Extraction, preliminary structural characterization, and antioxidant activities of polysaccharides from Salvia miltiorrhiza Bunge

Four polysaccharides were extracted from Salvia miltiorrhiza Bunge using hot water, ultrasonic, alkali, and enzyme methods. Preliminary structural characterization was conducted by physicochemical property, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses. Antioxidant activities against 2,2-diphenyl-1-picryl-hydrazyl (DPPH), hydroxyl, and superoxide radicals were also evaluated. The physicochemical property analysis indicated the identicalness of the polysaccharide indices obtained by the hot water and ultrasonic methods. The indices obtained by the alkali and enzyme methods were significantly different. The FTIR spectra revealed the general characteristic absorption peaks of the four polysaccharides. The SEM images demonstrated significant differences in the surface features of the different polysaccharides. The antioxidant activity assay revealed the significant antioxidant activities of three polysaccharides. Overall, the polysaccharides from S. miltiorrhiza Bunge may have potential applications in the medical and food industries.     

球衣菌胞内聚β-羟基丁酸提取方法的研究

以球衣菌(Sphaerotilus natans FQ40)为材料,比较多种破壁方法对其胞内PHB提取率的影响。结果表明SDS-NaClO混合破壁法最适宜于提取球衣菌胞内PHB。细胞悬液先用10g/L SDS,35℃处理10min,再用体积分数5%的NaClO处理5min后,经离心、洗涤、烘干,用热氯仿抽提PHB,提取率可达56%,纯度与标准品相同。     

Comparison of different extraction methods of polysaccharides from cup plant (Silphium perfoliatum L.)

The purpose of the present research was to compare the effects of four extraction methods on the extraction yields, physicochemical characteristics, and antioxidant activities of polysaccharides from the cup plant (Silphium perfoliatum L.) (CPPs). The extraction methods included the hot water extraction method (HEM), ultrasonic-assisted extraction method (UEM), enzyme-assisted extraction method (EEM), and the ultrasonic-enzyme-assisted extraction method (UEEM). Four corresponding CPP extracts, HEM-CPPs, UEM-CPPs, EEM-CPPs, and UEEM-CPPs, were obtained. The results indicated that there were notable differences between the extraction methods regarding the yield, average molecular weight, uronic acid content, monosaccharide proportions, and the antioxidant activities of the CPPs. HEM-CPPs were extracted with the lowest yield (6.44%). EEM-CPPs had the largest extraction yield (9.87%) and the most notable antioxidant abilities of ferric reducing power and free radical scavenging activity. According to correlation analysis, the higher antioxidant abilities of EEM-CPPs might be due to their smaller average molecular weight and a higher content of uronic acid than those of the other extracted CPPs. Therefore, EEM could serve as a promising technique for extracting CPPs.     

Extraction efficiency,phytochemical profiles and antioxidative properties of different parts of Saptarangi (Salacia chinensis L.) – An important underutilized plant

The study aimed to evaluate extraction efficiency, detection and quantification of phytochemicals, minerals and antioxidative capacity of different parts of Salacia chinensis L. Continuous shaking extraction, steam bath assisted extraction, ultrasonic extraction and microwave assisted extraction with varied time intervals were employed for extraction of phenolics, flavonoids, and antioxidants. Preliminary screening revealed the presence of wide array of metabolites along with carbohydrates and starch. Steam bath assisted extraction for 10 min exposure was found most suitable for extraction phenolics (46.02 ± 2.30 mg of gallic acid equivalent per gram of dry weight and 48.57 ± 2.42 mg of tannic acid equivalent per gram of dry weight) and flavonoids (35.26 ± 1.61 mg of quercetin equivalent per gram of dry weight and 51.60 ± 2.58 mg of ellagic acid equivalent per gram of dry weight). In support, reverse phase-high performance liquid chromatography- diode array detector confirmed the presence of seven pharmaceutically important phenolic acids. Antioxidant capacity was measured by 1, 1- diphenyl-1-picryl hydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) scavenging (ABTS) and N, N-dimethyl-p-phenylenediamine (DMPD) assays and represented as trolox equivalent antioxidant capacity (TEAC) and ascorbic acid equivalent antioxidant capacity (AEAC). Antioxidant capacity ranged from 121.02 ± 6.05 to 1567.28 ± 78.36 µM trolox equivalent antioxidant capacity and 56.62 ± 2.83 to 972.48 ± 48.62 µM ascorbic acid equivalent antioxidant capacity. Roots showed higher yields of illustrated biochemical parameters, however fresh fruit pulp was found a chief source of minerals. Gas chromatography-mass spectroscopic analysis revealed the presence of a vast array of phytoconstituents associated with different plant parts. The present study revealed the amounts of minerals and diverse phytoconstituents in various parts of S. chinensis and confirmed its medicinal and nutritional implications.     

Evaluation of a small-scale method for the extraction of the K88 antigen from enterotoxigenic Escherichia coli

A small-scale method for the extraction of the K88 major fimbrial subunit from enterotoxigenic Escherichia coli (ETEC) based on heat extraction has been developed. Variation in the buffer composition, time and temperature of extraction had negligible effect on the subsequent SDS-PAGE profile. There was, however, a correlation between the pH of the extraction buffer and the ensuing amount of K88 released. Reduction of the pH from 7 to 4 reduced by six-fold the amount of K88 released from the cells. We suggest that the relative stability of the K88 fimbriae at acid pH may influence the site of infection by ETEC in the intestine.     

