Search

This study investigated the structural elucidation, anti-radical and immunomodulatory activities of polysaccharides from the roots of Glehnia littoralis. A crude polysaccharide was extracted from the roots of G. littoralis through the ultrasonic-assisted extraction and further purified by DEAE-52 cellulose and Sephadex G-100 gel column, a major polysaccharide fraction named GLP80-1 was obtained. The chemical properties and structure of GLP and GLP80-1 were characterized by acid hydrolysis, methylation analysis, along with high performance gel permeation chromatography, Fourier transform infrared, nuclear magnetic resonance, scanning electron microscope, thermogravimetric analysis and X-ray diffraction. The molecular weight distributions of GLP were determined as 1.89 × 106 and 1.26 × 104 Da. The monosaccharide composition of GLP was glucose, glucuronic acid, galactose and arabinose with molar ratios of 0.91:0.04:0.03:0.02, respectively. The average molecular weight of GLP80-1 was determined as 1.63 × 104 Da. The structure of GLP80-1 was deduced to be a homogenous glucan, comprised a main chain of (1→4)-linked-α-D-Glcp with a single α-D-Glcp branch substituted at C-6. The results of biological activities in vitro showed that GLP and GLP80-1 exhibited free radical scavenging effects, and displayed promotion for the proliferation of mouse spleen lymphocytes and RAW264.7 cells. The data indicated that GLP and GLP80-1 had the potential to be explored as novel natural antioxidant and immunomodulator for application in functional food.

Polysaccharide was one of the considered major active ingredient in

The spatial and temporal variability of soil CO2 emissions from agricultural soils is inherently high. While tillage and crop residue practices play vital roles in governing soil CO2 emission, their effects on the variability of soil CO2 fluxes across depths and seasons are still poorly understood. To address this, an experiment consisting of four treatments, namely conventional tillage with (CT+) and without crop residue application (CT−), as well as no tillage with (NT+) and without crop residue application (NT−), was conducted to investigate soil CO2 fluxes at top 40 cm soils with 10-cm depth intervals in a winter wheat-summer maize rotation system in the North China Plain. Our results showed soil CO2 fluxes increased with depth in both the wheat- and maize-growing seasons. However, the dominant factors in regulating soil CO2 fluxes changed with soil depth and seasons. In the wheat-growing season, increase in soil CO2 fluxes with depth was attributed to the increase of dissolved organic carbon-to-nitrogen ratio (DOC/DON) and a decline in soil DON concentration along the soil profile. These factors explained about 55–96% of the total variation in soil CO2 fluxes at different soil depths. In the maize-growing season, the dominant factors were soil DOC/DON ratio, soil DON concentrations, and soil moisture. These factors explained approximately 79–96% of the total variation in soil CO2 fluxes along the soil depth. Greater soil CO2 fluxes (except at 30–40 cm depth) were observed in NT− than CT− treatments. Furthermore, crop residue application enhanced soil CO2 fluxes across different depths, but the enhancement was more prominent in CT+ than NT+. Moreover, soil CO2 fluxes in the maize-growing season were greater than those in the wheat-growing season. Our results demonstrate that the effects of tillage regimes and crop residue management practices on soil CO2 emissions are not confined only to the plough layer but can extend to soils of over 30 cm depths. We also need to revisit the general conventional view that no tillage can significantly reduce soil CO2 emissions compared with conventional tillage for better climate change mitigation.

This study investigated the structural elucidation, anti-radical and immunomodulatory activities of polysaccharides from the roots of

Most studies on soil CO2 fluxes focus on the upper soil layers (i.e., 0–200 mm); however, there is a lack of investigation into soil layers below 200 mm, even though about half of soil organic carbon (SOC) is stored at these depths. In order to investigate the responses of CO2 fluxes in subsurface soils to crop residue incorporation in the topsoil, a field experiment comprising two treatments (i.e., conventional tillage with and without crop residue incorporation) was carried out under a winter wheat-summer maize cropping system from 2014 to 2016 in the Yucheng Agricultural Station, Shandong Province, China. The results showed that soil CO2 fluxes had large spatiotemporal variabilities and were significantly affected by crop residue applications (P

