Effect directed detection of Rhodiola rosea L. root and rhizome extract

Rhodiola rosea is a well-known adaptogen plant with antioxidant, antidepressant, anti-stress, and anti-dementive properties that seems to be important in the potential treatment of disorders associated with central nervous system such as Alzheimer's disease. The aim of this study was to effect directed detection (EDD) of biologically active substances in the root and rhizome of R. rosea L. based on chemical and biological assays performed directly on a thin-layer chromatography (TLC) plate. TLC-direct bioautography revealed the presence of both antioxidants (DPPH assay) and antibacterials (Bacillus subtilis assay) in the plant methanol extract. Unfortunately, the presence of acetylcholinesterase (AChE) inhibitors was not evident. The marker compounds, typical for R. rosea L. that is salidroside, rosavin, p-tyrosol, and hydroquinone were searched in the extract using TLC densitometry. In fact, only rosavin was found in the investigated extract.