Phytother Res. 1999 Sep; 13(6): 489-93.

Separation and some properties of Aloe vera L. leaf pulp lectins.

Akev N, Can A.

Department of Biochemistry, Faculty of Pharmacy, University of Istanbul, 34452 Universite, Istanbul, Turkey.

The separation and partial purification of two lectins from the leaf pulp of Aloe vera L. (=barbadensis Miller) is presented. The fraction showing haemagglutinating activity was precipitated at 50% ammonium sulphate concentration from the crude leaf pulp extract. The precipitate thus obtained, after dialysis, was applied to a hydroxylapatite column. Stepwise elution resulted in two peaks showing haemagglutinating activity eluted with 5 mM (Aloctin I) and 20 mM (Aloctin II) phosphate buffers. Haemagglutinating activity was estimated visually by adding a 4% rabbit erythrocyte suspension to serial two-fold dilutions of the lectins in microtitration plates. None of the 20 sugars tested inhibited haemag--glutinating activity of Aloctin I up a concentration of 500 mM. Aloctin II was inhibited by N-acetyl-D--galactosamine at 250 mM concentration. Of 10 metal ions tested, only Al(3+) salts were found to activate Aloctin I and II. On the other hand, it was shown that neither lectin possessed any alpha- and beta- galactosidase or alpha- and beta- glucosidase activity. The lectins were of glycoprotein structure containing approximately 5% neutral sugar. The specificity of the lectins towards human and rat erythrocytes was investigated.Copyright 1999 John Wiley & Sons, Ltd.