Plaque formation due to amyloid-β oligomerization and fibrillation is a key issue for its deposition in the brains of dementia and Alzheimer’s disease patients. Related drugs preventing this peptide fibril accumulation bear the potential of considerable medical and social value. In this study, we performed in vitro fibrillation inhibition tests with eight different medical plant extracts and nutraceuticals using fluorescence spectroscopy. Successful inhibition of the following plant extracts and nutraceuticals were obtained: Withania somnifera, Centella asiatica, Bacopa monnieri, and Convolvulus pluricaulis, providing new drug candidates for the prevention and treatment of Alzheimer’s disease.

Fluorescence spectroscopy for in vitro amyloid-␤ (A␤) fibrillation diagnosis and spectral fluorescence signature for the identification of bioactive compounds were applied to study traditional Ayurvedic nutraceuticals -Brahmi, Ashwagandha, Shanka pushpi, and Gotu kola -as well as their plant extracts for possible treatment of Alzheimer's disease. All samples manifest as inhibitors on three different variants of the A␤ peptide: methionine A␤ 1-40 , A␤ 1-40 , and A␤ 1-42 . The main compounds within the nutraceuticals were identified. Since related medicals are known to have reduced negative post-and side-effects and even may introduce further positive health impacts by preventing pathogen plaque formation and reducing free A␤ to a natural level, such treatment approaches could be of further interest.

Spectral fluorescence signature, Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Mass Spectrometry for identification of chemical and bioactive compounds were applied to study the plant extracts of Withania somnifera, Centella asiatica and Bacopa monnieri which are related to the possible treatment of mental diseases as Alzheimer, Parkinson and Depression. These plants are known for different positive phytotherapeutic effects on the human brain without negative post-, adverse or after effects to the treated individuals, and have been recommended in several medical studies. Therefore, we selected these plants for further analysis, based on the inhibition results of in vitro Amyloid Beta fibrillation tests made by previous measurements. With this study a first screening of the complex plant extract mixtures was performed, to get an initial overview about known and unknown ingredients. In all three plants, similar main compounds were identified, however in different quality and quantity. These may provide substantial information on which compound combinations might be mainly responsible for the positive effects and should be further investigated being responsible for reducing the fibrillation process of Amyloid Beta.