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Zhu H, Wang K, Chen S, Kang J, Guo N, Chen H, Liu J, Wu Y, He P, Tu Y, Li B. Saponins from Camellia sinensis Seeds Stimulate GIP Secretion in Mice and STC-1 Cells via SGLT1 and TGR5. Nutrients 2022; 14:nu14163413. [PMID: 36014921 PMCID: PMC9416400 DOI: 10.3390/nu14163413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/14/2022] [Accepted: 08/17/2022] [Indexed: 12/03/2022] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is one of the important incretins and possesses lots of physiological activities such as stimulating insulin secretion and maintaining glucose homeostasis. The pentacyclic triterpenoid saponins are the major active ingredients in tea (Camellia sinensis) seeds. This study aimed to investigate the effect of tea seed saponins on the GIP secretion and related mechanisms. Our data showed that the total tea seed saponins (TSS, 65 mg/kg BW) and theasaponin E1 (TSE1, 2–4 µM) could increase the GIP mRNA and protein levels in mice and STC-1 cells. Phlorizin, the inhibitor of Sodium/glucose cotransporter 1 (SGLT1), reversed the TSE1-induced increase in Ca2+ and GIP mRNA level. In addition, TSE1 upregulated the protein expression of Takeda G protein-coupled receptor 5 (TGR5), and TGR5 siRNA significantly decreased GIP expression in TSE1-treated STC-1 cells. Network pharmacology analysis revealed that six proteins and five signaling pathways were associated with SGLT1, TGR5 and GIP regulated by TSE1. Taken together, tea seed saponins could stimulate GIP expression via SGLT1 and TGR5, and were promising natural active ingredients for improving metabolism and related diseases.
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Affiliation(s)
- Huanqing Zhu
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Kaixi Wang
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Shuna Chen
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Jiaxin Kang
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Na Guo
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Hongbo Chen
- Department of Tea Science, Zhejiang Shuren University, 8 Shuren Road, Hangzhou 310000, China
| | - Junsheng Liu
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Yuanyuan Wu
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Puming He
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Youying Tu
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Bo Li
- Department of Tea Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
- Correspondence:
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