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The water-soluble polysaccharide from fruiting bodies of Russula virescens (RVP) was sulfated using sulfur trioxide·pyridine complex method under different reaction conditions. Five sulfated RVP derivatives (SRVP1-5, SRV1-10, SRVP1-15, SRVP1-20 and SRVP1-25) with different degrees of substitution (DS) ranging from 0.34 to 0.73 were prepared. Several structural features of RVP and SRVPs including chemical structure, monosaccharide composition, molecular weight and chain conformation were investigated. The spectra results indicated that the sulfate groups were successfully introduced on RVP. The molecular weights of SRVP decreased with the increasing DS. Both RVP and SRVPs were mainly composed of mannose, glucose and galactose, with different molar ratios. The triple-helical conformation was broken down into a random coil when the DS exceeded 0.34. In vitro activity test results indicated that the SRVPs showed better antioxidant, anticoagulant, antibacterial and anti-tumor activities compared with RVP. Among the five sulfated derivatives, SRVP1-25 exhibited the strongest ABTS and hydroxyl radical scavenging activities and anticoagulant activity, while SRVP1-20 showed the best antibacterial activity and anti-tumor activity. These results demonstrated that the SRVPs could be developed as one of potential antioxidant, anticoagulant, antibacterial and anti-tumor agents for industrial and biomedical use.

Mushrooms are known as an excellent source of nutrients including macronutrients and bioactive compounds. Nutritional values were investigated involving proximate analysis, total antioxidant capacity (TAC), total phenol content (TPC) and total flavonoid content (TFC) of 10 edible wild mushroom species—Amanita calyptroderma Ark. et al., Amanita princeps Corner et Bas, A., Astraeus odoratus, Heimiella retispora (Pat. et. Bak.) Boedijn., Mycoamaranthus cambodgensis (Pat.) Trappe, Russula alboareolata Hongo, Russula cyanoxantha Schaeff.ex.Fr., Russula emetic (Schaeff. ex Fr.) S.F.Gray., Russula virescens (Schaeff.) fr., Termitomyces clypeatus Heim—and five cultivated mushroom species—Auricularia auricula-judae, Lentinus polychrous Lev., Lentinus squarrosulus Mont., Pleurotus sajor-caju (Fr.) Sing, Volvariella vovacea (Bull. Ex.Fr.) Sing. From the proximate analysis, the moisture contents of both wild and cultivated mushrooms ranged from 84.15% fresh weight (FW) to 90.21% FW. The ash, crude protein, fat, crude fiber and carbohydrate contents of both wild and cultivated mushrooms were in the dry weight ranges 2.56–13.96%, 11.16–50.29%, 1.43–21.94%, 2.11–38.11% and 9.56–59.73%, respectively, and the contents of macronutrients in the mushrooms varied by variety. Wild mushrooms had a high fiber content compared to cultivated mushrooms. The contents of biologically active compounds of both wild and cultivated mushrooms also varied depending on the variety. Values for the TAC, TPC and TFC of wild mushrooms were higher than those of cultivated mushrooms. In conclusion, the proximate analysis for both wild and cultivated mushrooms was variety dependent and wild mushrooms contained a higher fiber content and more biologically active compounds than cultivated mushrooms.

Antioxidant properties and total phenolic, flavonoid, ascorbic acid, b-carotene and lycopene contents of ethanol and water extracts from the edible mushroom Russula virescens (RV) were examined in this study. Various experimental models including 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2′-azino-bis(3ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), nitrite, hydroxyl and superoxide radical scavenging activity, inhibition of linoleic acid oxidation, DNA protection and catalase activity were used to characterize the antioxidant activity of the extracts. The IC50 values for DPPH and ABTS radical scavenging activities were 0.22 and 0.44 mg/mL, respectively, for water extract and 1.90 and 0.65 mg/mL, respectively, for ethanol extract. The levels of phenolic compounds were 8.74 and 2.21 mg gallic acid/100 g dry mass, and flavonoid compounds were 2.83 and 1.02 mg catechin/100 g dry mass for the water and ethanol extracts, respectively. In addition, high-performance liquid chromatography (HPLC) analyses of RV extract revealed the presence of different phenolic compounds. R. virescens can therefore be considered to be a potential source of natural antioxidants.

