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: 1034
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016
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
Purpose: To perform a qualitative and quantitative analysis of catechin and quercetin in flavonoids extracted from Rosa roxburghii Tratt.
Methods: Total flavonoids were determined using ultraviolet spectrophotometry (UV) at 500 nm. The optimal gradient program started with 15 % methanol and was kept within a period of 0 - 20 min, while 25 % methanol was kept within 20 - 33 min. Subsequently, the concentration of methanol was reduced to 15 % and was held for 10 min until the next injection. Mass spectrometry spray voltage was 4,000 V, ionization temperature 350 °C, atomizer pressure 35 psi, nitrogen flow rate 8 L/min, and mass scan range 200 - 800 m/z. The detection wavelength used for catechin and quercetin was 270 and 368 nm, respectively.
Results: Based on the UV results, Rosa roxburghii Tratt content was 73.85 %, which is in agreement with the national standard. Liquid chromatography-mass spectrometry (LC-MS) results indicate that Rosa roxburghii Tratt flavonoids contained quercetin, 34.26 %, with relative standard deviation (RSD) of 2.88 % and catechin content of 2.97 % with RSD of 1.49 %.
Conclusion: The proposed measurement method for determining the content of flavonoids in Rosa roxburghii Tratt has the advantage of simplicity, feasibility, good repeatability, and rapid and accurate analysis.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6402602 | PMC |
http://dx.doi.org/10.4314/tjpr.v17i1.11 | DOI Listing |
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!