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In vitro study of antibacterial activity of organic solvent extracts of three marine macroalgae viz., Chaetomorpha linum (Mell) Kuetzing, Enteromorpha compressa (L) Greville and Polysiphonia subtilissima Mont. showed specific activity in inhibiting the growth of three Gram-negative bacteria (Shigella flexneri, Vibrio cholerae and Escherichia coli) and two Gram positive bacteria (Bacillus subtilis and Bacillus brevis). The results revealed that the chloroform and ethyl acetate extracts were active against most of the pathogens whereas methanol and ethanol extracts were active only against S. flexneri.

This study aimed to assess soil nutrient status and heavy metal content and their impact on the predominant soil bacterial communities of mangroves of the Mahanadi Delta. Mangrove soil of the Mahanadi Delta is slightly acidic and the levels of soil nutrients such as carbon, nitrogen, phosphorous and potash vary with season and site. The seasonal average concentrations (ng/g) of various heavy metals were in the range: 14810-63 370 (Fe), 2.8-32.6 (Cu), 13.4-55.7 (Ni), 1.8-7.9 (Cd), 16.6-54.7 (Pb), 24.4-132.5 (Zn) and 13.3-48.2 (Co). Among the different heavy metals analysed, Co, Cu and Cd were above their permissible limits, as prescribed by Indian Standards (Co=17 ng/g, Cu=30|ig/g.Cd=3-6|t.g/g), indicating pollution in the mangrove soil. A viable plate count revealed the presence of different groups of bacteria in the mangrove soil. i.e. heterotrophs, free-living N2 fixers, nitrifyers, denitrifyers, phosphate solubilisers, cellulose degraders and sulfur oxidisers. Principal component analysis performed using multivariate statistical methods showed a positive relationship between soil nutrients and microbial load. Whereas metal content such as Cu. Co and Ni showed a negative impact on some of the studied soil bacteria. [ABSTRACT FROM AUTHOR]

Background: The Apiaceae or Umbelliferae is one of the largest families in terms of species representation in the plant kingdom. It is also a prominent family in the field of phytochemicals and pharmacology. The family is also quite prominent in the production of spices and condiments and food supplements in nutrition, aside from the potential of species in the family to induce apoptotic, antimicrobial, antitumor, and hepatoprotective activities., Objective: This work presents a detailed structural elucidation and functional aspects of phytochemicals from the Apiaceae or Umbelliferae family., Methods: Furthermore, the application of members of this family in traditional and modern pharmacology is emphasized. This review also highlights the linkage of phytochemicals used in the conventional system of medication for the development of novel therapeutics through a chain of pre-clinical and clinical trials., Conclusion: This study may represent a valuable step ahead in the clinical development of natural drugs for curing several ailments, including respiratory and virus-related diseases., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The emergence of infections caused by Acinetobacter baumannii, a multidrug-resistant bacterium, has been a concern worldwide. This bacterium is an important hospitalacquired pathogen that causes several diseases including ventilator-associated pneumonia, bloodstream infections, and meningitis. This study aimed to determine antibioticresistant mechanisms in the pathogenesis of A. baumannii and the alternative treatment strategies against it. The combined actions of outer membrane protein A, formation of a biofilm on biotic and abiotic surfaces, phospholipases C and D, metal homeostatic system, lipopolysaccharides, and verotoxins are relevant for virulence and pathogenesis. A. baumannii resists the broad-spectrum antibiotics by its mechanisms of resistance, such as β-lactamases, efflux pump, aminoglycoside modifying enzymes, permeability changes, and alternation of targets. In an attempt to overcome the resistance mechanisms, plant-derived compounds and a combination of the antibiotics and the plant phytocompounds have been focused. Nanoparticles synthesised with the plant extract have been studied extensively. Furthermore, we projected modern methods, including multi-omics analysis, to study insight into mechanisms of actions of antibiotics. The information suggested that the potential antibiotic mechanisms of A. baumannii could lead to an alternative treatment against A. baumannii infections.

Objective: To investigate the in vitro antioxidant and antimicrobial activities along with phytochemical screening of organic and aqueous extracts of leaf and stem of Suaeda maritima (Dumort), a mangrove associate from Bhitarkanika of Odisha, India., Methods: Antioxidant activity of the crude extracts was evaluated in terms of total antioxidant capacity, total phenol content, ascorbic acid content, DPPH radical scavenging, metal chelating, nitric oxide scavenging, and reducing power etc. The antimicrobial activity of the plant was determined by agar well diffusion method along with MIC and MBC carried out by microdilution techniques against 10 gram positive and gram negative human pathogenic bacteria. The qualitative and quantative phytochemical screening were carried out by standard biochemical assays., Results: Out of the seven antioxidant bioassays, both the leaf and stem extracts were found to posses strong antioxidant properties of 70 % to 92 % for phenol, total antioxidant capacity, DPPH free radical scavenging activity and fairly good ascorbic acid content, metal chelating (1.33 %-22.55 %), reducing power (0.01-0.12) and nitric oxide scavenging (0.84 %-66.99 %) activities. Out of the four extracts evaluated for antimicrobial activity, two leaf extracts such as acetone and ethanol showed promising activity against four pathogenic bacteria and one stem methanol extracts against one pathogenic bacteria when compared with amoxcycillin as standard. The MIC and MBC values of the antimicrobial extracts ranged between 2.5 to 5.0 mg/mL. Screening of phytochemicals showed presence of carbohydrates, protein, tannins, alkaloids and flavonoids in comparatively higher amount than other phytochemicals tested., Conclusions: The present study reveals the presence of potential antioxidants and antimicrobial properties in the plant extract which could be exploited for pharmaceutical application., (Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.)