The preparation conditions of Glehniae Radix polysaccharide-iron complex (GLP80-Fe) were optimized and the physicochemical properties were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscope (TEM), Thermogravimetric analyzer, and Differential scanning calorimetry (TGA-DSC), respectively. The stability and reducibility of GLP80 and GLP80-Fe were analyzed, and the monosaccharide composition was determined by gas chromatograph (GC). In vitro antioxidant activity of GLP80 and GLP80-Fe were evaluated by determining the radical (DPPH and hydroxyl radical) scavenging abilities. The results showed that the highest iron content of GLP80-Fe (15.61%±0.04) was obtained at the optimum conditions: reaction temperature was 38.0°C, reaction time was 3.0 h, FeCl3 addition was 2.9 mL and pH was 9. GLP80-Fe was a complex with β-FeOOH as the core and polysaccharides on its surface, and it was stable at pH 3 ~ 14. GC showed that the major monosaccharides were mannose (Man) and galactose (Gal) with a ratio of 1:5.15. In vitro free-radical scavenging activity of GLP80-Fe was significantly better than GLP80. The IC50 of GLP80-Fe against DPPH and hydroxyl radical were 3.785 mg/mL and 1.460 mg/mL, respectively.

A novel polysaccharide (GLP) with a molecular weight of 1.37 × 105 Da was purified from the roots of G. littoralis. Using monosaccharide composition, methylation analysis, GC-MS, 1D and 2D NMR, the structure of GLP was determined to be a 1 → 4)-α-D-Glcp glycoside linkage, while the terminal group of 1→)-α-D-Glcp was bonded to the main chain via O-6. Then, GLP-NPs were prepared by nano-precipitation method, the particle size of GLP-NPs was 288.4 nm and PDI was 0.340. GLP-NPs-AgNPs were prepared using GLP-NPs as reducing agent. GLP-NPs-AgNPs were characterized by ultraviolet-visible spectrophotometer (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM) and X-ray diffraction (XRD). The yield of GLP-NPs-AgNPs was 38.77%, the particle size was 12.5 nm and the chelation rate of silver nanoparticles with polysaccharides was 67.5%. GLP-NPs-AgNPs had better antioxidant and antibacterial activities than GLP and GLP-NPs. In the present work, a simple and eco-friendly approach for the synthesis of silver nanoparticles (AgNPs) using G. littoralis polysaccharides nanoparticles (GLP-NPs) as reducing agent.

In this study, the crude polysaccharides of

The effects of straw retention on soil bacterial community structure, microbial function, and biochemical properties were assessed. Terminal restriction fragment length polymorphism (T-RFLP) and community-level physiological profile (CLPP) assays were used to assess the bacteria community structure and microbial function respectively. Treatments included straw removal with conventional tillage (CT), straw retention with conventional tillage (SRCT) and straw retention with no tillage (SRNT). SRCT and SRNT significantly (p

Crop residue-derived dissolved organic matter (DOM) plays an important role in soil carbon (C) cycling. To investigate the effects of maize residue-derived DOM and urea additions on the native soil organic carbon (SOC) decomposition and soil net C balance a pot experiment was carried out during the winter wheat growing season in the North China Plain (NCP). The results showed that adding maize residue-derived DOM alone (RDOM) or together with urea (RDOM + N) accelerated the decomposition of native SOC and resulted in a net SOC loss. The net loss of SOC was 3.90 ± 0.61 and 3.53 ± 0.48 g C m−2 in RDOM and RDOM + N treatments, respectively. The stimulatory effect of per unit DOM-C addition on the native SOC decomposition was 0.25 ± 0.05 and 0.45 ± 0.07 for the RDOM and RDOM + N treatments, respectively. Increases in the microbial biomass and the activity of β-glucosidase, invertase and cellobiohydrolase as well as soil mineral N content were responsible for a more intense priming effect in DOM-amended soils. The positive relationship between primed soil C and soil available N (R = 0.76, P

The quality of polysaccharides from different regions was studied by using multiple fingerprint analysis and chemometric analysis. Polysaccharides from 10 batches of Glehnia littoralis were compared based on Fourier-transform infrared spectroscopy (FT-IR), high-performance liquid chromatography (HPLC), gel permeation chromatography (GPC), and proton nuclear magnetic resonance (1H-NMR). According to the results, the 10 batches of polysaccharides from G littoralis had high similarity by analyzing HPLC, FT-IR, 1H-NMR, and GPC fingerprints. Through cluster analysis, samples and adulterants in different regions could be classified. Three monosaccharides (galactose, glucose, and galacturonic acid), molecular weights (4.33 × 105-4.91 × 105, 4.04 × 104-4.71 × 104, and 5.02 × 103-5.83 × 103), and H-1 (4.99, 5.39, and 5.42 ppm) of α-glucose could be used as markers for quality control of medicinal materials of the roots of G littoralis.

