Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks

Abstract

a b s t r a c tThe total phenols content and antioxidant and antimicrobial activities were studied in walnut (Juglans regia L.) green husks aqueous extracts of five different cultivars (Franquette, Mayette, Marbot, Mellanaise and Parisienne). Total phenols content was determined by colorimetric assay and their amount ranged from 32.61 mg/g of GAE (cv. Mellanaise) to 74.08 mg/g of GAE t (cv. Franquette). The antioxidant capacity of aqueous extracts was assessed through reducing power assay, scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and b-carotene linoleate model system. A concentration-dependent antioxidative capacity was verified in reducing power and DPPH assays, with EC 50 values lower than 1 mg/ mL for all the tested extracts. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. All the extracts inhibited the growth of Gram positive bacteria, being Staphylococcus aureus the most susceptible one with MIC of 0.1 mg/mL for all the extracts. The results obtained indicate that walnut green husks may become important in the obtainment of a noticeable source of compounds with health protective potential and antimicrobial activity.

Synthesis and antibacterial activity of stable bio-conjugated nanoparticles mediated by walnut (Juglans regia) green husk extract

“…[13,14] The relatively small size, homogeneity and spherical shape of the nanoparticles made by walnut green husk extract may propose new applications, as compared to nanoparticles made by other biogenic methods. [8][9][10][11][12] Optimisation of the biosynthesis process for large-scale production, including the kinetics and efficiency of the reaction, besides the size and shape of the obtained nanoparticles, is currently under investigation in our lab.…”

Phenolic content and antioxidant capacity of extracts ofLaurus nobilisL.,Coriandrum sativumL. andAmaranthus hybridusL.

“…The total phenols content in the obtained extracts of L. nobilis, C. sativum and A. hybridus was determined using FolinCiocalteu reagent by slightly modifying the procedure previously described (Makkar, 1999;Oliveira et al, 2008). Briefly, 800 µL of sample was mixed with 800 µL of Folin-Ciocalteu phenol reagent.…”

In vitro antioxidant activities of Solanum surattense leaf extract

“…The reducing power of a compound may serve as a significant indicator of its potential antioxidant activity [27] . In The reducing power increased with the increasing amount of extract.…”