An evaluation of the RNase H inhibitory effects of Vietnamese medicinal plant extracts and natural compounds

Context: Acquired immune deficiency syndrome (AIDS) is a severe pandemic disease especially prevalent in poor and developing countries. Thus, developing specific, potent antiviral drugs that restrain infection by human immunodeficiency virus type 1 (HIV-1), a major cause of AIDS, remains an urgent priority.

Objective: This study evaluated 32 extracts and 23 compounds from Vietnamese medicinal plants for their inhibitory effects against HIV-1 ribonuclease H (RNase H) and their role in reversing the cytopathic effects of HIV.

Materials and methods: The plants were air-dried and extracted in different solvent systems to produce plant extracts. Natural compounds were obtained as previously published. Samples were screened for RNase H inhibition followed by a cytopathic assay. Data were analyzed using the Microsoft Excel.

Results and discussion: At 50?μg/mL, 11 plant extracts and five compounds inhibited over 90% of RNase H enzymatic activity. Methanol extracts from Phyllanthus reticulatus and Aglaia aphanamixis leaves inhibited RNase H activity by 99 and 98%, respectively, whereas four extracts showed modest protection against the cytopathic effects of HIV.

Conclusion: The screening results demonstrated that the butanol (BuOH) extract of Celastrus orbiculata leaves, methanol (MeOH) extracts of Glycosmis stenocarpa stems, Eurya ciliata leaves, and especially P. reticulatus leaves showed potential RNase H inhibition and protection against the viral cytopathic effects of HIV-1. Further chemical investigations should be carried out to find the active components of these extracts and compounds as potential anti-HIV drug candidates.     

Fluoride bioactive glass paste improves bond durability and remineralizes tooth structure prior to adhesive restoration

ObjectiveThe current study aimed at examining a fluoride containing bioactive glass (BiominF®) paste as a temporary filling material capable of remineralizing the demineralized enamel or dentin, and its ability to decrease a simulated dentinal fluids pressure on the resin/dentin interface, without affecting the shear bond strength of a universal bonding agent to enamel and dentin.Methods60 premolars were utilized for the acid resistance, trans-microradiography (TMR) and shear bond strength (SBS) experiments. Enamel and dentin discs were demineralized for 4 days to create a subsurface demineralized zone followed by applying BiominF® paste, 1.23% acidulated phosphate fluoride, or a temporary filling material for 24 h.30 extracted human non-carious third molars were utilized for the pulpal pressure experiment in which direct communication to the pulp chamber was created by cutting at a level approximately 1 mm below the cemento-enamel junction while the coronal enamel was ground to expose mid coronal dentin. The dentin surface was exposed to a simulated pulpal pressure. The dentin surfaces had BiominF® paste, an oxalate desensitizing agent, or temporary filling material followed by application of a universal adhesive system.ResultsOne way ANOVA showed that BiominF® paste remineralized effectively the demineralized enamel or dentin, did not affect the bond strength of the enamel and dentin surfaces to the tested adhesive system p < 0.05, and improved the acid resistance of the demineralized enamel and dentin against a secondary erosive challenge. Moreover, BiominF® paste decreased the nanoleakage expression in the dentin/adhesive interface exposed to a simulated pulpal pressure.SignificanceBiominF® paste may serve as a temporary filling material that may improve the longevity of adhesive restorations and help to conserve tooth structures by preserving the demineralized enamel and dentin form cutting during cavity preparation.     

Interstitial telomeric sequences are not preferentially involved in the chromosome damage induced by the methylating compound streptozotocin in chinese hamster cells

The effect of the methylating compound streptozotocin (STZ) on interstitial telomeric sequences (ITSs) was investigated in Chinese hamster ovary (CHO) cells by using peptide nucleic acid‐fluorescence in situ hybridization with a pantelomeric probe. Cells were exposed to increasing concentrations of STZ, and chromosomal aberrations were analyzed at the first mitosis after treatment. The frequency of chromosomal aberrations directly involving ITSs increased in STZ‐treated cells by a factor of 2.6 (2 mM) and 3.6 (4 mM) when compared with the frequency of these aberrations in control cells (P < 0.05). However, no significant differences were found between control and exposed cells in the percentage of aberrations directly involving ITSs, demonstrating that these repeat regions were not preferentially involved in the chromosome damage induced by STZ. In addition, STZ did not alter telomerase activity, suggesting that this enzyme may not be involved in the induction of chromosomal aberrations by this compound. Environ. Mol. Mutagen., 2013. © 2012 Wiley Periodicals, Inc.     

Recent Chemical Exposures and Blood Volatile Organic Compound Levels in a Large Population-Based Sample

Little is known about factors that influence blood levels of volatile organic compounds in nonoccupationally exposed populations. The authors examined the possible relationship between recent self-reported chemical exposures and elevated blood volatile organic compound levels among 982 adult participants in the Third National Health and Nutrition Examination Survey. A strong dose-response effect was indicated (p < .001) for increasing lifetime pack-years of cigarettes smoked for elevated levels of toluene, styrene, and benzene. A positive dose-response effect was indicated for daily alcohol consumption with respect to elevated blood levels of 2-butanone and acetone. For volatile organic compounds typically found in 10-75% of the population, the establishment of a link with specific environmental exposures is relatively easy because there is less effect of confounding in this group. Some volatile organic compounds, however, are seen in less than 10% of the general population; finding these compounds at any level may warrant a search for a particular exposure.     

