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

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

doi:10.3389/fphar.2021.655008

Yuanyuan Song, Minzhen Xie + Show 7 more

Open Access

https://doi.org/10.3389/fphar.2021.655008

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Abstract

Eggplant (Solanum melongena 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 n-trans-p-coumaroyltyramine (1), n-trans-p-coumaroyloctopamine (2), n-trans-p-coumaroylnoradrenline (3), n-trans-feruloyloctopamine (4), and a phenylpropanoid neochlorogenic acid (5) were selected. In this study, these five representative compounds showed cytotoxic activities on A549, HCT116, and MCF7 cells. In addition, the metabolites of 1–5 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 (1-M2 and 2-M3) were clearly identified by comparison with reference standards. Rat liver microsome incubation experiments indicated that P450 enzymes could hydroxylate 1–5, and the methylation reaction of the 7-hydroxyl was also observed. This is the first study on the in vivo metabolism of these compounds, which lays a foundation for follow-up studies on pharmacodynamic evaluations and mechanisms.

Highlights

Solanum melongena is the calyx of Solanum melougeua L., and it is a widely used traditional Chinese herb in medicinal and edible fields
Methylation, glucuronidation, or sulfation were the main metabolic pathways of amides 1–4 and phenylpropanoid 5
Compounds 1–4 showed no significant change in cytotoxic activity over time in different cell lines, while the inhibition effect of 5 in MCF7 cells gradually increased with time, and the inhibition rate reached 86.5% at 72 h

Summary

Introduction

Solanum melongena is the calyx of Solanum melougeua L., and it is a widely used traditional Chinese herb in medicinal and edible fields. It has been described as having anticancer, antiinflammatory, antioxidant, and antiviral properties (Umamageswari and Maniyar, 2015; Di Sotto et al, 2018; Fekry et al, 2019; Jin et al, 2020; Khazaei et al, 2020). The chemical constituents of eggplant (Solanum melongena L.) mainly contain flavonoids, multiple alkaloids (including amides and glycoalkaloids), phenolic acids, and steroids.

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