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AHL (acyl homoserine lactone) is a signaling molecule responsible for communication in gram negative bacteria, which is liable for bacterial virulence as well as biofilm formation. This study aims in targeting the AHL formation and AHL mediated virulence factor using plant extracts / plant metabolites. AHL plays a major role in pigment production, motility and rhamnolipid production in Pseudomonas aeruginosa. Inhibition of these mechanism by any mean implies that it is having impact in biofilm formation too. Plant derived metabolites/ extracts were subjected for swarming motility assay, the metabolite which inhibited the swarming motility was subjected for further study, where P. aeruginosa SU-3 was allowed to grow in the presence of the metabolite and its impact over the AHL production, pigment production and rhamnolipid production was evaluated. Curcumin was found to be effective against all the metabolites used. Thus curcumin subjected for molecular docking against ENR (enoyl carrier protein reductase), the enzyme involves in fatty acid synthesis and production of AHL.

Besides being an essential source of nutrients, the bioactive components of some fruits also help in enhancing the physiological functions by expressing its therapeutic action, acting as radical scavenger, improving digestion and healing. Here, seven edible fruits juices of Punica granatum, Citrus reticulata, Anana scomosus, Ficus carica, Vitis vinifera, Vitis amurensis and Carica papaya were utilized against biofilm forming Gram negative bacteria, Pseudomonas aeruginosa to evaluate its effect on Quorum sensing. On proving its antibacterial activity and anti-swarming motility in our earlier report, this work is extended to determine the biofilm inhibitory action of these fruit juices due to the impact on AHL (Acyl Homoserine lactone), the signaling molecule responsible for developing cell-cell communication and also on AHL mediated metabolites production. The fruit juices were evaluated for their Antioxidant activity on subjecting to TLC bioautography, DPPH and FRAP assay. AHL, Pyocyanin and Rhamnolipid were extracted from fruit juices treated Pseudomonas aeruginosa and the influence of fruit juice was identified by FT-IR and LC-MS analysis. However, AHL production was not stopped by fruit juice molecules but showed least production level in Punica granatum treated P.aeruginosa. Whereas the production of pyocyanin pigment was disturbed in Punica granatum, Citrus reticulata, Vitis amurensis and Vitis vinifera treated culture. The production of a biosurfactant called Rhamnolipid (Rha 10) was a failure in Citrus reticulata, Vitis amurensis, Vitis vinifera and Ficus carica treated P.aeruginosa. Thus the organism was restrained by the fruit juice molecules from expressing its virulence factors in spite of having no impact on AHL synthesis.

Several studies have suggested that irrespective of the mode of action of antibiotics, induction of oxidative stress also contributes to their bactericidal actions. When antioxidants are supplemented with antibiotics, the bactericidal effect of the antibiotic are reduced. Thus, in this study, sensitivity of norfloxacin was analysed in the presence of antioxidants like glutathione and ascorbic acids, then the influence of multivitamins in the sensitivity was also analysed. The effect was studied though disc diffusion, MIC (minimal inhibitory concentration) and DNA damage assays against the model organisms - Pseudomonas aeruginosa and Klebsiella pneumoniae. This study suggested that the antioxidant and vitamin solution were having influence over sensitivity towards the antibiotics whose MIC was determined at highest concentration with reduced zone of inhibition and DNA damage. Hence, these results lead to a hypothetical claim for the involvement of multivitamins / antioxidants to have antibacterial resistance development.

Dry beans and nuts are vital in our daily diet and contains high dietary fiber, poly-unsaturated fatty acids and phytochemical compounds such as phenolic and flavonoids. The objective of this study was to compare the antioxidant activities in selected dry beans and nuts and the effect of roasting. Roasted and raw dried nuts and beans were grounded into powder, extracted in 70% methanol and evaporated. The methanol extracts were subjected to 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging assay, 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, total phenolic content (TPC) assay and total flavonoid content (TFC) assay. Results were analyzed using ANOVA (p value