Xin-Hua Wang

Inhibition viral RNP and anti-inflammatory activity of coumarins against influenza virus

Influenza viruses pose a severe threat to human health and a significant increase in antiviral drug-resistant among influenza viruses worldwide has been observed. Therefore, there is an urgent need to develop the new antiviral drugs, specifically from the natural products. In this study, the anti-viral and anti-inflammatory activities of coumarins against influenza A virus in vitro were investigated. One of the derivatives eleutheroside B1 showed a wide spectrum of anti- human influenza virus effect with the IC50 value of 64-125μg/ml in vitro, but it showed no effects against avian influenza virus. The time of addition was done and the results indicated that it had a potent antiviral effect when added at 0-6h, and also the virus yield was reduced by 60%. The influenza virus ribonucleoprotein was inhibited at 200μg/ml, and also the NP mRNA expression was inhibited at 50 and 200μg/ml. The expression level of cytokines and chemokines influenced by eleutheroside B1 was further demonstrated, the IL-6, CXCL-8, CCL-2 expression were all inhibited by the eleuthe roside B1 at concentration 200μg/ml. The findings of study suggest that eleutheroside B1 can be as potential agent to develop for the prevention and treatment of influenza A virus.

Unprecedented sugar bridged bisindoles selective inhibiting glioma stem cells

Unlike reported bisindoles linked by single bond directly, alstoniasidines A (1) and B (2), from Alstonia scholaris featuring unprecedented skeleton with two indole moieties bridged by a sugar, represented a novel bisindole type having strictosamide-glucopyranose-picraline scaffold. Both compounds exhibited selective cytotoxicity against human glioma stem cells (GSCs) and induced caspase-3 dependent extrinsic apoptosis by increasing the expression of interleukin 1 (IL-1), tumor necrosis factor (TNF-α), and the cleaved caspase-3, while damaged the unlimited proliferation and self-renewal capacity of GSCs. This finding might provide new type of leads for the selective killing of human glioma stem cells.

Inhibition of influenza virus via a sesquiterpene fraction isolated from Laggera pterodonta by targeting the NF-κB and p38 pathways

BackgroundInfluenza virus poses serious threats to human health, especially human infection with avian influenza virus. Laggera pterodonta (DC.) Benth is a medicinal plant that is widely used in Traditional Chinese Medicine, especially in Yunnan province, and has been used to treat influenza, pharyngolaryngitis, and bronchitis. However, the compound(s) responsible for the activity and their mechanisms of action against the influenza virus remain to be elucidated.MethodsL. pterodonta extract was fractionated, and the active fraction was identified as Fraction 14 (Fr 14). Fr 14 was further analysed and characterized by ultra-high-performance liquid chromatography hyphenated with quadrupole-time of flight mass spectrometry (UHPLC/Q-TOF-MS). The inhibitory effect against influenza virus was evaluated using a cytotoxicity assay. Then, cytokines and chemokines were detected by qRT-PCR and a bio-plex assay. Signalling pathways that inhibited the influenza virus were identified using a western blotting assay.ResultsThe active fr 14 showed a wide spectrum of anti-influenza virus activity. The pharmacological mechanisms showed that Fr 14 acts on the early stage of virus replication (0–6 h). It inhibited the p38/MAPK pathway and then inhibited the NF-κB pathway and COX-2. Fr 14 also prevented the increased expression of cytokines and chemokines.ConclusionThis study demonstrated the preliminary mechanisms of fr 14 against the influenza virus. Fr 14 possessed antiviral and anti-inflammatory effects. L. pterodonta can be used to develop innovative antiviral drugs, and further studies will be performed to illustrate the detailed mechanisms.

Antibacterial Indole Alkaloids with Complex Heterocycles from Voacanga africana

Voacafricines A and B, two unique monoterpenoid indole alkaloids each bearing five fused heterocycles, were obtained from the fruits of Voacanga africana. Their structures were elucidated by extensive spectroscopic methods and computational studies. A plausible biogenetic pathway was proposed from a common precursor, 19- epi-voacristine. Both compounds exhibited potent activity against Staphylococcus aureus and Salmonella typhi, and their activities were superior to those of the well-known antibacterial drugs berberine and fibrauretine.

