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

• Published in: Glycobiology (Oxford) 2004-06, Vol.14 (6), p.501-510
• Main Authors: Leung, M.Y.K., Liu, C., Zhu, L.F., Hui, Y.Z., Yu, B., Fung, K.P.
• Format: Article
• Language: English
• Subjects: Aloe - chemistry; Animals; Antineoplastic Agents - chemistry; Antineoplastic Agents - isolation & purification; Antineoplastic Agents - pharmacology; biological response modifier; BRM; CAM; capillary electrophoresis; Carbohydrate Sequence; Chromatography, High Pressure Liquid; complementary and alternative medicine; Drug Screening Assays, Antitumor; Electrophoresis, Capillary; ELISA; enzyme-linked immunosorbent assay; Female; gas chromatography; high-performance liquid chromatography; HPLC; INF; interferon; interleukin; LAL; Limulus amebocyte lysate; lipopolysaccharide; LPS; Magnetic Resonance Spectroscopy; mannose receptor; mass spectrometry; Mice; Mice, Inbred BALB C; Mice, Nude; Molecular Sequence Data; Molecular Weight; molecular weight cutoff; MWCO; NMR; nuclear magnetic resonance; PBS; phosphate buffered saline; Polysaccharides - chemistry; Polysaccharides - isolation & purification; Polysaccharides - pharmacology; TLR; TNF; toll-like receptor; tumor necrosis factor
• ISSN: 0959-6658; 1460-2423; 1460-2423
• DOI: 10.1093/glycob/cwh050

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 be91.5% 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 β-(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-α, IL-1β, INF-γ, 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.