Evaluation of antioxidant, antitumor and immunomodulatory properties of polysaccharide isolated from fruit rind of Punica granatum

Polysaccharide (PSP001) isolated from Punica granatum was evaluated for its radical scavenging and antitumor activities in vitro. The fruit of Punica granatum (pomegranate) has been reported to possess several vital biological activities. This study aimed to determine the antioxidant and anticancer properties of polysaccharide PSP001 isolated from the fruit rind of pomegranate. Antioxidant activities were evaluated using various assays such as the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging assay, ferric reducing antioxidant power assay, linoleic acid emulsion thiocyanate assay, and superoxide, hydroxyl and nitric oxide radical scavenging assays. PSP001 exhibited a dose-dependent enhancement in activity using concentrations from 10 to 1000 mu g/ml except for the DPPH assay for which the highest activity was obtained at 200 mu g/ml. The anticancer properties of PSP001 evaluated on MCF-7 (breast cancer), KB (nasopharyngeal carcinoma) and K562 (leukemia) cells by MTT assay indicate its potential as an antitumor agent. An IC50 value of 97.21 +/- 1.06 mu g/ml and 52.8 +/- 0.9 mu g/ml were obtained following 72 h incubation for MCF-7 and K562 cells, respectively. PSP001 showed in vitro growth stimulatory effect on isolated normal lymphocytes, and a proliferative index of 1.21 +/- 0.01 at a concentration of 1000 mu g/ml was obtained, indicating immunomodulatory activity. The results of the present study indicate that further studies are required on PSP001 in order to use this compound as an antitumor agent.