Screening of Nutraceuticals and Plant Extracts for Inhibition of Amyloid-β Fibrillation

Abstract

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.

Compound’s Pre-Screening of <i>Withania somnifera</i>, <i>Bacopa monnieri</i> and <i>Centella asiatica</i> Extracts

“…SFS extracts were prepared with maceration with mortar and pestle (3 g plant material with 30 ml solvent) and were directly used after [10] [23].…”

“…The LED-based illumination system (LED Company, Estonia) provided a light wavelength distribution of 380 -780 nm. Defined light conditions were achieved for 24 hours: daylight from 8:00 -19:59 and darkness from 20:00 -7:59 [10] [23].…”

“…The 65% EtS was added to 15 g fresh plant material shortly before the extraction process which was initialized at a temperature of 95˚C for 30 minutes and continued at a stable temperature of 90˚C for 16 h. The SE of 50% EtS with 15 g green and fresh plant material run at a stabilized temperature of 100˚C for 14 h. Hereby, an initial temperature of 120˚C for 30 minutes was applied. The SEs were annealed and stored at 4˚C and at −80˚C in 2 ml tubes till further usage [10] [23]- [28]. All prepared extracts were centrifuged at 15.000 rpm (4˚C) to separate solutions from suspended particles and poorly dissolved materials.…”

“…All prepared extracts were centrifuged at 15.000 rpm (4˚C) to separate solutions from suspended particles and poorly dissolved materials. The upper solvent layer was pipette into marked tubes and stored in an ice box until experimental application [10] [23].…”

“…Such herbal medicines and medical plant extracts are complex bioactive compound mixtures for which an improved insight with specifications and proof-of-effectiveness of the ingredients is recommended [6] In this study we performed an ingredients' screening of promising Ayurvedic plants-Withania somnifera, Centella asiatica, and Bacopa monnieri-to make first steps gaining insight into the prevention or treatment of diverse mental disorders like Alzheimer, Parkinson, Schizophrenia, and Depressions [10]. Extracts were selected from eight traditional Indian medicines-used since more than 2000 years-for a possible Alzheimer treatment and are known for several positive phytotherapeutic effects on the human brain and body without negative post-, adverse or after effects to the treated individuals (positive memory influence, stress reduction, mental health regeneration and reduction of anxiety), and have been recommended in several medical studies [11]- [22] which we previously investigated by in vitro Amyloid Beta fibrillation inhibition measurements by luminescence spectroscopy [10] [23]. Here, we applied Gas Chromatography-Mass Spectrometry (GC-MS), Liquid Chromatography-Mass Spectrometry (LC-MS) and Spectral Fluorescence Signature (SFS) on related nutraceuticals and plant extracts.…”