Leifa Fan

Effects of extraction methods on the antioxidant activities of polysaccharides obtained from Flammulina velutipes

Four polysaccharides (CFP, UFP, MFP and EFP) were extracted from Flammulina velutipes using hot water, ultrasonic, microwave or enzymatic methods optimized by orthogonal test. Preliminary structural characterizations were conducted using physicochemical properties. Polysaccharides extracted by all four methods showed similar physicochemical characteristics and FT-IR spectra. However, SEM images of tissues of F. velutipes were significantly different. EFP demonstrated better antioxidant activities against hydroxyl radical as well as improved metal chelating activity. UFP showed higher DPPH scavenging activity, but CFP exhibited higher antioxidant activity in reducing power. Hence, these polysaccharides can be used as natural antioxidants in functional foods or medicine. Further experiments on the biological activities of these four polysaccharides are currently in progress.

Antioxidant and hepatoprotective potential of endo-polysaccharides from Hericium erinaceus grown on tofu whey.

Three fractions of the endo-polysaccharides from the mycelium of Hericium erinaceus (HEP) grown on tofu whey were obtained by the fractional precipitation with gradient concentrations of ethanol (HEP40, HEP60 and HEP80). The chemical and physical characteristics of the three crude polysaccharides were investigated by the combination of chemical and instrumental analysis methods. The studies to evaluate the antioxidant potential and the hepatoprotective effects of the three polysaccharides showed that they had different activities in different evaluation system. HEP80 showed strong activity on antioxidant in vitro and potent hepatoprotective effect in vivo and the hepatoprotective effect may be due to its potent antioxidant capacity. The HEP could be exploited as antioxidant product and a supplement in the prevention of hepatic diseases. The study also opens an avenue for the efficient utilization of tofu whey, which is usually discarded in environment, causing concerns.

Effect of caffeine and tannins on cultivation and fructification of Pleurotus on coffee husks

The objective of this work was to study the effect of caffeine and tannins on Pleurotus sp. cultivation and to evaluate the feasibility of using coffee husks as substrate for mushroom cultivation. Eight strains of P. ostreatus and two strains of P. sajor-caju were screened on a medium prepared from agar extract of coffee husk. Based on best mycelial growth and biomass production, the strain P. ostreatus LPB 09 was selected for detailed studies. With the increase of caffeine concentration, the mycelial growth and the biomass production decreased, and no growth was observed when concentration of caffeine was 2500 mg/L. Furthermore, Pleurotus did not degrade the caffeine, but absorbed it. Tannin under 100 mg/L in the medium stimulated the growth of mycelia, but above 500 mg/L it had a negative effect. When the concentration reached 1000 mg/L, the fungus still survived and showed a certain tolerance to it. No tannic acid was found in the mycelia, but its concentration decreased in the medium. This fact confirmed that Pleurotus had the capacity of degrading tannic acid. Fructification occurred after 20 days of inoculation and the biological efficiency reached about 97% after 60 days. Caffeine content in the husk after cultivation was reduced to 60.7% and tannins to 79.2%. The results indicated the feasibility of using coffee husk without any pretreatment for the cultivation of Pleurotus.

Extraction optimization and biological properties of a polysaccharide isolated from Gleoestereum incarnatum.

Extraction was optimized of polysaccharides from Gleoestereum incarnatum (GIP). The three parameters, extraction temperature, extraction time and the ratio of water to raw material, were optimized using the Box-Behnken design. As a result, the optimal extraction conditions were: extraction temperature 87.5 °C, extraction time 1 h and the ratio of water to raw material of 39.7 mL/g, where the highest yield of polysaccharide (13.18%) was obtained. GIP-II was the main fraction purified form GIP. GIP-II was composed of galactose, glucose, xylose, and mannose, with glucose was the predominant monosaccharide. GIP-II exhibited strong scavenging activities against DPPH and hydroxyl radials in vitro, as well as a strong inhibitory effect on the growth of HepG2 cells. The overall findings indicated that GIP-II is worthy of further exploration for its potential applications in antitumor drugs or health foods.

Biological decolorization of malachite green by Deinococcus radiodurans R1.

