Order Of Inhibitory Effect Research Articles

Combined effect and mechanism of microplastic with different particle sizes and levofloxacin on developing Rana nigromaculata: Insights from thyroid axis regulation and immune system

Microplastics (MPs) usually appear in the aquatic environment as complex pollutants with other environmental pollutants, such as levofloxacin (LVFX). After 45-day exposure to LVFX and MPs with different particle sizes at environmental levels, we measured the weight, snout-to-vent length (SVL), and development stages of Rana nigromaculata. Furthermore, we analyzed proteins and genes related to immune system and thyroid axis regulation, intestinal histological, and bioaccumulation of LVFX and MPs in the intestine and brain to further explore the toxic mechanism of co-exposure. We found MPs exacerbated the effect of LVFX on growth and development, and the order of inhibitory effects is as follows: LVFX-MP3>LVFX-MP1>LVFX-MP2. 0.1 and 1 μm MP could penetrate the blood–brain barrier, interact with LVFX in the brain, and affect growth and development by regulating thyroid axis. Besides, LVFX with MPs caused severer interference on thyroid axis compared with LVFX alone. However, 10 μm MP was prone to accumulating in the intestine, causing severe histopathological changes, interfering with the intestinal immune system and influencing growth and development through immune enzyme activity. Thus, we concluded that MPs could regulate the thyroid axis by interfering with the intestinal immune system.

Chemical composition and antimicrobial activity of essential oil obtained from the rhizomes of Kaempferia champasakensis: in vitro and molecular docking studies

Kaempferia champasakensis Picheans. & Koonterm (Zingiberaceae) is locally known as “Dia Lien hoa trang” in Vietnam. Despite a previous study on the essential oils (EO) of K. champasakensis leaves, no other studies have reported the chemical components and biological activities of K. champasakensis. Therefore, this study aims to identify the chemical constituents of the EO from the rhizomes of K. champasakensis and evaluate their antimicrobial activity, which has been re-confirmed through molecular docking studies. The gas chromatography-mass spectrometry (GC/MS) analysis revealed sixty-one constituents (95.4%) present in the EO of K. champasakensis rhizomes. Among them, camphene (40.7%), α-pinene (10.2%), and β-pinene (7.6%) were identified as the main compounds in the EO. Bioassays indicated its antimicrobial activity in the order of inhibitory effectiveness: Staphylococcus aureus > Enterococcus faecalis ≈ Candida albicans > Bacillus cereus ≈ Escherichia coli > Salmonella enterica > Pseudomonas aeruginosa. The molecular docking study of ligand-protein interactions involving the major constituents of EO was conducted against target proteins related to Staphylococcus aureus, Enterococcus faecalis, Candida albicans, Bacillus cereus, and Escherichia coli main activities. The results revealed that α-pinene exhibited strong binding affinity against E. coli, β-pinene demonstrated more effective inhibition against E. faecalis and B. cereus, and camphene primarily exhibited activity against C. albicans and S. aureus. Furthermore, the analysis of interactions between the main compounds and the selected proteins was elucidated in the current study. This is the first time that chemical components of the EO of K. champasakensis rhizomes and their antimicrobial activity have been reported. These findings contributed to the basis for further studies on the chemical compositions and biological effects of K. champasakensis.

ANTIFUNGAL ACTIVITY AND STAINING PROPERTIES OF SOME SYMMETRICALLY FUNCTIONALIZED METAL PHTHALOCYANINE DYES

Effects of 1, 8, 15, 22-tetranitro Co(II) and Zn(II) phthalocyanines [3-NO2CoPc, 3-NO2ZnPc], 1,8,15,22-tetracyano Co(II) phthalocyanine [3-CNCoPc] and 2, 9, 16, 23-tetranitro iron(III)chlorophthalocyanine [4-NO2FePc] on the growth of the fungus Aspergillus niger were studied. All the four complexes inhibited the radial spread of the fungus selected for the study to different extents. A considerable inhibitory effect on growth was seen even in l ppm concentration. The order of inhibitory effect, measured for a period of 5 days is 3-NO2 ZnPc > 3-CNCoPc > 3-NO2CoPc > 4-NO2FePc. The presence of the peripherally substituted phthalocyanine complexes is found to alter the pigmentation property of the selected fungus. Safranin-phthalocyanine double staining technique using 3-NO2CoPc, 3-NO2ZnPc, 4-NO2FePc and 2, 9, 16, 23-tetrahydroxy iron(III)chlorophthalocyanine [4-OHFePc] on the stem sections of Hemidesmus indicus R Br and Polygonum punctatum Buch-Hum have been studied.

