Diammonium glycyrrhizinate alleviates hepatopulmonary syndrome via restoring superoxide dismutase 3 activity in rats

Diammonium glycyrrhizinate ameliorates portal hypertension by regulating portal macrophage oxidation and superoxide dismutase 3

Portal hypertension (PHT) is a complication of liver diseases. Increased intrahepatic vascular resistance is attributed to reduced bioavailability of vasodilator substances. The macrophage activation and superoxide dismutase 3 (SOD3) involve in the pathogenesis of PHT. Diammonium glycyrrhizinate (DG) is the salt form of glycyrrhizin derived from Radix glycyrrhizae, exerting anti-oxidant activities and be beneficial for liver injury. Here, we aimed to investigate effects of DG on PHT and explore its underlying mechanisms on regulation of macrophages and SOD3. The carbon tetrachloride induced PHT rats received administration of liposome-encapsulated clodronate for hepatic macrophage depletion, or PBS liposomes for matched control. DG (25 mg/kg) or vehicle was gavaged. Portal pressure in vivo, and serum biomarkers of macrophage activation were measured. The nitric oxide (NO) and prostacyclin (PGI₂) bioavailability was evaluated in the isolated portal perfused rat livers. Liver tissues were collected to evaluate cirrhosis, macrophage oxidation, and SOD3 activity. Depletion of hepatic macrophages decreased portal pressure, increased bioavailability of NO and PGI₂, and restored SOD3 activity. DG effectively decreased portal pressure, relieved cirrhosis, inhibited macrophage activation. DG increased bioavailability of NO and PGI₂ to relax portal veins. DG relieved portal macrophage oxidation through decreasing nicotinamide adenine dinucleotide phosphate oxidase 2 and inducible NO synthase expressions, elevated SOD3 activities and increased SOD3 expressions at portal triads. These findings indicated that DG restored SOD3 activity, against portal macrophage oxidation, protected bioavailability of NO and PGI₂, thereby reduced portal pressure. It suggested a potential use of DG for PHT treatment.

Advances in Pharmacological Activities and Mechanisms of Glycyrrhizic Acid

Licorice (Glycyrrhiza glabra L.) is widely regarded as an important medicinal plant and has been used for centuries in traditional medicine because of its therapeutic properties. Studies have shown that metabolites isolated from licorice have many pharmacological activities, such as antiinflammatory, anti-viral, participation in immune regulation, anti-tumor and other activities. This article gives an overview of the pharmacological activities and mechanisms of licorice metabolites and the adverse reactions that need attention. This review helps to further investigate the possibility of licorice as a potential drug for various diseases. It is hoped that this review can provide a relevant theoretical basis for relevant scholars' research and their own learning.

Optimization of ultrasonic-assisted ultrafiltration process for removing bacterial endotoxin from diammonium glycyrrhizinate using response surface methodology

Ultrasonic-assisted ultrafiltration (UAU) removing bacterial endotoxin from diammonium glycyrrhizinate, was firstly applied to surfactant separation. Separation efficiency was related with four variables, including ultrafiltration molecular weight cut off (MWCO), ultrasonic power, concentration and pH. The SCQ-9200E ultrasonic system was provided for the study with adjustable ultrasonic power 80 W to 800 W, and the ultrasonic frequency was 40 KHz. On the basis of response surface methodology (RSM), the optimal separation conditions were determined to be the ultrafiltration MWCO as 10 kDa, the ultrasonic power as 570 W, diammonium glycyrrhizinate concentration as 150.00 μg/mL and the pH as 4.70. The experimental rejection of bacterial endotoxin was 94.08%, meanwhile the transmittance of diammonium glycyrrhizinate was 93.65%. Based on the ultrasonic power, solution volume, and ultrasonic container size, the experiments with UAU at different power intensities showed that ultrasonic at a power intensity of 57 W/L and the power density of 0.32 W/cm² could solve the separation contradiction between diammonium glycyrrhizinate and bacterial endotoxin. This study indicated that UAU could be an innovation in ultrasonic separation fields, and had a vast range of prospects for making use in pharmaceutical preparation area.

Diammonium Glycyrrhizinate Mitigates Liver Injury Via Inhibiting Proliferation Of NKT Cells And Promoting Proliferation Of Tregs

Purpose

Diammonium glycyrrhizinate (DG) is a replacement for glycyrrhizic acid, which is used as a hepatic protector in clinical practice for most liver diseases. The potential role of immune response during autoimmune hepatitis—induced by concanavalin A (Con A)—remains to be elucidated.

Methods

C57BL/6J mice were treated with two different doses of DG (75 and 200 mg/kg) 2 hrs before administering Con A. The mice were sacrificed after administering Con A for 0, 6, and 24 hrs. Liver damage grade and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin levels were evaluated. The expression level of cleaved-caspase 3 in liver was detected by Western blotting. Inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interferon γ (IFN-γ) in liver were detected by RT-PCR. Thymus, peripheral blood, spleen, and liver tissues were collected to analyze the percentages of NKT cells, subsets of CD4⁺CD25⁻CD69⁺ and CD8⁺CD69⁺ T cells, and subsets of regulatory T cells (Tregs).

Results

Our results revealed that DG pre-treatment significantly decreased the serum ALT and AST levels and improved the histological damage in Con A-induced autoimmune liver injury. Pre-treatment with DG down-regulated the inflammatory cytokines upon challenge with Con A. The DG pre-treatment inhibited the apoptosis of T lymphocytes in the thymus. Further, it effectively suppressed the proliferation of CD4⁺CD25⁻CD69⁺ and CD8⁺CD69⁺ subsets in the peripheral blood and spleen. In addition, the DG pretreatment significantly downregulated the frequency of NKT cells, while upregulating the frequency of Tregs in the liver.

Conclusion

We believe that the potential protective effect of DG against Con A-induced hepatitis may be partially attributed to its inhibitory activities on inflammatory cytokines in the livers, lymphocyte apoptosis in the thymus, NKT cells proliferation, and activation of CD8⁺T cells; further, there may also be a possibility of DC promoting Tregs proliferation.

Selective binding, magnetic separation and purification of histidine-tagged protein using biopolymer magnetic core-shell nanoparticles

In previous studies, we synthesized the magnetic core-shell structured Fe₃O₄/PMG/IDA-Ni²⁺ nanoparticles. The Ni²⁺ on the surface of nanoparticles provides abundant docking sites for histidine, and the composite nanoparticles showed potential applications in the separation and purification of histidine-tagged (His-tagged) proteins. Meanwhile, the presence of the superparamagnetic core (Fe₃O₄) in the nanoparticles allows them to be quickly separated and purified by an external magnetic field. Herein, the ability of magnetic nanoparticles to purify His-tagged human superoxide dismutase 1 (hSOD1) was verified. SDS-PAGE and activity data showed His-tagged hSOD1 specifically bound to Fe₃O₄/PMG/IDA-Ni²⁺, and there was no significant competition for binding between final and three intermediate products. The binding capacity of nanoparticles can reach to 62.0 mg/g (dry weight of hSOD1/nanoparticles). The nanoparticle-bound hSOD1 exhibited better thermal and storage stability compared to free hSOD1. Furthermore, the purification efficiency of the magnetic nanoparticles in the separation and purification of His-tagged proteins was comparable to the other two commercial materials (High Affinity Ni-NTA Resin, HisPur Ni-NTA Magnetic Beads). Finally, the magnetic nanoparticles can be reused in the binding of His-tagged protein for multiple times. In conclusion, the nanoparticles are ready to be applied in the separation and purification of His-tagged protein.