Quantification of amyloid-β aggregation inhibitors gallic acid and rosmarinic acid in biological samples by LC-MS/MS

The decline of the cognitive functions encountered at patients diagnosed with Alzheimer's disease (AD) together with the findings of extracellular amyloid deposits, intracellular neurofibrillary tangles and microvascular angiopathy in brain were described at beginning of the 20th century. According to the amyloid cascade hypothesis, the overproduction of amyloid-β peptide and its aggregation into neurotoxic oligomers, fibrils, and amyloid plaques is considered the cause of AD. Amyloid-β fibril formation was experimentally proven in vitro using thioflavin T assay in the absence of interfering chemical compounds and the assay became an analytical tool for assessing the effects of different molecules against amyloid-β aggregation. Recent research studies provided experimental results that indicated the reduction of fibril formation by gallic acid and rosmarinic acid. Mass spectrometry was often employed in studies aiming at identifying, characterizing, and quantitating chemical compounds able to modify the progress of AD. The purpose of this review is to present current research studies regarding the identification and quantitation of the water-soluble gallic acid and rosmarinic acid in biological samples using liquid chromatographs coupled to triple quadrupole mass spectrometers as bioanalytical tools. The present study highlights the presence and amount of these chemical compounds in commonly used medicinal plants and culinary herbs and provides a list of extraction and liquid chromatography coupled to electrospray-triple quadrupole mass spectrometry methods examples described in previous pharmacokinetic studies. The article underlines the bioavailability and safety of gallic acid and rosmarinic acid for further research studies aiming at preventing and slowing the progress of AD.