Hot Alkali Extraction Research Articles

Characterization and biological activity of acidic sugarcane leaf polysaccharides by microwave-assisted hot alkali extraction

As a waste of sugarcane, the added value of sugarcane leaves has not been fully utilized, and sugarcane leaf polysaccharide is an important active component of sugarcane leaves. Using new extraction methods to study the structure and biological activity of polysaccharides from sugarcane leaves is of great significance for the development and application of sugarcane leaves. To determine the structural characteristics and biological activities of different acidic sugarcane leaf polysaccharides (ASLPs) extracted by microwave-assisted hot alkali extraction (MALE), three new acidic sugarcane leaf polysaccharides (ASLP-50, ASLP-70 and ASLP-90) were precipitated by ethanol. The structure of ASLPs extracted by MALE contains protein, sulfate and uronic acid. ASLP-50 (195.88 kDa), ASLP-70 (94.62 kDa) and ASLP-90 (16.37 kDa) were acidic polysaccharides composed of mannose, galacturonic acid, glucose, arabinose and fucose. The results of XRD and NMR showed that ASLPs were amorphous polysaccharides composed of α-L-Araf-(1→ main chain, and its branching points were composed of Arap and GalpA residues. In addition, ASLPs showed significant antioxidant, hypoglycemic, hypolipidemic and antibacterial activities in vitro. The research and application of ASLPs provide a reference for the recycling of sugarcane leaves, which is conducive to the development of food, agriculture and pharmaceutical industries.

An Experimental Study on the Hot Alkali Extraction of Xylan-Based Hemicelluloses from Wheat Straw and Corn Stalks and Optimization Methods.

In this paper, we describe an experimental study on the hot alkali extraction of hemicelluloses from wheat straw and corn stalks, two of the most common lignocellulosic biomass constituents in Romania. The chemical compositions of the raw materials were determined analytically, and the relevant chemical components were cellulose, hemicelluloses, lignin, and ash. Using the response surface methodology, the optimum values of the hot alkaline extraction parameters, i.e., time, temperature, and NaOH concentration, were identified and experimentally validated. The physicochemical characterization of the isolated hemicelluloses was performed using HPLC, FTIR, TG, DTG, and 1H-NMR spectroscopy. The main hemicellulose components identified experimentally were xylan, arabinan, and glucan. The study emphasizes that both corn stalks and wheat straw are suitable as raw materials for hemicellulose extraction, highlighting the advantages of alkaline pretreatments and showing that optimization methods can further improve the process efficiency.

Kelarutan Lignin Kayu Cepat Tumbuh dalam Ekstraksi Alkali

The dissolution of wood lignin in the alkali solution were analyzed for two fast growing species, sengon (Paraserianthes falcataria) dan leda (Eucalyptus deglupta). Wood samples were extracted in 1% sodium hydroxide solution in cold and hot temperatures for 24 and 1 h, respectively. Extractable substances content, permanganate consumption (expressed as assumed lignin content) were analyzed from the filtrates, lignin content and diastereomeric of β-O-4 structure were analyzed from the wood residue after alkali extraction. The extracted substances from both of wood in hot alkali was higher than in cold alkali solution, although the time of cold alkali extraction was much longer that hot alkali extraction. Assumed lignin content in the extract was quite high in both samples which were 34.4-42.9% and 35.5-39.8% including 2,15-2,29% dan 1,04-1,32% of lignin for cold and hot alkali extraction, respectively. The changes in stereo isomeric form, erythro and threo, of β-O-4 structure of lignin in wood residue indicated that partial depolimerization of lignin was takec place during alkali treatment.

