Bioactivities and Synergistic Effect of Elsholtzia ciliata Essential Oil and Its Main Components against Lasioderma serricorne.

Investigations have shown that storage bugs seriously harm grains during storage. In the interim, essential oils (EOs) have been proven to be a good botanical pesticide. The anti-Lasioderma serricorne properties of Elsholtzia ciliata essential oil, which was obtained by steam distillation, were evaluated using DL-limonene, carvone, and their two optical isomer components using contact, repelling, and fumigation techniques. Simultaneously, the fumigation, contact, and repellent activities of carvone and its two optical isomers mixed with DL-limonene against L. serruricorne were evaluated. The results showed that E. ciliata, its main components (R-carvone, DL-limonene), and S-carvone exhibited both fumigations (LC50 = 14.47, 4.42, 20.9 and 3.78 mg/L) and contact (LD50 = 7.31, 4.03, 28.62 and 5.63 µg/adult) activity against L.serricorne. A binary mixture (1:1) of R-carvone and DL-limonene displayed an obvious synergistic effect. A binary mixture (1:1) of carvone and its two optical isomers exhibited an obvious synergistic effect, too. Furthermore, the repellent activity of the EO, carvone, and its two optical isomers, DL-limonene, and a combination of them varied. To stop insect damage during storage, E. ciliata and its components can be utilized as bio-insecticides.

Novel insights into the kinetics and mechanism of arsenopyrite bio-dissolution enhanced by pyrite.

Arsenopyrite and pyrite often coexist in metal deposits and tailings, thus simultaneous bioleaching of both sulfides has economic (as well as environmental) significance. Important targets in bio-oxidation operations are high solubilization rates and minimized accumulation of Fe(III)/As-bearing secondary products. This study investigated the role of pyrite bioleaching in the enhancement of arsenopyrite dissolution. At a pyrite to arsenopyrite mass ratio of 1:1, 93.6% of As and 93.0% of Fe were solubilized. The results show that pyrite bio-oxidation can promote arsenopyrite dissolution, enhance S0 bio-oxidation, and inhibit the formation of jarosites, tooeleite, and amorphous ferric arsenate. The dry weight of the pyrite & arsenopyrite residue was reduced by 95.1% after bioleaching, compared to the initial load, while only 5% weight loss was observed when pyrite was absent. A biofilm was formed on the arsenopyrite surface in the presence of pyrite, while a dense passivation layer was observed in the absence of pyrite. As(III) (as As2O3) was a dominant As species in the pyrite & arsenopyrite residue. Novel and detailed findings are presented on arsenopyrite bio-dissolution in the presence of pyrite, and the presented approach could contribute to the development of novel cost-effective extractive bioprocesses. ENVIRONMENTAL IMPLICATION: The oxidation of arsenopyrite presents significant environmental hazards, as it can contribute to acid mine drainage generation and arsenic mobilization from sulfidic mine wastes. Bioleaching is a proven cost-effective and environmentally friendly extractive technology, which has been applied for decades in metal recovery from minerals or tailings. In this work, efficient extraction of arsenic from arsenopyrite bioleaching was presented through coupling the process with bio-oxidation of pyrite, resulting in lowered accumulation of hazardous and metastable Fe(III)/As-bearing secondary phases. The results could help improve current biomining operations and/or contribute to the development of novel cost-effective bioprocesses for metal extraction.

Synthesis of Se polysaccharide catalyzed by sulfonic acid functionalized ionic liquids: Synergism effect of anion/cation.

