AUTHOR=Song Yuanyuan , Mei Ting , Liu Yan , Kong Shengnan , Zhang Jincheng , Xie Minzhen , Ou Shan , Liang Meixia , Wang Qi 

TITLE=Metabolites Identification of Chemical Constituents From the Eggplant (Solanum melongena L.) Calyx in Rats by UPLC/ESI/qTOF-MS Analysis and Their Cytotoxic Activities

JOURNAL=Frontiers in Pharmacology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.655008

DOI=10.3389/fphar.2021.655008

ISSN=1663-9812

ABSTRACT=<p>Eggplant (<italic>Solanum melongena</italic> L.) Calyx is a medicinal and edible traditional Chinese medicine with anti-inflammatory, anti-oxidant, and anti-cancer properties. However, the pharmacodynamic components and metabolic characteristics remain unclear. Amide and phenylpropanoid were the two main constituents, and four amides, including <italic>n</italic>-trans-<italic>p</italic>-coumaroyltyramine (<bold>1</bold>), <italic>n</italic>-trans-<italic>p</italic>-coumaroyloctopamine (<bold>2</bold>), <italic>n</italic>-trans-<italic>p</italic>-coumaroylnoradrenline (<bold>3</bold>), <italic>n</italic>-trans-feruloyloctopamine (<bold>4</bold>), and a phenylpropanoid neochlorogenic acid (<bold>5</bold>) were selected. In this study, these five representative compounds showed cytotoxic activities on A549, HCT116, and MCF7 cells. In addition, the metabolites of <bold>1–5</bold> from the eggplant calyx in rats were identified. In total, 23, 37, 29, and 17 metabolites were separately characterized in rat plasma, urine, feces, and livers, by UPLC/ESI/qTOF-MS analysis. The metabolism of amides and phenylpropanoid was mainly involved in hydroxylation, methylation, glucuronidation, or sulfation reactions. Two hydroxylated metabolites (<bold>1-M2</bold> and <bold>2-M3</bold>) were clearly identified by comparison with reference standards. Rat liver microsome incubation experiments indicated that P450 enzymes could hydroxylate <bold>1–5</bold>, and the methylation reaction of the 7-hydroxyl was also observed. This is the first study on the <italic>in vivo</italic> metabolism of these compounds, which lays a foundation for follow-up studies on pharmacodynamic evaluations and mechanisms.</p>