Bioassay-guided isolation and evaluation of anti-osteoporotic polysaccharides from Morinda officinalis

Ethnopharmacological relevanceMorinda officinalis is a well-known Chinese tonic herb that has shown clinical efficacy in the treatment of bone disease. However, its anti-osteoporotic potential and the M. officinalis polysaccharides (MOPs) responsible for activity require further investigation. Aim of the studyThis study aimed to investigate the anti-osteoporotic effects of different MOP fractions in ovariectomized (OVX) rats, and to identify the osteoprotective components by bioassay-guided isolation. Materials and methodsMOPs were prepared by hot water and alkali extraction, separated into three fractions (MO50, MO70, and MOB) and evaluated in the classic OVX rat model and in MC3T3-E1 cells for anti-osteoporotic activity. ResultsAdministration of MOPs (400 mg/kg/day) provided significant protection against ovariectomy-induced bone loss and biomechanical dysfunction in rats. Treated animals exhibited reduced deterioration of trabecular microarchitecture and lower levels of bone turnover markers. Bioactivity-guided fractionation led to the isolation of two inulin-type fructans from MO50, MOW50-1 and MOP50-2, with potential anti-osteoporotic activities. These consisted of (2 → 1)-linked β-D-fructosyl residues with degrees of polymerization (DP) of 7 and 13, respectively. Furthermore, MOW50-1 promoted osteogenic differentiation of MC3T3-E1 cells by increasing alkaline phosphatase activity. ConclusionsThese data suggest very strongly that MOPs, especially MO50 and MOW50-1, may play important roles in the prevention and treatment of osteoporosis.

Effects of different extraction methods on the properties of pine cone polysaccharides from Pinus koraiensis

In order to realize the resource utilization of the Pinus koraiensis pine cone, the polysaccharides were obtained by a traditional hot water extraction process, and the optimal extraction process was confirmed. The effects of a traditional hot water, alkali, and ultrasound assisted extraction on the yield and properties of polysaccharides were studied. The structure, monosaccharide composition, and content of polysaccharides obtained by different extraction methods were analyzed by means of Fourier infrared chromatography and liquid chromatography. Effects of polysaccharides extracted by different methods on the antimicrobial activity of Staphylococcus aureus and Escherichia coli were studied. The scavenging effect of DPPH free radicals were also examined. The optimum condition of the hot water extraction was identified as an extraction temperature of 100 °C, a ratio of material to water at 1:16 (w/v), an extraction time of 4 h, and a yield of polysaccharide at 10.2%. In comparison, the yield of the pine cone polysaccharide was improved significantly to 29.1% by using NaOH solution extraction method. The FTIR spectra of polysaccharides showed that the samples possessed the typical chemical structure of a polysaccharide.

CHEMICAL CONSTITUENTS AND ANTIOXIDANT PERSPECTIVES OF EXTRACTS OF CHARA GLOBULARIS AND CLADOPHORA SPECIES (STRING ALGAE) SPECIES

Objectives: Marine organisms are capable of producing unusual bioactive compounds that are not observed in terrestrial sources. Algae are now drawing a greater interest following the increase in demand for biodiversity in the screening programs seeking therapeutic drugs from natural products.Methods: Hot acid extraction and cold alkali extraction of Chara globularis and Cladophora species (string algae), respectively, were carried out successfully. The extracted materials were tested for the qualitative reactions and subjected for thin-layer chromatography, ultraviolet, and infrared spectral studies so as to characterize the extracted materials of two algae. They were estimated for their antioxidant perspectives by hydrogen peroxide radical scavenging and reducing power assay methods.Results: Percentage yield of the extracts was found to be 80% and 40%, respectively, for the two algal species. The IC50 value of hydrogen peroxide scavenging activity of C. globularis and Cladophora species was found to be 30 μg/ml and 20 μg/ml, respectively, and the same for the standard ascorbic acid was 20 μg/ml. The results were found to be dose dependent, i.e., higher the concentration, and more was the scavenging activity.Conclusion: Despite the widespread uses and claimed advantages of the algae, only a few investigations on the chemical composition have been reported. A good correlation between the structure and activities of these most popular categories can be brought about.

Different Conformations of Surface Cellulose Molecules in Native Cellulose Microfibrils Revealed by Layer-by-Layer Peeling.

