Goma de cajueiro (Anacardium occidentale L.) como biossensor para lectinas vegetais

Abstract

The use of natural gums, taken from the exudates and extracts of plants, has been given a strong stimulus as a result of the many and lucrative possibilities for industrial use. In the present work, we studied the resin/gum secretor ducts that appear along the cashew tree bark, using histological procedures and microscopic observations. The gum was studied at its crude state and then chemically treated in order to obtain a kind of gel (microbiofilm). Besides the chemical composition proteins, lipids, sugars, fibers and ashes), the gum's electric conductivity was studied to determine possible use as a biosensor/bioidentificator for plant proteins. By natural exudation, or by means of incision, a gum or resin of a yellowish color soluble in water, and which presents a great biotechnological potential, appears on the trunk and branches of the cashew tree (Anacardium occidentale L.). Cashew gum extraction represents one more source of revenue for the producer, in addition to the cashew nut and the peduncle, as well as an alternative for the utilization of non-productive cashew trees in a phase of decline or senescence. Gum ducts biological origin was investigated through histological procedures, showing high similarity with other ducts from the same family Anacardiaceae The potential of bioaffinity as a tool for the study of biologicalrecognition mechanisms is gaining increasing value. Its potential use as a chromatographic matrix and/or for bioaffinity ligand for lectins was investigated. Gum was cross-linked in order to obtain a kind of chromatographic matrix (gel). Cashew-gum hydrogels swell and shrink in presence or absence of water and if the water is completely removed, they collapse to form a xerogel. To evaluate the gum's ability to retain glycoproteins (lectins), affinity chromatography and bioindicative procedures were performed and, in addition some of the chemical, physical-chemical and biological characterizations were done, such as the secretory bark ducts origin and characterization. The results clearly indicate the possibility of using the exudates gum from cashew tree as a new and non expensive biotechnological tool for glycobiology and glycobiochemistry.