Antioxidant Activity of Bioactive Polysaccharides Isolated from Natural Sources

Some polysaccharides isolated from natural sources show various important biological activities including antitumor, and are known to act as immunomodulators and specifically, antioxidants. These activities are strongly affected by their chemical structures and chain conformations. This article reviewed the current literature on the antioxidant properties of some important bioactive polysaccharides isola-ted from natural sources,, including plants, microorganisms, algae and animals. Possible antioxidarlt mechanisms of polysaccharides are also summarized. The continuing evaluation of bioactive polysaccharides provides a unique opportunity for the discovery of novel pharmaceuticals and healthcare products that exhibit beneficial antioxidant properties.

The natural sources,extraction,and nephroprotective function of oleanolic acid and ursolic acid:a review

Oleanolic acid(OA)and ursolic acid(UA)are commonly present in the cuticular wax of many edible fruits and medicinal herbs.OA and UA belong to the group of bioactive pentacyclic triterpenoids,exhibiting a wide range of beneficial effects including protection for the kidneys,liver,heart,gastrointestinal tract,and spinal cord.Additionally,OA and UA exhibit antioxidant,anti-ferroptotic,anti-apoptotic,anti-inflammatory,anti-tumor,anti-viral,anti-diabetic,anti-microbial,anti-parasitic,analgesic,wound-healing,hypolipidemic,and hypoglycemic properties,often without notable side effects.Due to the extensive array of their positive functions,it is not feasible to thoroughly cover all aspects in this review.Therefore,the primary focus lies on reviewing the natural sources,extraction,and nephroprotective properties of OA and UA.To summarize,current literatures highlight the nephroprotective mechanisms of OA and UA,primarily involving inhibiting oxidative stress,endoplasmic reticulum stress,glycative stress,dyslipidemia,inflammation,apoptosis,pyroptosis,and renal fibrosis,promoting diuresis,as well as fine-tuning autophagy.

Green Synthesis of Titanium Oxide Nanoparticles Using Natural Extracts

Green synthesis is an alternative method for obtaining nanoparticles for environmentally friendly purposes. The present work describes the synthesis and characterization of titanium oxide nanoparticles, starting from three natural sources: orange peel, hibiscus rosa sinensis and Aloe vera. Titanium (IV) tetrabutoxide in ethanol solution was used as precursor. The methodology used was based on the sol-gel technique, through which TiO2 nanoparticles were obtained in the anatase phase. The characterization of the nanoparticles was carried out by means of x-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectrophotometry (FTIR), which allowed the identification of a good degree of purity and crystallinity of the samples obtained.

Gas Sources of Natural Gas Hydrates in the Muli Permafrost of Qilian Mountain

The gas hydrates in the permafrost region of Qilian Mountain are characterized by low latitude, thin thickness, shallow burial depth, abundant coal seams, high contents of heavy hydrocarbons and multiple sets of source rocks. Up to date, the source of gas or the main source rocks of the Mull gas hydrates have remained unclear.

Gas Sources for Natural Gas Hydrates in the Permafrost Region of the Qilian Mountains

Objective As a new type of gas hydrates,the natural gas hydrates in the perfost region of the Qilian Mountains are characterized by their shallow burial depth,welldeveloped coal seam,high content of heavy hydrocarbons and multiple sets of mature and over-mature source rocks.Gas sources of these gas hydrates in the study area include coal-type gas and oil-type gas.

Enhanced Loading of ^(40)K from Natural Abundance Potassium Source with a High Performance 2D^+ MOT

40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration （0.012%） of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10 6 cold 40K atoms with the help of a high performance of two-dimensional magneto-optical trap （2D＋ MOT）, which is almost three orders of magnitude greater than previous results without the 2D＋ MOT. The number of the 40K atoms is sufficient for most ultra-cold 40K experiments, and our approach provides an ideal alternative for the field.

