Phytochemical analysis and antibacterial activity of Gentiana macrophylla extract against bacteria isolated from burn wound infections

The management of burn wound victims is often considered a difficult task due to frequent infections. Moreover, the treatment with conventional antibiotics is associated with the upsurge of drug resistant bacterial strains. Therefore there is pressing need to explore antimicrobials that could overcome these problems. Plant extracts have been used as antimicrobials in different systems of medicine. Gentiana species have been widely used in Chinese system of traditional medicine for the treatment of various ailments including microbial infections. The aim of the present study was therefore to evaluate the antimicrobial activity of methanolic root extract of Gentiana macrophylla against bacterial strains isolated from wound bums. Preliminary phytochemical screening revealed the phenolic and flavonoids content of the extract to be 26.70 +/- 1.5 mg gallic acid equivalent (GAE)/g DW and 10.11 +/- 0.8 mg quercetin equivalent/g DW respectively. The phenolics and flavonoids content of the extract positively correlated with antioxidant activity of the extract. Evaluation of antimicrobial activity against bacterial strains isolated from wound bums revealed that the G. macrophylla extract exhibited significant antibacterial against all the tested bacterial strains. The MIC values ranged between 60 and 240 mu g/ml. The lowest MIC was observed for S. epidermidis and the highest MIC was observed for E. coll. The MBCs also followed the similar trend and ranged between 106 to 300 mu g/ml. To identify the active constituents responsible for the bioactivity of the extract LC/MS analysis was carried out which lead to the putative identification of five compounds including chlorogenic acid, rutin, sweroside, isogentisin, and gentisin. Taken together, these results indicate G. macrophylla can prove to be an important source of antioxidants and antimicrobials and may be used for the management of wound burns.