Currently, straw transformation in saline soil is largely unknown. The effect of soil salinity on wheat straw transformation and the roles of nitrogen (N) and phosphorus (P) were evaluated in a greenhouse experiment. By sodium chloride (NaCl) addition, straw was applied at the rate of 30 g kg−1 in various saline soils (2.0–4.0 g kg−1). N or combined N and P added in straw amended saline soil (3.0 g kg−1). Three replications of each treatment were sampled to determine straw residues at 30, 60, and 90 d. Results showed straw application significantly increased microbial biomass, especially fungal biomass. Soil salinity increased by 1.0 g kg−1, which decreased straw decomposed rate by 6.3 ~ 11.1%. N application significantly increased straw decomposed rate (p

Owing to an irrigation water shortage and a shallow underground water table in coastal zones, soil salinization is becoming a serious and complicated problem. Different practices are being explored to reduce its negative effect on land productivity. In this work, the effect of combined straw and inorganic N applications at different rates on topsoil (0–20 cm) salinity and wheat growth was evaluated in a coastal field. Maize straw was applied at the rates of 5.0 × 10 3 kg ha −1 (S) and 1.0 × 10 4 kg ha −1 (2S) and inorganic N was applied at the rates of 75 kg ha −1 (N1/2), 150 kg ha −1 (N), and 300 kg ha −1 (N2). Treatment without addition of straw but with inorganic N application at the rate of 150 kg ha −1 was used as the control (CK). Thus, there were six treatments: SN1/2, SN, SN2, 2SN, 2SN2, and CK. During the early growth stages (seedling, jointing, and booting) of wheat, straw application significantly decreased topsoil salinity from 13.8% to 30.4% in comparison to the CK treatment ( p 0.05), and the decrease was enhanced with increase in the straw application rate. This positive influence decreased substantially during wheat growth. Soil dissolved organic carbon and microbial biomass carbon both increased significantly ( p 0.05) after straw addition; in contrast, there was a significant reduction in available N from March to April. The greatest wheat grain yield and aboveground biomass were produced in 2SN2, and yield increased by 15.1% in comparison to CK. In contrast, yield decreased by 5.1–9.6% in SN, 2SN, and SN1/2. Thus, straw application may be an effective practice for reducing topsoil salinity in the coastal zones, and an adequate N supply should be applied to maximize crop yield.

The spatial and temporal variability of soil CO

In this study, the crude polysaccharides of C. javanica (CJP) was obtained from Codonopsis javanica (Blume) Hook. f. et Thomson using hot water extraction method, which was separated and purified by DEAE-cellulose column and Sepharose CL-6B column. The structure of the purified component was preliminary characterized by gas chromatography-mass spectrometer (GC-MS), high performance gel permeation chromatography (HPGPC) and infrared spectroscopy (IR). By examining the degree of delayed-type hypersensitivity (DTH) in mice and carbon particle clearance index, the immunomodulatory activity was clarified. The results showed that the extraction rate of CJP was 24.9 ± 0.5%. After purification, the refined polysaccharides component (CJP-2) was obtained. The structural characterization results indicated that CJP-2 was mainly composed of mannose, glucose, and galactose, and its molecular weight was 790 Da. Immunomodulation results showed that the low and medium levels of CJP significantly enhanced the degree of DTH in mice (P < 0.05). CJP can improve the clearance index of mice and enhance their charcoal removal function. The study indicates that C. javanica is a good source of polysaccharides, and CJP may be a new type of immunomodulator.

In this study, response surface methodology (RSM) was used to optimize the ultrasonic-assisted extraction parameters of Sojae Semen Praeparatum polysaccharides (SSPP-80), the optimum conditions were determined as follows: ultrasonic frequency of 100 W, ultrasonic power of 80 Hz, ultrasonic temperature of 52℃, ultrasonic time of 23 minutes, and liquid to raw material ratio of 40 mL/g. Based on these conditions, polysaccharides extraction rate was 7.72% ± 0.26%. Then, 2 novel polysaccharides (SSPP-80‐1, SSPP-80‐2) were isolated from SSPP by DEAE-cellulose 52 chromatography. The chemical compositions, physicochemical properties, and structure of SSPPs were investigated by simultaneous thermal analyzer (TGA), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FI-IR), and high-performance liquid chromatography (HPLC). The results showed that SSPP-80 and 2 fractions were mainly composed of mannose (Man), glucose (Glc), galactose (Gal), xylose (Xyl), and arabinose (Ara). In addition, the antioxidant activities were evaluated against the DPPH and hydroxyl radical in vitro, the IC50 of SSPP-80, SSPP-80‐1 and SSPP-80‐2 against DPPH free radical were 4.407, 8.267, and 5.204 mg/mL, respectively, whereas the IC50values for removing hydroxyl groups were 5.318, 3.516, and 4.016 mg/mL, respectively. It demonstrated that SSPP-80 and 2 fractions had certain antioxidant activity. Theoretical basis for use of Sojae Semen Praeparatum polysaccharides was provided by this study.