Estimation of vegetative mercury emissions in China

Vegetative mercury emissions were estimated within the framework of Biogenic Emission Inventory System (BEIS3 V3.11). In this estimation, the 19 categories of U.S. Geological Survey landcover data were incorporated to generate the vegetation-specific mercury emissions in a 81-km Lambert Conformal model grid covering the total Chinese continent. The surface temperature and cloud-corrected solar radiation from a Mesoscale Meteorological model (MM5) were retrieved and used for calculating the diurnal variation...

THE NATURE AND SOURCE OF ESR SIGNAL IN BILIRUBIN

The ESR signals of bilirubin-IXα were studied including the samples treated with free radical generating and inhibiting systems,i.e.X-X0., Fe/EDTA,SOD,mannitol/ascorbate,DTPA,KCN et al.These stable signals all comprise those originated from a semiquinone radical(g=2.0012)and superoxide radical(g_=2.041,g_=2.0040).The latter is shown to be bound with metal ions especially iron,chelated by bilirubin.The iron probably comes from bilirubin precursor——hemootobin.Active oxygen free radical scavengers may destroy these radicals.Kinetic curves of regeneration of the bilirubin radicals have been determined.Bilirubin is discussed as'active oxygen trap'in mammatians.

On the Naturally Induced Sources for Obstacle Scattering

We introduce the equivalent sources for the Helmholtz equation and estab-lish their connections to the naturally induced sources for the sound-soft,sound-hard,and impedance obstacles for the inverse scattering problems of the Helmholtz equation.As two applications,we employ the naturally induced sources to improve the bound-ary integral equation formulations for the obstacle scattering problems,and develop a unified,straightforward approach to establishing boundary conditions governing the domain derivatives of scattered waves for the soft,hard,and impedance obstacles.

Honokiol: A naturally occurring lignan with pleiotropic bioactivities

Honokiol is the dominant biphenolic compound isolated from the Magnolia tree,and has long been considered as the active constituent of the traditional Chinese herb,‘Houpo’,which is widely used to treat symptoms due to‘stagnation of qi’.Pharmacological studies have shown that honokiol possesses a wide range of bioactivities without obvious toxicity.Honokiol protects the liver,kidneys,nervous system,and cardiovascular system through reducing oxidative stress and relieving inflammation.Moreover,honokiol shows anti-diabetic property through enhancing insulin sensitivity,and anti-obese property through promoting browning of adipocytes.In vivo and in vitro studies indicated that honokiol functions as an anti-cancer agent through multiple mechanisms:inhibiting angiogenesis,promoting cell apoptosis,and regulating cell cycle.A variety of therapeutic effects of honokiol may be associated with its physiochemical properties,which make honokiol readily cross the blood brain barrier and the blood-cerebrospinal fluid barrier,with high bioavailability.In the future,more clinical researches on honokiol are needed to fully authenticate its therapeutic values.

Molecular characterization of effluent organic matter in secondary effluent and reclaimed water:Comparison to natural organic matter in source water

Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter（Ef OM） in the treated effluents of municipal wastewater treatment plants（WWTPs） is crucial for ensuring the safety of water reuse. In this study, the molecular composition of Ef OM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation–sedimentation–ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry（FT-ICR MS） method and compared to that of natural organic matter（NOM） in the local source water from a reservoir. It was found that the molecular composition of Ef OM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in Ef OM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted.

SecA inhibitors:next generation antimicrobials

Health problems caused by bacterial infection have become a major public health concern in recent years due to the widespread emergence of drug-resistant bacterial strains.Therefore,the need for the development of new types of antimicrobial agents,especially those with a novel mechanism of action,is urgent.SecA,one of the key components of the secretion(Sec) pathway,is a new promising target for antimicrobial agent design.In recent years,promising leads targeting SecA have been identified and the feasibility of developing antimicrobial agents through the inhibition of SecA has been demonstrated.We hope this review will help stimulate more research in this area so that new antimicrobials can be obtained by targeting SecA.