Analysis of phytochemical profile of Terminalia arjuna bark extract with antioxidative and antimicrobial properties

Objective:To investigate phytochemical screening,antimicrobial activity and qualitative thin layer chromatographic separation of flavonoid components,antioxidant activity and total flavonoid compound of Terminalia arjuna.Methods:For phytochemical screening,some common and available standard tests were done.Antimicrobial bioassay was done through agar well diffusion method.Detection of antioxidant activity and flavonoid compounds were done through thin layer chromatography.Total antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl(DPPH)in colorimetric method.Aluminum chloride colorimetric method was used for total flavonoid determination.Results:Phytochemical screening showed the active compounds presence in high concentration,such as phytosterol,lactones,flavonoids,phenolic compounds and tannins and glycosides.The anlimicrobial activity of extract showed that greater inhibition zone against Gram negative bacteria than Gram positive bacteria.This methanolic extract showed a promising antioxidant activity,as absorption of DPPH redicles decreased in DPPH free radical scavenging assay.Flavonoids components having antioxidant property present in the methanol extract at a level of199.00 mg quercetin equivalent/g of dried methanol extract in colorimetric method.Conclusions:The Terminalia arjuna bark extract revealed the presence of bio-active constituents which are known to exhibit medicinal as well as physiological activities.

Pathogenicity of Vibrio harveyi and its biocontrol using bacteriophages

Vibrio harveyi is a Gram-negative,rod-shaped,polar flagellate,facultatively anaerobic,halophilic,bioluminescent marine bacteria that belongs to the family of Vibrionaceae,class,Gammaproteobacteria.This pathogenic organism is responsible for various diseases of vertebrates and invertebrates in marine habitats,including shrimp aquaculture.Various symptoms like lesions,gastroenteritis,skin ulcers,eye lesions,and tail rot have been observed due to V.harveyi infection.The pathogenic-ity mechanism of V.harveyi involves endotoxin lipopolysaccharide,extracellular proteases,and bacteriophage interaction.Hemolysin genes encoded extracellular hemolysin-like phospholipase B toxin could inactivate fish species via the caspase inactivation pathway,ultimately leading to apoptosis.In addition,VBNC(viable but nonculturable)cells are another basis of vibriosis outbreaks in the shrimp aquaculture sector.The extensive amount of antibiotic use promotes the generation of multidrug-resistant strains.Therefore,as an alternative strategy to combat V.harveyi infection,bacteriophages are utilized as a biocontrol agent.However,there is a lack of research on the immobilization and development of encapsulation strategies of V.harveyi-infecting bacteriophages which need to be studied further.In conclusion,the pathogenicity of V.harveyi and its biocontrol by bacteriophages has been documented in this review.