Accumulation of tau protein is a hallmark of several neurodegenerative diseases collectively known as tauopathies. A major tau related disorder is Alzheimer's disease and to a lesser extent Parkinson's disease. Screening of organic extracts of Plocamium cartilagineum showed considerable reduction in tau protein level. Further purification of extract yielded two acyclic monoterpenes, anverene and (1E,3R,4R,5E,7S)-1,8-Dibromo-3,4,7-trichloro-3,7-dimethyl-1,5-octadiene and one cyclic monoterpene (1R,2R,4R)-2,4-dichloro-1-((E)-2-chlorovinyl)-1-methyl-5-methylenecyclohexane. Structures and absolute stereochemistry of acylic monoterpenes were confirmed by single crystal X-ray analysis. Our data on drug screening in cell culture models for tau revealed one halogenated monoterpene as a potential treatment for tauopathies.
