Abstract

• This research focuses on the molecular confirmation of Pseudomonas aeruginosa isolated from the clinical soil sample collected from Insein General Hospital, Yangon Region, and evaluation of some bioactive secondary metabolites from it. The isolated P. aeruginosa strain characterized by microscopic examination and biochemical tests was confirmed by 16S rRNA sequencing technique. The chloroform extract was prepared from the P. aeruginosa culture in a large scale for the investigation of the chemical constituents. According to silica gel chromatographic separation on the chloroform extract, five nitrogeneous compounds such as 1-hydroxyphenazine, phenazine-1- carboxylic acid, cyclo-(L-Leu-L-Pro), cyclo-(D-Pro-D-Leu) and cyclo-(D-Pro-L-Val) were isolated. These isolated secondary metabolites were structurally identified by using modern NMR spectroscopic techniques such as 1H NMR, 13C NMR, COSY, HSQC, ROESY, HMBC spectroscopies, and mass spectrometry. The two isolated phenazines: 1-hydroxyphenazine and phenazine-1-carboxylic acid were found to be potent in antimicrobial activity with the inhibition zone diameters ranged between (21 ~ 32 mm) and (15 ~ 31 mm), whereas the remaining three diketopiperazines showed mild antimicrobial activity (inhibition zone diameters between 12 mm ~ 14 mm). In addition, 1-hydroxyphenazine (IC50 = 14.12 µg/mL) and phenazine-1-carboxylic acid (IC50 = 15.0 µg/mL) were found to exhibit good antiproliferative activity against human breast cancer cell MCF7 and the remaining three compounds: cyclo(L-Leu-L-Pro) (IC50 = 176.4 µg/mL), cyclo(D-Pro-D-Leu) (IC50 = 87.7 µg/mL) and cyclo(D-Pro-L-Val) (IC50 = 196.5 µg /mL) have mild antiproliferative activity.