Compound Analysis of Jing Liqueur and nrf2 Activation by Jing Liqueur—One of the Most Popular Beverages in China

Abstract

The aim of this study is to identify the minor compounds in Jing liqueur, determine the concentration of metals, amino acids, and polysaccharides, and evaluate their Nrf2 activity and cytotoxicity. Jing liqueur that contains Chinese medicine is one of the best-selling liqueurs in China, which is also marketed in the United States. Totally, we have isolated 189 minor compounds including one new molecule (7) from a concentrated Jing liqueur, with the concentrations of most isolated compounds at micromolar levels. The structures of all these compounds were determined by using MS and NMR (1D and 2D) or by comparison of their chemical and physical data with reported values in the literatures. Besides, the concentrations of iron (0.52 mg/L), zinc (0.21 mg/L), calcium (11.0 mg/L), L-proline (2.33 mg/L), L-arginine (1.73 mg/L), total amino acids (9.84 mg/L), and total polysaccharides (337.4 mg/L) were determined. Jing liqueur, the five fractions and most of the compounds isolated from Jing liqueur were screened for their activities in the Nrf2-ARE and MTT assays. At 5.2 mg/mL the crude enhanced the Nrf2 activity. At 80 μg/mL, fraction IV weakly but fraction V strongly activated Nrf2. Among the compounds screened in the Nrf2 assay, eighteen activated Nrf2 at 40 μg/mL and compounds 51 and 126 from fraction V were the most active. The crude, all the five fractions, and Nrf2 activators were not cytotoxic toward HepG2 cells. In conclusion, Jing liqueur contains different classes of compounds including flavonoids, terpenoids, alkaloids, coumarins, cinnamic acid or coumaric acid, and phenyl ethanol (or acetic acid) derivatives, benzoquinone, naphthoquinone, anthraquinones or phenanphrene derivatives, xanthones, chromone, and γ-pyrone derivatives, lignans, other aromatic compounds, and others. Jing liqueur and the eighteen compounds, which were isolated from Jing liqueur, could activate Nrf2 without any cytotoxicity.

Cytoprotection against Oxidative Stress by Methylnissolin-3-O-β-d-glucopyranoside from Astragalus membranaceus Mainly via the Activation of the Nrf2/HO-1 Pathway

“…In our previous study, we isolated 189 minor compounds from Jing liqueur [13]. Most of the compounds were assayed on Nrf2-HepG2 stable cells using the luciferase system to identify Nrf2 activators at 40 µg/mL in triplicate [13]. Eighteen compounds were tested active, but they only activated Nrf2 moderately [13].…”

“…Most of the compounds were assayed on Nrf2-HepG2 stable cells using the luciferase system to identify Nrf2 activators at 40 μg/mL in triplicate [13]. Eighteen compounds were tested active, but they only activated Nrf2 moderately [13]. Further assay-guided separation of a crude extract led to the identification of MNG (3.1 μg/L = 7.7 nM; Figure 1; MS and 1 H NMR: Figures S1 and S2) as a potent Nrf2 activator.…”

“…Jing liqueur is a beverage containing biologically active compounds from some herbs, including Astragalus membranaceus, etc. [13]. In a previous study, we have isolated 189 minor compounds, among which 18 compounds activated Nrf2 at 40 µg/mL in an Nrf2-ARE assay [13].…”

“…[13]. In a previous study, we have isolated 189 minor compounds, among which 18 compounds activated Nrf2 at 40 µg/mL in an Nrf2-ARE assay [13]. In our continuing search for Nrf2 activators from the Jing liqueur, we obtained an extract.…”

“…Nrf2 assay-guided separation led to the isolation of methylnissolin-3-O-β-Dglucopyranoside [14] (MNG, Figure 1), a new Nrf2 activator that significantly activated Nrf2 at 40 µg/mL. MNG was much more active than any of the previously isolated 18 Nrf2 activators [13]. MNG was a component of A. membranaceus, which is a well-known tonic herb that has been used as both a traditional Chinese medicine and a food or beverage.…”