Dammarane-type triterpenoid saponins are regarded as the main active constituents of Gynostemma longipes C.Y.Wu. By using MCI and silica gel column chromatography, as well as preparative HPLC, we isolated four new dammarane-type triterpenoid saponins from the polar saponin fraction of G. longipes C.Y.Wu. Their structures were determined by comprehensive analyses of NMR and MS data and identified as (20S)-3β, 20, 21-trihydroxydammar-19-oxo-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl}-21-O-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside (1), (20S)-3β, 20, 21-trihydroxydammar-24-ene-19-oxo-3-O-[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl-21-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside (2), (20S)-3β, 19, 20, 21-terahydroxydammar-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-xylopyranosyl(1→3)]-α-L-arabinopyranosyl}-21-O-[β-D-glucopyranosyl(1→6)]-β-D-glucopyranoside (3), (20S)-3β, 20, 21-trihydroxydammar-24-ene-3-O-{[α-L-rhamnopyranosyl(1→2)]-[β-D-glucopyranosyl(1→3)]-β-D-glucopyranosyl}-21-O-[β-D-glucopyranosyl(1→6)]-β-D-glucopyranoside (4). Compounds 1-4 are new dammarane-type triterpenoid saponins which contain five glycosyl residues.

There is no specific drug against COVID-19, but berberine (BBR) has moderate anti-SARS-CoV-2 pseudovirus activity. Taking BBR as the lead, 18 novel N-cycloberberine derivatives were synthesized and evaluated for their anti-SARS-CoV-2 pseudovirus activities in vitro. Structure-activity relationship analysis revealed that introducing an appropriate heterocyclic group at position 9 might be beneficial for potency. Among the tested compounds, compound 3m showed the most potent activity against SARS-CoV-2, with EC₅₀ value of 1.61 μmol·L^-1 and SI value of 22.2, much better than that of BBR. Additional experiment indicated that 3m had inhibitory activity on multiple processes in viral invasion, including adsorption and membrane fusion, suggesting a multi-target synergistic mechanism of action. These results provide a novel family of lead compounds for the discovery of anti-SARS-CoV-2 candidates.

In this study, in vitro experiments were conducted to investigate that sinomenine inhibits the macrophage classic activation by up-regulating the expression of paired immunoglobulin-like receptor B (PIR-B). A macrophage model with classic activation was established by lipopolysaccharide and interferon-gamma co-stimulation. Real-time fluorescence reverse transcription-polymerase chain reaction was executed for evaluating the PIR-B gene expression, and Western blot for PIR-B protein expression, in macrophages, respectively. The tumor necrosis factor α and interleukin 8 in cell culture supernatant were measured by enzyme-linked immunosorbent assay. The flow cytometry was utilized to detect M1 macrophages. The PIR-B expression in situ was observed by laser scanning confocal microscope. The results showed that sinomenine significantly increased the expression of PIR-B, markedly reduced the percentage of M1 macrophages, and decreased the levels of tumor necrosis factor α and interleukin 8 in the culture supernatant. The above results indicated that sinomenine can significantly inhibit the macrophage classic activation, and its mechanism may be related to the increase of PIR-B expression in macrophages. This pharmacological effect helps explain the pharmacodynamic mechanism of sinomenine in treating rheumatoid arthritis.

The compatibility of kanamycin with sodium citrate for the formulation of kanamycin sulfate injection was determined, including optimization of the amount of sodium citrate in the injection and the sterilization process. An HPLC coupled with an evaporative light scattering detector (ELSD) was used to measure the amount of sodium citrate and the impurity profiles. A validated post-column derivatization HPLC coupled with a fluorescence detector (FLD) was used to determine the correlation between specific impurities in a domestic factory and sodium citrate, and then the formulation was evaluated by HPLC coupled with mass detector (MS) characterization of degradation products. The results show that the amount of sodium citrate in kanamycin sulfate injection from a domestic factory is about 40 times higher than that of the Meiji formulation. Several specific impurities can be detected in solutions heated under simulated sterilization conditions (121 ℃), which were correlated with the amount of sodium citrate. Impurities were characterized by HPLC-MS/MS, and data showed that the identified impurities were interaction products of kanamycin and sodium citrate. These results indicate that greater attention should be directed at formula optimization in domestic factories, as it is crucial to the safety and efficacy of the preparations. Drug-excipient chemical compatibility should also be evaluated in the development of pharmaceutical dosages forms especially when the active pharmaceutical ingredients have a primary amine group.

