Honeysuckle aqueous extract and induced let-7a suppress dengue virus type 2 replication and pathogenesis.

ETHNOPHARMACOLOGICAL RELEVANCE: Honeysuckle (Lonicera japonica Thunb.), a traditional Chinese herb, has widely been used to treat pathogen infection. However, the underlying-mechanism remains elusive. AIMS OF THE STUDY: To reveal the host microRNA (miRNA) profile with the anti-viral activity after honeysuckle treatment. MATERIALS AND METHODS: Here we reveal the differentially expressed miRNAs by Solexa® deep sequencing from the blood of human and mice after the aqueous extract treatment. Among these overexpressed innate miRNAs both in human and mice, let-7a is able to target the NS1 region (nt 3313-3330) of dengue virus (DENV) serotypes 1, 2 and 4 predicated by the target predication software. RESULTS: We confirmed that let-7a could target DENV2 at the predicated NS1 sequence and suppress DENV2 replication demonstrated by luciferase-reporter activity, RT-PCR, real-time PCR, Western blotting and plaque assay. ICR-suckling mice consumed honeysuckle aqueous extract either before or after intracranial injection with DENV2 showed decreased levels of NS1 RNA and protein expression accompanied with alleviated disease symptoms, decreased virus load, and prolonged survival time. Similar results were observed when DENV2-infected mice were intracranially injected with let-7a. CONCLUSION: We reveal that honeysuckle attenuates DENV replication and related pathogenesis in vivo through induction of let-7a expression. This study opens a new direction for prevention and treatment of DENV infection through induction of the innate miRNA let-7a by honeysuckle.

Synthesis and antiproliferative activities against Hep-G2 of salicylanide derivatives: potent inhibitors of the epidermal growth factor receptor (EGFR) tyrosine kinase.

A series of salicylanilide derivatives (compounds 1-32) were synthesised by reacting substituted salicylic acids and anilines. The chemical structures of these compounds were determined by (1)H-NMR, electrospray ionisation mass spectrometry (ESI-MS) and elemental analysis. The compounds were assayed for their antiproliferative activities against the Hep-G2 cell line by the 3-(4,5-dimethylthylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Among the compounds tested, 22 and 28 showed the most favouable antiproliferative activities with 50% inhibitory concentration (IC(50)) values of 1.7 and 1.3 µM, respectively, which were comparable to the positive control of 5-fluorouracil (IC(50)=1.8 µM). A solid-phase ELISA assay was also performed to evaluate the ability of compounds 1-32 to inhibit the autophosphorylation of the epidermal growth factor receptor tyrosine kinase (EGFR TK). Docking simulations of 22 and 28 were carried out to illustrate the binding mode of the molecule into the EGFR active site, and the result suggested that both compounds 22 and 28 could bind the EGFR kinase well.

Anti-adhesive effect of an acidic polysaccharide from Aloe vera L. var. chinensis (Haw.) Berger on the binding of Helicobacter pylori to the MKN-45 cell line.

OBJECTIVES: The emergence of antibiotic-resistant Helicobacter pylori strains has necessitated a search for alternative therapies for the treatment of this infection. The aim of this study was to evaluate whether or not polysaccharide fractions from Aloe vera are effective in inhibiting the adherence of H. pylori in vitro. METHODS: Polysaccharide fractions were extracted from A. vera and subjected to carbohydrate analysis. The adhesive effect was determined by co-incubation of H. pylori and cells with polysaccharides followed by fluorescein isothiocyanate labelling and Gram staining in vitro. Inhibition of H. pylori growth and cellular viability was tested by agar diffusion and MTT assay. KEY FINDINGS: APS-F2 contained significant amounts of galacturonic acid, galactose and arabinose. APS-F1 was galacturonic acid-free and consisted of mannose, glucose and galactose. APS-F2 (0.1, 0.5 and 1.0 mg/ml) reduced the count of H. pylori attached to MKN45 cells to 88, 76 and 64%, respectively. APS-F1 did not show the same effect. Neither polysaccharide revealed an inhibitory effect on the growth of H. pylori or cell viability. In addition, APS-F2 was shown to have a potent anti-adhesive effect against Escherichia coli. CONCLUSIONS: The results show that the acidic polysaccharide from A. vera has a potent anti-adhesive effect against H. pylori in vitro. However, there have yet to be any in-vivo studies to demonstrate the clinical relevance of this finding.

Analysis of free and conjugated phytosterols in tobacco by an improved method using gas chromatography-flame ionization detection.

An improved and simple method using capillary gas chromatography coupled with a flame ionization detection system (GC-FID) has been developed for quantitative analysis of free and conjugated phytosterols in tobacco. Direct acid and alkaline hydrolysis were first introduced into tobacco analysis to liberate free phytosterols from conjugates, followed by extraction with hexane, derivatization to trimethylsilyl ether derivatives and finally GC quantitative determination. The generality and applicability of this improved method for analyzing free and conjugated phytosterols in tobacco were validated after a series of optimization and comparison were done. Compared with traditional methods, this improved method not only simplified procedures, but also saved time and solvent. The limits of detection (LODs) of phytosterols varied from 0.35 to 0.10 microg mL(-1), the relative standard deviations (RSD) were from 2.3% to 3.3% and recovery ranged from 87% to 99%. The analysis results showed that total phytosterols' content in tobacco ranged from 1.0 to 2.5 mg g(-1), and most phytosterols existed as conjugates, only approximately 15-25% phytosterols existed in free-form. Ergosterol was only found in mildewy flued-cured tobacco and the level was approximately 0.2-0.25 mg g(-1).