چكيده لاتين
Among the many factors that have brought the global environmental burden in recent years, the impact of fruit and vegetable waste has been recognized as a major problem. Pomegranate skin is the main by-product during pomegranate processing, and its most important composition is water-soluble pectin. Pectin is a structural heteropolysaccharide whose antioxidant and anticancer properties have been proven in various studies. Studies have shown that the breakdown of pectin into its component subunits improves the bioactive effects of the resulting compounds on human health. The aim of this research is to investigate the possibility of microbial decomposition of pomegranate waste pectin and the production of pectic oligosaccharide subunits. For this purpose, first pectin extracted from pomegranate fruit waste was broken down into pectic oligosaccharide subunits using extracellular pectinolytic enzymes of Streptomyces hydrogenans YAM1, then the type of products produced was checked by thin layer chromatography and liquid chromatography- mass spectrometry- ESI methods. Next, the bioactive effects of pectic oligosaccharide compounds obtained from the microbial decomposition of pomegranate pectin were investigated using DPPH reagent to measure antioxidant effects, and the anticancer effects of the compounds on MCF-7, Caco-2 and SHSY5Y cell lines by MTT and flow cytometry methods was evaluated. Also, the toxicity effect of the mentioned compounds was measured on healthy L929 and HUVEK cell lines. In order to investigate the anticancer properties of pectic oligosaccharides under theoretical conditions, using docking and molecular dynamics simulation, the binding free energy of each pectic oligosaccharide compound to galectin-3 receptor was calculated using MM/PBSA method. The results of the investigations showed that pectin extracted from pomegranate was broken down into pectic oligosaccharide subunits by bacterial pectinolytic enzymes, and the compounds obtained from the breakdown include types of unsaturated mono, di, and trigalacturonic acid, which in some cases have methyl and acetyl groups attached to them. The maximum antioxidant activity of pectic oligosaccharide compounds obtained from the microbial decomposition of pomegranate pectin is at a concentration of 5 mg/ml. In the study conducted by MTT method for 24-hour treatment at a concentration of 30 mg/ml, the survival percentage of MCF-7 and Caco-2 cell lines was 9% and 18%, respectively, and at a concentration of 5 mg/ml The survival rate is 82.89% and 82.41%, respectively. In the 24-hour treatment of SHSY5Y cell line, cell viability of 8% and 71% has been observed at concentrations of 15 and 5 mg/ml, respectively. In the study conducted by flow cytometry, 91% and 83% lethality was shown for MCF-7 and Caco-2 cell lines, respectively, at a concentration of 30 mg/ml. Also, 93% lethality was shown in the SHSY5Y cell line for a concentration of 15 mg/ml. In the study of cytotoxicity, for a concentration of 30 mg/ml in healthy L929 and HUVEK cell lines, the cell viability was 91% and 88%, respectively, which shows that the mentioned compounds did not show significant toxicity. In the theoretical evaluation, the most suitable compound is unsaturated digalacturonic acid, whose binding free energy to the active site of galectin-3 receptor is -96.15±12.04 kJ/mol.