Inhibitory effect of green antioxidants acting on surface groups and structure on lignite

To contain coal fires, three green antioxidants of plant extract which cover resveratrol (Res), tea polyphenols (TP), and β-carotene (β-car) are investigated in this paper, and their inhibitory effects on surface groups and structure are revealed. X-ray diffraction test tells that antioxidants exert a slight augment of d100 and Lc and are able to destroy the unstable side chains to some extent. Though coal samples are affected by antioxidants, minimal differences of aromatic structure have been proved. Fourier-transform infrared spectroscopy technique is employed and a new concept of influence sensitivity value is introduced. The results indicate that antioxidants and addition amounts have an impact on various groups, and the majority of groups tend to be inhibited within 3 wt% addition. Further, the optimal inhibitory concentration of Res, TP, and β-car is 1 wt%, 3 wt%, and 1 wt%, respectively. Combined with gaseous indexes, CO2 emissions of Res and TP exhibit a wave variation under 100 °C, and exponential growths of others occurred twice is acquired. Antioxidants can bring out the decline of apparent activation energy (Ea), and TP worked most brilliantly and it increases Ea by 7.503 kJ/mol. In summary, the order of inhibitory effect is TP > Res >β-car.

Antioxidant activity and α-glucosidase inhibitability of Distichochlamys citrea M.F. Newman rhizome fractionated extracts: in vitro and in silico screenings.

Distichochlamys citrea M.F. Newman (commonly known as “Black Ginger”) is an endemic plant to Vietnam and has been extensively exploited by folk medication for treatments of infection-related diseases and diabetes. In this work, its rhizomes were subjected to fractionated extraction, phytochemical examination, evaluation of antioxidant effect by DDPH free radical neutralization, and inhibitory activity toward α-glucosidase. The compositional components were subjected to in silico screening, including density functional theory calculation, molecular docking simulation, physicochemical analysis, and pharmacokinetic regression. In the trials, EtOAc fraction is found as the bioactive part of most effectiveness, regarding both antioxidant effect (IC50 = 90.27 µg mL−1) and α-glucosidase inhibitory activity (IC50 = 115.75 μg mL−1). Chemical determination reveals there are 13 components of its composition. DFT-based calculations find no abnormal constraints in their structures. Docking-based simulation provides order of inhibitory effectiveness: 3-P53341 > 12-P53341 > 7-P53341 > 4-P53341 > 11-P53341 > 10-P53341. QSARIS-based investigations implicate their biocompatibility. ADMET-based regressions indicate that all candidates are generally safe for medicinal applications. The findings would contribute to the basis for further studies on the chemical compositions of Distichochlamys citrea and their biological activities.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11696-022-02273-2.

Evaluation of the Effects of Particle Sizes of Silver Nanoparticles on Various Biological Systems.

Seven biological methods were adopted (three bacterial activities of bioluminescence, enzyme, enzyme biosynthetic, algal growth, seed germination, and root and shoot growth) to compare the toxic effects of two different sizes of silver nanoparticles (AgNPs). AgNPs showed a different sensitivity in each bioassay. Overall, the order of inhibitory effects was roughly observed as follows; bacterial bioluminescence activity ≈ root growth > biosynthetic activity of enzymes ≈ algal growth > seed germination ≈ enzymatic activity > shoot growth. For all bacterial activities (bioluminescence, enzyme, and enzyme biosynthesis), the small AgNPs showed statistically significantly higher toxicity than the large ones (p < 0.0036), while no significant differences were observed among other biological activities. The overall effects on the biological activities (except shoot growth) of the small AgNPs were shown to have about 4.3 times lower EC50 (high toxicity) value than the large AgNPs. These results also indicated that the bacterial bioluminescence activity appeared to be an appropriate method among the tested ones in terms of both sensitivity and the discernment of particle sizes of AgNPs.

