Anti-Proteus Activity,Anti-Struvite Crystal,and Phytochemical Analysis of Sida acuta Burm. F. Ethanolic Leaf Extract

Proteus mirabilis is a significant cause of urinary tract infection that may contribute to struvite stones. Anti-infection of this bacterium and anti-struvite formation must be considered. Sida acuta Burm. F. (SA) has been used for the treatment of diseases related to kidneys. Therefore, we investigated the effects of the SA leaf ethanolic extract (SAEE) on growth and on virulent factors (swarming motility and urease activity) of Proteus mirabilis isolated from kidney stone formers. We also evaluated anti-struvite crystal formation and phytochemical constituents of SAEE. The minimum inhibitory concentrations (MICs) of SAEE against three clinical P. mirabilis isolates were 8 mg/mL. Intriguingly, the 1/2MIC of SAEE had significant inhibitory effects on the swarming motility and urease activity of clinical P. mirabilis isolates when compared with the condition without SAEE. The SAEE at the various concentrations significantly inhibited the average weights of struvite crystals in a dose-dependent manner, compared with the control. The phytochemical analysis revealed that SAEE contained catechin, chlorogenic acid, rutin, and ferulic acid. This study indicated that SAEE has anti-P. mirabilis and anti-struvite crystal activities via its bioactive compounds. For this reason, SAEE may be developed as a new agent for the treatment of struvite stone induced by P. mirabilis.     

Selective determination of homocysteine levels in human plasma using a silver nanoparticle-based colorimetric assay

The first use of silver nanoparticles (AgNPs) for the rapid, simple, and selective determination of homocysteine (Hcy) levels in human plasma was studied. Hcy and five other amino acids, including cysteine (Cys), could be distinguished by their different aggregation kinetics, which caused a change in the visible color and a shift in the UV-vis absorption spectra. The difference in the cross-linking (aggregation) rate between Hcy and Cys was used as the basis for developing a selective probe for Hcy and allowed the detection of Hcy in the linear range of 2-12 μM (R² = 0.9936). The limits of detection and quantification were found to be 0.5 μM and 1.7 μM, respectively. To investigate its selectivity and potential applicability, this AgNP-based method was successfully applied for the determination of Hcy levels in actual biological (human plasma) samples, where the determined levels of Hcy were within the error range of the measured level using the traditional chemiluminescence microparticle immunoassay (CMIA). Thus, the use of AgNPs is a feasible and potentially reliable method for the determination of Hcy levels in biological samples.     

Diaporthichalasin, a novel CYP3A4 inhibitor from an endophytic Diaporthe sp.

A novel CYP3A4 inhibitor, diaporthichalasin, together with pycnidione were isolated from an endophytic fungus, Diaporthe sp. Their structures were elucidated on the basis of spectral data and the structure of diaporthichalasin was confirmed by X-ray crystallographic analysis. Diaporthichalasin exhibited significantly potent inhibition of CYP3A4 with an IC₅₀ value of 0.626 μM, while the IC₅₀ value of pycnidione was 465 μM.     

Formulation and stability of Moringa oleifera oil microemulsion

Moringa oleifera oil with comparable caprylic triglyceride to Lexol® 865 and higher oleic acid was prepared into microemulsions. A system comprising natural and synthetic oils (O_mix), surfactant (Tween 80 and Span 80; S_mix), and water was microemulsion prepared by a visual grading. Twelve microemulsions with diameter of 83.75–286.76 nm, pH of 6.75–8.23, and viscosity of 280.00–517.20 mPa?s were produced. Their antioxidant were 0.926–2.921 μg Trolox/mg. Microemulsions with O_mix:S_mix mass ratio of 2:8 and 5:5 that had O_mix of 2:1 and 1:1 were stable following a 4 months stability evaluation at 25°C and 45ºC. Microemulsions containing moringa oil produced by a practical low-energy method exhibited good viscosity with an acceptable pH and antioxidant activity were therefore applicable for further applications.     

Crystal Structure of Curcumenol: Evidence of Asymmetric O–H...O (bridged) Hydrogen-Bonded Closed Dimer

Curcumenol, C₁₅H₂₂O₂, was isolated from Globba malaccensis Ridl. The compound was crystallized from ethylacetate/hexane solution in the monoclinic system, space group C2, with cell dimensions a = 16.8467(4) , b = 7.6799(2) , c = 11.8613(10) , = 115.9970(10)°. The molecules form a distorted centrosymmetric dimer linked by hydrogen bonds between the hydroxyl O2 atom and the bridged O1 ether atom (O2...O1(–x+2, y, –z+1), 2.8297(15) ; (O2–H2O–O1), 169(2)°). This is an interesting example of an O–H...O (bridged ether) asymmetric hydrogen-bonded dimer.     

HIV-1 neutralization by monoclonal antibody against conserved region 2 and patterns of epitope exposure on the surface of native viruses

Background  

Conserved neutralizing epitopes are considered to be a key role for eliciting broadly neutralizing antibody (NAb). Previously, two conserved neutralizing epitopes of HIV-1 CRF01_AE envelope were identified at amino acid 93-112 of the C1 (C1E) and at 218-239 of the C2 (C2E) regions. To access the potency of antibody directed against conserved epitopes, a monoclonal antibody (MAb) specific to the C2E region was developed and characterized.