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Chen CH, Yu JY, Yang Z, Ke JP, Qi Y, Yang Y, Gao B, Yao G, Bao GH. Novel methylated flavoalkaloids from Echa 1 green tea inhibit fat accumulation and enhance stress resistance in Caenorhabditis elegans. Food Chem 2023; 413:135643. [PMID: 36773353 DOI: 10.1016/j.foodchem.2023.135643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 01/19/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023]
Abstract
Methylation is a common structural modification of catechins in tea, which can improve the bioavailability of catechins. Flavoalkaloids are catechin derivatives with a nitrogen containing five-membered ring at the C-6 or C-8 position. Here we isolated three new methylated flavoalkaloids from Echa 1 green tea (Camellia sinensis cv. Echa 1) and synthesized another four new methylated flavoalkaloids. The structures of the new ester-type methylated catechins (etmc)-pyrrolidinone A-G (1-7) were elucidated by various spectroscopic techniques, including nuclear magnetic resonance (NMR), optical rotation, infrared, UV-vis, experimental and calculated circular dichroism (CD) spectra, and high-resolution mass. Among them, 6 and 7 showed the strongest α-glucosidase inhibitory activity and significantly lowered lipid content of Caenorhabditis elegans with 73.50 and 67.39% inhibition rate, respectively. Meanwhile, 6 and 7 also exhibited strong antioxidant activity in vitro and stress resistance to heat, oxidative stress, and UV irradiation in nematodes.
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Affiliation(s)
- Chen-Hui Chen
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Jing-Ya Yu
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Zi Yang
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Jia-Ping Ke
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Yan Qi
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Yi Yang
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
| | - Biao Gao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Guangmin Yao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Guan-Hu Bao
- Natural Products Laboratory, International Joint Laboratory of Tea Chemistry and Healthy Effects, State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China.
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Zhang YY, Zhang P, Le MM, Qi Y, Yang Z, Hu FL, Ling TJ, Bao GH. Improving flavor of summer Keemun black tea by solid-state fermentation using Cordyceps militaris revealed by LC/MS-based metabolomics and GC/MS analysis. Food Chem 2023; 407:135172. [PMID: 36508871 DOI: 10.1016/j.foodchem.2022.135172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 10/04/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
Cordyceps militaris (C. militaris) has been approved and widely used in healthy food. The present study aimed to improve the flavor of summer Keemun black tea (KBT) using C. militaris solid-state fermentation. Combined with sensory evaluation, the volatile and non-volatile components of solid-state fermentation of KBT (SSF-KBT) and KBT were analyzed. The results showed that after the solid-state fermentation, the contents of total polyphenol, total flavonoid, and total free amino acids were significantly reduced. Further non-targeted metabolomics analysis revealed that the contents of non-galloylated catechins and d-mannitol increased, while the galloylated catechins and flavonoid glycosides decreased as did the bitterness and astringency of KBT. Dihydro-β-ionone and β-ionone (OAV = 59321.97 and 8154.17) were the aroma-active compounds imparting woody and floral odors in SSF-KBT, respectively. Current study provides a new avenue to develop summer-autumn KBT.
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