To be ionized or not to be ionized: the vital role of physicochemical properties of galbanic acid derivatives in AChE assay

Alzheimer’s disease is a progressive neurodegenerative disorder and patients suffer from memory loss, a decline in language skill and impairment in other cognitive functions. In the cholinergic hypothesis, dysfunction of cholinergic neurons especially in the hippocampus and cerebral cortex contributes to cognitive decline in patients. So agents that enhance acetylcholine concentration could improve cognitive function. AChEIs are among the most studied anti-Alzheimer agents. Galbanic acid as a natural compound with a sesquiterpene coumarin scaffold is a weak inhibitor of AChE. In the present contribution, we discussed the impact of carboxylic group ionization on inhibitory effects. We performed in vitro and in silico studies on galbanic acid, methyl and ethyl galbanates as AChE inhibitors. The order of inhibitory effect on AChE was obtained as ethyl galbanate ∼ methyl galbanate > galbanic acid. Our study highlights the important role of the physicochemical properties of natural lead compounds in each specific assay.Communicated by Ramaswamy H. Sarma

Subunit-specific effects of poricoic acid A on NMDA receptors.

N-methyl-D-aspartate (NMDA) receptor is a tetrameric protein complex composed of glycine-linked NR1 subunits and glutamate-linked NR2 subunits. There are four NR2 subunits (A-D) that differ in development, anatomy, and function profiles. They play various roles in normal and neuropathologic conditions. Specific agonists, antagonists, and modulators of subunits for selective NMDA receptors may be precious mediational tools and potent agents for treating diseases. The objective of this study was to determine the effect of poricoic acid A on NMDA receptor known to mediate excitatory synaptic transmission factors and cause changes in synaptic strength. Inhibitory effect of poricoic acid A on NR1a combined with NR2A, NR2B, NR2C, or NR2D receptor was evaluated. Glutamate-mediated currents for each NR1a and NR2 subunits were investigated using two-electrode voltage-clamp techniques. Molecular modeling and molecular dynamics simulation studies were carried out with Autodock Tools. Poricoic acid A and NMDA receptor protein complex were examined with Ligplot and Pymol docking program. Ligplot shows binding activity at the protein and the ligand. The inhibitory effect of poricoic acid A on glutamate-induced inward current in a concentration-dependent manner that was reversible. Half inhibitory concentrations of glutamate on NR1a/NR2A, NR1a/NR2B, NR1a/NR2C, and NR1a/NR2D receptors were 9.6 ± 1.2, 5.7 ± 0.4, 46.1 ± 21.5, and 21.5 ± 8.2μM, respectively. This corresponded to the order of inhibitory effect of oocyte expressing NR1a and NR2s subunit of NR1a/NR2B > NR1a/NR2A > NR1a/NR2C > NR1a/NR2D. Taken together, these results indicate that poricoic acid A can modulate the expression of NMDA receptor. In addition, the regulation of excitatory ligand-gating ion channel by poricoic acid A may have pharmaceutical functions on excitatory synaptic transmission of neuronal system.

The impact of azole antifungal drugs on imatinib metabolism in human liver microsomes

1. Imatinib is widely used for the treatment of hematologic malignancies. It is common that imatinib is clinically co-prescribed with azole antifungal agents since these patients are more prone to invasive antifungal infection. The present study was to investigate the effects of azole antifungal drugs, including ketoconazole, fluconazole, voriconazole, itraconazole and posaconazole on imatinib metabolism.2. The main metabolites, 1-OH midazolam and N-desmethyl imatinib, were determined in the absence and in the presence of various levels of ketoconazole, fluconazole, voriconazole, itraconazole and posaconazole. The relevant assay was also performed to screen mechanism-based inhibitors (MBI).3. The inhibition ability of 1-OH midazolam formation from midazolam based on IC50 values was ketoconazole (0.09 µM)>itraconazole (0.31 µM)> posaconazole (0.68 µM)>voriconazole (2.10 µM) > fluconazole (8.90 µM). Similarly, the rank order of inhibitory effects on formation of N-desmethyl imatinib from imatinib was ketoconazole (4.58 µM)>itraconazole (17.45 µM)> posaconazole (31.02 µM)> voriconazole (367.9 µM) >fluconazole (1.11 mM). Posaconazole and itraconazole displayed evidence of MBI. Additionally, imatinib was also shown as a MBI of CYP3A with IC50 value of 5.40 µM against the midazolam.4. The significant difference in IC50 values of midazolam and imatinib inhibited by azole antifungal agents was observed. The role of CYP2C8 in imatinib metabolism and imatinib autoinhibits CYP3A activity may explain this difference. Our findings suggest that the azole antifungal agents might have limited impacts on imatinib exposure by CYP3A activity.

