Characterization, antioxidant and antimicrobial activities of green synthesized silver nanoparticles from Psidium guajava L. leaf aqueous extracts

2018 ◽  
Vol 86 ◽  
pp. 1-8 ◽  
Author(s):  
Lu Wang ◽  
Yanan Wu ◽  
Jia Xie ◽  
Sheng Wu ◽  
Zhenqiang Wu
2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Kaliyamoorthy Kalidasan ◽  
Nabikhan Asmathunisha ◽  
Venugopal Gomathi ◽  
Laurent Dufossé ◽  
Kandasamy Kathiresan

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.


2014 ◽  
Vol 76 ◽  
pp. 256-263 ◽  
Author(s):  
S. Lokina ◽  
A. Stephen ◽  
V. Kaviyarasan ◽  
C. Arulvasu ◽  
V. Narayanan

2017 ◽  
Vol 6 (7) ◽  
pp. 5441 ◽  
Author(s):  
Geetha Venugopal

In the present study, Psidium guajava leaves were taken for synthesizing silver nanoparticles and checked their antibacterial activity against E.coli, Klebsiella, Pseudomonas, Staphylococcus and Acinetobacter. The plant extract was analysed for the detection of the presence of protein, carbohydrate, flavonoids, terpenoids, glycosides, steroids, saponins, phenols and tannins. In this present study, the antibacterial activity of green synthesized silver nanoparticles from guava leaf shows the zone of inhibition against all the five pathogens.


2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Rudabeh Rufchaei ◽  
Mahdi Abbas-Mohammadi ◽  
Alireza Mirzajani ◽  
Shiva Nedaei

Background: Water hyacinth (WH) is an aquatic weed and one of the most productive plants on earth, causing serious environmental problems. Herein, some nutritional and phytochemical constituents of WH were investigated. Methods: Chemical analysis of Eichhornia Crassipes was carried out to determine total ash, humidity, crude protein, fat, fiber, and carbohydrate contents. Total phenolic and total flavonoid contents of the hydro-methanolic and aqueous extracts of the plant were determined using the Folin Ciocalteu and aluminum chloride colorimetric methods, and HPLC was performed to quantify eight phenolic compounds. The antioxidant and antimicrobial activities of the extracts were also evaluated. Results: The dry matter, total ash, crude protein, crude fiber, nitrogen-free extract, and ether extract contents of WH constituted 9.4, 12.9, 24, 11.5, 49.9, and 1.7%, respectively. The total phenolic contents of the hydro-methanolic and aqueous extracts were 491.2 ± 31.9 and 258.3 ± 10.8 mg gallic acid equivalents/g of dried extract, respectively. The total flavonoid content of the hydro-methanolic extract (76.8 ± 7.8) was higher than that of the aqueous extract (46.1 ± 6). Ferulic acid was found to be the most abundant phenolic compound in both extracts. The antioxidant activities of the hydro-methanolic and aqueous extracts were determined to be 221.52 and 97.07 mg ascorbic acid equivalent/g dry weight, respectively. The aqueous and hydro-methanolic extracts showed the highest antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, respectively. Conclusions: In conclusion, the present study indicated the applicability of WH as a natural source of antioxidants and antimicrobial agents.


2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
JongKwon Seo ◽  
Soo Jung Lee ◽  
Marcus Elam ◽  
Ashley Carter ◽  
Sarah A. Johnson ◽  
...  

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