Magnolia bark extract is a potent Nrf2 activator

Oxidative and xenobiotic stress have been shown to be causative agents for many diseases including cancer, age-related macular degeneration, cardiovascular diseases, and age-related memory loss. Cells have protection mechanisms against these stressors, in part, through the activation of the Nrf2 pathway. Research suggests that promoting health resilience could be achieved by transiently activating the Nrf2 pathway through an intake of dietary phytochemicals in the absence of oxidative stressors. Magnolia (Magnolia officinalis) bark has been widely used in traditional Chinese medicine they are rich in Magnolol and Honokiol. Here, we demonstrate that magnolia bark extract stimulates the Nrf2 pathway in mammalian liver cells both by reporter and gene expression assay. We also show that Magnolia bark helps protect cells against oxidative stress toxicity. We further carried out bioassay directed fractionation of the extract and show that the NRF2 activation is due to, in part, by the phytochemicals, magnolol and 4 methoxy honokiol, present in the magnolia bark extract.