The rational design and construction of controllable selenylation strategy are important for the study on the structure-activity relationship of Se polysaccharides. Herein, selenized Artemisia sphaerocephala polysaccharides (SePASs) were synthesized by using sulfonic acid functionalized ionic liquids (SFILs) as catalysts in order to study the regulation of the cation/anion constitute on the selenylation efficiency and Se polysaccharide structure. Impressively, SFILs could promote the efficient substitution of seleno-group on the polysaccharide backbone through the synergistic catalysis by cation/anions (Se content up to 5582.7 µg/g). Further, reaction mechanism and potential dissolution effect was supported by DFT calculation and polarized light microscopy. 13C NMR and FT-IR spectra analysis of SePASs exhibited that selenite existed in polysaccharides and the substitution position occured at C-6. SEC-MALLS, monosaccharide composition results revealed that strong acidity of SFILs lead to the driving forces toward low molecular mass polysaccharide fragments and synergistic effect of anion/cations in SFILs (-SO3H group of cations as proton donor, anions as nucleophile) showed regulation on average molecular mass. In addition, the strong attractions between the seleno-groups generated agglomeration of polysaccharide chain, which was proved by applying AFM analysis. Therefore, this work provided a new insight for manipulate Se content and MW of Se polysaccharides.

A comprehensive comparison of Chinese olive oils from different cultivars and geographical origins.

China has become increasingly interested in producing olive oil in recent years. In this study, we determined the characteristics of virgin olive oil in five typical cultivars (cv. 'Arbequina,' 'Coratina,' 'Ezhi 8,' 'Frantoio,' and 'Koroneiki') from two of the most suitable production areas for olive cultivation in China. In addition, linear discriminant analysis (LDA) was used to differentiate oils originating from various cultivars and geographical origins. Heatmap was also constructed to describe the differences straightly. Compared to Xichang oils, Longnan oils generally contained higher levels of C18:0, lignans, total esters and total furans, and lower levels of phenolic acids and phenolic alcohols. A variety of cultivars differed in total sterols, hydroxytyrosol derivatives, and volatile compounds. Coratina oils showed excellent properties in two regions. Our findings are closely related to select the optimum olive cultivars in different regions to promote the development of Chinese olive industry scientifically.

Community composition and trophic mode diversity of fungi associated with fruiting body of medicinal Sanghuangporus vaninii.

BACKGROUND: The microbial symbionts of macrofungal fruiting body have been shown to play momentous roles in host growth, development, and secondary metabolism. Nevertheless, there is no report on the fungal diversity of Sanghuangporus, a medicinal and edible homologous macrofungus as "forest gold", which has good effects on antioxidation, boosting immunity and curing stomachache. Here, the diversity and functional group of fungi associated with the fruiting body of the most widely applied S. vaninii were characterized by high-throughput sequencing and FUNGuild tool for the first time. RESULTS: Total 11 phyla, 34 classes, 84 orders, 186 families, and 328 genera were identified in the fruiting body, and our results revealed that the fungal community was dominated by the host fungal taxonomy with absolute superiority (more than 70%), namely, Basidiomycota, Agaricomycetes, Hymenochaetales, Hymenochaetaceae, and genus of Phellinus corrected to Sanghuangporus. Simultaneously, the reads allocated into non-host fungal operational taxonomic units were largely dominated by Ascomycota, Sordariomycetes, Sordariales, Mortierellaceae, and Mortierella. Furthermore, the endophytic fungi were assigned into three trophic modes of "saprotroph" (53.2%), "symbiotroph" (32.2%), and "pathotroph" (14.1%), in which the category of "plant pathogen" was highest enriched with relative abundance of 91.8%, indicating that the endophytic fungi may have the potential to adjust the growth and metabolism of host S. vaninii. CONCLUSION: Altogether, this report firstly provided new findings that can be inspiring for further in-depth studies to exploit bioactive microbial resources for increased production of Sanghuangporus via coculture, as well as to explore the relationship between macrofungi and their associated endophytes.

Identification and profiling of the community structure and potential function of bacteria from the fruiting bodies of Sanghuangporus vaninii.