Layer-by-layer peeling of surface molecules of native cellulose microfibrils was performed using a repeated sequential process of 2,2,6,6-tetramethylpiperidine-1-oxyl radical-mediated oxidation followed by hot alkali extraction. Both highly crystalline algal and tunicate celluloses and low-crystalline cotton and wood celluloses were investigated. Initially, the C6-hydroxy groups of the outermost surface molecules of each algal cellulose microfibril facing the exterior had the gauche-gauche (gg) conformation, whereas those facing the interior had the gauche-trans (gt) conformation. All the other C6-hydroxy groups of the cellulose molecules inside the microfibrils contributing to crystalline cellulose I had the trans-gauche (tg) conformation. After surface peeling, the originally second-layer molecules from the microfibril surface became the outermost surface molecules, and the original tg conformation changed to gg and gt conformations. The plant cellulose microfibrils likely had disordered structures for both the outermost surface and second-layer molecules, as demonstrated using the same layer-by-layer peeling technique.

Physicochemical characterization, antioxidant activity of polysaccharides from Mesona chinensis Benth and their protective effect on injured NCTC-1469 cells induced by H2O2

Polysaccharides MP-A, MP-U and MP-C were extracted from Mesona chinensis Benth by hot-alkali extraction (HAE), ultrasonic-assisted extraction (UAE) and cellulose-enzyme assisted extraction (CAE), respectively. The yields, physicochemical properties and antioxidant of polysaccharides were investigated. Results showed that the yields of MP-A (11.14%), MP-U (10.62%) and MP-C (9.70%) were similar, and they were all heteropolysaccharides with average molecular weights of 1.9×105Da, 1.5×105Da, 1.4×105Da. Glucose, galactose, and galacturonic acid were the main monosaccharides in MP-A, MP-U and MP-C with molar ratios of 1.00:1.34:0.25, 1.00:2.49:0.19 and 1.00:2.95:0.84, respectively. MP-C extracted by CAE exhibited higher antioxidant activities in FRAP, DPPH, hydroxyl radical assays and the H2O2-induced injury cell model. The three extraction methods had only slight effects on chemical composition, while MP-C extracted by CAE exhibited the highest antioxidant activity, which could potentially be used for an addition ingredient as it was previously shown to have good gelling property in food products.

Characterization and Antiproliferative Effect of Novel Acid Polysaccharides from the Spent Substrate of Shiitake Culinary-Medicinal Mushroom Lentinus edodes (Agaricomycetes) Cultivation.

In this study, a high yield of crude polysaccharide (16.73 ± 0.756%) was extracted from the spent mushroom substrate of Lentinus edodes using a hot alkali extraction method. Two groups of polysaccharides (designated as LSMS-1 and LSMS-2) were obtained from the crude extract by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index detector system. The weight-average molar masses of LSMS-1 and LSMS-2 were determined to be 6.842 × 106 and 2.154 × 106 g/mol, respectively. The SEC/MALLS analysis revealed that the molecular shapes of LSMS-1 and LSMS-2 were sphere-like forms in aqueous solution. Carbohydrate composition analysis using chromatography--mass spectrometry revealed that they were both acid heteropolysaccharides. LSMS-1 comprised mainly glucose and galacturonic acid, whereas LSMS-2 mainly consisted of xylose and glucuronic acid. Fourier transform infrared spectral analysis of the purified fractions revealed typical characteristic polysaccharide groups. In addition, MTT assays with refined polysaccharide doses of 25, 50, 100, 200, and 400 µg/mL suggested that both of the polysaccharide fractions exhibited antiproliferative activity against 6 tested human tumor cell lines in a concentration-dependent manner, and LSMS-2 had better anticancer capacity in vitro than LSMS-1. The inhibition ratio of LSMS-2 against A549 human lung cancer cells, the SGC7901 gastric cancer cell line, MCF-7 breast cancer cells, the U937 histiocytic lymphoma cell line, and the MG-63 human osteosarcoma cell line reached 43.55%, 29.97%, 19.63%, 18.24%, and 17.93%, respectively, at a concentration of 400 µg/mL.

A novel alkali extractable polysaccharide from Plantago asiatic L. Seeds and its radical-scavenging and bile acid-binding activities.

