Short-term feeding of baicalin inhibits age-associated NF-kappaB activation

Baicalin is a flavonoid isolated from Scutellaria baicalensis and is known to affect multiple biological functions, including the inhibition of aldose reductase, HIV infection, and nitric oxide producing activity. Oxidative stress is considered a major cause of aging and various age-related diseases, and among the key cellular components exquisitely sensitive to oxidative stress is the transcription factor, nuclear factor-kappaB (NF-kappaB). In the present study, we attempted to elucidate the mechanisms underlying the suppression of age-related NF-kappaB activation by baicalin in kidney tissue from old rats. Results showed NF-kappaB activation and the upregulation of NF-kappaB targeting genes, hemoxygenase-1, inducible nitric oxide synthase (iNOS), and COX-2 with age. In contrast, the increased expression of these NF-kappaB targeting genes was effectively inhibited by baicalin. Baicalin was shown to inhibit the NF-kappaB cascade via three signal transduction pathways, NIK/IKK, extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinase (MAPK). Our results clearly indicated the anti-oxidative effects of baicalin on age-related redox imbalance. Thus, the significance of the current study is the new information revealing the anti-oxidative properties of baicalin and the role it plays in the regulation of age-related alterations.