Protein extracted from Douchi was hydrolyzed by alcalase based on a single-factor experiment and response surface methodology was employed to optimize hydrolysis conditions. The optimum conditions were determined to be: 63℃ extraction temperature, 1.4% quantities of enzyme and substrate, and 1.7 h extraction time. The optimal protein hydrolysate was subsequently subjected to ultrafiltration, and the fraction of molecular weight 10–50 kDa was identified as the most potent contributor to antioxidant activity. Amino acid analysis indicated that acidic amino acids were the most abundant in all fractions of the protein hydrolysate. Infrared spectroscopy showed there were no significant differences in secondary structure between fractions.

To investigate the effects of urea nitrogen (N) and crop residues on soil organic carbon (SOC) decomposition, a batch of incubation experiments was carried out for 250 days by incorporating N-15-labeled urea and C-13-labeled maize residue into soil. Adding maize residue alone or adding maize residue together with urea N had a significant priming effect on SOC. Furthermore, the direction of the priming effect changed over the incubation. This effect could be characterized by three stages. The first stage occurred just after maize residue addition when the substrate for microorganisms switched from native SOC to easily available maize C (lasting similar to 7 days). The second stage showed a positive effect on the decomposition of native SOC (lasting similar to 28-58 days). The third stage showed a negative effect on the decomposition of native SOC. In contrast, adding N alone caused a positive effect over the first 65 days of incubation, followed by a slight negative priming effect. The overall effect of maize residue C and urea N addition on the decomposition of native SOC was dependent on the balance between the inhibitory and stimulatory effects. At the end of the incubation, adding maize residue alone had little effect on the decomposition of native SOC; urea N addition alone increased SOC decomposition by 9.1%, while adding N to soil amended with maize residue decreased SOC decomposition by 9.5%. The amount of residue-inhibited SOC decomposition per unit maize C mineralized was 0.21 +/- 0.06 in the Maize + N treatment. Application of urea N significantly increased the mineralization rate of maize residue after 20 days of incubation. The increased N availability, microbial biomass and dissolved organic carbon (DOC) induced by the addition of N were responsible for the higher mineralization rate of maize residue. This indicates that the priming effect induced by maize residues could persist for a long time and involved not only one mechanism but a succession of processes. The response of the priming effect to the addition of maize residue and urea N differed depending on the microbial biomass, substrate C and N availability and the stage of decomposition. Adding N to soil amended with maize residue led to a more efficient use of maize residue at the slow mineralization stage. (C) 2015 Elsevier B.V. All rights reserved.

Little is known about the effects of straw incorporation on saline soil aggregate formation or salt distribution in coastal zones. In this study, a 4-year coastal wheat/maize rotation field experiment was employed. In each growing season, maize/wheat straw was applied at the rates of 5.0 × 10³ kg ha⁻¹ (S) and 1.0 × 10⁴ kg ha⁻¹ (2S), and inorganic N was applied at the rates of 75 kg ha⁻¹ (N1/2), 150 kg ha⁻¹ (N), and 300 kg ha⁻¹ (N2). Treatment without straw addition and applied with 150 kg ha⁻¹ inorganic N was used as the control (CK). Dry- and wet-sieving techniques were used to fractionate the soils into large macroaggregates (> 2 mm, LM), small macroaggregates (0.25–2.0 mm, SM), microaggregates (0.053–0.25 mm, MI), and silt-plus-clay particles ( 0.25 mm, LA + SA) ranged from 74.2 %–88.3 % and 28.4 %–37.6 % in straw applied treatments, which significantly increased by 14.7 %–19.0 % and 21.1 %–32.4 % compared to CK, respectively (p < 0.05). The mean weight diameter (MWD) and aggregate stability rate (AR) enhanced as straw and N application rate increased. After straw application, soil organic carbon (SOC) preferentially accumulated in MI fractions, which was significantly higher than other aggregate fractions, except SN1/2 and CK (p < 0.05). MWD and AR were significantly negatively correlated with soil salinity (p < 0.05), and soil salinity decreased by 20.5 %–26.9 % in straw treatments compared to the initial soil salinity. In the CK and SN1/2 treatments, soil salinity of LA + SA fractions was significantly higher than < 0.25 mm fractions (MI + CS) (p < 0.05). The same difference in soluble Ca²⁺ was also observed in CK, SN1/2, or SN. In conclusion, saline soil aggregate formation and stability improved after straw and N application, which caused the salinity to decrease and affected salt distribution in aggregates. The findings of this study suggest that adequate N should be applied in order to maximize saline soil reclamation efficiency with straw.

