Identificação e isolamento de uma lectina do colmo da Guadua angustifolia Kunth (1822) (POALES: POACEAE)

Abstract

Guadua angustifolia Kunth is a plant species often found in Latin America that has several applications such as civil engineering, ornamentation, crafts, among other uses. This plant develops well in tropical environments, being found in the state of Alagoas. Currently, scientific research is increasing to explore the properties and components present in bamboo. The component studied in this work are lectins. Among the various functions of this protein or glycoprotein, potential insecticidal, antimicrobial, antitumor and other actions stand out. The stems of Guadua angustifolia Kunth were collected at the Centro de Engenharia e Ciências Agrárias (UFAL), dried and crushed. For the preparation of the crude extract, the powder was weighed and homogenized in different solutions to select the one with the greatest power to extract the target protein and to avoid denaturation, the supernatant was refrigerated at -20°C. Then, saline precipitation with ammonium sulfate was performed to obtain different concentrations using 10 mL of the extract, in order to eliminate contaminating proteins and concentrate the lectins. Hemagglutinating activity and protein dosage were performed. Liquid chromatography was the step of isolation of this macromolecule through the column of chitin matrix of the F0-20% fraction that contains greater hemagglutinating activity. After elution in 1M acetic acid, a single active protein peak was obtained. From 10 g of bamboo stem, it was possible to isolate 0.88 mg of lectin with a yield of 80%. To verify the degree of purity of this molecule, the sample was submitted to the 10% polyacrylamide gel electrophoresis method under non-reducing and reducing conditions, confirming its purification with 18.4 kDa. This research presents the first lectin isolated and purified from the stem of Guadua angustifolia Kunth, being of great relevance for future studies on the biotechnological potential of this biomolecule.