Caracterização do polissacarídeo de reserva de parede das sementes de Mimosa tenuiflora (Willd)

Abstract

Popularly known as Jurema-preta, Mimosa tenuiflora (Willd.), belongs to the Fabaceae family, subfamily Mimosoideae. It occurs from Piauí to Bahia, Caatinga and Carrasco. This species is found in secondary floodplain formations with good moisture content, deep, alkaline soils and good fertility. However, it blooms even in areas of eroded, or dry soil. It has potential as a regenerating plant in degraded environments, and an indicator of ecological succession. In addition to uses with pharmacological potential, as several studies have already demonstrated. Among them, polysaccharides, which are natural macromolecules found in all living organisms, and which constitute a group of the most abundant and important compounds in the biosphere, are, for example, cellulose and starch, in plants, and glycogen in animals. Among the polysaccharides we find, in M. tenuiflora we have galactomannans, which are usually located in the cell walls of the endosperm cells of the seeds of some legumes, for example, M. tenuiflora. Therefore, the objective of this work was to characterize chemically the galactomannan extracted from M. tenuiflora (Willd) seeds. The tests carried out were magnetic resonance imaging, which consists of an important spectroscopic technique in the study of structural and dynamic aspects of organic molecules in solution; zeta potential, particle size, which aims to determine the stability of the colloidal dispersion; and rheology, which studies the deformation and flow of materials under the influence of stresses. The galactomannan yield was approximately 3%. NMR analysis indicated a ratio of mannose: galactose to galactomannan of 0.62: 1. Which suggests that the polysaccharide has a higher amount of galactose than mannose in its structure, influencing the solubility of galactomannan. The result for zeta potential was - 5.81 mV, as it is close to zero, which demonstrates that the polysaccharide may have a low stability. However, through combinations with other components, M. tenuiflora galactomannan can be used to modulate drug release characteristics through gum-polymer or gum-ion interaction, for example. The verified particle size was 3283 d. nm. As for rheology, all samples showed non-Newtonian and pseudoplastic fluid behavior regardless of galactomannan concentrations.