ALLELOPATHIC INFLUENCE OF SOME WEED RESIDUES ON GROWTH AND DEVELOPMENTAL CHANGES OF GREEN GRAM (VIGNA RADIATA (L.) WILCZEK)

The term allelopathy refers to the detrimental effects of higher plants of one species (the donor) on the germination, growth, or development of another species (the recipient). In the present studyallelopathic influence of weed species, Echinochloa colona (L.) Link, (Poaceae), Cleome viscosa L. (Capparidaceae) and Ammania baccifera L. (Lythraceae) on green gram (Vigna radiata (L.) Wilczek were investigated. The individual and combined residues of three weeds wereincorporated to the soil at the quantities of 0,1,2,3 and 4% (w/w) in the plots and the germination, seedling growth dry weight of green gram were assessed. The results showed that all the concentrations of combined weed residues exhibited higher degree of inhibitory effects than the individual weed residues in all the parameters employed in the study except at 1% of C. dactylon, where insignificant growth promotion observed. The percentage of inhibitory effects of weedresidues increases with increasing the magnitude of the residues. The degree of reduction percentage of all the growth parameters was concentration dependent.Among the three weeds, A. baccifera had more retarding effects on the growth of green gram and the order of inhibitory effect of three weed was A.baccifera, C. viscosa and E. colona.

English

Recent research has focused on natural plant products as alternative for disease control in both developed and developing countries. Medicinal plants can be a possible source for new potent antimicrobial agents to which pathogenic strains are not resistant. The present study was carried out to determine the in vitro antimicrobial activity of 14 plant species namely; Allium sativum, Aloe vera, Bryophyllum pinnatum, Cassia ocidentalis, Citrus sinensis, Euphorbia hirta, Mangifera indica, Myristica fragrans, Ocimium gratissimum, Piper guineese, Psidium guajava, Spermacoce verticilata, Vernonia amygdalina and Zingiber officinale and 3 antibiotic drugs namely; ampicillin, ciprofloxacin and streptomycin on Escherichia coli O157:H7 isolated from human clinical sample. The extracts of the plant species were prepared by cold percolation method using ethanol and water as solvents. Phytochemical analyses of the extracts of the different plant species were determined using standard methods. Agar well diffusion method was used to evaluate the antimicrobial sensitivity test of the plant extracts and that of antibiotic drugs at different concentrations ranging from 31.25 to 500 mg/ml. The minimum inhibitory concentration (MIC) of the antimicrobial agents against Escherichia coli O157:H7 was also conducted. Phytochemical analyses of the plant species revealed the presence of bioactivity principle such as alkaloids, balsam, cardiac glucoside, flavonoids, phenols, resins, saponins, tannins, terpenes and steroids. The results showed that all the antimicrobial agents exhibited inhibitory effects against the growth of the bacterial isolate at various degrees. Among the plant species employed in the study, the ethanolic and water extracts of P. guajava showed the highest inhibitory effect against the bacterium with growth inhibition mean zone diameters of 29.9 and 26.0 mm respectively at 500 mg/ml. Following P. guagava in order of inhibitory effect against E. coli O157:H7 are ethanolic extracts A. sativum, Z. officinale, V. amygdalina and M. indica with mean zones of inhibition of 21.2, 20.8, 20.3 and 19.9 mm respectively at 500 mg/ml. The results also revealed that of the three antibiotic drugs used in the study, ciprofloxacin exhibited the highest inhibitory effect against the organism with zone of inhibition of 38.6 mm, followed by streptomycin 30.2 mm, while ampicilin had the least 22.3 mm. The MIC results reveal that some of the plant species showed similar inhibitory effect against the bacterium, while the MIC results of the rest of the plants varied from one another. The in vitro study of the antimicrobial activity of the extracts of the various plant species and that of the antibiotic drugs against E. coli O157:H7 has demonstrated that certain folk medicine can be as effective as modern medicine in combating pathogenic microorganisms. Key words: In vitro, antimicrobial activity, plant species and antibiotic drugs, Escherichia coli O157:H7.

