Chemical constituents and structural characterization of polysaccharides from four typical bamboo species leaves.

In order to find bamboo leaves with high contents of bioactive polysaccharides, 32 samples were chosen to analyze their polysaccharide content by GC and sulfuric acid-anthrone colorimetric assays. Purified polysaccharides (BLPS) were separated from the four varieties P. nigra (Lodd.) Munro (PN), P. vivax McClure (PV), Chimonobambusa quadrangularis (Fenzi) Makino (CQ), and P. bambussoides cv. Tanakae (PB) by ultrasound extraction, solution precipitation, ion exchange resin, DEAE-52 and Sephadex G-100 chromatography. BLPS structural characterization was accomplished by HPLC-GPC, Fourier transform infra-red spectroscopy (FTIR) and NaIO4-HIO4 oxidation reactions. The results showed that the total polysaccharides of the bamboo leaves in samples 1-32 ranged between 1.4% and 5.4%, Samples No. 29-No. 32 (PN, PV, CQ, and PB) contained 2-3 fold more polysaccharides than No. 1~No. 28 among the 32 different species, particularly the content of galactose was in a range of 21.5%-34.1% for these four typical bamboo species leaves, which was also more than 2-3 fold higher than in No. 1-No. 28. Sugar analysis indicated that PN-PBLPS-1, PV-PBLPS-1, CQ-PBLPS-1 and PB-PBLPS-1 from the four varieties were homogeneous polysaccharides with molecular weights of 2.04 × 104, 1.15 × 104, 8.75 × 104 and 1.48 × 104 Da, respectively. PB-PBLPS-1 was a mixture of α-galactopyranose and β-d-glucopyranose linkages with α-(1→6) or β-(1→6)glycosidic bonds, while PN-PBLPS-1, PV-PBLPS-1, and CQ-PBLPS-1 had α galactopyranose linkages with α-(1→6) glycosidic bonds.