Purification of glutathione obtained from natural sources and evaluation in pharmaceutical form

Glutathione (GSH) is a tripeptide consist of low molecular weight glutamic acid, cysteine and glycine amino acids synthesized in cells. GSH plays critical roles in protecting cells from oxidative damage and the toxicity of xenobiotic electrophiles and maintaining redox homeostasis. GSH is with potent antioxidant activity, which is involved in numerous basic biological processes and has been used for interventions in various degenerative diseases. Oral delivery of GSH remains challenging similarly to that of other protein and peptide drugs, due to physicochemical barriers in the gastrointestinal (GI) tract, which cause to low oral bioavailability. To improve delivery, new generation strategies are used such as hydrogels, encapsulation into nanoparticles, microemulsions and liposomes, appropriate formulations with clinical therapeutic effects. In the thesis, first of all, that lyophilized and fresh broccoli (Brassica oleracea), spinach (Spinacia oleracea), cabbage (Brassica oleracea var. capitata f. alba), and purslane (Portulaca oleracea) were used to obtain efficient levels of GSH. We enhanced analytical methods both by using HPLC with an ultraviolet detector and a fluorescence detector to determine GSH quantitatively and qualitatively, and then compared the results. In the results of HPLC-UV, the highest level of GSH was obtained with the lyophilized spinach plant. However, no peak was obtained in fresh purslane. In the results of HPLC-FLD, the highest level of GSH was obtained with the lyophilized spinach plant. Likewise, no peak was obtained in fresh and lyophilized purslane. When the HPLC results were compared, the results achieved similar results for both analytical methods. Then, the research was focused on strategies to enhance the bioavailability of GSH, with the ultimate goal of developing a pharmaceutical product for therapeutic studies. To this end, natural-source glutathione-based injectable hydrogel and commercial glutathione-based injectable hydrogel were designed. While similar results were obtained in terms of chemical structure, a natural-source glutathione-based injectable hydrogel had a better homogeneous distribution. The results indicate that a novel strategy for a new generation GSH based on injectable hydrogel from natural sources with highly improved antioxidant and bioactive properties.