Extraction,Purification and Structural Characterization of Polysaccharide from Transgenic Aloe vera L.

Aloe has been used in Chinese traditional medicine for over two thousand of years. Polysaccharides as main active components in Aloe vera L. have aroused much interest. Aloe polysaccharide (AP-1) was extracted from fresh leaves of three-year-old transgenic Aloe vera L. by cold ethanol precipitation. The amount of total carbohydrates in AP-1 was measured by phenolsulfuric acid method to be 57.3%. AP-1 was proved to be a mixture of acetylated β-D-pyranmannans and the molecular weight was within the range of 12900-13100 dalton detected by IR spectrometry analysis. The amount of total carbohydrates in AP-2 was increased by 9.6% when compared with that in AP-1 after purification by Sevag method. Neutral polysaccharide (AP-3) and acidic polysaccharide (AP-4) were obtained from AP-2 by DEAE Sephadex A-25 and AP-5 and AP-6 were obtained from AP-3 by Sepharose CL-6B. The monosaccharide composition analysis indicated that AP-3 was structurally identified as a polymannan type polysaccharide and the bioactivity of AP-5 was deduced to be higher than that of AP-6.