Sanghuangporus sp., a medicinal and edible homologous macrofungus known as 'forest gold', which has good effects on antitumor, hypolipidemia and the treatment of gynecological diseases. However, the natural resources of fruiting body are on the verge of depletion due to its long growth cycle and over exploitation. The growth and metabolism of macrofungi are known to depend on the diverse bacterial community. Here, we characterized the diversity and potential function of bacteria inhabiting in the fruiting body of the most widely applied S. vaninii using a combination method of high-throughput sequencing with pure culturing for the first time, and tested the biological activities of bacterial isolates, of which Illumina NovaSeq provided a more comprehensive results on the bacterial community structure. Total 33 phyla, 82 classes, 195 orders, 355 families, 601 genera and 679 species were identified in the fruiting body, and our results revealed that the community was predominated by the common Proteobacteria, Gammaproteobacteria, Burkholderiales, Methylophilaceae (partly consistent with pure-culturing findings), and was dominated by the genera of distinctive Methylotenera and Methylomonas (yet-uncultured taxa). Simultaneously, the functional analysis showed that companion bacteria were involved in the pathways of carbohydrate transport and metabolism, metabolism of terpenoids and polyketides, cell wall/membrane/envelope biogenesis, etc. Hence, it was inferred that bacteria associated with fruiting body may have the potential to adjust the growth, development and active metabolite production of host S. vaninii combined with the tested results of indole-3-acetic acid and total antioxidant capacity. Altogether, this report first provided new findings which can be inspiring for further in-depth studies to exploit bioactive microbial resources for increased production of Sanghuangporus, as well as to explore the relationship between medicinal macrofungi and their associated endophytes.

Deep eutectic solvents boosting solubilization and Se-functionalization of heteropolysaccharide: Multiple hydrogen bonds modulation.

In this study, the favorable feasibility of deep eutectic solvents (DESs) in solubilization and functionalization of natural heteropolysaccharide was validated by experiments and density functional theory calculations. This revealed that choline chloride-based DES/DMSO (dimethyl sulfoxide) binary mixed solvents possessed more and stronger hydrogen bonding sites, facilitating the balance between disruption and reconstruction of hydrogen bonds within branched heteropolysaccharide from Artemisia sphaerocephala (PAS) and achieving efficient solubilization. Further, due to the full exposure and activation of polysaccharide hydroxyls, the efficiency of DES/DMSO-mediated novel Se-functionalization was substantially enhanced compared to the conventional selenylation methods. The derivative exhibited conversion to lower molecular mass with rigid solution conformation based on co-solvent effect and predominant acidic environment influence. This study offered a framework for exploring the potential of individualized polysaccharide functionalization by modulating DES constituents to achieve multiple controllabilities in terms of conversion efficiency and derivative structure.

Changes in Quality and Antioxidant Properties of Virgin Olive Oil of 'Cornicabra' According to Fruit Maturation in Longnan, China.

This work aims to study the influence of olive fruit maturity on physicochemical properties and antioxidant activity which determine the quality of virgin olive oils (VOO). According to the results, the values of all parameters were within the range specified by the Codex Alimentarius (2017). With the increase of fruit maturity, the oil content continued to increase until reached the maximum value (20.05%) in the 7th maturity (M7). K232, K270 and peroxide value (PV) decreased with the increase of maturity, while ΔK increased linearly with the increase of maturity. Free fatty acidity (FFA) first decreased and then increased, until reached the maximum value of (0.52 ± 0.03) % in M7. The total polyphenols (TP) and total flavonoids (TF) that characterized the antioxidant properties of olive oil increased with the increase of fruit maturity, which indicated that the oxidative stability (OS) of VOO of 'Cornicabra' increased with the increase of fruit maturity. The oleic acid (C18:1) content remained above 70 % and reached the maximum of (76.68 ± 0.17) % at M7. The values of monounsaturated fatty acids (MUFA) / polyunsaturated fatty acids (PUFA) and oleic acid (C18:1) / linoleic acid (C18:2) showed a decreasing trend with the maturity stage. Principal component analysis (PCA) showed that the quality of FFA, PV, K232, K270, TP, TF and OS were higher at the 5th maturity (M5), the quality of fatty acid were higher at M7. It can be seen from the analysis that the olive fruit maturity was an important parameter to characterize and distinguish olive oil.

Chemical Constituents of the Essential Oil Extracted from Elsholtzia densa and Their Insecticidal Activity against Tribolium castaneum and Lasioderma serricorne.