Comparative Effects of Food Preservatives on the Production of Staphylococcal Enterotoxin I from Staphylococcus aureus Isolate

Staphylococcal enterotoxin I (SEI) is associated with staphylococcal food poisoning, but little is known about different food preservatives on the production of SEI. In this study, the effect of different food preservatives (sodium nitrite, polylysine, chitosan, and tea catechin) on the bacteria growth, sei gene expression, and extracellular SEI production of Staphylococcus aureus isolate H4 was detected in tryptone soya broth (TSB) culture. Our results showed that all of these preservatives depressed S. aureus H4 growth and the order of inhibitory effect was 0.8 g/L tea catechin &gt; 6 g/L chitosan &gt; 0.25 g/L polylysine &gt; 0.4 g/L tea catechin &gt; 0.15 g/L sodium nitrite. Furthermore, 0.25 g/L polylysine or 0.15 g/L sodium nitrite did not significantly alter sei gene transcription, while 6 g/L chitosan obviously increased the relative mRNA level of sei gene expression. 0.4 g/L tea catechin remarkably inhibited sei gene transcription. In addition, 0.15 g/L sodium nitrite and 6 g/L chitosan significantly enhanced SEI secretion. 0.25 g/L polylysine, especially 0.4 g/L tea catechin, sharply inhibited the level of SEI secretion. The results indicated that tea catechin not only suppressed Staphylococcus aureus growth, but also inhibited SEI production and secretion, suggesting that tea catechin may be better than sodium nitrite, polylysine, or chitosan for keeping the food from the contamination of SEI. These investigations would be useful for food industry to provide safer food products due to S. aureus enterotoxins-related control strategy.

The Causes of Dormancy and the Changes of Endogenous Hormone Content in &amp;lt;i&amp;gt; Cephalotaxus sinensis &amp;lt;/i&amp;gt;Seeds

In many wild species, seeds are dormancy at maturity and will not germinate even under favorable environment conditions. Dormancy is a complex trail that is determined by many factors. Some studies have shown that cold stratification and the application of gibberellic acid (GA) can break seed dormancy and promote seed germination. The present study investigated the causes of plant dormancy and the effect of cold stratification and different concentrations of exogenous GA3 in regulating Cephalotaxus sinensis seed germination. Results showed that C. Sinensis seeds have good water permeability, which suggested that seed coats were not the main cause that inhibited the seed germination. There were germination inhibitions in all parts of seeds, and the order of inhibitory effect was: testa < endosperm (embryo), which indicated that existence of germination inhibitions was the main reason causing seed dormancy. Endogenous GAs and IAA (indole-3-acetic acid) content increased, while ABA (abscisic acid) content decreased over the experiments. ZR (zeatin riboside) content decreased in the early phase of cold stratification, but rebounded by the end of the experimental period. The changes of endogenous hormone indicated that GA, IAA and ZR played a positive role in seed germination, whereas ABA was associated with seed dormancy. Besides, the relative ratio of GA/ABA, IAA/ABA and ZR/ABA may play a more important role than their absolute level during the seed development.

Effect of common inorganic ions on aniline degradation in groundwater by activated persulfate with ferrous iron

Aniline is widespread in groundwater and of great toxicity. Advanced oxidation processes, such as the ferrous iron (Fe2+)-activated persulfate process, have been proven to be effective for organic pollutants. However, few studies have focused on the effects of coexisting ions on the degradation of aniline. In this study, the degradation efficiency of aniline and the effects of common inorganic ions (CO32−, PO43−, HCO3−, SO42−, NO3−, Na+, K+, Mg2+, and Ca2+) on aniline degradation were examined. Under the optimum operating conditions, 86.33% aniline degradation (C0 = 11 mmol/L) was observed within 60 min. The effects of cations on aniline degradation were negligible. Anions decreased the removal efficiency of aniline because of the radicals generated by the reaction between sulfate radical or hydroxyl radical and these anions. As the concentrations of PO43−, CO32−, SO42−, HCO3−, and NO3− increased from 0 mmol/L to 5 mmol/L, the removal efficiency of aniline decreased to 19.72%, 24.56%, 66.76%, 68.76%, and 82.42%, respectively. The order of inhibitory effects was PO43− &amp;gt; CO32− &amp;gt; &amp;gt;SO42− &amp;gt; HCO3− &amp;gt; &amp;gt;NO3−.

Screening test for rapid food safety evaluation by menadione-catalysed chemiluminescent assay

The chemiluminescent assay of menadione-catalysed H2O2 production by living mammalian cells was proposed to be useful for rapid food safety evaluation. The tested foods were extracted with water, ethanol and dimethylsulfoxide, and each extract was incubated with NIH3T3, Neuro-2a and HepG2 cells for 4h. Menadione-catalysed H2O2 production by living mammalian cells exposed to each extract was determined by the chemiluminescent assay requiring only 10min, and the viability of the cells was estimated as percentage based on H2O2 production by intact cells. In this study the cytotoxicity of food was rated in order of inhibitory effect on H2O2 production by intact cells. The well known natural toxins such as Fusarium mycotoxin, tomato toxin tomatine, potato toxin solanine and marine toxins terodotoxin and brevetoxin could be detected by the above chemiluminescent assay.