A new acidic polysaccharide (PLP) was isolated and characterized from Plantago asiatic L. seeds by hot alkali extraction and chromatographic purification using DEAE cellulose and Sephacryl S-400 columns. PLP has a molecular weight of 1.15 × 10(6) Da, and a monosaccharide composition of xylose (Xyl), arabinose (Ara), glucuronic acid (GlcA), and galactose (Gal) in a molar ratio of 18.8:7.2:6.1:1. The results of methylation analysis, FT-IR, and 1D and 2D NMR indicated that PLP was a highly branched heteroxylan of β-1,4-linked Xylp backbone with three α-GlcAp-(1→3)-Araf attached to the O-3 position and one α-T-linked-GlcAp and one α-Araf-(1→5)-Araf attached to the O-2 position every eight monosaccharide residues. PLP exhibited scavenging abilities against hydroxyl, peroxyl anion, and DPPH radicals in vitro and showed significant binding capacities against cholic and chenodeoxycholic acids, suggesting its possible cholesterol-lowering activity. The results demonstrated the potential use of PLP in functional foods and nutraceuticals.

Did the Iceman Know Better? Screening of the Medicinal Properties of the Birch Polypore Medicinal Mushroom, Piptoporus betulinus (Higher Basidiomycetes).

The birch polypore Piptoporus betulinus was among two mushrooms that were found in the Iceman's bag. Recent studies indicated that P. betulinus was probably used as a religious and medicinal item. In order to examine the medicinal potential of P. betulinus, hot water (HW), partially purified (PP), and alkali extract (HA) were prepared and tested for antioxidant, antimicrobial, cytotoxic, and angiotensin I-converting enzyme (ACE) inhibitory activity. All tested samples exhibited moderate cytotoxic activity, and HW appeared as the most effective (IC50 = 0.8 ± 0.1 mg/ml for HeLa cells). HA proved to be a good 1,1-diphenyl-2-picrylhydrazyl radical scavenger and exhibited the strongest ferric-reducing power (EC50 = 0.07 ± 0.3 mg/ml). The same extract (HA) also expressed the strongest ferric-reducing power (EC50 = 0.99 ± 0.1 mg/ml). Hot alkali extraction contributed significantly to ACE inhibitory activity (EC50 = 0.06 ± 0.00 mg/ml) and to antimicrobial activity, especially against highly resistant Enterococcus faecalis (minimum inhibitory concentration: 0.156 ± 0.000 mg/ml; and minimum bactericidal concentration: 1.25 ± 0.00 mg/ml).

Modification of pine pulp during oxygen delignification by xylan self-assembly

Self-assembly is a technique of preparing functional materials based on targeted intermolecular interactions involving different macromolecules. In this work, hardwood xylan was disassembled from wood and birch bleached kraft pulp using pressurized hot water extraction (HWX) and cold alkali extraction (CAX), respectively. The extracted biopolymers were characterized using gas chromatography (GC), size exclusion chromatography (SEC) and Fourier transform infrared spectroscopy (FTIR), and subsequently added into an oxygen delignification reactor containing pine kraft pulp. The assembly of xylan-pulp fiber was characterized using advanced time-of-flight secondary ion mass spectrometry (ToF-SIMS) and imaging. The xylan-pine pulp assembly was not significantly removed during the whole elemental chlorine free bleaching sequence or during low consistency refining. Modified fibers had superior mechanical properties compared to the reference pulp. Our concept can be easily applied in the pulp and paper industry, and it opens new possibilities for the utilization of fully bio-based fibers in new materials.

Effects of extraction methods on antioxidant activities of polysaccharides from camellia seed cake

Four purified polysaccharides (COP-H, COP-U, COP-E, and COP-A) were obtained from seed cake of Camellia oleifera Abel. by hot water extraction, ultrasonic-assisted extraction, enzyme extraction, and alkali extraction, respectively. Their structural characterizations were determined, and antioxidant activities were investigated. The results of FT-IR demonstrated that the characteristic absorption bands exhibited slight difference among four polysaccharides. HLPC analysis presented that the molecular weights were calculated to be 394, 297, 462, and 429 kDa for COP-H, COP-U, COP-E, and COP-A, respectively. GC–MS analysis showed that the monosaccharide compositions were identical to four polysaccharides, while the molecular ratios exhibited significant difference. Four polysaccharides showed antioxidant activities in a concentration-dependent manner. Among four polysaccharides, COP-E showed a higher scavenging activity on DPPH, hydroxyl radical, and superoxide anion radical. These findings suggest camellia seed cake polysaccharides have potential as a natural antioxidant.

