Surajit Samanta

Antioxidant and immunostimulant β-glucan from edible mushroom Russula albonigra (Krombh.) Fr.

A water soluble β-glucan (PS) with an average molecular weight ∼1.95 × 10(5)Da was isolated from the alkaline extract of ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr. and found to consist of terminal, (1 → 3)-, (1 → 6)-, and (1 → 3,6)-linked β-D-glucopyranosyl moieties in a ratio of nearly 1:2:2:1. The structure of this PS was elucidated on the basis of total hydrolysis, methylation analysis, Smith degradation, partial hydrolysis, and 1D/2D NMR experiments. On the basis of these experiments, the repeating unit of the PS was found to contain a backbone of three (1 → 6)-β-D-glucopyranosyl residues, one of which was branched at O-3 position with the side chain consisting of two (1 → 3)-β-D-glucopyranosyl and a terminal β-D-glucopyranosyl residue. This PS showed in vitro macrophage activation by NO production as well as splenocytes and thymocytes proliferation. Moreover, it also exhibited potent antioxidant activities.

Structure elucidation and antioxidant properties of a soluble β-d-glucan from mushroom Entoloma lividoalbum

A water soluble branched β-D-glucan (PS-I) with an average molecular weight ~2.1×10(5) Da was isolated from alkaline extract of the fruit bodies of the edible mushroom Entoloma lividoalbum (Kühner & Romagn) Kubička which consists of terminal β-D-glucopyranosyl, (1→3)-β-D-glucopyranosyl, (1→6)-β-D-glucopyranosyl, and (1→3,6)-β-D-glucopyranosyl moieties in a molar ratio of nearly 1:3:2:1. The structure of PS-I was elucidated using acid hydrolysis, methylation analysis, periodate oxidation study, partial hydrolysis, and 1D/2D NMR experiments. The repeating unit of the polysaccharide (PS-I) contains a backbone chain of three (1→6)-β-D-glucopyranosyl residues, one of which was branched at O-3 position with the side chain consisting of three (1→3)-β-D-glucopyranosyl and a terminal β-D-glucopyranosyl residues. Total antioxidant capacity of 1mg PS-I was measured and found equivalent to 70±15 μg of ascorbic acid. The PS-I was found to possess hydroxyl and superoxide radical-scavenging activities with EC50 values of 480 and 150 μg/mL, respectively. The reducing power of PS-I was determined 0.5 at 480 μg/mL.

Glucan from hot aqueous extract of an ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr.: structural characterization and study of immunoenhancing properties

A water soluble glucan (PS-I) was isolated from the hot aqueous extract of the fruit bodies of an ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr. The total hydrolysis, methylation analysis, periodate oxidation, and NMR ((1)H, (13)C, DEPT-135, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, and HMBC) studies revealed the presence of the following repeating unit in the polysaccharide: This glucan showed excellent activation of macrophages as well as splenocytes and thymocytes in vitro.

Structural and immunological studies of hetero polysaccharide isolated from the alkaline extract of Tricholoma crassum (Berk.) Sacc.

An immunoenhancing water-soluble hetero polysaccharide was isolated from an alkaline extract of the fruit bodies of an ectomycorrhizal edible mushroom, Tricholoma crassum (Berk.) Sacc. The structure of the molecule was investigated using acid hydrolysis, methylation analysis; periodate oxidation study, and NMR spectroscopy techniques ((1)H, (13)C, DEPT-135, DQF-COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC). On the basis of the above-mentioned experiments the structure of the repeating unit of the polysaccharide was established as: This polysaccharide exhibited splenocyte, thymocyte as well as macrophage activations.

A glucan from an ectomycorrhizal edible mushroom Tricholoma crassum (Berk.) Sacc.: isolation, characterization, and biological studies

A water soluble glucan of average molecular weight ∼1.74×10(5)Da was isolated from hot aqueous extract of the fruiting bodies of an ectomycorrhizal edible mushroom Tricholoma crassum (Berk.) Sacc. The structure of this glucan was elucidated on the basis of total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR studies. Based on the above experiments the repeating unit of the glucan was established as: [formula see text]. This glucan showed macrophage activation in vitro by NO production in a dose dependent manner and strong splenocyte and thymocyte immunostimulation in mouse cell culture medium. It also exhibited good inhibition activity toward lipid peroxidation.

Structural elucidation of an immunoenhancing heteroglycan isolated from Russula albonigra (Krombh.) Fr.