비파엽 추출물의 항산화 효능과 성분분석

본 연구에서는 비파엽 추출물의 항산화 활성, 타이로시네이즈 저해 활성, 및 추출물/분획의 성분 분석에 대한 연구를 수행하였다. 비파엽 추출물의 자유라디칼(1,1-diphenyl-2-picrylhydrazyl, DPPH) 소거활성(<TEX>$FSC_{50}$</TEX>)은 50 % 에탄올 추출물(<TEX>$22.63{\mu}g/mL$</TEX>) < 에틸아세테이트(ethyl acetate) 분획(6.75) < 당을 제거시킨 아글리콘(aglycone) 분획(5.06) 순으로 증가하였다. 루미놀(luminol)-의존성 화학발광법을 이용한 <TEX>$Fe^{3+}-EDTA/H_2O_2$</TEX> 계에서 생성된 활성산소종(reactive oxygen species, ROS)에 대한 총항산화능은 에틸아세테이트 분획(<TEX>$OSC_{50}$</TEX>, <TEX>$0.75{\mu}g/mL$</TEX>), 아글리콘 분획(0.79) 및 50 % 에탄올 추출물(1.61)에서 모두 큰 활성을 나타내었다. 비파엽 추출물의 rose-bengal로 증감된 사람 적혈구의 광용혈에 대한 보호효과를 조사하였다. 비파엽 추출물은 모든 분획에서 농도 의존적(<TEX>$5{\sim}50{\mu}g/mL$</TEX>)으로 증가하였으며, 특히 에틸아세테이트 분획은 <TEX>$10{\mu}g/mL$</TEX> 농도에서 <TEX>${\tau}50$</TEX>이 390.8 min, <TEX>$50{\mu}g/mL$</TEX> 농도에서 <TEX>${\tau}50$</TEX>이 1471.5 min으로 높은 세포 보호 활성을 나타내었다. 타이로시네이즈 저해 활성(<TEX>$IC_50$</TEX>)은 에틸아세테이트 분획(<TEX>$75.25{\mu}g/mL$</TEX>) < 50 % 에탄올 추출물(<TEX>$74.1{\mu}g/mL$</TEX>) < 아글리콘 분획(<TEX>$43.35{\mu}g/mL$</TEX>) 순으로 미백제로 알려진 알부틴보타 타이로시네이즈 저해활성이 크게 나타났다. 비파엽 추출물 중 에틸아세테이트 분획의 TLC 분석 결과 7개의 띠(EJL 1 - EJL 7)가 나타났다. HPLC로 아글리콘 분획을 분석한 결과 kaempferol 및 quercetin이 각각 53.7 % 및 46.3 %였으며, 따라서 추출물 중에는 kaempferol 및 그 배당체 비율이 다소 높은 것으로 나타났다. 이상의 결과들은 비파엽 추출물 또는 분획이 <TEX>$^1O_2$</TEX> 및 다른 ROS를 소거 또는 소광함으로써 그리고 ROS에 대항해서 세포막을 효과적으로 보호함으로써 태양 자외선에 노출된 피부를 보호하는 항산화제로서 작용할 수 있음을 가리키며, 타이로시네이즈 저해 효과로부터 비파엽 추출물 및 분획물은 기능성 화장품 원료로서 응용가능성이 있음을 시사한다. In the present study, the antioxidative properties, inhibitory activity on tyrosinase, and active components of Eriobotrya japonica (E. japonica) leaf extract were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity (<TEX>$FSC_{50}$</TEX>) of extract/fraction of E. japonica leaf was in the order 50 % ethanol extract (<TEX>$22.625{\mu}g/mL$</TEX>) < ethyl acetate fraction (6.75) < deglycosylated aglycone fraction (5.06). Reactive oxygen species (ROS) scavenging activities (<TEX>$OSC_{50}$</TEX>) of fraction/extracton ROS generated in <TEX>$Fe^{3+}-EDTA/H_2O_2$</TEX> system using the luminol-dependent chemiluminescenceassay were investigated. <TEX>$OSC_{50}$</TEX> of the ethyl acetate fraction, deglycosylated aglycone fraction, and ethanol extract were 0.75, 0.79, and <TEX>$1.61{\mu}g/mL$</TEX>, respectively. The cellular protective effects of E. japonica leaf extract on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The protective effects of extract/fraction of E. japonica leaf were increased in a in a concentration dependent manner (<TEX>$5{\sim}50{\mu}g/mL$</TEX>). Especially, <TEX>${\tau}50$</TEX> of ethyl acetate fraction at concentrations of <TEX>$10{\mu}g/mL$</TEX> and <TEX>$50{\mu}g/mL$</TEX> showed the most protective effects at 390.8 min and 1471.5 min. The inhibitory effect (<TEX>$IC_50$</TEX>) on tyrosinase of E. japonica leaf extracts was higher than arbutin, known as a skin-whitening agent. The order of inhibitory effects was acetate fraction (<TEX>$75.25{\mu}g/mL$</TEX>) < 50 % extract (74.1) < deglycosylated aglycone fraction (43.35). TLC of the ethyl acetate fraction showed 7 bands (EJL 1 - EJL 7). HPLC of the aglycone fraction exhibited 2 peaks, kaempferol and quercetin. The amounts of kaempferol and quercetin were 53.7 and 46.3 %. respectively. Therefore, The amounts of kaempferol and its glucoside were a little bit higher than quercetin and its glucoside in E. japonica leaf extract. Accordingly, these findings suggest that extracts/fractions of E. japonica leaf can function as antioxidants in biological systems, especially skin exposed to UV radiation, and protect cellular membranes against ROS. Thus, the extract/fraction of E. japonica leaf may be used in novel functional cosmetics as antioxidants against skin photoaging.