Anti-Inflammatory Isoquinoline with Bis-seco-aporphine Skeleton from Dactylicapnos scandens

Dactyllactone A (1), which was isolated from Dactylicapnos scandens, is an isoquinoline alkaloid with a rearranged and reconstructed D ring, making it the first of a new subtype of aporphines. Compound 1 might be derived from a common aporphine skeleton, which may have undergone biogenetic rearrangement and cleavage of the aromatic ring. Its structure was determined by extensive spectroscopic analysis and single-crystal X-ray diffraction. Compound 1 exhibited anti-inflammatory activity in vitro significantly by inhibiting the expression of IL-1β and PGE2 in a dose-dependent manner.

Novel nor-monoterpenoid indole alkaloids inhibiting glioma stem cells from fruits of Alstonia scholaris

BACKGROUND Glioblastoma multiforme (GBM) is a highly aggressive and frequently recurrent malignant brain tumor, and to date, the clinically effective drugs against GBM remain scarce. Natural products play an important role in drug discovery, and might be the resource of antitumor agents for GSCs. Alstonia scholaris (L.) R. Br. is rich in monoterpenoid indole alkaloids (MIAs) and used extensively for treatment of tumor in the traditional medicine system of Asia. PURPOSE To search for new MIAs with antitumor activity against glioma stem cells from clinical patients and explore their mechanism. METHODS Compounds were obtained from the fruits of A. scholaris by chromatographic separation, including silica gel, Sephadex LH-20 and recrystallization. Their structures were elucidated by the use of UV, IR, NMR and MS spectra. The antitumor activity of the compounds against the glioma stem cells (GSC-3#, GSC-12#, GSC-18#) were investigated by phenotypic screening and MTS assays. Cell proliferation assay by BrdU immunofluorescence staining, and apoptosis assay by cleaved-caspase-3 immunofluorescence staining and real-time PCR assay. The soft-agar clonal formation assay was performed to determine the antitumor efficacy of the compounds in vitro. RESULTS Two new nor-monoterpenoid indole alkaloids were isolated from the fruits of A. scholaris. They exhibited selective antitumor activity against glioma stem cells (GSC-3#, GSC-12#, GSC-18#) with IC50 values of 15-25 µg/ml. Furthermore, they inhibited GSCs proliferation, induced GSCs apoptosis by increasing the expression of TNF-α and cleavage of caspase-3, and significantly damaged colony forming capacity of GSCs. CONCLUSION New nor-monoterpenoid indole alkaloids from the fruits of A. scholaris provide new type promising molecule for the selective killing of human glioma stem cells.

Effects of indole alkaloids from leaf of Alstonia scholaris on post-infectious cough in mice

Abstract Ethnopharmacological relevance Leaf of Alstonia scholaris (L.) R. Br. (Apocynaceae), a wide used ethic-medicine in many Asia and Africa counties, has also been recorded as the common traditional Chinese medicine for treatment of illnesses in respiratory system by Dai people. Aim of the study To provide experimental data of clinical adaption of total indole alkaloids (TA) from leaf of A. scholaris for treating post-infectious cough in phase II clinical trial. Materials and methods To model post-infectious cough, all animals except control group were instilled intra-tracheal with lipopolysaccharide (LPS) (80 μg/50 µL/mouse), followed by subsequent exposure to cigarette smoke (CS) for 30 min per day for a total of 30 days. Mice were orally given TA at dose of 10, 25, 50 mg/kg, and four main alkaloids (Sch: scholaricine, Epi: 19-epischolaricine, Val: vallesamine, Pic: picrinine) once daily. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expression of interleukin-6 (IL-6) and C-reactive protein (CRP) in the serum was determined, the superoxide dismutase (SOD) activity as well as malondialdehyde (MDA) content in the serum and homogenate were examined. Finally, histopathological examination in the lungs was assessed by H. E. staining. Results After administration of TA and four major alkaloids respectively, the symptoms of cough in mice were obviously attenuated. Total white blood cells (WBC) and neutrophils (NEU) amounts in BALF were reduced obviously and the pathological damage of lung was also attenuated. There was also significant reduction in IL-6, CRP, MDA and a marked improvement in SOD. Conclusions The efficacy of indole alkaloids against post-infectious cough (PIC) was shown in the down-regulation of inflammatory cells, cytokines, and the balance of antioxidants. Whats more, the pharmacological effects of TA were better than single indole alkaloid, which might be related to the synergic effect of four major alkaloids.

