Seven new flavonoid glycosides from the roots of Glycyrrhiza uralensis and their biological activities

Spatial Distribution and Characterization of the Small-Molecule Metabolites and In Situ Hydrolyzed Oligosaccharides in the Rhizome of Glycyrrhiza uralensis by Desorption Electrospray Ionization-Mass Spectrometry Imaging and High-Resolution Liquid Chromatography-Mass Spectrometry

Characterization and spatial distribution studies of the metabolome in plants are crucial for revealing the physiology of plants and developing functional foods. Using the rhizome of Glycyrrhiza uralensis as a case, we integrated desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) and high-resolution liquid chromatography/mass spectrometry approaches aimed at characterizing and locating both the small molecules and the macromolecular polysaccharides. Under the optimal conditions, 21 flavonoids and 12 triterpenoids were detected and characterized in different tissues of the rhizome and another 19 components were characterized exclusively by DESI-MSI. Combined with hydrophilic interaction chromatography/ion mobility-quadrupole time-of-flight mass spectrometry, eight different degrees of polymerization of oligosaccharides (after in situ acid hydrolysis) were characterized from the rhizome of G. uralensis. Majority of these metabolites are located in the cortex, phloem, and medulla, which lays the foundation for understanding the physiology of G. uralensis. The useful information can benefit the sustainable utilization and further development of Glycyrrhiza resource.

Identification and quantification of compounds with Angiotensin-converting enzyme inhibitory activity in licorice by UPLC-MS

Licorice is a famous medicine-food herb for treating cardiovascular diseases in many compound prescriptions. Angiotensin-converting enzyme (ACE) is a key target of cardiovascular diseases. Despite its significance, there is limited scientific investigation regarding the ACE inhibitory effects of licorice. In this study, we used an activity-guided approach with an aggregation-induced emission (AIE) fluorescent probe to identify compounds with ACE-inhibitory activity in licorice. Nine components of licorice were found to have ACE inhibitory activity, in which 46 compounds were identified by using UPLC-QTOF-MS. Seven active compounds were found in this study. Among them, licochalcone B had best ACE inhibitory activity (IC50 = 0.24 μM). Finally, an UPLC-Q-MS method was established to quantify the five major active compounds in three batches of licorice. The findings of this study offer valuable insights into the potential of licorice as a source of ACE inhibitors and its relevance in the development of related products.

Glycyrrhizin inhibits LPS-induced inflammatory responses in goat ruminal epithelial cells in vitro

Inflammation plays a crucial role in the progression of Subacute Ruminal Acidosis (SARA). The experiment was designed to investigate anti-inflammatory effects of glycyrrhizin on goats ruminal epithelial cells (GREC) which were induced SARA by Lipopolysaccharide (LPS) in vitro. The GREC were induced SARA by adding LPS at the concentration of 5 μm and glycyrrhizin was added at different concentration of 0, 60, 90, 120, 150 μm. The structural integrity of LPS-induced GREC with the treatment of glycyrrhizin were observed by electron microscope; The levels of inflammatory factors TNF-α, IL-1β, IL-6, IL-8 and IL-12 were measured by ELISA; The number of Zo-1 and Occludin were measured, the expression of tight junction protein Occludin were measured by Western blot, and the mRNA expression of NF-κB, TNF-α, IL-1β, IL-6, IL-8 and IL-12 were measured in vitro. The results showed that higher concentration treatment of glycyrrhizin led to better morphology in LPS-induced GREC. Glycyrrhizin inhibited the growth of inflammatory factors TNF-α, IL-1β, IL-6, IL-8 and IL-12 in a dose-dependent manner. The number of ZO-1 and Occludin increased with the increase of adding of glycyrrhizin. Western blot analysis showed that the expression of tight junction protein Occludin in LPS-induced GREC increased with the adding of glycyrrhizin in a dose-dependent manner. Furthermore, the mRNA expression of NF-κB, TNF-α, IL-1β, IL-6, IL-8 and IL-12 decreased significantly with the increase treatment of glycyrrhizin. Glycyrrhizin significantly inhibits LPS-induced inflammatory mediators in GREC and the effects are better with the increase treatment of glycyrrhizin in vitro.

Isoliquiritigenin attenuates acute renal injury through suppressing oxidative stress, fibrosis and JAK2/STAT3 pathway in streptozotocin-induced diabetic rats

The aim of the current study was to evaluate the protective effects and mechanisms of isoliquiritigenin (ISO) on acute renal injury. CCK-8 assays were applied to assess the effects of ISO at different doses (20, 40, and 80 μg/mL) on oxidative damage in human renal HK-2 cells incubated with high glucose. After the diabetic nephropathy (DN) rat model was established, the model animals were randomly assigned to saline-treated control, three model groups received the 10, 20 and 40 mg/kg ISO, respectively, using the healthy Sprague-Dawley (SD) rats as normal control. The blood biochemical indexes, renal functions, oxidative stress, morphological changes, fibrosis- and JAK2/STAT3-related factors in DN model rats were all assessed. The cellular viability of the renal HK-2 cells with oxidative damages were all markedly ameliorated via the incubation of ISO between 10 and 80 μg/mL compared with negative control. In addition, the significantly down-regulated ROS content and up-regulated expression levels of GSH, SOD2, and GPX1 were all observed in ISO-treated groups. Long-term administration of ISO at different doses in DN rats effectively improved general diabetic characteristics and renal morphology. Furthermore, long-term administration of ISO could ameliorate excessive oxidation stress, down-regulate the expression levels of renal fibrosis- and inflammation-related factors, as well as inhibit the JAK2/STAT3 signaling pathway. In conclusion, ISO at all three dosages could efficiently improve the renal injury induced by STZ via ameliorating renal fibrosis, oxidative stress, and inhibiting JAK2/STAT3 signaling pathways in the DN rats.

Glycoside Compounds From Glycyrrhiza uralensis and Their Neuroprotective Activities

This paper concerns the study of the roots and rhizomes of Glycyrrhiza uralensis where one new alkaloid glycoside, 3,4-dihydroxyquinoline 4- O-β-d-glucopyranoside, along with 13 known compounds (12 phenolic glycosides and one triterpene glycoside) were isolated and identified. The structure of the new compound and the known ones were identified on the basis of nuclear magnetic resonance (NMR) and mass spectrometric (MS) analysis. All the glycosides were tested for their anti-neuroinflammatory activities by inhibiting nitric oxide (NO) release in lipopolysaccharide (LPS)-induced murine microglial BV-2 cells. Several compounds were tested for their antioxidant activities in rat adrenal pheochromocytoma PC12 cells. A structure–activity relationship (SAR) analysis was carried out and revealed that the position and amount of sugar moieties have significant impact on antioxidant activities.