Uptake of AMP, ADP, and ATP inEscherichia coliW

The uptake activity ratio for AMP, ADP, and ATP in mutant (T-1) cells of Escherichia coli W, deficient in de novo purine biosynthesis at a point between IMP and 5-aminoimidazole-4-carboxiamide-1-β-D-ribofuranoside (AICAR), was 1:0.43:0.19. This ratio was approximately equal to the 5'-nucleotidase activity ratio in E. coli W cells. The order of inhibitory effect on [2-³H]ADP uptake by T-1 cells was adenine > adenosine > AMP > ATP. About 2-fold more radioactive purine bases than purine nucleosides were detected in the cytoplasm after 5 min in an experiment with [8-¹⁴C]AMP and T-1 cells. Uptake of [2-³H]adenosine in T-1 cells was inhibited by inosine, but not in mutant (Ad-3) cells of E. coli W, which lacked adenosine deaminase and adenylosuccinate lyase. These experiments suggest that AMP, ADP, and ATP are converted mainly to adenine and hypoxanthine via adenosine and inosine before uptake into the cytoplasm by E. coli W cells.

Purification and Biochemical Characteristics of Pectinesterase from Malatya Apricot (Prunus armeniaca L.)

Pectinesterase (PE) in Malatya apricot pulp (Prunus armeniaca L.) was extracted and purified through (NH4)2SO4 precipitation, dialysis, and DEAE-Sephadex gel filtration chromatography. The samples obtained from the dialysis procedure, named partially purified enzyme, were used for characterization of the apricot pectinesterase. The effect of various factors such as pH, temperature, heat, and storage stability on the partially purified apricot PE enzyme was investigated. Optimum pH value was 9.0 for PE with 1% pectin in 0.1 N NaCl (w/v). The optimum temperature for apricot PE was found to be 60°C on standard analysis conditions. Heat inactivation studies showed a decrease in enzymatic activity at temperatures above 70°C. Km and Vmax values were 0.77 mM and 1.75 µmol min−1 mg−1 for apricot PE. Five inhibitors were tested in the study; the most effective inhibitor was found to be sodium carbonate (100% inhibition). The order of inhibitory effectiveness was: Na2CO3, iodine, lauril sulphate, AgNO3, EDTA. Thermal inactivation data indicated that apparent activation energy with pectin substrate was 2.96 kcal mol−1 for the enzyme. Ascorbic acid, CaCl2, and KCl showed activatory effect on the apricot PE enzyme.