Extraction of polysaccharides from Fomes officinalis Ames and their antitumor activity

The aim of this study was to optimize the extraction parameters of Fomes officinalis Ames polysaccharides (FOAPs) and evaluate their antitumor activity. FOAPs were extracted using the hot water extraction, acid extraction and alkali extraction methods, respectively. Alcohol precipitation and acetone washes were conducted to separate and purify the FOAPs. The FOAP content was determined using the phenol-sulfuric acid method. The effects of raw material particle size, extraction time and material-liquid ratio on the yield of FOAPs were investigated, and the effects of FOAPs on the immune function of S180 tumor-bearing mice and their antitumor activity were evaluated. The yield of FOAPs obtained with the hot water extraction method was higher compared with the yields of the other methods. The optimum extraction conditions were as follows: a raw material particle size of 24 mesh; an extraction time of 2.5 h; and a material-liquid ratio of 1 g:12 ml. Under these conditions, the yield of FOAPs was 1.13%. FOAPs significantly inhibited tumor growth and enhanced the immune function in S180 tumor-bearing mice. FOAPs extracted using the hot water extraction method have antitumor activity.

Characterization of water and alkali-soluble polysaccharides from Pleurotus tuber-regium sclerotia

Pleurotus tuber-regium sclerotia, an edible and medicinal mushroom, is a rich source of polysaccharides used as a functional food to promote health and longevity. The crude polysaccharides were isolated from the P. tuber-regium by hot aqueous and alkali extraction and then further purified by DEAE-52 cellulose chromatography and Sephadex G-100 chromatography. Two polysaccharides, water and alkaline extraction of polysaccharides (W-PTR and A-PTR), were obtained and their extraction process were optimized through orthogonal array design. Structure characteristics (physicochemical property analysis, molecular weight, monosaccharide composition, sulfate and uronic acid contents, triple helical structures, ultraviolet spectrum and infrared spectroscopy) of the two polysaccharides were investigated. Results showed that the main difference between the two polysaccharides is reflected in color, solubility, molecular weight and monosaccharide composition. Conformational analysis showed that both W-PTP and A-PTP had triple-helix conformation. The 3D structure of the two polysaccharides and their structure–function relationship will be challenge in the future.

잎새버섯(Grifola frondosa) 균사체의 기능성 다당류 최적 추출방법 및 항암효과

Abstract Grifola frondosa has been used as an herbal medicine for the treatment of cancer, diabetes mellitus and high blood pressure. In this study, functional polysaccharide was obtained from Grifola frondosa using four different extraction methods: hot water(HwFP), homogenize(HgFP), acid(AcFP), and alkali(AlFP) extraction methods. The effects of these extracts on KB and HepG2 cell lines were then examined for any anti-cancer activity. Alkaline extraction produced a yield of 0.175% and the total sugar content of the extract was 54.97%. We were able to confirm that the polysaccharide extracts from the mushroom produce an anti-cancer effect. The cytotoxicity of AlFP and AcFP against HepG2 cells were 22.86% and 28.88%, respectively, and the cytotoxicity of AlFP against the KB cell lines was 47.76% at a concentration of 1,000 ㎍/㎖. Therefore, these results suggest that the optimum method for extracting functional polysaccharides from G. frondosa is the alkali extraction method.Key words: Grifola frondosa, polysaccharide, alkali extraction, anti-cancer effect

Carbohydrates, uronic acids and alkali extractable carbohydrates in contrasting marine and estuarine sediments: Distribution, size fractionation and partial chemical characterization

