Exploring Zembrin Extract Derived from South African Plant, Sceletium tortuosum in Targeting cAMP-driven Phosphodiesterase (PDE) Signaling in Alzheimer’s Disease: Synthesis of Evidence

Recently with the changing landscape of the aging population and the increase in incidence of Alzheimer’s disease (AD), there has been marked interest to develop strategies to prevent, delay and modify AD. We review the diverse lines of evidence in support of the emerging role of cAMP-mediated Phosphodiesterase (PDE) signalling with respect to aging, inflammation and depression. In view of the link of PDE to Epigenetic complex, targeting PDE through designing modulators and inhibitors of PDE may represent a novel approach in AD therapeutics. We review critically the translational studies of the proprietary Zembrin extract harvested and processed from the South African plant, Sceletium tortuosum, highlighting the dual property of Zembrin in targeting coupling of PDE and serotonin signaling mechanisms in vitro and in vivo models of AD and cognition. The promising clinical findings of Zembrin in cognition suggest that Zembrin extract may merit randomized controlled trials in AD to establish the efficacy and safety in AD.