To investigate the impact of different forms of plant-derived organic matter on nitrous oxide (N2O) emissions, an incubation experiment with the same rate of total nitrogen (N) application was carried out at 25 °C for 250 days. Soils were incorporated with maize-derived organic matter (i.e., maize residue-derived dissolved organic matter and maize residues with different C/N ratios) and an inorganic N fertilizer (urea). The pattern and magnitude of nitrous oxide (N2O) emissions were affected by the form of N applied. Single application of maize-derived organic matter resulted in a higher N2O emission than single application of the inorganic N fertilizer or combined application of the inorganic N fertilizer and maize-derived organic matter. The positive effect of maize residue-derived dissolved organic matter (DOM) addition on N2O emissions was relatively short-lived and mainly occurred at the early stage following DOM addition. In contrast, the positive effect induced by maize residue addition was more pronounced and lasted for a longer period. Single application of maize residues resulted in a substantial decrease in soil nitric nitrogen (NO3(-)-N), but it did not affect the production of N2O. No significant relationship between N2O emission and NO3(-)-N and ammonium nitrogen (NH4(+)-N) suggested that the availability of soil N was not limiting the production of N2O in our study. The key factors affecting soil N2O emission were the soil dissolved organic carbon (DOC) content and metabolism quotient (qCO2). Both of them could explain 87% of the variation in cumulative N2O emission. The C/N ratio of maize-derived organic matter was a poor predictor of N2O emission when the soil was not limited by easily available C and the available N content met the microbial N demands for nitrification and denitrification. The results suggested that the magnitude of N2O emission was determined by the impact of organic amendments on soil C availability and microbial activity rather than on soil N availability. In agricultural management practices, if the N inputs from organic and inorganic N fertilizers are equivalent, addition of organic N fertilizers that contain high amounts of available C will result in a higher N2O emission.

Dissolved organic matter (DOM) in soils play an essential role in soil physical, chemical and biological processes, but little information is available on the biodegradability of plant-derived DOM and its effect on soil carbon and nitrogen sequestration in field soils. The objectives of this study were to investigate the impacts of crop residue-derived DOM on soil CO2 and N2O emissions, as well as soil carbon and nitrogen sequestration by adding water extracts of maize stalk (i.e., plant-derived DOM) to soils. In this study, wheat was grown in pots under field conditions with treated soils, the soils treatments were: plant-derived DOM (PDOM), urea nitrogen (N), PDOM + urea nitrogen (PDOM + N), as well as a control with no additions to soil (CK). Adding plant-derived DOM to soil increased soil CO2 and N2O emissions (P < 0.05). During the wheat growing season, the cumulative CO2-C emission from CK, PDOM, N and PDOM + N was 107 +/- 1, 157 +/- 7, 136 +/- 2 and 149 +/- 6 g Cm-2, respectively. Meanwhile, the cumulative N2O-N emission from CK, PDOM, N and PDOM + N was 188 +/- 8, 256 +/- 5, 239 +/- 10 and 258 +/- 7 mg N m(-2), respectively. Compared with N treatment, DOM addition had little effect on soil N sequestration, but it accelerated the decomposition of native soil organic carbon (SOC) and caused a net loss of SOC. The soil C sequestration decreased about 151 +/- 67 and 51 +/- 45 g C m(-2) in PDOM and PDOM + N treatments, respectively. The increased microbial biomass and root biomass were responsible for the greater CO2 emission in DOM-amended soils. Negative correlation between dissolved organic carbon (DOC) content and N2O flux suggested that the release of N2O was dependent on the supply of DOC. These results indicated that the supply of plant-derived DOM exacerbated soil CO2 and N2O emissions and reduced soil C sequestration. Therefore, agricultural management practices that increase the stability of highly soluble C inputs and/or retard the decomposition of crop residues should be adopted to decrease soil greenhouse gas emission and increase soil C sequestration. (C) 2015 Elsevier B.V. All rights reserved.

