Structure Analysis Of Pectic Polysaccharides From Six Types Of Bee Pollen And Their Inhibitory Activities On Neuraminidase

Bee pollen is the male gametophyte of gymnosperm and angiosperm, which containsmost of the nutrients afford to plant growth and development. It is well known as a naturalnutrition and healthy food especially in improving human’s immunity. Bee pollen had manyactivities, such as antitumor, antivirus and immunobiological activities. Polysaccharides arethe main active components in the bee pollen. In this paper, we analyzed the structure ofpectic polysaccharides from six types of bee pollen and their antivirus activity, including thestructure comparision of type I rhamnogalacturonan (RG-I) and homogalacturonan (HG); therelationship of structure and inhibitory activity on H1N1and H5N1neuraminidase; the fluvirus inhibitory mechanism of RG-I pectin; the fine structure of RG-I pectin from bee pollenof Nelumbo nucifera (WNPP-2-RG) and its structure-activity relationship. The results of thispaper can offer some datas about structure-activity relationship of pectins, improved theapplication of pectin.In this paper, we choosed six kinds of bee pollens, including Nelumbo nucifera,Papaver rhoeas, Rosa rugosa, Fagopyrum esculentum, Schisandra chinensis and Brassicacampestris, for studying the structure features and structure-activity relationship of pectins.Six RG-I and six HG pectins were obtained by a combination of DEAE-Cellulose andSepharose CL-6B colume. Structure analysis showed six RG-I pectins from bee pollencontained RG-I core region, both type I arabinogalactan (AG-I) and type II arabinogalactan(AG-II) sidechains except RG-I pectin from Rosa Rugosa which only contained AG-Isidechains; the ratio of rhamnose (Rha) and galacturonic acid (GalA) was nearly1:1,contained little HG region; RG-I mainchain contents was about16%~50%; total contents ofgalactose (Gal) and arabinose (Ara) were among70%~75%; the RG-I pectin from Brassicacampestris was contained glucan and xylan sidechains; the molecular weight of RG-Ifractions is about3.8×10~5Da. HG pectins from six kinds of bee pollen contains largeamounts of GalA; HG and RG-I region composed the core structure, ratio of Ara and Galwas nearly1:1; HG pectin from Nelumbo nucifera contained both AG-I and AG-IIsidechains, HG pectin from Papaver rhoeas and Rosa rugosa contained1,5-arabinan and1,3-galactan sidechains, HG pectin from Schisandra chinensis contained1,5-arabinan and1,4-galactan sidechains, HG pectin from Fagopyrum esculentum contained1,4-xylansidechains; HG pectin Papaver rhoeas and Brassica campestris contained glucose (Glc,about20%); the molecular weight was among8×103~3.6×10~4Da. The inhibitory activity of RG-I and HG fractions on H1N1and H5N1neuraminidaseswas studied by bioluminescent assay and typical fluorescent method. The results indicatedHG fractions had better inhibition activity than RG-I fractions, especially the HG fracionsfrom Papaver rhoeas and Brassica campestris, IC50were below1mg/mL. According to thestructure features of each fraction, we can concluded HG region was the important region oninhibitory activity of H1N1and H5N1neuraminidases, the Glc sidechains can improve thisactivity.The immunological activity of RG-I pectin (WNPP-2-RG) from bee pollen of Nelumbonucifera was analysed, it can improve the immunological activities, suggested RG-I mighthave antivirus activity through immunological way. Structure analysis showed WNPP-2-RGhas an RG-I core region, both AG-I and AG-II sidechains.1,6-Gal composed of thebackbone of sidechains, branched at O-3or O-4. Most of the Gal residues were determinedto be close to the molecular core, some Gal and Ara on the surface of the molecules. Theimmunological activitiy of WNPP-2-RG was related to its side chains. Ara residues affectedits macrophage phagocytosis and NO production, but no effect on lymphocyte proliferation.The comparation of structure-immunological activity between WNPP-2-RG and ginsengRG-I fraction WGPA-2-RG was performed. Ara residues in different RG-I pectins haddifferent effects on their activities.