Novel methylated flavoalkaloids from Echa 1 green tea inhibit fat accumulation and enhance stress resistance in Caenorhabditis elegans

Novel Flavonol Alkaloids in Green Tea: Synthesis, Detection, and Anti-Alzheimer’s Disease Effect in a Transgenic Caenorhabditis elegans CL4176 Model

“…The HRMS, 1 H, and 13 C NMR spectra of 1 suggest that myricetin was successfully substituted by the N -ethyl-2-pyrrolidinone group (Figure and Table ). − The 13 C and DEPT-135 NMR spectra reveal that 1 has 21 carbons, consisting of one methyl at δ C 11.8 (C-7″), three methylenes at δ C 30.5 (C-3″), δ C 23.6 (C-4″), δ C 34.2 (C-6″), four methines at δ C 98.3 (C-6), δ C 93.4 (C-8), δ C 107.9 (C-6′), δ C 56.9 (C-5″), and 13 quaternary carbons (Figures B and S6). The proton and carbon signals of the N -ethyl-2-pyrrolidinone group were determined by 2D NMR spectroscopic correlations including COSY (2.46, 3.32:0.69, 2H-6″/H-7″; 2.12, 2.27:4.49, 2H-4″/H-5″), NOESY (2.36:4.49, H-3″β/H-5″; 2.27:4.49, H-4″β/H-5″), HSQC (0.69:11.8, H-7″/C-7″; 2.12, 2.27:23.6, 2H-4″/C-4″; 2.21, 2.36:30.5, 2H-3″/C-3″; 2.46, 3.32:34.2, 2H-6″/C-6″; 4.49:56.9, H-5″/C-5″), and HMBC correlations (2.46, 3.32:11.8, 2H-6″/C-7″; 2.46, 3.32:56.9, 2H-6″/C-5″; 2.46, 3.32:173.1, 2H-6″/C-2″; Figures S7–S10).…”

“…A one-pot reaction was applied to synthesize flavonol alkaloids. , Compounds 1 – 3 : myricetin (318.0 mg), l -theanine (348.0 mg), and pTsOH (17.2 mg) were dissolved in water and heated under 120 °C, pH 2 for 48 h. Compounds 4 – 5 : quercetin (302.0 mg), l -theanine (348.0 mg), and pTsOH (17.2 mg) were dissolved in 20% MeOH (MeOH/H 2 O, v/v) and heated under 120 °C, pH 2 for 48 h. Compounds 6 – 7 : kaempferol (286.0 mg), l -theanine (348.0 mg), and pTsOH (17.2 mg) were dissolved in 50% MeOH and heated under 120 °C, pH 2 for 72 h. The target compounds ( m / z 428.1006 [M – H] − , 412.1051 [M – H] − , and 396.1088 [M – H] − ) were detected in the reaction mixture by HPLC-ESI-HRMS.…”

“…The adults were transferred to a new NGM every day, and the eggs were cultured at 16 °C to incubate. Only the number of successfully incubated offspring was counted at the L3-stage …”

“…Only the number of successfully incubated offspring was counted at the L3-stage. 24 CL4176 Strain Paralysis Assay. The synchronized L3-stage CL4176 strain was transferred to NGM plates containing inactivated OP50 and corresponding compounds (myricetin, quercetin, 1, 2, 3, 4, and huperzine A at 100 μM, with 0.1% DMSO as the control group).…”

“…Ethylpyrrolidinonyl theasinensin A is the first identified flavoalkaloid isolated from black tea . Since then, puerins I–VIII, etc-pyrrolidinone A–J, etmc-pyrrolidinone A–G, and spiro-flavoalkaloids A–D were reported in tea. Tea flavoalkaloids are inferred to form from the reaction between l -theanine and catechins. − Flavoalkaloids with flavonol frameworks have also been identified in many plants, but not in tea yet.…”