Storage pests pose a great threat to global food security. Here, we found that the essential oil (EO) extracted from E. densa possesses obvious effects against the insects that threaten stored-products. In this work, we investigated the chemical constituents of the essential oil extracted from Elsholtzia densa, and their insecticidal (contact and fumigant) toxicity against Tribolium castaneum and Lasioderma serricorne. A total of 45 compounds were identified by GC-MS, accounting for 98.74% of the total EO. Meanwhile, 11 compounds were isolated from the EO, including limonene, ß-caryophyllene, ρ-cymene, trans-phytol, α-terpineol, linalool, acetophenone, 1,8-cineole, ρ-cymen-7-ol, 1-O-cerotoylgly-cerol, and palmitic acid. Furthermore, acetophenone, ρ-cymen-7-ol, and 1-O-cerotoylgly-cerol were isolated for the first time from Elsholtzia spp. The results of the bioassays indicated that the EO had the property of insecticidal toxicity against T. castaneum and L. serricorne. All of the compounds showed different levels of insecticidal toxicity against the two species of insects. Among them, 2-ethyl-1H-imidazole had no insecticidal toxicity against T. castaneum, but possessed fumigant and obvious contact toxicity against L. serricorne. ρ-Cymen-7-ol had beneficial insecticidal toxicity against the two species of insects, and fumigant toxicity against L. serricorne. ρ-Cymen-7-ol (LD50 = 13.30 µg/adult), 1-octen-3-ol (LD50 = 13.52 µg/adult), and 3-octanol (LD50 = 17.45 µg/adult) showed significant contact toxicity against T. castaneum. Acetophenone (LD50 = 7.07 µg/adult) and ρ-cymen-7-ol (LD50 = 8.42 µg/adult) showed strong contact toxicity against L. serricorne. ρ-Cymene (LC50 = 10.91 mg/L air) and ρ-cymen-7-ol (LC50 = 10.47 mg/L air) showed powerful fumigant toxicity to T. castaneum. Limonene (LC50 = 5.56 mg/L air), acetophenone (LC50 = 5.47 mg/L air), and 3-octanol (LC50 = 5.05 mg/L air) showed obvious fumigant toxicity against L. serricorne. In addition, the EO and its chemical compounds possessed different levels of repellent activity. This work provides some evidence of the value of exploring these materials for insecticidal activity, for human health purposes. We suggest that the EO extracted from E. densa may have the potential to be developed as an insecticidal agent against stored product insect pests.

Quality Assessment of Five Mono-cultivar Virgin Olive Oils Produced in Longnan (China) from 2013 to 2017.

The aim of this work was to evaluate the quality of the five mono-cultivar (Frantoio, Leccino, Picholine, Coratina and Ezhi-8) virgin olive oils (Mc-VOOs) produced in Longnan (China) from 2013 to 2017 through analysing the organoleptic quality, physicochemical properties, phenolic contents, antioxidant activity and fatty acid composition. The leading principal components for assessing the quality of Mc-VOOs were extracted by principal component analysis (PCA). The results indicated that the five Mc-VOOs showed obvious differences (p < 0.05) in flavour and substance composition with the variation of cultivar and production year; however, the same cultivar of VOO displayed certain homogeneity in five consecutive years of assessment. The five Mc-VOOs were rich in phenolic compounds and unsaturated fatty acids such as oleic acid. The quality of VOO was mainly determined by the genetic characteristics of olive cultivar, meanwhile, fruit maturity, soil and climate factors also affected its quality. The content of phenolic compound, DPPH· scavenging rate, proportion of unsaturated fatty acids and iodine value of Coratina were the highest, on the contrary, Ezhi-8 was the lowest in general. The results of PCA showed that the five leading principal components to evaluate the quality of Mc-VOOs were oleic acid, linoleic acid, acid value, total phenol and trace components (such as C20:1 and squalene) successively. In conclusion, the five Mc-VOOs from Longnan show excellent quality and have certain uniformity in different production years.

In silico analysis of epitope-based vaccine candidate against tuberculosis using reverse vaccinology.