The metal (Cu, Ni, Cd, Hg, As, Pb) contents in wild edible mushrooms collected from three different sites in China were determined by atomic absorption spectrometry and atomic fluorescence spectrometry. All element concentrations were determined on a dry weight basis. A total of 11 species was studied, five being from the urban area and six from rural areas in China. The As content ranged from 0.44 to 1.48 mg/kg. The highest As content was seen in Macrolepiota crustosa from the urban area, and the lowest in Russula virescens from rural areas. A high Ni concentration (1.35 mg/kg) was found in Calvatia craniiformis from the urban area. The lowest Ni level was 0.11 mg/kg, for the species R. virescens and Cantharellus cibarius. The Cu content ranged from 39.0 to 181.5 mg/kg. The highest Cu content was seen in Agaricus silvaticus and the lowest in C. cibarius. The Pb content ranged from 1.9 to 10.8 mg/kg. The highest Pb value was found in C. craniiformis. The Cd content ranged from 0.4 to 91.8 mg/kg. The highest Cd value was found in M. crustosa. The Hg content ranged from 0.28 to 3.92 mg/kg. The highest Hg level was found in Agaricus species. The levels of the heavy metals Cd, Pb, and Hg in the studied mushroom species from urban area can be considered high. The metal-to-metal correlation analysis supported they were the same source of contamination. High automobile traffic was identified as the most likely source of the contamination. Based upon the present safety standards, consumption of those mushrooms that grow in the polluted urban area should be avoided.

A monomeric feruloyl esterase (FAE) with a molecular mass of 62 kDa was acquired from fresh fruiting bodies of the edible mushroom Russula virescens. The isolation procedure involved ion exchange chromatography on CM-cellulose, Q-Sepharose, and SP-Sepharose and finally fast protein liquid chromatography-gel filtration on Superdex 75. Two amino acid sequences were obtained after tryptic digestion, and they both showed some homology with the esterase of some fungi. Maximal activity was observed at pH 5.0 and at 50 °C. The enzyme displayed relatively high thermostability as evidenced by over 70 % residual activity at 70 °C and about 34 % residual activity at 80 °C. The K m and V max for this enzyme on methyl ferulate were 0.19 mM and 1.65 U/mg proteins, respectively. The purified FAE prefers methyl ferulate over methyl caffeate and is least active on methyl p-coumarate. The FAE activity was not significantly affected by the presence of cations such as Mn(2+), Ca(2+), Cd(2+), Zn(2+), Mg(2+), Cu(2+), and K(+) ions but inhibited by Al(3+), Hg(2+), Fe(2+), and Pb(2+) ions at a tested concentration of 2. 5 mM.

A ribonuclease with an N-terminal sequence different from those of other ribonucleases has been purified from fruiting bodies of the mushroom Russula virescens . The RNase was adsorbed on DEAE–cellulose and Q-Sepharose in 10 mM Tris–HCl buffer (pH 7.1–7.3) and on CM–Sepharose in 10 mM NH 4 OAc buffer (pH 4.6), unlike other mushroom ribonucleases which are unadsorbed on DEAE–cellulose. The RNase demonstrated a molecular mass of 28 kDa in both gel filtration and sodium dodecyl sulfate–polyacrylamide gel electrophoresis. In contrast to other mushroom ribonucleases which are monospecific, it exhibited co-specificity towards poly A and poly C. It demonstrated a pH optimum of 4.5, which is lower than values reported for other mushroom ribonucleases, and a temperature optimum of 60 °C.

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Mushrooms that are morphologically indistinguishable from Russula virescens (Schaeff.) Fr. are among the most popular wild edible mushrooms in Yunnan province, southwestern China. However, almost nothing is known about their biology. This study investigated the diversity and population genetics of a R. virescens ally from Yunnan. A total of 210 samples were collected from 13 geographical locations throughout the main distribution range in Yunnan. The patterns of genetic variation within and among these geographic populations were analyzed using sequences from three nuclear and two mitochondrial DNA fragments. Analysis of the ITS sequences revealed that samples from Yunnan showed 3-6% sequence difference from R. virescens samples from North America and Europe and formed a distinct clade. Our multilocus population genetic analyses suggested frequent gene flow among geographic populations of the R. virescens ally in Yunnan. Interestingly, the nuclear and mitochondrial genes exhibited different levels of gene flow and recombination. We discuss the implications of our results for understanding speciation, reproduction and conservation of this important biological resource.