Drug delivery applications of exopolysaccharides from endophytic bacteria Pseudomonas otitidis from Tribulus terrestris L

Abstract

The present study aimed to produce a novel biocompatible, stable and biodegradable exopolysaccharide (EPS) from endophytic bacteria to deliver drugs into malignant cells effectively. EPS-producing endophytic bacteria, Pseudomonas otitidis was isolated and identified from the roots of the medicinal plant Tribulus terrestris L. The ice-cold ethanol precipitation method was used to isolate EPS from an endophytic bacterial culture. The isolated EPS was partially characterized by FTIR, NMR spectroscopy, and the presence of reducing sugar and protein contents were also measured. The isolated EPS contained 26.665±1.302% of reducing sugar and 0.912±0.023% of proteins. Further, EPS-based quercetin-loaded nanoparticles (NPs) were formulated through the precipitation method to deliver quercetin into breast cancer cells. The fabricated nanoparticles size, shape, physical nature, drug release and release kinetics properties were studied and confirmed. EPS-based nanoparticles could cause the highest release of quercetin in an acidic medium at pH 5.0, and they had high biocompatibility in a physiological medium. In addition, the NPs showed significant free radicals (DPPH* and ABTS*) scavenging and ferric ion reducing potentials and concentration-dependent cytotoxic effects against breast cancer cell lines (MCF-7 cells) after 24 h treatment with IC50 value of 14.313 μg ml−1. The obtained results demonstrated that the isolated EPS from endophytic bacteria can positively applied as a drug delivery vehicle and enhanced the activity of the loaded drug.

Biological Activity of Lactic Acid Bacteria Exopolysaccharides and Their Applications in the Food and Pharmaceutical Industries

“…This activity was mainly mediated through penetration, loss of cytoplasmic contents, and cell lysis. Kalimuthu et al [129] used bacterial EPS as a carrier for quercetin to achieve targeted release to breast cancer cells, which exerted concentrationdependent toxicity on breast cancer cells and even enhanced the effect of quercetin.…”