Walnut (Juglans regia L.) leaves: Phenolic compounds, antibacterial activity and antioxidant potential of different cultivars

• Type: Article in International Scientific Journal
• Date: 2007

Authors

Jose Alberto Pereira (Author) Other; Ivo Oliveira (Author) Other; Anabela Sousa (Author) Other; Patricia Valentao (Author) FFUP; Paula B Andrade (Author) FFUP; Isabel C F R Ferreira (Author) Other; Federico Ferreres (Author) Other; Albino Bento (Author) Other; Rosa Seabra (Author) Other; Leticia Estevinho (Author) Other

Journal

Title: Food and Chemical Toxicology

Vol. 45 No. 10

Pages: 2287-2295

ISSN: 0278-6915

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 188 Citations

ISI Web of Science

Scopus - 299 Citations

Scientific classification

FOS: Agrarian Sciences > Other Agrarian Sciences

CORDIS: Health sciences

Other information

Authenticus ID: P-004-6GG

DOI: 10.1016/j.fct.2007.06.004

Resumo (PT): Different cultivars of walnut (Juglans regia L.) leaves (Cv. Lara, Franquette, Mayette, Marbot, Mellanaise and Parisienne) grown in Portugal, were investigated in what concerns phenolic compounds and antimicrobial and antioxidant properties. Phenolics analysis was performed by reversed-phase HPLC/DAD and 10 compounds were identified and quantified: 3- and 5-caffeoylquinic acids, 3- and 4-p-coumaroylquinic acids, p-coumaric acid, quercetin 3-galactoside, quercetin 3-pentoside derivative, quercetin 3-arabinoside, quercetin 3-xyloside and quercetin 3-rhamnoside. The antimicrobial capacity was screened against Gram positive (Bacillus cereus, B. subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Walnut leaves selectively inhibited the growth of Gram positive bacteria, being B. cereus the most susceptible one (MIC 0.1 mg/mL). Gram negative bacteria and fungi were resistant to the extracts at 100 mg/mL. Lara walnut leaves were also submitted to antibacterial assays using 18 clinical isolates of Staphylococcus sp. Antioxidant activity was accessed by the reducing power assay, the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and β-carotene linoleate model system. In a general way, all of the studied walnut leaves cultivars presented high antioxidant activity (EC50 values lower than 1 mg/mL), being Cv. Lara the most effective one. <br> <br> Keywords: Walnut leaves; Phenolics; Antimicrobial activity; Antioxidant properties <br> <a target="_blank" href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6P-4NYD8W0-4&_user=2460038&_coverDate=11%2F30%2F2007&_rdoc=24&_fmt=high&_orig=browse&_srch=doc-info(%23toc%235036%232007%23999549988%23669681%23FLA%23display%23Volume)&_cdi=5036&_sort=d&_docanchor=&_ct=30&_acct=C000057398&_version=1&_urlVersion=0&_userid=2460038&md5=253e6be04eeb9e3ee5ccfb6828c475e3"> Texto integral</a> <br> <br>

Abstract (EN): Different cultivars of walnut (Juglans regia L.) leaves (Cv. Lara, Franquette, Mayette, Marbot, Mellanaise and Parisienne) grown in Portugal, were investigated in what concerns phenolic compounds and antimicrobial and antioxidant properties. Phenolics analysis was performed by reversed-phase HPLC/DAD and 10 compounds were identified and quantified: 3- and 5-caffeoylquinic acids, 3- and 4-p-coumaroylquinic acids, p-coumaric acid, quercetin 3-galactoside, quercetin 3-pentoside derivative, quercetin 3-arabinoside, quercetin 3-xyloside and quercetin 3-rhamnoside. The antimicrobial capacity was screened against Gram positive (Bacillus cereus, B. subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Walnut leaves selectively inhibited the growth of Gram positive bacteria, being B. cereus the most susceptible one (MIC 0.1 mg/mL). Gram negative bacteria and fungi were resistant to the extracts at 100 mg/mL. Lara walnut leaves were also submitted to antibacterial assays using 18 clinical isolates of Staphylococcus sp. Antioxidant activity was accessed by the reducing power assay, the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and beta-carotene linoleate model system. In a general way, all of the studied walnut leaves cultivars presented high antioxidant activity (EC(50) values lower than I mg/mL), being Cv. Lara the most effective one.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9