Chemical and biological characterization of a polysaccharide biological response modifier from Aloe vera L. var. chinensis (Haw.) Berg.

Abstract

Three purified polysaccharide fractions designated as PAC-I, PAC-II, and PAC-III were prepared from Aloe vera L. var. chinensis (Haw.) Berg. by membrane fractionation and gel filtration HPLC. The polysaccharide fractions had molecular weights of 10,000 kDa, 1300 kDa, and 470 kDa, respectively. The major sugar residue in the polysaccharide fractions is mannose, which was found to be 91.5% in PAC-I, 87.9% in PAC-II, and 53.7% in PAC-III. The protein contents in the polysaccharide fractions was undetectable. NMR study of PAC-I and PAC-II demonstrated the polysaccharides shared the same structure. The main skeletons of PAC-I and PAC-II are beta-(1-->4)-D linked mannose with acetylation at C-6 of manopyranosyl. The polysaccharide fractions stimulated peritoneal macrophages, splenic T and B cell proliferation, and activated these cells to secrete TNF-alpha, IL-1 beta, INF-gamma, IL-2, and IL-6. The polysaccharides were nontoxic and exhibited potent indirect antitumor response in murine model. PAC-I, which had the highest mannose content and molecular weight, was found to be the most potent biological response modifier of the three fractions. Our results suggested that the potency of aloe polysaccharide fraction increases as mannose content and molecular weight of the polysaccharide fraction increase.

Influence of extraction parameters on physico-chemical characters and antioxidant activity of water soluble polysaccharides from Macrocybe gigantea (Massee) Pegler & Lodge

“…Monosaccharides were derivatized to alditol-acetates followed by the method of Leung et al (2004) with modifications. 50 mg sodium borohydrate (NaBH 4 ) and 5 ml of 50 % ethanol were added to concentrated TFA hydrolysate.…”

Effect of Ascophyllan from Brown Algae Padina tetrastromatica on Inflammation and Oxidative Stress in Carrageenan-Induced Rats

“…Uronic acid was estimated by carbazole method described by Bitter and Miur [19]. The monosaccharide composition of ascophyllan fraction was determined by the method described by Leung et al [20]. Sample was hydrolysed with 2 M trifluoroacetic acid (TFA) at 120°C for 2 h in a sealed tube.…”

Phylogenetic conservation of the cell-type-specific Lan3-2 glycoepitope in Caenorhabditis elegans

“…(Hill and Zipser, in progress). Furthermore, like the core α-(1,3)-fucose glycoepitope, β-(1,4)-linked mannopyranose was also detected in plants: It was initially reported for palm seeds (Aspinall et al, 1953;Clermont-Beaugiraud and Percheron 1968) and more recently, as the active ingredient in Aloe vera to which medicinal benefit is attributed (Leung et al 2004).…”