Exploring in vitro neurobiological effects and high-pressure liquid chromatography-assisted quantitation of chlorogenic acid in 18 Turkish coffee brands

The hydro alcoholic extracts of the Turkish traditional coffee samples from 18 commercial brands were tested for their neurobiological effects through enzyme inhibition based on enzyme-linked immunosorbance microtiter assays against acetylcholinesterase, butyrylcholinesterase, and tyrosinase, linked to Alzheimer's and Parkinson's diseases. The extracts were also subjected to several antioxidant test systems to define their antiradical, metal-chelation capacity, and reducing power. Total phenol and flavonoid contents in the extracts were delineated by spectrophotometric methods, while chlorogenic acid in the coffee samples was quantified by high-pressure liquid chromatography. The extracts displayed low to moderate inhibition (from 2.13 +/- 0.01% to 36.12 +/- 1.07% at 200 mu g/mL) against the tested enzymes, whereas they had notable 2,2'-diphenyl-l-picrylhydrazyl radical scavenging activity up to 56.15 +/- 2.03% at 200 mu g/mL. The extracts exerted a remarkable ferric-reducing antioxidant power values, while chlorogenic acid was found to range between 0.288 +/- 0.005% and 2.335 +/- 0.010%. Copyright (C) 2015, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http.//creativecommons.org/licenses/by-nc-nd/4.0/).