In Vivo and in Vitro Regulatory Effect of Silibinin on Some Metabolic Enzyme Activities against Cobalt Induced Toxicity in Rats: A Biochemical Approach.

The study aimed to examine the in vivo inhibition effect of cobalt ion and silibinin on metabolic enzymes such as glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), and glutathione S-transferase (GST) and their in vitro inhibition effect on 6PGD. Twenty-four Wistar Albino rats weighing approximately 250-300 g were used in the study. The rats were divided into 4 groups as group 1 (control): isotonic serum (0.5 mL i.p), group 2 (cobalt): (150 mg kg/day cobalt), group 3 (silibinin): (100 mg/kg/day silibinin), group 4 (cobalt + silibinin). As a result of the in vivo applications, a statistically significant decrease was observed in the activities of G6PD ( p < 0.05), 6PGD ( p < 0.05), GR ( p < 0.05), and GST ( p < 0.05) enzymes in the groups that were administered cobalt compared to the control group. It was also found that the activities of G6PD ( p < 0.05), 6PGD ( p > 0.05), GR ( p > 0.05), and GST ( p > 0.05) enzymes increased in groups that were administered cobalt + silibinin compared to the group that was administered cobalt. As for in vitro applications, it was found that different Co 2+ ions inhibited 6PGD enzyme which was obtained as a result of purification with IC 50 = 346.6 μM value, while silibinin increased 6PGD enzyme activity within the concentration range of 100-750 μM by 40%. As a result, it was found that cobalt ions had an inhibition effect on G6PD, GR, and GST enzymes, which are vitally important for living metabolism, in vitro and in vivo and inhibited 6PGD enzyme activity in vitro, and silibinin increased these enzyme activities in vivo and 6PGD enzyme activity both in vivo and in vitro and decreased the inhibition effect.