Tuberculosis (TB) kills more individuals in the world than any other disease, and a threat made direr by the coverage of drug-resistant strains of Mycobacterium tuberculosis (Mtb). Bacillus Calmette-Guérin (BCG) is the single TB vaccine licensed for use in human beings and effectively protects infants and children against severe military and meningeal TB. We applied advanced computational techniques to develop a universal TB vaccine. In the current study, we select the very conserved, experimentally confirmed Mtb antigens, including Rv2608, Rv2684, Rv3804c (Ag85A), and Rv0125 (Mtb32A) to design a novel multi-epitope subunit vaccine. By using the Immune Epitopes Database (IEDB), we predicted different B-cell and T-cell epitopes. An adjuvant (Griselimycin) was also added to vaccine construct to improve its immunogenicity. Bioinformatics tools were used to predict, refined, and validate the 3D structure and then docked with toll-like-receptor (TLR-3) using different servers. The constructed vaccine was used for further processing based on allergenicity, antigenicity, solubility, different physiochemical properties, and molecular docking scores. The in silico immune simulation results showed significant response for immune cells. For successful expression of the vaccine in E. coli, in-silico cloning and codon optimization were performed. This research also sets out a good signal for the design of a peptide-based tuberculosis vaccine. In conclusion, our findings show that the known multi-epitope vaccine may activate humoral and cellular immune responses and maybe a possible tuberculosis vaccine candidate. Therefore, more experimental validations should be exposed to it.

Evolution of Phenotypic Traits and Main Functional Components in the Fruit of 'Chenggu-32' Olives (Olea europaea L.) Cultivated in Longnan (China).

China has taken olive cultivation as a significant part of its agricultural development. Longnan city of Gansu province was marked into the world olive distribution map by International Olive Oil Council in 1998. However, so far, little research has been done on the growth and development stages of Chinese olives. The objective of this study was to investigate the dynamics changes of several quality characteristics of olive oil at different sampling times. Olive fruit of 'Chenggu-32' grown in Longnan were harvested at twenty-four time periods and used for determination of phenotypic traits and oil quality characteristics: total polyphenols and flavonoids contents, as well as fatty acid composition by using Gas Chromatography-Mass Spectrometer (GC-MS) and analysed by using Principal Components Analysis (PCA). Towards maturation, fruit moisture content decreased while oil content increased. Levels of both total flavonoids and total polyphenols contents slightly decreased first then increased. The ratio of unsaturated to saturated fatty acids was close to three. The ratio of monounsaturated fatty acids (MUFA)/ polyunsaturated fatty acids (PUFA) was from 2.28 to 4.05. The oleic acid (C18:1)/linoleic acid (C18:2) ratio was varied between 5.23 and 10.67 according to different sampling dates. The olive oil had lower oleic acid (C18:1) levels, higher linoleic acid (C18:2), linolenic acid (C18:3), and palmitic acid (C16:0) levels compared to Codex values (2017) in some periods, which is the characteristics fatty acid composition of 'Chenggu-32' variety in Longnan, China.

Synthesis of Se-polysaccharide mediated by selenium oxychloride: Structure features and antiproliferative activity.

Selenium oxychloride (SOC) was employed as a highly reactive selenide reagent to synthesize selenized Artemisia sphaerocephala polysaccharides (SeASP). Se content of SeASP was significantly increased (∼22,400 µg/g) as compared to HNO3/H2SeO3 selenylation method (1703 µg/g). Furthermore, selenized ASP was prepared by using microwave-assisted synthesis which obviously enhanced selenylation kinetics. FT-IR, Raman, XPS and NMR results exhibited seleno-group was substituted at C6 position in the form of selenite (Se4+). SEC-MALLS suggested SOC system could effectively avoid the degradation of polysaccharide chain. Meanwhile, MALLS calculation, MB spectrophotometric method and AFM observation showed SeASP appeared spherical and rod-shaped conformation after selenylation. Seleno-groups were more likely to affect the conformational transformation of polysaccharide chains. Moreover, SeASP could significantly enhance antiproliferative activity against three tumor cells, of which the IC50 value of HepG2 was calculated as 24.35 µg/mL. It was found that higher Se content could effectively improve the antitumor activities of Se-polysaccharides in vitro.