The influence of the extraction procedure on yield of indole-3-acetic acid in plant extracts

Different types of plant material, including both dry and swollen maize kernels, swollen bean seeds, bean seedlings and dry rose seeds, were extracted by different methods and the yield of IAA was determined with the indolo-α-pyrone method. Extraction of dry maize kernels during short time experiments, varying from 3 to 24 h, gave the highest IAA yield when methanol was the extractant and a significant lower yield when diethyl ether or dichloromethane were used. The duration of the extraction period increased the yield with all the extractants. Progressive extractions for several days or weeks had little effect on the yield when 100% acetone was used in contrast to methanol and ether as extractants, which increased the yield during prolonged extraction. Extractions of tissue treated to 100°C for 1 h contradicted the hypothesis that IAA is enzymatically liberated during ether extraction. Water in the extractant solvents increased the yields. This was most pronounced when aqueous acetone was used instead of 100% acetone. Increased extraction temperature augmented the IAA yields. The yield of IAA from other types of tissue extracted with methanol for periods of 3 or 24 h was, however, independent of the duration of the extraction time. This indicates that some tissues contain less not easily extractable IAA than dry maize kernels. The terms “free” and “bound” IAA are discussed; they should be replaced by “easily extractable” and “not easily extractable” IAA. The results also show that IPyA in vitro can partly be converted to IAA during extraction and fractionation.     

Methods of downstream processing for the production of biodiesel from microalgae

Despite receiving increasing attention during the last few decades, the production of microalgal biofuels is not yet sufficiently cost-effective to compete with that of petroleum-based conventional fuels. Among the steps required for the production of microalgal biofuels, the harvest of the microalgal biomass and the extraction of lipids from microalgae are two of the most expensive. In this review article, we surveyed a substantial amount of previous work in microalgal harvesting and lipid extraction to highlight recent progress in these areas. We also discuss new developments in the biodiesel conversion technology due to the importance of the connectivity of this step with the lipid extraction process. Furthermore, we propose possible future directions for technological or process improvements that will directly affect the final production costs of microalgal biomass-based biofuels.     

A Screening Analysis of the High‐Pressure Extraction of Anthocyanins from Red Grape Pomace with Carbon Dioxide and Cosolvent

In the work described here, a set of screening factorial design experiments was carried out in order to study the extraction process of anthocyanins from red grape pomace with carbon dioxide, along with either methanol or water as cosolvent, at high pressure. The variables studied were pressure, temperature, solvent flow‐rate, cosolvent percentage, cosolvent type (methanol or water) and extraction time. The quantification of the total amount of anthocyanins was performed by a colorimetric method. The results of the ANOVA study show a strong influence of the type and percentage of cosolvent. The best results were obtained with 20 mol‐% of methanol, 100 bar, 60 °C and a flow‐rate of 22 mmol/min after two hours of extraction.     

Efficiency of Extraction of Nematodes by Flotation-Sieving Using Molasses and Sugar and by Elutriation

Blackstrap molasses was studied as an economical substitute for sucrose in the preparation of an extracting solution for removal of nematodes from soil by the flotation-sieving technique. The maximal number of nematodes extracted from soil was obtained with molasses solutions with specific gravity values in the range 1.000-1.073. Results of studies on the relation between size of soil sample and the amount of extracting solution are presented. In paired comparisons, a molasses solution with sp. gr. = 1.100 at 27 C extracted greater numbers of plant parasitic, dorylaimoid, mononchoid, and other soil nematodes than did the standard 1.0 M sucrose solution (sp. gr. = 1.100); the superiority of the molasses solution is attributed to its higher viscosity. The molasses method also was superior or equal in efficiency to the elutriation technique.     

Intracellular metabolite profiling and the evaluation of metabolite extraction solvents for Clostridium carboxidivorans fermenting carbon monoxide

Clostridium carboxidivorans ferments CO, CO₂, and H₂ via the Wood-Ljungdahl pathway. CO, CO_2, and H₂ are unique substrates, unlike other carbon sources like glucose, so it is necessary to analyze intracellular metabolite profiles for gas fermentation by C. carboxidivorans for metabolic engineering. Moreover, it is necessary to optimize the metabolite extraction solvent specifically for C. carboxidivorans fermenting syngas. In comparison with glucose media, the gas media allowed significant abundance changes of 38 and 34 metabolites in the exponential and stationary phases, respectively. Especially, C. carboxidivorans cultivated in the gas media showed changes of fatty acid metabolism and higher levels of intracellular fatty acid synthesis possibly due to cofactor imbalance and slow metabolism. Meanwhile, the evaluation of extraction solvents revealed the mixture of water-isopropanol-methanol (2:2:5, v/v/v) to be the best extraction solvent, which showed a higher extraction capability and reproducibility than pure methanol, the conventional extraction solvent. This is the first metabolomic study to demonstrate the unique intracellular metabolite profiles of the gas fermentation compared to glucose fermentation, and to evaluate water-isopropanol-methanol as the optimal metabolite extraction solvent for C. carboxidivorans on gas fermentation.