hand suggesting an important practical aspect.