In the Yucheng region along the lower reach of the Yellow River, current border irrigation systems in all three irrigation districts have low irrigation performances with the applied depth per irrigation event >150 mm, and application efficiency

Soil organic carbon (SOC) mineralization is important for the regulation of the global climate and soil fertility. Decomposition of SOC may be significantly affected by the supply of plant-derived labile carbon (C). To investigate the impact of plant-derived dissolved organic matter (DOM) and urea (N) additions on the decomposition of native SOC as well as to elucidate the underlying mechanisms of priming effects (PEs), a batch of incubation experiments was conducted for 250 days by application of (13)C-labeled plant-derived DOM and urea to soils. The direction of PE induced by the addition of DOM was different from the addition of N, i.e. it switched from negative to positive in DOM-amended soils, whereas in the N-treated soil it switched from positive to negative. Adding DOM alone was favorable for soil C sequestration (59 ± 5 mg C per kg soil), whereas adding N alone or together with DOM accelerated the decomposition of native SOC, causing net C losses (-62 ± 4 and -34 ± 31 mg C per kg soil, respectively). These findings indicate that N addition and its interaction with DOM are not favorable for soil C sequestration. Adding DOM alone increased the level of dissolved organic carbon (DOC), but it did not increase the level of soil mineral N. Changes in the ratio of microbial biomass carbon (MBC) to microbial biomass nitrogen (MBN) and microbial metabolic quotient (qCO2) after the addition of DOM and N suggest that a possible shift in the microbial community composition may occur in the present study. Adding DOM with or without N increased the activities of β-glucosidase and urease. Changes in the direction and magnitude of PE were closely related to changes in soil C and N availability. Soil C and N availability might influence the PE through affecting the microbial biomass and extracellular enzyme activity as well as causing a possible shift in the microbial community composition.

OBJECTIVE To study the rubrofusarin glucosides from whole plants of Berchemia polyphylla var. leioclada, and their scavenging activities for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. METHOD The chemical constituents were isolated and purified via repeated silica gel and Sephadex LH-20 column chromatography. Their structures were elucidated by spectral analysis and the compounds were tested for their scavenging activities on DPPH radical. RESULT Three rubrofusarin glucosides compounds were isolated and identified as rubrofusarin-6-O-beta-D-glucopyranoside (1), rubrofusarin-6-O-beta-D-(6'-O-acetyl) glucopyranoside (2), rubrofusarin-6-O-alpha-L-rhamnosyl-(1-6) -O-beta-D-glucopyranside (3). Three isolated compounds showed strong scavenging activities on DPPH radical, the concentration of half elimination ratio( micromol x L(-1)) of VitC and Compounds 1-3 were 18.2, 40.5, 23.3 and 13.6, respectively. CONCLUSION Compounds 1-3 were isolated from this plant for the first time and compound 2 was a new compound. They showed significant antioxidant activity, and the scavenging activity of compound 3 was a little stronger than that of VitC.

To characterize the structure of polysaccharide LTC-II obtained from Pyrola corbieri.The polysaccharide was extracted from P. corbieri by hot water and ethanol precipitation. Crude polysaccharide was purified by DEAE-Cellulose chromatography and Sephacryl S-300 HR column chromatography. The purity and molecular weight of polysaccharide was determined by gel permeation chromatography. UV, IR, optical rotation, complete acid hydrolysis, periodate oxydation, Smith degradation, partial acid hydrolysis and methylation analysis were applied to determine the structural features.A homogeneous fraction LTC-II was obtained and its relative molecular mass was 22 000 Da. It consisted of arabinose, mannose, glucose, galactose in the molar ratio of 35. 2: 1.0: 13. 4: 4. 2. LTC-II had a backbone consisting glucose, mannose, galactose and mainly contained (1 --6)-linkaged glucose. The side chain possessed arabinose, glucose, galactose and mainly contained (1 --5)-linkaged arabinose. The terminal sugar were mainly glucose and galactose.Studies on the preliminary characterization of polysaccharide LTC-II from P. corbieri for the first time.