Microcapsules are highly desirable for attaining the most effective utilization of the pesticide as well as reducing environmental pollution. In this work, a novel urease-responsive system was prepared using isocyanate-functionalized silica cross-linked with polyethylenimine (silica–IPTS–PEI) via urea bonds. The results demonstrated that the silica–IPTS–PEI microcapsules had a high pendimethalin loading efficiency (approximately 30% w/w) and could effectively enhance the thermal and light stability of pendimethalin. The release curves agreed with the Ritger and Peppas equation, and the release of pendimethalin was diffusion-controlled. The release rates of synthesized silica-IPTS-PEI microcapsules showed positive correlation with the temperature. In weak acid and base conditions, the pendimethalin release rates were higher than under neutral conditions, and the silica–IPTS–PEI microcapsules displayed excellent urease-responsive property with controlled release performance. Compared with pendimethalin emulsifiable concentration, the silica-IPTS-PEI microcapsules had a longer duration and higher herbicidal activity against weeds in a greenhouse experiment. Allium cepa chromosome aberration assays showed that the microcapsules had lower genotoxicity than pendimethalin technical. Thus, the urease-responsive silica–IPTS–PEI microcapsules have a great potential application as an environmentally friendly herbicide formulation.

Hepatitis B remains a major public health problem worldwide and hepatitis B virus (HBV) is the chief inductive factor of acute and chronic hepatitis.1,2) Several anti-viral drugs have been approved for the treatment of hepatitis B; however they cause significant complications such as dose-dependent side-effects and drug resistance. There exists a significant unmet medical need for safe and efficacious new anti-HBV drugs 3) and finding new anti-HBV agents is still a big challenge. Due to the well-known potency of Chinese herbs in diverse disease areas, we are interested in studying their anti-HBV activities.Radix Astragali (Huangqi), the dried root of Astragalus membranaceus (FISCH.) BGE. var. mongholicus (BGE.) HSIAO, or A. membranaceus (FISCH.) BGE., is one of the most widely prescribed Chinese herbs in many formulas. It has been widely used in Chinese medicine since ancient times with an excellent safety record and demonstrated efficacy in the improvement of immune disorders and liver diseases. The major active constituents of Radix Astragali are believed to be the total saponins and the total flavonoids. 4) Astragaloside IV (AS) is a naturally occurring saponin isolated from Radix Astragali, and has been used for the quality evaluation of Radix Astragali, as listed in the 2005 edition of Pharmacopoeia of the People's Republic of China. In recent years, as a major saponin of this herb, astragaloside IV has been shown to possess many pharmacologic activities including anti-cancer, anti-fatigue, anti-coxsackie B virus, and anti-inflammatory activities.5,6) However, there have not been many studies on its anti-viral activities. Particularly, to date there has been only one study on its anti-viral activity against HBV. 7) In this study, further to investigate this well-known Chinese medicine for its anti-HBV activity, we isolated astragaloside IV from Radix Astragali by the bioactivity-guided method and evaluated its anti-HBV activity both in vitro and in vivo. Total ethanol extract and saponins from Chinese herb Radix Astragali (Huangqi) have been previously shown to possess anti-hepatitis B virus (HBV) activities in vitro. To identify the active ingredients, we isolated a triterpenoid saponin that was determined to be astragaloside IV. In the human HBV-transfected liver cell line HepG 2 2.2.15, astragaloside IV effectively suppressed secretion of HBV antigens with inhibition rates of 23.6% for the secretion of Hepatitis B surface antigen (HBsAg) and 22.9% for that of Hepatitis B e antigen (HBeAg) at 100 m mg/ml after 9 d of treatment. The inhibitory activity of astragaloside IV on secretion of HBV antigens is more potent than that of 3TC without significant cytotoxicity. In duck hepatitis B virus (DHBV)-infected ducklings, astragaloside IV caused 64.0% inhibition at 120 mg/kg, 49.6% inhibition at 40 mg/kg, and 41.7% inhibition at 10 mg/kg to serum DHBVs after 10 d of treatment, and also reduced serum DHBV DNA levels. Together, our results demonstrate that astragaloside IV possesses potent anti-HBV activity. MAT...

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Many herbicides exhibit some disadvantages such as high water solubility and volatility after application, which lead to potential threats to the aquatic and atmospheric environment and human health.

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The synthesis and characterization of a series of biphenyl-derived binuclear ruthenium complexes with terminal {RuCl(CO)(PMe3)3} moieties and different structural arrangements of the phenyl rings are reported. Electrochemical studies revealed that the two metal centers of the binuclear ruthenium complexes interact with each other through the biphenyl bridge, and the redox splittings ΔE1/2 show a strong linear correlation with cos(2)  ϕ, where ϕ is the torsion angle between the two phenyl rings. A combination of electrochemical, UV/Vis/NIR, and in situ IR differential spectroelectrochemical analysis clearly showed that: 1) the intramolecular electronic couplings in the binuclear ruthenium complexes could be modulated by changing ϕ; 2) the electronic ground state of the mixed-valent cations changes from delocalized to localized through the biphenyl bridge with increasing torsion angle ϕ, that is, the redox processes of these complexes change from significant involvement of the bridging ligand to an oxidation behavior with less participation of the bridge.

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