Preparation, development and characterization of Leucaena leucocephala galactomannan (LLG) conjugated sinapic acid: A potential colon targeted prodrug

Abstract

Sinapic acid (SA), a widely prevalent hydroxycinnamic acid, possess numerous biological activities owing to its antioxidant property. The present study was aimed to prepare colon targeted polysaccharidic/polymeric ester prodrug of SA (a microbially triggered system) using Leucaena leucocephala galactomannan (LLG) as a polysaccharidic carrier. The polymeric conjugates of SA-LLG were found to exhibit an increase in % yield and DS with increase in amount of SA and volume of thionyl chloride. The degree of depolymerization of SA-LLG prodrug batches were evaluated using optimized concentration of galactomannase. The SA-LLG prodrug was characterized employing UV and FTIR spectroscopy, 1H NMR and XRD. In vitro release study of the optimized prodrug batch (SL10) suggested stable nature of SA-LLG conjugate under acidic (pH 1.2) and alkaline conditions (pH 6.8). The treatment of prodrug with galactomannase (15 mg/mL) followed by esterase (10 U/mL) enzyme released approximately 81% of SA after 24 h. The cell viability results revealed that free SA and SA-LLG were found to have similar antiproliferative potential against human colon cancer cell lines (HCT-116 cells). Our investigation revealed that polysaccharidic prodrug, SA-LLG, has the potential for colon targeting of SA and thus can be employed for the treatment of Inflammatory Bowel Diseases (IBDs).