A comparative study of sulfated tara gum: RSM optimization and structural characterization.

Interest in galactomannans and its derivatives as a functional health supplement is growing based on physicochemical properties. In this work, the optimized conditions of sulfated tara gum (STG) with a maximum DS of 0.66 by box-behnken design (BBD) were obtained as following: ratio of chlorosulfonic acid/pyridine 3:1, reaction time 4 h and reaction temperature 40 °C. The structure features of STG such as the degree of substitution (DS), substitution position, weight average molar mass (MW), monosaccharide components and chain conformation were investigated. Decreasing of MW, the increasing of Z-average radius of gyration (〈S2〉Z1/2) and specific volume for gyration (SVg) were obtained by SEC-MALLS. In addition, the structural properties of four sulfated galactomannans were comparatively investigated and analyzed based on our earlier reports of sulfated fenugreek gum, guar gum and locust bean gum. A conclusion was drown that higher galactose branch could enhance steric hindrance, which was inferred as one of the significant factors for the derivatization efficiency, thus affecting the DS, MW and conformational transition of sulfated galactomannans. This study will provide valuable information for further research on the comparison of bioactivities and medical application of galactomannans family.

A bibliometric-based analysis of the high-value application of Chlorella.

This bibliometric-based review analyses the trends in 1010 published articles (1990 to mid-2018) on the high-value application of Chlorella, and illustrates the evolution and latest tendencies at a global level by the number of publications and their distribution, issuing institutions and countries or regions, the sources and research direction, as well as the core-author and keywords. The results demonstrated that there is a burst in terms of the number of articles, and China, USA, Mexico, and Japan are the dominant countries in this area. The most relevant journals with this subject are Bioresource Technology and Hydrobiology, and the research mainly focuses on marine and freshwater biology, biotechnology and applied microbiology, energy and fuels, food science and technology, and environmental sciences. Overall, bibliometric analysis has shown that Chlorella application research is a very active field, and the future research will be conducted into construction of genetic engineering algae, high-density and low-cost culture systems, efficient harvesting and separation techniques, effective energy conversion, integrated photo-bioreactors, and molecular biology technology. Wastewater treatment, CO2 bio-fixation, biomass production, and biosynthesis of useful substances by cultivating microalgae are promising research fields.

Light irradiation can regulate the growth characteristics and metabolites compositions of Rhodotorula mucilaginosa.

Light is an important factor that can induce the growth of varieties of organisms including fungi and their secondary metabolites. The evolutions of biomass, carotenoids, lipid production, compositions and contents of fatty acid and amino acid in Rhodotorula mucilaginosa were investigated under different light irradiation conditions. The results indicated that irradiation with 1700 lx could promote the growth and glucose assimilation of R. mucilaginosa, compared to the dark control, while the trial with 3500 lx had certain inhibiting effects. The carotenoids concentrations and percentages of unsaturated fatty acid (USFA, C16:1 and C18:1) increased with the improvement of irradiation intensity. Conversely, the proportions of saturated fatty acids (C16:0, C18:0 and C20:0) were decreased. The relative contents of amino acid and total protein were reduced under illumination compared to dark control. Conclusively, irradiation could change the cell growth and metabolites of the pigmented fungus, which implied that there may be a photoinduced mode exists in R. mucilaginosa similar to that of Neurospora crassa, and it also could be applied to regulate the biosynthesis and production of valuable components such as carotenoids and USFA.

Growth behavior, glucose consumption and phenol removal efficiency of Chlorella vulgaris under the synergistic effects of glucose and phenol.

The use of algae is an effective approach to remove phenol and its derivatives from polluted water. The growth behavior, glucose consumption and phenol removal efficiency of Chlorella vulgaris under the synergistic effects of glucose and phenol were investigated. The evolutions of tolerance and removal efficiency of C. vulgaris to phenol under different trophic modes and glucose contents were observed. The results revealed that growth of C. vulgaris were inhibited with the increase of phenol from 0 to 400 mg L-1 in culture media; the tolerance to phenol enhanced with the addition of glucose from 2 to 10 g L-1, while glucose consumption was inhibited with the increase of phenol content; phenol removal efficiency varied with glucose concentrations in mixotrophic media. The finding suggested that phenol inhibited the growth of C. vulgaris and glucose assimilation under mixotrophic cultivation, while appropriate glucose addition could enhance the tolerance of C. vulgaris to phenol and affect the phenol removal efficiency.