Research on polymer impurities has always been important in the quality control of cephalosporins. Research on polymers in cephalosporins that lack active amino groups on the C-7 side chain has not been reported. Therefore, our study used cefazolin sodium, which is widely used in the clinic, as an example. The polymer in cefazolin sodium and its product "cefazolin sodium pentahydrate for injection" was analyzed by column switching liquid chromatography-high resolution mass spectrometry. Two polymer impurity peaks were detected and the possible structures of these polymers were suggested. Through two-dimensional liquid chromatography, the chromatographic peaks following Sephadex gel chromatography and high-performance gel chromatography were compared to those obtained by reverse high-performance liquid chromatography (HPLC) for cefazolin sodium as reported in the Chinese Pharmacopoeia. The HPLC method proves more suitable for polymer detection than Sephadex gel chromatography and high-performance gel chromatography. The method of polymer detection for cefazolin sodium was established using the method of related substances HPLC as described in the Chinese Pharmacopoeia.

This study was designed to explore the protective effect and underlying mechanism of catalpol on hepatocyte apoptosis in nonalcoholic fatty liver disease (NAFLD). High fat diet (HFD) was used to establish NAFLD model in the in vivo experiment, and the procedures of the experiments and animal care protocol were approved by the Animal Care and Use Committee of Jianghan University. Human liver cancer cell line HepG2 was treated with palmitate (PA) to establish a lipid toxicity model in the in vitro experiments. The results showed that catalpol significantly decreased the contents of serum total glyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), and aspartate transaminase (AST) in HFD-fed mice. Results of TUNEL staining and flow cytometry analyses revealed that catalpol significantly inhibited hepatocytes apoptosis in HFD-fed mice and PA-treated HepG2 cells. Moreover, catalpol treatment significantly reduced the endoplasmic reticulum stress-related protein expression levels of binding immunoglobulin protein (BiP), phosphorylated PKR-like endoplasmic reticulum kinase (p-PERK), inositol-requiring kinase 1α (IRE1α), and transcriptional factor activating transcription factor 6 (ATF6), and apoptosis-related protein expression levels of C/EBP homology protein (CHOP), phosphorylated c-Jun N-terminal kinase (p-JNK), and cleaved cysteinyl aspartate specific proteinases (caspases)-12, -9, and -3 in HFD-fed mice and PA-treated HepG2 cells. Furthermore, endoplasmic reticulum stress agonist tunicamycin (TM) significantly reversed the inhibitory effect of catalpol on protein expression levels of BiP, p-PERK, IRE1α, and ATF6, subsequently the inhibitory effect of catalpol on expression levels of CHOP, p-JNK, Bcl-2, Bax, and cleaved caspases (-12, -9, and -3) was also attenuated in PA-treated HepG2 cells. Taken together, these findings demonstrated that catalpol could inhibit hepatocytes apoptosis and had a significant protective effect on liver injury, and its mechanism might be related to the relief of endoplasmic reticulum stress.

The tumor microenvironment (TME), a dynamic and complex local environment, interacts with the tumor cells and is closely related to tumor growth, metastasis, immune escape and drug resistance. Thus, targeting the TME has been a worldwide focus in cancer therapy. Many natural products possess the advantages of multiple targets, multiple pathways and wide pharmacological functions, and are the main source of antitumor drugs. In recent years studies have found that some natural products had advantageous effects on the TME. In this review, we summarize the components and functions of the TME and some natural products that target the TME, with references to the drug therapy of cancer.