Characterization and induction of cementoblast cell proliferation by bioactive glass nanoparticles

Cementum is a mineralized tissue that lines the surface of the tooth root enabling attachment of the periodontal ligament to the root and surrounding alveolar bone. Studies examining the mechanisms involved in the formation of root cementum have been hindered by an inability to isolate and culture the cells required for cementum production (cementoblasts). This study isolated and characterized cementoblast cells derived from rat molar periodontal ligament. It was observed that the isolated cells expressed F‐Spondin, a cementoblast marker, while F‐Spondin expression was not observed in the cells of other tissues such as gingival fibroblasts and osteoblasts. As expected, the isolated cementoblast cells also expressed osteocalcin (OC), bone sialoprotein (BSP), alkaline phosphatase (ALP), and type I collagen, demonstrating the presence of mineralized tissues genes in cementoblast cells. These cells showed high ALP activity and calcified nodule formation in vitro. Since cementogenesis could be a critical event for regeneration of periodontal tissues, this study investigated whether bioactive glass particles could affect the proliferation of cementoblasts since they are known to enhance osteoblast proliferation. It was found that the ionic products from bioactive glass nanoparticles increased cementoblast viability, mitochondrial activity, and induced cell proliferation. Together, these results show the characterization of cementoblast cells from rat molar periodontal ligament. Additionally, it was shown that bioactive glass nanoparticles induced cementoblast to proliferate, indicating that they could be a potential material for use in cement regeneration through tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd.     

Recognizing drug‐facilitated crimes: Detection and quantification of benzodiazepines in beverages using fast liquid–liquid extraction with low temperature partitioning and paper spray mass spectrometry

A novel methodology using liquid–liquid extraction with low temperature partitioning (LLE–LTP) and paper spray mass spectrometry (PS–MS) was developed to identify and quantify benzodiazepines in beverages. Four types of alcoholic beverages usually consumed in parties and bars were spiked with 5 distinct benzodiazepines (diazepam, alprazolam, bromazepam, clonazepam, and cloxazolam) simulating a drug‐facilitated crime occurrence. The direct PS–MS analysis of the spiked beverages revealed a remarkable matrix effect with an unclear detection of protonated benzodiazepines. However, by the application of the LLE–LTP using liquid nitrogen, a prompt and doubtless detection of such compounds was achieved. The quantification potential of the LLE–LTP/PS–MS methodology was demonstrated by using beer as matrix, diazepam as target analyte and cloxazolam as an internal standard. Figures of merit (linearity, limit of detection, linear dynamic range, relative standard deviation, and recovery) were determined and adequate values were obtained. In conclusion, we demonstrated herein that the LLE–LTP/PS–MS methodology has potential to be applied directly at the crime scene through of a portable mass spectrometer and a thermal container for the transport of liquid nitrogen.     

Matricryptins and matrikines: biologically active fragments of the extracellular matrix

Numerous extracellular proteins and glycosaminoglycans (GAGs) undergo limited enzymatic cleavage resulting in the release of fragments exerting biological activities, which are usually different from those of the full‐length molecules. In this review, we define matrikines and matricryptins, which are bioactive fragments released from the extracellular matrix proteins, proteoglycans and GAGs and report their major biological activities. These fragments regulate a number of physiopathological processes including angiogenesis, cancer, fibrosis, inflammation, neurodegenerative diseases and wound healing. The challenges to translate these fragments from molecules biologically active in vitro and in experimental models to potential drugs are discussed in the last part of the review.     

Effect of soybean fortification on Ghanaian fermented maize dough aroma

The effect of soy fortification on the development of aroma compounds, dough acidity and growth of the predominant microorganisms were investigated in Ghanaian maize dough fermented spontaneously over a period of 72 h. The fortified maize dough was prepared from a milled mixture of soaked maize grains and pre-soaked, blanched and dehulled soybeans added at 20% replacement level. Extracts of volatiles from the soy-fortified and unfortified dough samples were obtained by Likens–Nickerson simultaneous distillation and extraction method analysed by gas chromatography-mass spectrometry and gas chromatography-olfactometry (gas chromatography-sniffing). Major aroma compound groups identified in the fermented dough samples were carbonyls, alcohols, esters and volatile organic acids. Twenty-nine carbonyls were found in soy-fortified maize dough compared with 21 in the unfortified dough. Although the same alcohols were found in both dough samples, the total concentration of alcohols was slightly different, being less for the soy-fortified sample. Total concentration of esters in soy-fortified dough decreased after 72 h while levels in the unfortified dough increased. Increases in the production of lactic and acetic acids occurred in soy-fortified samples, but the maximum concentrations of acetic acid achieved did not differ significantly between the two types of dough. Twenty-three compounds were perceived to be contributing to the typical aroma of soy-fortified maize dough by the method of gas chromatography-sniffing. These included 12 carbonyls, six alcohols, two esters, two acids and one furan.     

Characterization of indoor air contaminants in a randomly selected set of commercial nail salons in Salt Lake County,Utah, USA

Air samples were collected in 12 randomly selected commercial nail salons in Salt Lake County, Utah. Measurements of salon physical/chemical parameters (room volume, CO₂ levels) were obtained. Volatile organic compound (VOC) concentrations were collected using summa air canisters and sorbent media tubes for an 8-h period. Multivariate analyses were used to identify relationships between salon physical/chemical characteristics and the VOCs found in the air samples. The ACGIH^® additive mixing formula was also applied to determine if there were potential overexposures to the combined airborne concentrations of chemicals monitored. Methyl methacrylate was detected in 58% of the establishments despite having been banned for use in nail products by the state of Utah. Formaldehyde was found above the NIOSH REL^® (0.016?ppm) in 58% of the establishments. Given the assortment of VOCs to which nail salon workers are potentially exposed, a combination of engineering as well as personal protective equipment is recommended.