Isolation and Characterization of the Polysaccharides from the Crust of the Fruit Litchi chinensis Sonn (Lichia)
Mattana, F.C.2; Bombarda, A.P.2; Kadowaki, M.K.2; Wagner, R.1; Sassaki, G.L.1; Osaku, C.A.2
1Departamento de Bioquímica - Universidade Federal do Paraná - Curitiba - PR
2Laboratório de Bioquímica - Centro de Ciências Médicas e Farmacêuticas - Universidade Estadual do Oeste do Paraná - Cascavel - PR
E-mail: flaviamattana@yahoo.com.br
Lichia (Litchi chinensis Sonn) is a tree from Sapindaceae family, native to China, where is known like national fruit. The fruits are round, with a red crust evolved a white sweet pulp and are rich in carbohydrates, proteins, fats, calcium, iron and other minerals and vitamins. Their fruits are used in occasions of coughs, tumors and stomachaches. The polysaccharides were obtained by extraction of the triturated crust with cold water, hot water (decoction and infusion), maceration with ethanol and the residue extracted successively with different concentration of the aq. KOH at 80oC under reflux. The KOH extract was neutralized with Acetic acid before and dialyzed. The polysaccharides were obtained by precipitation with excess EtOH and then submitted to freeze-thawing, giving a water-insoluble and water-soluble fraction. In the neutralization of the fractions 1% KOH, 2% KOH and 10% KOH happened a precipitation. The resultant fractions were analyzed by GC-MS of their derived alditol acetates, obtained on successive hydrolysis, NaBH4 reduction and acetylation. The monosaccharides components the fractions soluble from decoction extraction had only uronic acid:Ara:Gal (42,5:37,8:19,7 molar ratio), and the precipitate from the neutralization of the 10% KOH had uronic acid:Rha:Xyl:Gal (7,1:2:85,9:5 molar ratio). Besides, many fractions showed the presence of ramnose that is a curiosity because we are using the crust. The fractions, water-soluble and insoluble, resulted from the 2% KOH extraction had all the monosaccharides in your compositions. In the water-insoluble fraction from the 10% KOH extraction had 88,1% of xylose. The fractions water-insoluble of the decoction and 2% KOH had the majority quantity of uronic acid: 54 and 54,4 molar ratio, respectively. The fractions from precipitation with acetic acid of the extractions 2% KOH and 10% KOH, the water-soluble fractions from decoction and 5% KOH extraction have been analyzed by 13C-NMR and HPSEC-MALLS, purified with membranes with different sizes of pores to elucidate the molecular structure, and after this step, can be test the biological activity.
Supported by Fundação Araucária/UNIOESTE- Cascavel and PRONEX- Carboidratos .
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