Chemical characterization of a PD-1/PD-L1 inhibitory activity fraction of the ethanol extract from Gymnadenia conopsea

Abstract

Searching for PD-1/PD-L1 inhibitor from medicinal plants has become a potential method to discover small molecular cancer immunotherapy drugs. Using PD-1/PD-L1 inhibitory activity assay in vitro, a bioactive fraction was obtained from the ethanol extract of Gymnadenia conopsea. A sensitive UPLC-HRMS/MS method was established for the rapid screening and identification of compositions from bioactive fraction. Based on the characteristic fragmentation patterns of standards analysis and extracted ion chromatogram (EIC) method, 46 compounds were rapidly screened and identified (including 35 succinic acid ester glycosides and 11 other compounds), among which 17 compounds were tentatively identified as new compounds.

Graphical Abstract

Keywords:

• Gymnadenia conopsea
• PD-1/PD-L1 inhibitory activity fraction
• UPLC-HRMS/MS
• succinic acid ester glycosides

Disclosure statement

There are no potential conflicts of interest to declare.

Additional information

Funding

This work financially supported by the grants from the National Natural Sciences Foundation of China (NNSFC; Grant No. 81760783); the Innovation Platform for the Development and Construction of Special Project of Key Laboratory for Tibet Plateau Phytochemistry of Qinghai Province (2020-ZJ-Y20) and Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University (SWHX202005); the Scientific Research Common Program of Beijing Municipal Commission of Education (Grant No. KM201911417014).