Inhibitory Mechanism on Combination of Phytic Acid with Methanolic Seed Extract of Syzygium cumini and Sodium Chloride over Bacillus subtilis.

Abstract

The antibiotic resistance in bacteria responsible for causing community and health care-associated infection displayed a major threat to global health. Use of broad-spectrum antibiotics for the treatment of various ailments poses serious side effects. In the present research, we investigated the combined role of 2% phytic acid with 2% methanolic seed extract of Syzygium cumini and 0.5% sodium chloride for inhibition of Bacillus subtilis and Pseudomonas aeruginosa and found it to be efficient over B. subtilis. The zone of inhibition by present mixture was found to be 2.9 ± 0.0004 and 1.9 ± 0.0006cm against Bacillus subtilis and P. aeruginosa in comparison to individual component. Mixture was found more potent against B. subtilis and selected for further study. The underlying mechanism involved in inhibitory action of this mixture was determined by Scanning electron microscope, DNA fragmentation and propidium iodide staining. Scanning electron microscopy revealed that inhibition of B. subtilis by this mixture is mainly due to the disruption of bacterial cell membrane, leakage of internal cellular content which ultimately leads to the death of bacterial cells. DNA fragmentation showed apoptotic hallmark through degradation caused by mixture against B. subtilis at various time intervals. Likewise, PI staining also revealed the disruption of bacterial membrane by the mixture as the PI gives fluorescence after binding with DNA. The present study concludes that inhibitory potential of this mixture is mainly due to disruption of bacterial cell membrane, degradation of DNA and creation of pores in the membrane. The mixture could be used for inhibition of food pathogen B. subtilis.