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
Objective: To explore an HPLC method for determination of rhnchophylline and isorhnchophylline in Uncaria rhnchophylla.
Method: An HPLC method has been developed for determination of rhnchophylline and isorhnchophylline. The transformation of rhnchophylline and isorhnchophylline after heating was also studied by HPLC-ESI-MS.
Result: Good linearities of rhynchophylline and isorhynchophylline were 0.064-5.100, 0.064-5.110 mg, respectively. The average recoveries were from 87.51% to 88.83% for rhynchophylline and from 107.9% to 113.9% for isorhynchophylline. The recoveries of rhynchophylline and isorhnchophylline reference solutions after extraction were 12.60% and 40.00% in the reflux extraction procedure, respectively. While in the ultrasonic extraction procedure, the average recoveries of rhynchophylline and isorhynchophylline was from 99.48% to 103.2% and from 97.00% to 99.59%, resepectively. The recoveries of rhynchophylline and isorhnchophylline reference solutions after extraction were 47.08% and 51.03%, respectively. The unqualified recovery could be elucidated by HPLC-ESI-MS analysis, indicating that trhynchophylline could be transformed mostly into isorhynchophylline and a little amount of unkown composition, while isorhynchophylline could be transformed into rhynchophylline isocorynoxeine, corynoxeine and 22-O-beta-D-glucopyranosyl isocorynoxeinic acid during the extraction procedure.
Conclusion: Ultrasonic extraction procedure was more sutble for HPLC determination of the content of rhynchophylline and isorhynchophylline in U. rhnchophylla, however, the recovery problems should be paid attention to when it comes to the determination.
Download full-text PDF |
Source |
---|
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!