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

CIMO/Escola Superior Agrária, Instituto Politécnico de Bragança, Campus Sta Apolónia, Apartado 1 172, 5301-855 Bragança, Portugal.
Food and Chemical Toxicology (Impact Factor: 2.9). 08/2008; 46(7):2326-31. DOI: 10.1016/j.fct.2008.03.017
Source: PubMed

ABSTRACT The 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 beta-carotene linoleate model system. A concentration-dependent antioxidative capacity was verified in reducing power and DPPH assays, with EC50 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.

Download full-text


Available from: Ivo Oliveira, Sep 25, 2015
477 Reads
  • Source
    • "Antimicrobial secondary metabolites are produced by many plants, as a part of plant's normal growth process as well as a response to pathogen attack. Many investigations confirm the great antimicrobial potential of plant extracts (Kurc´ubicét al. 2014; Oliveira et al. 2008; Tekwu et al. 2012, Manojlovicét al. 2012; Vieira et al. 2014; Aleksic and Knezevic 2014). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Main conclusion The work investigated differences in apigenin content, as well as in other compounds, and examined the chemical profiles, antioxidant, antimicrobial and cytotoxic effects of extracts obtained from native and fermented chamomile ligulate flowers. Chamomile (Chamomilla recutita L.) has a long history of being used as a medicinal plant due to many health benefits, including antiinflammatory, anticancer, antispasmodic, radical-scavenging effects and others. Apigenin is recognized as one of the most bioactive phenolic compounds in chamomile. In comparison to its bound forms, which include mostly apigenin-7-O-β-glucoside and various acylated forms, the aglycone is attributed with much higher bioactivity. Due to this fact, in this work ligulate florets of chamomile anthodium were subjected to a fermentation process using native chamomile enzymes to hydrolyze bound forms of apigenin to free aglycone. The contents of apigenin and apigenin-7-O-β-glucoside were determined in both fermented and nonfermented samples by UHPLC-MS–MS analysis to define the efficiency of conversion. After defining their chemical profiles, the extracts of fermented and nonfermented chamomile samples were also compared with respect to their antioxidant, antimicrobial and cytotoxic effects. The antioxidant effects of the obtained extracts were defined by electron spin resonance analysis for hydroxyl and superoxide radicals. The antimicrobial activity was defined for eight microbial strains, whereas cytotoxic activity was evaluated using two human cell lines (human cervix carcinoma and human rhabdomyosarcoma) and murine fibroblasts.
    Planta 05/2015; DOI:10.1007/s00425-015-2308-2 · 3.26 Impact Factor
  • Source
    • "c o m / l o c a t e / u l t s o n which can produce serious side effects [25]. Polyphenols are the major plant compounds associated with healthy properties due to their antioxidant activity and free radical scavenging ability [26] [27], and several studies have demonstrated their antimicrobial activity, which make them a good alternative to chemical preservatives [28]. For example, desert Mexican plants are rich in polyphenols (i.e., tannin) [4] [17]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Several plants that are rich in polyphenolic compounds and exhibit biological properties are grown in the desert region of Mexico under extreme climate conditions. These compounds have been recovered by classic methodologies in these plants using organic solvents. However, little information is available regarding the use of alternative extraction technologies, such as ultrasound. In this paper, ultrasoundassisted extraction (UAE) parameters, such as the liquid:solid ratio, solvent concentration and extraction time, were studied using response surface methodology (RSM) for the extraction of polyphenols from desert plants including Jatropha dioica, Flourensia cernua, Turnera diffusa and Eucalyptus camaldulensis. Key process variables (i.e., liquid:solid ratio and ethanol concentration) exert the greatest influence on the extraction of all of the phenolic compounds (TPC) in the studied plants. The best conditions for the extraction of TPC involved an extraction time of 40 min, an ethanol concentration of 35% and a liquid-solid ratio ranging from 8 to 12 ml g�1 depending on the plant. The highest antioxidant activity was obtained in the E. camaldulensis extracts. The results indicated the ability of UAE to obtain polyphenolic antioxidant preparations from desert plants.
    Ultrasonics Sonochemistry 01/2015; DOI:10.1016/j.ultsonch.2014.06.001 · 4.32 Impact Factor
  • Source
    • "The study revealed a considerable level of variation among cultivars tested; this was not surprising when considering that cultivar dependent phenolic content variations have previously been observed in walnut (Oliveira et al., 2008; Cosmulescu and Trandafir, 2011b) and many other horticultural crops: apple (Lata et al., 2009), pear (Ozturk et al., 2009) and plum (Vasantha Rupasinghe et al., 2006). The difference of walnut cultivars in terms of phenolics is supposed to be resulting from cultivar's genetic origin, because all cultivars have the same age, and they were grown under the same ecological and farming conditions. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Walnut (Juglans regia L.) leaves constitute a good source of healthy compounds, namely phenolics, suggesting that they could be useful in prevention of diseases in which free radicals are involved. Leaves of different walnut cultivars grown in Romania were investigated as concerns phenolic compounds. Determination of phenolic compounds was conducted at the beginning of September. Total phenols and six phenolic compounds (ferulic acid, vanillic acid, coumaric acid, elagic acid, myricetin and juglone) were quantified. In order to identify and quantify the phenols, the colorimetric assay and method high performance liquid chromatographic method in reverse phase (HPLC-RP) was used. Phenolic compounds were identified in all cultivars, but quantitative differences were observed between cultivars. Results have proved that cultivar has influence on content of phenolic compounds, while mature leaves can be a source of phenolic compounds.
    Acta horticulturae 08/2014; 1050:205-212.
Show more