No abstract

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.

Five plant species namely, Phyllanthus acidus, Piper aduncum, Pandanus amaryllifolius, Macaranga peltata and Acacia mangium were analysed for their effective in-vitro bioactivity. The chloroform and aqueous extracted of the selected plants were subjected to TLC bioautography for antioxidant activity later all the extracted were subjected for DPPH assay where the chloroform extracts were found to express maximum antioxidant property. Amongst all the plants, Macaranga peltata accounted to 95% DPPH scavenging activity. The antimicrobial studies of the plant extracts were performed via agar well diffusion method, MIC determination, Biofilm inhibition assay in microtitre plate against clinical isolates like Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. It was found that Piper aduncum (chloroform and aqueous extract) and Macaranga peltata (only aqueous) expressed antibacterial activity, of which only chloroform extract of Piper aduncum could show negative influence against the biofilm development of P.aeruginosa.

In this study, SPIONs were produced in the presence of cobalt as catalyst. SPIONs formed by this chemical co-precipitation were size around 20 nm. After producing the SPIONs, it was subjected for functionalization with oleic acid and loaded with drug-itraconazole (a drug possess antifungal and antibacterial activity) and encapsulated with polyhydroxybutyrate (PHB). The produced core-shell SPIONS was used for antimicrobial study against two bacteria namely-Pseudomonas aeruginosa and Brevibacillus brevis and a fungi-Candida albicans. It was found to be effectively releasing drug for more than 3 hours. The SPIONs alone was acting good as contrasting agent and used for enhancing X-ray imaging.

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.