Silver ions (Ag+) and its compounds are highly toxic to microorganisms, exhibiting strong biocidal effects on many species of bacteria but have a low toxicity toward animal cells. In the present study, silver nanoparticles (SNPs) were biosynthesized using aqueous extract of Chlorella vulgaris as reducing agent and size of SNPs synthesized ranged between 15 and 47 nm. SNPs were characterized by UV–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Fourier infrared spectroscopy, and analyzed for its antibacterial property against human pathogens. This approach of SNPs synthesis involving green chemistry process can be considered for the large-scale production of SNPs and in the development of biomedicines.

ArticleSynthesis of silver nanoparticles and the antibacterial and anticancer activities of the crude extract of sargassum polycystum C. Agardh AbstractThe potential of the methanolic extract of the seaweed, Sargassum polycystum in the synthesis of silver nanoparticles was investigated. The extract synthesized appreciable quantities of silver nanoparticles of the size 5-7 nm, in 24 hrs. The particles were characterized by UV-Vis, FT-IR spectroscopy, HRTEM and XRD analysis. The results indicated that the algal extract can be utilized as an eco-friendly system for the synthesis of silver nanoparticles for various applications in the field of medicine. The methanolic extract of the alga, silver nitrate solution and their combination were tested for their antimicrobial activities against Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus. Anticancer activity of the extract and the silver nanoparticles were evaluated against the breast cancer line MCF-7. Active compounds in the crude extract of the alga were separated and identified as fatty acids by GC-MS analysis. These fatty acids together with the silver nanoparticles exhibited anticancer activity against the breast cancer cell line MCF-7. Results are presented and discussed in detail. Citation: N. Thangaraju, et al. Synthesis of silver nanoparticles and the antibacterial and anticancer activities of the crude extract of sargassum polycystum c.

In this study, biosynthesis of self-assembled gold nanoparticles (GNPs) was accomplished using an aqueous extract of green microalga, Chlorella vulgaris. The optical, physical, chemical and bactericidal properties of the GNPs were investigated to identify their average shape and size, crystal nature, surface chemistry and toxicity, via UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and antimicrobial activity. The sizes of the spherical selfassembled cores of the synthesized GNPs ranged from 2 to 10 nm. The XRD patterns showed a (111) preferential orientation and the crystalline nature of the GNPs. The results of the FTIR analysis suggested that the peptides, proteins, phenol and flavonoid carried out the dual function of effective Au III reduction and successful capping of the GNPs. Human pathogen Candida albicans and Staphylococcus aureus were susceptible to synthesized aqueous GNPs. Thus, biosynthesis, stabilization and self-assembly of the GNPs by Chlorella vulgaris extract can be an example of green chemistry and effective drug in the medicinal field.

50 50 50 48.01 and 51.02 µg/ml), respectively. Phytochemical screening of red seaweed extracts revealed the presence of phenols, protein, lipids and carbohydrates. The result suggest that crude methanolic extract of Conclusion: S. filamentosa have anti-diabetic potential through inhibition of-amylase and α-glucosidase. α

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