Protective activity of 30Â kDa phytoglycoprotein from glucose/glucose oxidase-induced cell death in primary cultured mouse thymocytes

Dioscorea batatas Decne (DBD) has been traditionally used as herbal agent in folk medicine. DBD glycoprotein with a molecular weight of 30 kDa consists of carbohydrate (83.75%) and protein (16.25%), and has a strong anti-oxidative activity. To understand the protection from thymocytes death, we evaluated the activity changes of pro-apoptotic factors [cytochrome c, caspase 3, poly(ADP-ribose) polymerase (PARP), AP-1, NF-κB and nitric oxide (NO)] by DBD glycoprotein from glucose/glucose oxidase (G/GO)-induced cell death in primary cultured mouse thymocytes. In the activity of the apoptotic related proteins [cytochrome c, caspase 3 and PARP], the results showed that DBD glycoprotein (200 μg/ml) has an inhibitory effect on cytochrome c release into cytosol, caspase 3 activation and PARP cleavage in thymocytes. In the transcription factors (AP-1 and NF-κB) activity and NO production, the activities of NF-κB and NO production significantly decreased after DBD glycoprotein (200 μg/ml) treatment for 4 h in G/GO-induced thymocytes, compared with the control. Therefore, we speculate that DBD glycoprotein is one of the natural compounds for the protection of thymocytes that can produce cytokines.