Concentration, size fractionation and monosaccharide composition of carbohydrates and uronic acids were investigated in contrasting sediments of the Mandovi estuary (ME), Arabian Sea (AS) and the Bay of Bengal (BOB). Concentrations and monosaccharide composition of carbohydrates and uronic acids varied spatially. Average yields of carbohydrates and uronic acids were higher for the estuarine compared to marine sediments. Interestingly, yields of carbohydrates and uronic acids increased in sediments with water column depth, implying preferential removal of other constituents, selective preservation and/or lateral input of carbohydrate rich material. Analysis of monosaccharide biomarkers indicates that carbohydrates were derived from terrestrial plants, bacteria and phytoplankton, however, the influence of the former was relatively greater in sediments of the ME and BOB, as well as in residual sediments of ME. Approximately 11–21% of total carbohydrates could be extracted using hot alkali extraction followed by sonication. Irrespective of the depositional environment, carbohydrates and uronic acids were greater in the very high molecular weight size fraction (>30 kDa). The abundance of glucose increased with the decrease in molecular size of extracted organic matter. This probably indicates its association with less degradable carbohydrates.

Conformation of grifolan in the fruit body of Grifola frondosa assessed by carbon-13 cross polarization-magic angle spinning nuclear magnetic resonance spectroscopy.

Grifola frondosa produces an antitumor (1→3) -β-D-glucan, grifolan, which possesses two kinds of conformations in the solid state, i. e., helix (curdlan type) and native (laminaran type) (Ohno et al., Chem. Pharm. Bull., 34, 2555 (1986)). In this paper, the glucan conformation in the fruit body was examined by using carbon-13 cross polarization-magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) spectroscopy. Before analysis, the fruit body was treated as follows : amylase digestion, amylase digestion-periodate-borohydride treatment, hot water extraction, cold alkali extraction, or hot alkali extraction. Except for the cold and the hot alkali-extracted fruit bodies, all preparations showed C-3 signals at about 86 ppm, resembling those of the native form. These findings suggested that the (1→3) -β-D-glucan conformation in the fruit body is the “native form.”

Elastin and collagen in the aortic wall: Changes in the Marfan syndrome and annuloaortic ectasia

Elastin and collagen concentrations were determined in intimal-medial samples of ascending aortas from healthy controls of different ages and from 20 patients with annuloaortic ectasia (AAE). Five patients had the Marfan syndrome. In controls the highest elastin concentrations (estimated from desmosine concentrations or insoluble residues after hot-alkali extraction) were found in children. During aging until 60 years, elastin concentration decreased when determined by the hot-alkali extraction method while desmosine concentration changed less. Aorta samples from the Marfan-syndrome patients showed a great variation of elastin concentration from total lack to normal values. Samples from the other AAE patients could be divided into two groups. One contained clearly less elastin and more collagen than the controls whereas in the other group this difference was less marked. Histological examination of the aortic wall of the first group also showed marked fibrosis accompanied by severe elastin fragmentation and acellularity. From the 15 non-Marfan patients 14 were men. By means of clinical examination these patients could also be divided into “familial” and “nonfamilial” groups, because increased diameter of the aortic root was found in relatives of almost half of the patients. However, there were no differences in elastin and collagen concentrations between the familial and nonfamilial cases. As well, no correlation was found between biochemical findings and diameters of the aortic roots. These results point to altered elastin and/or collagen metabolism in the aortic wall of AAE patients.

Desmosines in aneurysms of the ascending aorta (annulo-aortic ectasia)

Amino acid chromatography was used for determination of the elastin-specific amino acids desmosine and isodesmosine in acid hydrolyzates of intima-medial samples taken intraoperatively from aneurysms of human ascending aorta. Elastin concentration of the specimens was also estimated by hot alkali extraction followed by nitrogen determination of the extracted material and the insoluble residue. All patients studied had annulo-aortic ectasia i.e., dilatation of the aortic annulus and the ascending aorta. Two patients with the Marfan syndrome had low aortic elastin concentration determined by both methods. A third Marfan syndrome patient, youngest of the three, also had a slightly reduced concentration of elastin in the aorta. Aortic samples were studied from five patients who did not have the classical Marfan syndrome. Two patients of those five had decreased aortic elastin concentration. The change in elastin concentration was accompanied by high hydroxyproline/proline or hydroxylysine/lysine ratios which indicates that the proteins of the aneurysmatic aortic wall contained more collagen than the proteins of the control aortic wall. These findings point to a change in the structure or metabolism of elastin in the aortic wall in the Marfan syndrome and at least in some other patients with annulo-aortic ectasia.