Pectin-like Polysaccharide Extracted from the Leaves Caesalpinia pulcherrima is a Promising Antioxidant and Immunomodulator Agent

ABSTRACT

Abstract Studies have shown that Caesalpinia pulcherrima extracts promote antioxidant, healing, immunomodulating and antiparasitic activities and its polysaccharides can be used as functional food. In this sense, this work had as objective the isolation and characterization of a polysaccharide-like pectin, extracted from the C. pulcherrima leaves and its possible applications as an antioxidant and immunomodulator agent. The molecule was characterized by high performance liquid chromatography, fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Its antioxidant potential was evaluated through the methods of phosphomolybdenum, ABTS radical scavenging [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid], DPPH (1,1-diphenyl-2-picrylhydrazyl) and nitric oxide radical. The immunostimulating effects of pectin were tested in splenocytes to evaluate its toxic, proliferative and cell activator and immunomodulatory potential. The polysaccharide obtained has structural characteristics similar to pectins. Pectin showed high in vitro antioxidant activity for ABTS radical scavenging, moderate activity for phosphomolybdenum and low activity for DPPH and nitric oxide. In vitro immunomodulation assays showed that pectin obtained did not promote a cytotoxic effect (viability > 90%). The increase in cytosolic ROS levels indicates a possible mechanism of cell activation without causing damage. Immunophenotyping showed that pectin increased a subpopulation of CD8+ T lymphocytes and monocytes. In addition, it promoted a mostly pro-inflammatory response confirmed by the production of cytokines IL-2, -4, -6, IFN-γ and TNF-α. These results reinforce the ethnopharmacological use of C. pulcherrima leaves and expand the use of this plant for future applications as herbal medicines.