Cultures of Deinococcus radiodurans R1 were observed to decolorize malachite green (MG) dye. The effects of various factors on decolorization efficiency were investigated. The optimal decolorization temperature and pH ranges were 25-50°C and 6.0-8.0, respectively. With increasing initial MG concentration, the decolorization efficiency decreased, and the kinetic parameters, R(MG,max) and K(m) were 416.7 mg-MG/g-cell/h and 1033.7 mg/L, respectively. The D. radiodurans R1 cells were capable of tolerating and rapidly degrading high concentrations of the dye. When MG concentration was 200 mg/L, decolorization efficiency was up to 97.2% within 30 min. The intermediate products of MG biodegradation were 4-(dimethylamino)phenol and 4-(dimethylamino)benzophenone, as identified by gas chromatography/mass spectrometry analysis. Toxicity tests indicated that D. radiodurans R1 did not detoxify an MG solution completely, but clearly reduced its toxicity. This study demonstrated that this strain was an efficient degrader compared to other microorganisms.

Comparison of the preliminary characterizations and antioxidant properties of polysaccharides obtained from Phellinus baumii growth on different culture substrates

Three polysaccharides (PPB-MB, PPB-MW and PPB-MM) were obtained from the fruiting body of Phellinus baumii growth on different culture substrates (mulberry branches, mixed wood sawdust and an equal combination of the two materials) and their chemical composition was investigated. PPB-MM contained the highest contents of neutral sugar (66.59%) and uronic acid (23.38%), followed by PPB-MW and PPB-MB, with PPB-MW having the highest protein content. The three polysaccharides were all composed of six kinds of monosaccharides, namely fucose, mannose, glactose, xylose, arabinose and glucose. The antioxidant activities of the three polysaccharides were determined using lipid peroxidant inhibition, ABTS radical scavenging, and Fe(2+)-chelating assay. Results showed that PPB-MM exhibited the highest antioxidant properties in all the assays. As a result, an equal combination of mulberry branches and mixed wood sawdust serves as a good culture substrate for producing such antioxidant polysaccharides.

Antioxidant and DNA damage protecting potentials of polysaccharide extracted from Phellinus baumii using a delignification method

A delignification method was employed to extract the polysaccharide from the fruiting body of Phellinus baumii. The three parameters, processing temperature, ratio of water to raw material and amount of acetic acid every time were optimized using the Box-Behnken design. As a result, the optimal extraction conditions were: processing temperature 70.3°C, ratio of water to raw material of 34.7mL/g and amount of acetic acid of 0.32mL every time. Under these conditions, the highest yield of polysaccharide (10.28%) was obtained. The main fraction (PPB-2) purified from PPB was composed of fucose, arabinose, galactose, glucose, xylose and mannose, while glucose was the predominant monosaccharide. PPB-2 exhibited noticeable antioxidant activity and strong protection against oxidative DNA damage. These findings implied that acid-chlorite delignification was a superior method to extract the polysaccharide from P. baumii and PPB-2 may be useful for cancer chemoprevention.

Antidiabetic activities of ethanol extract of dry matters of culture broth of Coriolus versiolor in submerged culture

The study aimed to investigate the antihyperglycemic and antilipidperoxidative effects of ethanol extract of the dry matter from culture broth of Coriolus versicolor (ECBC) in streptozotocin-induced diabetes mice. Blood glucose level, insulin level, total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol(LDL-C), high density lipoprotein -cholesterol (HDL-C) in serum and reduced glutathione level (GSH), lipid peroxidation, glycogen, antioxidant enzymes in liver were evaluated. Moreover, histopathological observation was conducted. Streptozotocin treatment (150 mg/kg body weight) induced the decrease of GSH level, antioxidant enzymes activities, glycogen content in liver, HDL-C content and insulin level in serum, accompanied by the elevation of the lipid peroxidation in liver, serum blood glucose level, contents of TC, TG and LDL-C. Treatment with ECBC restored the changes in the above parameters up to the basal level. The protective effects were further supported by the attenuation of the degree of pancreas damage in ECBC treated mice.