Synthesis and structure characterization of sulfated galactomannan from fenugreek gum.

Sulfated derivatives of the galactomannan family have multiple biological activities. In the present study, sulfated galactomannan from fenugreek gum (SFG) were prepared by chlorosulfuric acid/pyridine (CSA/Py) method. In order to acquire the derivatives with the highest degree of substitution (DS), the experiment optimum conditions of the sulfation were determined by Box-Behnken design (BBD). The quadratic regression model analysis confirmed that reaction time was the most significant parameter for the impact of DS. Under the selected conditions, maximum DS was obtained as 0.490. Results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated the present of SO3- group. In 13C NMR spectroscopy, the original C-6 peaks did not disappear completely and the newly peaks appeared at δ 63.2 and 64.0 illustrating the incomplete substitution were predominantly on C-6 position. After sulfation, size exclusion chromatography combined with multi-angle laser light scattering (SEC-MALLS) detected all the weight average molecular mass (MW) of sulfated derivatives decrease rapidly. The introduction of the electrostatic interaction of negatively charged SO3- groups and the decrease in MW could have a significant effect on its biological activity.

Efficient synthesis of polysaccharide with high selenium content mediated by imidazole-based acidic ionic liquids.

Exploring new solvents or catalysts has great prospect for the derivatization of poorly soluble natural polysaccharides as bio-resources which were extracted from food or industrial waste residue, as compared to traditional reaction system. In this work, selenized Artemisia sphaerocephala polysaccharide (SePAS) was synthesized by using imidazolium-based acidic ionic liquids (AILs) as catalyst. The results showed the highest Se content increased to 20438 µg/g compared to conventional method (1703 µg/g), indicating AILs could enhance selenylation reactivity and Se content was controlled by the acidity due to the protonation effect of H2SeO3 by AILs. FT-IR, X-ray photo-electron spectroscopy (XPS) and 13C NMR results exhibited that seleno-group exists in SePAS and the substitution position was at C-6. The hydrogen bonding effect and acidity of AILs showed regulation on weight average molecular mass of SePAS. Therefore, AILs with excellent catalytic efficiency could be as potential catalyst for full use of polysaccharide-rich resources.

An efficient approach to prepare sulfated polysaccharide and evaluation of anti-tumor activities in vitro.

Use of microwave radiation is one of the most potential techniques in polysaccharide derivatives synthesis due to its advantages such as higher yields, milder reaction conditions and shorter reaction times. This study was aimed at producing sulfated polysaccharides by microwave irradiation using polar reagents and solvent. Six sulfated Artemisia sphaerocephala polysaccharide derivatives (SPAS) were obtained by using chlorosulfuric acid/pyridine method in the reaction duration range of 15-300 min at a fixed microwave power of 100W. Synthesis of SPAS under microwave filed was highly effective and characterized by time saving and high degrees of substitution (DS). The chemical structure of SPAS was confirmed by FT-IR and 13C NMR that sulfation had occurred and the substitution position was mainly at C-6. Size-exclusion chromatograph combined with multi-angle laser photometer (SEC-MALLS) data indicated that short reaction time minimized acid-catalyzed degradation of polysaccharide chains. AFM observation demonstrated that low-MW derivative exhibited aggregation of polysaccharide chain as irregular spherical lumps. In anti-tumor activity assays, sulfation of PAS significantly improved the capacity to inhibit tumor cells growth by arresting the cell cycle progress in specific phases. It could be concluded that MW and molecular mass distribution had much greater influence on anti-tumor activities of SPAS against human non-small cell lung cancer A549 cells, human hepatocellular carcinoma HepG2 cells and human cervical cancer Hela cells. Microwave-assisted synthesis might possess widespread application in preparation of new polysaccharide derivatives with rich variety of structural features and bioactivities.