A water soluble heteroglycan (PS-II) of average molecular weight ∼1.45 × 10(5)Da was isolated from the aqueous extract of an ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr. Structural characterization of PS-II was carried out using acid hydrolysis, methylation analysis, periodate oxidation, and 1D/2D NMR studies. Structural analysis revealed that PS-II was composed of terminal 2-O-methyl-Fucp, terminal Manp, (1→2)-Fucp, (1→3)-Glcp, (1→3,4)-Glcp, (1→6)-Galp, and (1→2,6)-Galp residues in a relative proportion of approximately 1:1:1:1:1:1:1. The proposed repeating unit of the PS-II had a backbone consisting of two (1→3)-β-d-glucopyranosyl, two (1→6)-α-d-galactopyranosyl, and one (1→2)-α-l-fucopyranosyl residues, out of which one (1→3)-β-d-glucopyranosyl residue was branched at O-4 position with terminal 2-O-methyl-α-l-fucopyranosyl and one (1→6)-α-d-galactopyranosyl residue was branched at O-2 position with terminal α-d-mannopyranosyl residue. This PS-II showed in vitro macrophage activation by NO production as well as splenocytes and thymocytes proliferation.

An immunostimulating water insoluble β-glucan of an edible hybrid mushroom: isolation and characterization.

An immunostimulating water-insoluble β-glucan isolated from hot alkaline extract of the fruiting bodies of an edible somatic hybrid mushroom of Pleurotus florida and Calocybe indica var. APK2 showed significant macrophage, splenocyte, and thymocyte activations. On the basis of total hydrolysis, methylation analysis, and NMR experiments ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, DEPT-135, and HSQC), the repeating unit of the polysaccharide is established.

Studies on antioxidative and immunostimulating fucogalactan of the edible mushroom Macrolepiota dolichaula

A water soluble fucogalactan (PS-II) of an average molecular weight ∼1.2×10(5) Da was isolated from the aqueous extract of an edible mushroom Macrolepiota dolichaula. It was composed of fucose, galactose and 3-O-methyl galactose in a molar ratio of nearly 1:4:1. Structural characterization of PS-II was carried out using total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR experiments. These results indicated that the proposed repeating unit of the PS-II had a backbone chain consisting of four (1→6)- linked α-d-Galp residues, one residue methylated at O-3, and another one substituted at O-2 by (1→2)-α-d-Galp residue, which is terminated with a α-l-Fucp moiety. The PS-II exhibited the antioxidant properties in different in vitro test systems, and also showed in vitro macrophage activation in RAW 264.7 cell line as well as splenocyte and thymocyte activation in mouse cell culture medium.

Structural characterization of an immunoenhancing glucan isolated from a mushroom Macrolepiota dolichaula

A water soluble branched glucan (PS-I) was isolated from aqueous extract of the fruit bodies of an edible mushroom Macrolepiota dolichaula, having average molecular weight ~2.02×10(5) Da. The structure of this PS-I was determined using total hydrolysis, methylation analysis, Smith degradation, partial hydrolysis, and 1D/2D NMR experiments. Total hydrolysis and methylation analysis results showed the presence of (1→3, 6)-, (1→6)-, (1→4)-, (1→3)-linked and terminal β-D-glucopyranosyl residues in a relative proportion of nearly 1:2:1:1:1. All the chemical and NMR results indicated that the PS-I was a branched glucan, and the repeating unit of this glucan consisted of a backbone chain of three (1→6)-linked-β-D-glucopyranosyl residues where one of the backbone residues is branched at O-3 with (1→3)- moiety which is further attached to another (1→4)- residue and terminated with a non-reducing β-D-glucopyranosyl residue. The PS-I exhibited in vitro macrophage activation in RAW 264.7 cell line as well as splenocyte and thymocyte activation in mouse cell culture medium.

Pectic polysaccharide from immature onion stick (Allium cepa): Structural and immunological investigation

The structure of a water-soluble pectic polysaccharide (PS) isolated from immature onion stick (Allium cepa) was investigated using acid hydrolysis, methylation analysis, periodate oxidation study, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC). The results of the above experiments indicated that the PS contained d-galactose, 6-O-Me-D-galactose, 3-O-acetyl-D-methyl galacturonate and D-methyl galacturonate in a molar ratio of nearly 1:1:1:1 and possesses a backbone of [→4)-α-D-GalpA6Me-(1→4)-α-D-GalpA6Me-(1→] in which one methyl galacturonate was substituted at O-3 position by an acetyl group and the neighboring methyl galacturonate being substituted at O-2 with a side chain, α-D-Galp-(1→4)-6-O-Me-β-D-Galp-(1→. The probable structure of repeating unit of the pectic polysaccharide was established as: [formula in text] The pectic polysaccharide showed in vitro splenocyte, thymocyte as well as macrophage activations.