Preparation, structural characteristics and antioxidant activity of polysaccharide and its metal chelates from the peel of Dioscorea oppositifolia L.

Two metal chelates of Dioscorea oppositifolia L. peel polysaccharides (DTP) were prepared: iron chelate (DTP-Fe) and zinc chelate (DTP-Zn). The physicochemical properties of the polysaccharide and its metal chelates were assessed by UV-Vis absorption spectroscopy, Fourier-transform infra-red spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Antioxidant activities were evaluated by DPPH, ABTS + and hydroxyl radical scavenging assays. According to ICP-MS, the iron content of DTP-Fe was 9.47%, while the zinc content of DTP-Zn was 4.02%. The antioxidant capacity of DTP-Fe increased with the increase of concentration, and its overall activity was higher than that of DTP and DTP-Zn. This polysaccharide-iron chelate can be developed and utilised as an antioxidant and multifunctional iron supplement. DTP-Zn showed the potential to be a natural antioxidant and zinc supplement food.

Structure and Bioactivities of a Novel Polysaccharide Extracted From Dendrobium huoshanense by Subcritical Water.

In this study, the polysaccharide was extracted by subcritical water from Dendrobium huoshanense. A novel polysaccharide (DHPs-1) was obtained through several purification steps and its structure and bioactivity were investigated. Structural analysis indicated that the weight-average molecular weight of DHPs-1 was 5.0 × 104 Da and it was mainly composed of glucose (65.04%), mannose (14.23%), galactose (8.17%), galacturonic acid (6.41%), rhamnose (2.34%), and xylose (1.25%). 1,4-Glcp, and 1,4,6-Galp were existed in the backbone of DHPs-1. The residues of 1,3,4-Galp, 1,4-Manp, 1,4-Galp, and 1,3,4,6-Galp could be in the backbone or the side chains with the non-reducing terminal of α-Manp. Bioactivity tests indicated that DHPs-1 had immunomodulatory activity in that it significantly enhanced transcript levels of cytokines [Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1ß (IL-1ß), and Interleukin-10 (IL-10)]. DPPH and hydroxyl radical scavenging tests showed that it had good antioxidant activity. These results reveal that DHPs-1 could be developed as a safe immunomodulatory agent and antioxidant for pharmacological or functional food applications.

Physicochemical properties and bioactivities of original and Se-enriched polysaccharides with different molecular weights extracted from Pleurotus ostreatus.

Three polysaccharides (WZP1, WZP2, WZP3) and their Se-enriched products (SeWZP1, SeWZP2 and SeWZP3) were obtained from Pleurotus ostreatus using a simple, rapid method and HNO3-Na2SeO3 method, respectively. The molecular weight distribution profiles of all samples except SeWZP2 showed double peaks. The average molecular weights (Mw) of WZP1-3 were 48.6 kDa, 20.2 kDa and 11.8 kDa, respectively, and of SeWZP1-3 were 19.6 kDa, 37.7 kDa, 14.5 kDa, respectively. The complexity of monosaccharide composition of WZP1-3 was inversely proportional to the ethanol concentration used in the ethanol precipitation process. Additionally, the results of biological activity tests indicated that α-glucosidase inhibitory activity of WZP1-3 was related to the molecular weight and the monosaccharide composition complexity. The selenized modification can improve the α-glucosidase-inhibiting, hydroxyl radical-scavenging activity of P. ostreatus polysaccharides. Therefore, by improving their bioactivities by selenization, the polysaccharides of P. ostreatus could be utilized as a natural health food supplement.

Chinese quince seed gum: Flow behaviour, thixotropy and viscoelasticity.

Characterization of the rheological properties of Chinese quince seed gum (CQSG) is fundamental when using it in food production. In the present paper, the chemical compositions and the rheological properties of CQSG at different concentrations, types of salts, temperatures and pH values were characterized by using shear or dynamic rheological experiments. The results demonstrated that uronic acid content of CQSG (31.7%) was high and different concentration CQSG solutions presented Newtonian plateaus followed by shear thinning regions. The viscosities of the gum solutions decreased with the addition of any salt, with increase in temperature and at extreme pH values (3 and 11). The stress and frequency sweep tests demonstrated a unique result in that the crossover frequency shifted to a higher value when the CQSG solution concentration increased. It is the basis for CQSG product development and quality control for its potential applications.

Prenylated Indole Diterpene Alkaloids from a Mine-Soil-Derived Tolypocladium sp.

Ten new prenylated indole diterpene alkaloids, tolypocladin A-J (1-10), including four chlorinated metabolites, have been isolated from a culture of a mine-soil-derived fungus, Tolypocladium sp. XL115. The structures and absolute configurations of 1-10 were determined by spectroscopic analysis, ECD calculations, and comparison with known compounds. Compounds 1 and 8 displayed significant antimicrobial activities. In addition, compound 1 also showed weak cytotoxic activity against all tested human cancer cell lines and suppressed the growth and viability of the patient-derived HCC cells T1224.

Lycorine: a potential broad-spectrum agent against crop pathogenic fungi.

A screening test showed that lycorine exhibited significant antifungal activity against 24 pathogenic crop fungi at concentrations of 500 µg/ml and 100 µg/ml, respectively. Fusarium graminearum was selected for antifungal mechanism studies by observing its mycelial morphology and investigating the variations in its conductivity. In addition, the substance absorption and metabolism of F. graminearum were explored. The mechanism was revealed as being one by which lycorine destroyed the cellular membrane and further influenced substance absorption and cell metabolism.

