epiglucan and chlorosulfonic-acid

A water-soluble hyperbranched beta-glucan, coded as TM3b, extracted from sclerotia of an edible fungus (Pleurotus tuber-regium) was fractioned into eight fractions coded as F1-F8 by a nonsolvent addition method. Five fractions were treated with chlorosulfonic acid at 35 degrees C to synthesize successfully sulfated derivatives coded as S-F2, S-F3, S-F4, S-F5, and S-F8 with degree of substitution of 0.28-0.54. The 13C NMR results of these sulfated beta-glucans indicated that while the C-6 position was fully substituted, C-2, C-3, and C-4 were only partially substituted by the sulfate groups. The weight-average molecular weights (Mw) and intrinsic viscosities ([eta]) of the native and sulfated TM3b fractions were determined using multi-angle laser light scattering and viscometry in 0.15M aq NaCl at 25 degrees C, respectively. The dependences of [eta] on Mw for TM3b and sulfated TM3b were found to be [eta]=0.18Mw(0.28+/-0.03) (Mw range from 3.30 x 10(4) to 3.90 x 10(7)) and [eta]=2.24 x 10(-2)Mw(0.52+/-0.06) (Mw range from 3.24 x 10(4) to 3.15 x 10(5)) in 0.15M aq NaCl at 25 degrees C, respectively. It revealed that both the native TM3b and its sulfated derivatives exist in a spherical chain conformation in 0.15M aq NaCl. Furthermore, the native and sulfated TM3b fractions showed potent antitumor activities in vivo and in vitro. The sulfated derivatives exhibited relatively higher in vitro antitumor activity against human hepatic cancer cell line HepG2 than the native TM3b. Water solubility and introduction of sulfate groups were the main factors in enhancing the antitumor activities.

Topics: Algorithms; Animals; Antineoplastic Agents; beta-Glucans; Cell Line, Tumor; Cell Proliferation; Humans; Magnetic Resonance Spectroscopy; Male; Mice; Mice, Inbred BALB C; Molecular Weight; Neoplasms, Experimental; Pleurotus; Sarcoma 180; Solubility; Spectroscopy, Fourier Transform Infrared; Structure-Activity Relationship; Sulfates; Sulfonic Acids; Water

Six water-insoluble (1-->3)-beta-D-glucan fractions TM8-1 to TM8-6 with weight-average molecular mass Mw ranging from 5.76 to 77.4x10(4) obtained from the sclerotia of Pleurotus tuber-regium were sulfated to produce the water-soluble fractions S-TM8-1 to S-TM8-6 with Mw from 6.0 to 64.8x10(4). The degree of substitution (DS) of S-TM8 fractions was analyzed by elemental analysis (EA) to be 1.14-1.74. The 13C NMR results indicated that the C-6 was fully substituted, and C-2, C-4 were partially substituted by the sulfo-groups. The Mw and the intrinsic viscosity [eta] of the S-TM8 fractions were measured, respectively, by size-exclusion chromatography combined with laser light scattering (SEC-LLS), LLS and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The dependences of [eta] and radius of gyration z(1/2) on Mw for the S-TM8 samples were found to be [eta]=1.89x10(-2) Mw(0.70) (cm3/g) and z(1/2)=1.12x10(-4) Mw(0.81) (nm) in the Mw range tested. Based on current theories for a wormlike chain model, the molar mass per unit contour length ML and persistence length q of the S-TM8 were calculated to be 990 nm(-1) and 8.5 nm, respectively. The relatively higher q value suggested a more expanded flexible chain of S-TM8 in PBS. The water-solubility and relatively expanded chain conformation of the STM8 fractions were considered to be significant to their antiviral activity.

Topics: Algorithms; beta-Glucans; Carbohydrate Conformation; Chromatography, Gel; Glucans; Light; Magnetic Resonance Spectroscopy; Molecular Weight; Pleurotus; Scattering, Radiation; Spectrophotometry, Infrared; Sulfonic Acids; Sulfur; Viscosity

Topics: Animals; Anticoagulants; Antiviral Agents; beta-Glucans; Blood Coagulation; Carbohydrate Conformation; Cattle; Glucans; HIV-1; HIV-2; Magnetic Resonance Spectroscopy; Molecular Weight; Sulfonic Acids; Sulfur Oxides