Eleutheroside B1 mediates its anti-influenza activity through POLR2A and N-glycosylation

Influenza viruses represent a serious threat to human health. Although our research group has previously demonstrated the antiviral and anti-inflammatory activities of eleutheroside B1, a detailed explanation of the mechanism by which it is effective against the influenza virus remains to be elucidated. In the present study, the transcriptomic responses of influenza A virus-infected lung epithelial cells (A549) treated with eleutheroside B1 were investigated using high-throughput RNA sequencing, and potential targets were identified using a molecular docking technique, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay, and DNA methylation analysis. The transcriptomic data revealed that there are 1,871 differentially expressed genes (DEGs) between the cells infected with the influenza virus strain variant PR8, and the cells infected with PR8 and treated with eleutheroside B1. Among the DEGs, RNA polymerase II subunit A (POLR2A; encoding the largest subunit of RNA polymerase II) and mannosidase α class II member 1 (MAN2A1) were selected from the molecular docking analysis with eleutheroside B1. The docking score of Drosophila melanogaster MAN2A1 (3BVT) was 11.3029, whereas that of POLR2A was 9.0133. The RT-qPCR results demonstrated that the expression levels of host genes (MAN2A2, POLR2A) and viral genes (PA, PB1, PB2, HA) were downregulated following eleutheroside B1 treatment. Bisulfite-sequencing PCR was performed to investigate whether eleutheroside B1 was able to modify the DNA methylation of POLR2A, and the results suggested that the average proportion of methylated CpGs (-222-72 bp) increased significantly following treatment with eleutheroside B1. Taken together, these findings suggested that eleutheroside B1 may affect N-glycan biosynthesis, the chemokine signaling pathway, cytokine-cytokine receptor interaction and, in particular, may target the POLR2A to inhibit the production of influenza virus genes.

Pterodontic Acid Isolated from Laggera pterodonta Inhibits Viral Replication and Inflammation Induced by Influenza A Virus

Laggera pterodonta (DC.) Benth. is a traditional Chinese medicine. The previous study revealed that the crude extracts of this herb could inhibit influenza virus infection, but its anti-influenza components and underlying mechanism of action remain unknown. Column chromatography was performed to isolate components from the plant. Activity against influenza virus of the compound was determined by CPE inhibition assay. Neuraminidase (NA) inhibition was measured by chemiluminescence assay. The anti-virus and anti-inflammation effects were determined using dual-luciferase reporter assay, immunofluorescence, quantitative real-time PCR and luminex assay. Pterodontic acid was isolated from L. pterodonta, which showed selective anti-viral activities to H1 subtype of human influenza A virus. Meanwhile, the NA activity was not obviously inhibited by the compound. Further experiments exhibited that the compound can suppress the activation of NF-κB signal pathway and export of viral RNP complexes from the nucleus. In addition, it can significantly attenuate expression of the pro-inflammatory molecules IL-6, MIP-1β, MCP-1, and IP-10 induced by human influenza A virus (H1N1) and similarly downregulate expression of cytokines and chemokines induced by avian influenza A virus (H9N2). This study showed that in vitro antiviral activity of pterodontic acid is most probably associated with inhibiting the replication of influenza A virus by blocking nuclear export of viral RNP complexes, and attenuating the inflammatory response by inhibiting activation of the NF-κB pathway. Pterodontic acid might be a potential antiviral agent against influenza A virus.