几种新型Schiff碱及其稀土配合物抑菌活性的研究

采用琼脂稀释法测定了几种新型Schiff碱及其稀土配合物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的抑菌活性,测得了它们抑制细菌生长的最小浓度。结果表明几种新型Schiff碱及其稀土配合物对几种受试菌均有较强的抑制作用,配合物比相应配体具有更高的抑菌活性。     

The Relationship Between Inhibition of Return and Saccade Trajectory Deviations.

After presentation of a peripheral cue, a subsequent saccade to the cued location is delayed (inhibition of return: IOR). Furthermore, saccades typically deviate away from the cued location. The present study examined the relationship between these inhibitory effects. IOR and saccade trajectory deviations were found after central (endogenous) and peripheral (exogenous) cuing of attention, and both effects were larger with an onset cue than with a color singleton cue. However, a dissociation in time course was found between IOR and saccade trajectory deviations. Saccade trajectory deviations occurred at short delays between the cue and the saccade, but IOR was found at longer delays. A model is proposed in which IOR is caused by inhibition applied to a preoculomotor attentional map, whereas saccade trajectory deviations are caused by inhibition applied to the saccade map, in which the final stage of oculomotor programming takes place. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Angiotensin I‐converting enzyme inhibitory activity of protein hydrolysates prepared from three freshwater carps (Catla catla,Labeo rohita and Cirrhinus mrigala) using Flavorzyme

Fish protein hydrolysates from three freshwater carps, Catla catla, Labeo rohita and Cirrhinus mrigala with different degree of hydrolysis (DH) (5%, 10%, 15% and 20%), were prepared using Flavorzyme enzyme and designated as HCF, HRF and HMF, respectively. The angiotensin I‐converting enzyme (ACE) inhibitory activity of hydrolysates was found to vary from 43 ± 2% to 71 ± 3%. Based on ACE inhibitory activity, HRF with DH‐15% was taken up for further study. The mode of ACE activity inhibition by HRF‐DH 15% was mixed type as revealed by Lineweaver–Burk plot. Sequential digestion of HRF‐DH 15% using pepsin and pancreatin decreased the ACE inhibitory activity from 76% to 63%. Partial purification of HRF‐DH 15% by size exclusion chromatography gave three different fractions designated as F‐1, F‐2 and F‐3 with the molecular mass in the range of 6456–407 Da. Fraction 2 had significantly higher ACE inhibitory activity than the other fractions.     

Acquiring real kinetics of reactions in the inhibitory atmosphere containing product gases using micro fluidized bed

This study proposed an isotope-tagging method to investigate reactions under the atmosphere of product gas. To illustrate this method, the calcination kinetics of calcium carbonate Ca¹³CO₃ in CO₂ atmospheres were investigated by monitoring ¹³CO₂ produced using a micro fluidized bed reaction analyzer (MFBRA). The results demonstrated that the presence of CO₂ in reaction atmosphere increases the apparent activation energy. The increase in the apparent activation energy is, however, significantly overestimated by the thermogravimetric analyzer (TGA) because of the excessive suppression by stagnated product gas inside the sample crucible. Comparatively, the apparent activation energy increases with CO₂ from the MFBRA due primarily to the thermal equilibrium limitation, because the gas diffusion in the MFBRA is essentially eliminated. It is thus concluded that the MFBRA is quite capable of acquiring the real kinetics of reactions in such inhibitory atmospheres.     

Influences of pretreatment and drying methods on composition,micro/molecular structures and some health‐related functional characteristics of dietary fibre powder from orange pulp residues

Influences of pretreatment methods (washing, blanching, soaking in ethanol), drying methods (hot air‐drying, infrared‐drying, microwave‐drying) and drying temperature on selected characteristics of dietary fibre powder from orange pulp residues were investigated. Pretreatments improved the hydration properties, oil‐holding capacity and glucose dialysis retardation index, but led to losses of fibres, decreased α‐amylase inhibitory activity and aflatoxin B₁ adsorption capacity. Hydration properties, oil‐holding capacity and glucose uptake depended on the structure and porosity of the fibre, while the ability to inhibit α‐amylase and AFB₁ adsorption depended more on the content and molecular fingerprinting of the fibre. Drying condition did not significantly affect functional properties of the fibre, except for the ability to uptake glucose, inhibit α‐amylase and adsorb AFB₁ (P ≤ 0.05). Hot air‐drying at 60 °C resulted in fibre with the highest ability to decrease the rate of glucose and AFB₁ adsorption.     

Antioxidant and α-glucosidase inhibitory activities of eight neglected fruit extracts and UHPLC-MS/MS profile of the active extracts

The 70% ethanolic extracts from eight neglected fruits; Muntingia calabura, Leucaena leucocephala, Spondias dulcis, Syzygium jambos, Mangifera caesia, Ardisia elliptica, Cynometra cauliflora and Ficus auriculata were evaluated for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, α-glucosidase inhibitory activities as well as total phenolic content. The results of this study revealed that M. caesia fruit extract demonstrated the most potent radical scavenging activity. Among the fruits examined for α-glucosidase inhibitory activity, M. calabura and F. auriculata exhibited strong activity with no significant difference. The Pearson correlation indicated that the activities of M. caesia and F. auriculata contributed by phenolic compounds. A total of 65 metabolites were tentatively identified by using ultra-high-performance liquid chromatography tandem mass spectrometry (UHLPC-MS/MS). These findings suggested that the possible application of M. caesia and F. auriculata as a functional food with antioxidant and α-glucosidase inhibitory properties.     

A preliminary study of monosaccharide composition and α‐glucosidase inhibitory effect of polysaccharides from pumpkin (Cucurbita moschata) fruit

In this work, crude polysaccharide extracts were extracted from pumpkin (Cucurbita moschata) fruit by hot water. After removal of proteins and purification, polysaccharides of pumpkin fruit (PP1‐1) were subjected to structural identification. Gas chromatography analysis indicated that PP1‐1 comprised of galactose (86.4%), and glucose (13.6%). The molecular weight of PP1‐1 was measured to be 0.87 × 10⁴ Da by gel permeation chromatography. The inhibitory kinetic evaluation showed that it was non‐competitive inhibition of PP1‐1 on the α‐glucosidase‐catalysed hydrolysis of PNPG. The Michaelis–Menten constant (K_m) was 0.106 m , and the inhibitory constants (K_i), 0.435 mg.