Diterpenoids of macromycetes.

This review surveys the chemical and biological literature dealing with the isolation, structure elucidation and bioactivity of diterpenoids from the fruiting bodies of macromycetes, concentrating on work that has appeared in the literature up to December 2007. In addition, this paper examines the research of diterpenoids produced by macromycetes grown in mycelial culture and the culture conditions for the fermentation of macromycetes.

Activity of armillarisin B in vitro against plant pathogenic fungi.

The methanolic extract of the fruiting bodies of the mushroom Armillariella tabescens was found to show antifungal activity against Gibberella zeae. The active compound was isolated from the fruiting bodies of A. tabescens by bioassay-guided fractionation of the extract and identified as armillarisin B. Armillarisin B eventually corresponds to 2-hydroxy-2-phenylpropanediamide and its structure was confirmed on the basis of spectroscopic studies including 2D NMR experiments.

Egg white, a favourable solvent to extract the active ingredient of Mylabris phalerata.

To characterize the role of hen eggs used for analyzing the insect Mylabris phalerata a traditional Chinese medicine for curing liver cancer, egg white was separated from the whole egg and added to M. phalerata. The volatile compounds found in egg white when added to M. phalerata and therefore in M. phalerata itself were analyzed by GC. Cantharidin was detected both in egg white added to M. phalerata and M. phalerata itself. Egg white can be used as a favourable solvent for extracting the active ingredient of M. phalerata.

[Chemical constituents study on the fruiting bodies of Lactarius rufus].

OBJECTIVE: To investigate the chemical constituents of Lactarius rufus. METHODS: Chemical constituents of Lactarius rufus were isolated by column chromatography. RESULTS: Six compounds were isolated and identified as stearic acid (1), 3beta-hydroxyerg-osta-5,7,22-triene (2), sotolon (3), lactarorufin A (4), rufuslactone (5) and D-allitol (6), respectively. CONCLUSION: Compound 5 is the main sesquiterpenoid of Lactarius rufus and has the potential for the further investigation.

Scabronine J, a new cyathane-type diterpenoid from the basidiomycete Sarcodon scabrosus.

A new cyathane-type diterpenoid, named scabronine J was isolated from the fruiting bodies of the mushroom Sarcodon scabrosus. The structure of scabronine J was elucidated on the basis of spectroscopic studies including 2D NMR experiments.

[Chemical study of nucleosides on Cordyceps militaris].

OBJECTIVE: To investigate the nucleosides of Cordyceps militaris. METHODS: The primary extract technique of nucleosides from Cordyceps militaris was founded, the nucleosides were isolated by chromatography. RESULTS: Four compounds were isolated from the mycelium of Cordyceps militaris. They were identified as uridine (1), adenosine (2), guanosine (3) and p-tyrosine (4), respectively. CONCLUSION: Compounds 1, 2 and 3 are the main nucleosides in Cordyceps militaris.

[Chemical study on fruiting bodies of Boletus vioaceo-fuscus].

OBJECTIVE: To investigate the chemical constituents of Boletus vioaceo-fuscus. METHOD: The compounds were isolated with column chromatography. The structures were determined by spectroscopic techniques. RESULT: Six compounds were isolated from the fruiting bodies of Boletus vioaceo-fiuscus. They were identified as ergosta-5, 7, 22-triene-3beta-ol (1), dihydrofuran-2, 5-dione (2), (22E, 24R)-5alpha, 6alpha-epoxyergosta-8, 22-diene-3beta, 7alpha-diol (3), (22E, 24R)-5alpha, 6alpha-epoxyergosta-8 (14), 22-diene-3beta, 7alphadiol (4), cerebroside B (5) and adenosine (6), respectively. CONCLUSION: All the Compounds were obtained from the fruiting bodies of Boletus vioaceo-fiscus for the first time.

Trametes versatillis, a fungus highly producing eburicoic acid.

Eburicoic acid was produced and isolated from the cultured mycelia of the fungus, Trametes versatillis. The weight rate of eburicoic acid in the dry weight of cultured mycelia of Trametes versatillis was about to 1%. Trametes versatillis can be expected as an important bioresource to supply eburicoic acid for its industrial exploitation.

Monitoring of BHT-quinone and BHT-CHO in the gas of capsules of Asclepias physocarpa.

Three volatile components, namely benzoic acid ethyl ester (1), 2,6-di-tert-butyl-p-benzoquinone (BHT-quinone) (2), and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) (3), were detected from the gas in the capsules of Asclepias physocarpa by means of GC/MS analysis. BHT-quinone and BHT-CHO as organic pollutants are the degradation products of the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). Ground water, lake water and/or rain water are a source of BHT metabolites in the plant Asclepias physocarpa.

A new p-terphenyl derivative from fruiting bodies of the basidiomycete Sarcodon laevigatum.

A new metabolite with p -terphenyl core, named sarcodan (1), together with three known p -terphenyl metabolites (3, 4, 5) represented as Fig. 1, was isolated from the fruiting bodies of the basidiomycete Sarcodon laevigatum . The structures of these compounds were elucidated by spectroscopic and chemical methods.

A new bitter diterpenoid from Sarcodon scabrosus.

The new cyathane-type diterpenoid sarcodonin I was isolated from the fruiting bodies of the basidiomycete Sarcodon scabrosus. Its structure was determined on the basis of spectroscopic means, including 2D-NMR (HMBC, HMQC, ROESY, 1H, 1H-COSY).