Hyperglycemic kidney injury (HKI) is a common complication of diabetic patients. We examined the relationship between HKI and the abnormal expression of 5-hydroxytryptamine (5-HT) system induced by hyperglycemia in type 2 diabetes mellitus (T2DM). In animal experiments, a T2DM model was established in mice by feeding a high-fat diet with intraperitoneal injection of streptozotocin. The mice were treated with the 5-HT_2A receptor (5-HT_2AR) antagonist sarpogrelate hydrochloride (SH) and 5-HT synthesis inhibitor carbidopa (CDP) (respectively or in combination). In cell culture experiments, human glomerular mesangial cells (HMC) were stimulated with D-glucose (D-Glu), and 5-HT_2AR, 5-HT synthesis, and 5-HT degradation were inhibited by SH, CDP, or monoamine oxidase A (MAO-A) inhibitor clorgyline. Periodic acid-Schiff (PAS) staining and Masson staining, immunohistochemistry and Western blot, fluorescent probe, and enzyme linked immunosorbent assay (ELISA) and enzyme reagent were respectively used to detect histopathology, protein expression, intracellular reactive oxygen species (ROS), and biochemical indexes. The animal experiments were in accordance with the regulations of the Animal Ethics Committee of China Pharmaceutical University. The results showed that 5-HT_2AR, 5-HT synthases, and MAO-A were expressed in glomerular basement membrane and kidney tubular epithelial cells of mouse kidney and HMC. The expression of these proteins was significantly up-regulated in T2DM mice or when HMC cells were exposed to high concentration of D-Glu. HKI, characterized by abnormal renal function, glomerular swelling, and glomerular basement membrane thickening and fibrosis, is closely associated with an increase in kidney 5-HT_2AR, 5-HT synthesis, and 5-HT degradation. Among them, 5-HT_2AR can mediate the expression of 5-HT synthases and MAO-A; MAO-A can catalyze the degradation of 5-HT to increase the production of mitochondrial ROS, leading to the phosphorylation of nuclear factor kappa B (NF-κB) with the production of inflammatory cytokines, and the up-regulation of matrix metalloproteinase-2 (MMP-2) and α-smooth muscle actin (α-SMA) with the production of collagens. SH and CDP can effectively treat HKI, and the combination of SH and CDP has a clear synergistic effect.

Hyperuricemia is not only the biochemical basis of gout, but also closely related to the development of metabolic syndrome, cardiovascular diseases, chronic kidney disease, etc. Xanthine oxidase (XOD) is the key catalytic enzyme for uric acid biosynthesis, therefore the vital target for anti-hyperuricemic drugs. In this study, compound CC18022 was designed and synthesized specifically targeting to XOD. Molecular docking analysis indicated a fairly tight binding between CC18022 and XOD. In the in vitro study, CC18022 significantly inhibited XOD activity with a half maximal inhibitory concentration (IC₅₀) value in the order of nmol·L^-1, which is relative to the XOD inhibitor febuxostat. By using both acute and chronic hyperuricemic mice model, compound CC18022 was found to have serum uric acid-lowering effect in a dose-dependent manner in vivo. The animal welfare and experimental processes were in accordance with the provisions of the Animal Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences. In the acute hyperuricemic mice, CC18022 significantly inhibited serum XOD activity, and also the XOD activity in intestine and liver, which were related to purine absorption and metabolism. Therefore, the novel compound CC18022 exhibited significant inhibition on XOD activity and anti-hyperuricemic effects, making it a favorable candidate for further research.

Strict regulation of human immunodeficiency virus type 1 (HIV-1) protease function is critical for efficient production of mature viral particles. During viral protein expression and viral assembly, HIV-1 protease (PR) located within Gag-Pol precursor must be inactive to prevent premature cytoplasmic processing of the viral Gag and Gag-Pol precursors. Premature activation of HIV-1 precursors leads to major defects in viral assembly and production of viral particles. Specifically activating the protease in the precursor protein can directly inhibit the replication of the virus. In addition, HIV-1 PR is able to induce cell apoptosis. In this study, we identified 6 small molecule compounds using a cell-based assay for screening compounds that activate HIV-1 PR and induce premature of HIV-1 precursors. Results showed the active compounds are able to activate HIV-1 PR, inhibit HIV-1 replication, and induce cell apoptosis. This study provides ideas for the research and development of antiviral drugs.