ATP MODULATES THE RELEASE OF NORADRENALINE THROUGH TWO DIFFERENT PREJUNCTIONAL RECEPTORS ON THE ADRENERGIC NERVES OF RAT PROSTATE

1. The effects of adenosine and ATP receptor agonists on the release of endogenous noradrenaline from electrically stimulated (2 Hz, 0.1 msec) rat prostate were examined in order to clarify the pharmacological properties of prejunctional receptors for adenosine and ATP on the adrenergic nerve varicosities in the prostate. Noradrenaline was quantified by HPLC coupled with electrochemical detection techniques. 2. Both adenosine and ATP receptor agonists (1 micromol/L) inhibited noradrenaline release and the relative order of inhibitory effect was N(6)-cyclopentyl-adenosine (CPA) > 5'-N-ethylcarboxamidoadenosine > 2-chloroadenosine > adenosine > 2-methylthio-ATP (2mSATP) > AMP > ATP. 3. The adenosine receptor agonist CPA (1 nmol/L-1 micromol/L) and the ATP receptor agonist 2mSATP (100 nmol/L-100 micromol/L) inhibited the stimulation-induced release of noradrenaline in a concentration-dependent manner. The concentrations of CPA and 2mSATP that produced 50% inhibition of noradrenaline release were 9.6 nmol/L and 1.4 micromol/L, respectively. 4. 1,3-Dipropyl-8-cyclopentylxanthine, an adenosine A(1) receptor antagonist, significantly reduced the inhibitory effects of not only CPA, but also 2mSATP. 5. Suramin, an ATP receptor antagonist, significantly reduced the inhibitory effects of 2mSATP, but not those of CPA. 6. Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid, another ATP receptor antagonist, had no effect on the inhibitory action of either agonist. 7. These results suggest that, in the sympathetic nerve terminals of rat prostate, adenosine and ATP induce inhibition of noradrenaline release via the activation of adenosine A(1) and/or xanthine-sensitive ATP receptors, which play an inhibitory regulatory role in adrenergic neurotransmission in the prostate.

Comparative action of 1,4-phenylenebis(methylene)selenocyanate and its metabolites against 7,12-dimethylbenz[a]anthracene-DNA adduct formation in the rat and cell proliferation in rat mammary tumor cells

1,4-Phenylenebis(methylene)selenocyanate (p-XSC) inhibits 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis and DMBA–DNA binding in the rat mammary gland. Tetraselenocyclophane (TSC) was identified in rat feces as a metabolite of p-XSC. This led us to postulate the metabolic pathway: p-XSC→glutathione conjugate (p-XSeSG)→aromatic selenol (p-XSeH)→TSC. Whether p-XSC or one of its metabolites is responsible for cancer prevention is the focus of this study. We utilized the DMBA–DNA binding assay with p-XSC as a positive control to evaluate the chemopreventive potential of p-XSC metabolites at dietary selenium levels of 10ppm. Rats were fed AIN-76A diet supplemented with various selenium compounds for 1 week prior to the oral administration of a single dose of [3H]DMBA (5mg per rat, specific activity 51.3mCi/mmol). The rats were sacrificed 24h later and DNA was isolated from the mammary fat pads. Relative levels of total binding were: [pmol/mg DNA, mean±S.D., n=6]; DMBA [7.2±1.6]; DMBA+p-XSC [3.5±2.7]; DMBA+p-XSeSG [2.2±1.1]; DMBA+TSC [5.6±2.9]. All selenium compounds, except TSC, significantly inhibited DMBA–DNA adduct formation; however, the difference between p-XSC and p-XSeSG was not statistically significant. The inhibition of total binding was attributed to a reduction in the formation of the three major adducts derived from bay-region diol epoxides of DMBA. On the basis of their chromatographic characteristics, these were identified as anti-diol-epoxide:deoxyguanosine, syn-diol-epoxide:deoxyadenosine, and anti-diol-epoxide:deoxyadenosine. Our results suggest that p-XSeSG, but not TSC, is the likely inhibitor of mammary cancer. Selenium levels measured by atomic absorption spectroscopy in the target organ (mammary fat pads) and in plasma following the dietary administration of selenium compounds were in the order of p-XSeSG≅p-XSC>TSC. These results appear to be consistent with their order of inhibitory effects on total DMBA–DNA binding. Further in vitro studies of the effect of selenium compounds on cell proliferation suggest that, depending on the dose and time point selected, p-XSC is comparable to or better than p-XSeSG; but both are more effective than TSC. Collectively, our in vivo and in vitro results indicate that p-XSC and its conjugate are better candidates than TSC for future studies on mammary cancer chemoprevention.