Pyocyanin Quantification Assay

To perform pyocyanin pigment quantification assay, P. aeruginosa H103 cells untreated (grown in presence of 1% DMSO) and treated with 100, 50, 25, 12.5, 6.25, 3.12, 1.6 and 0.8 μg mL^–1 of P. lentiscus L. fruit extracts (PLFE1-4) or ginkgolic acid-enriched fractions (PLFE1-(2-4)) were grown on 96-well microtiter plate for 24 h at 37°C on a rotary shaker (180 rpm). Then, supernatants samples were collected by centrifugation and extracted with chloroform. The chloroform layer (blue layer) was acidified by adding 0.5 M HCl. The absorbance of the HCl layer (pink layer) was recorded at 520 nm using the Spark 20 M multimode Microplate Reader controlled by SparkControl^TM software Version 2.1 (Tecan Group Ltd.) and the data were normalized for bacterial cell density (OD_580nm).