Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Inside the human body, reactive derivatives of oxygen, known as reactive oxygen species (ROS) such as the superoxide radical (O•), hydroxyl radical (•OH) and hydrogen peroxide (HO), are constantly generated. The ROS easily cause oxidative damage to various biomolecules such as proteins, lipids and DNA leading to various disease conditions. Iron chelators function as antioxidants by scavenging ROS and also reduce the amount of available iron thereby decreasing the quantity of •OH generated by Fenton reactions. In this study, the antioxidant activity of the iron chelators: caffeic acid (CA), 2,3-dihydroxybenzoic acid (DHBA), desferroxamine B (FOB) and benzohydroxamic acid (BHA) were determined using five different antioxidant assays. The antioxidant assays used were: iron binding ability, reducing ability using the potassium ferricyanide reduction method, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, HO scavenging activity and •OH scavenging activity. The standard used for the iron binding ability was NaEDTA whereas vitamin C was used as a standard for the remaining assays. The iron chelators showed a concentration dependent increase in their radical scavenging activities as well as their reducing ability. At the concentration of 1 mM, FOB had the highest iron binding ability of 93.7% whereas DHBA had the lowest iron binding ability of 5.0% compared to the standard NaEDTA which had 94.8%. The iron chelators, with the exception of BHA, showed good reducing ability than vitamin C. Caffeic acid showed significant DPPH, hydrogen peroxide and hydroxyl radical scavenging activities of 84.7%, 99.8% and 14.5%, respectively. All the iron chelators were observed to show significant activities in all five antioxidant assays.
Download full-text PDF |
Source |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5598521 | PMC |
http://dx.doi.org/10.1016/j.toxrep.2015.04.005 | DOI Listing |
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