%0 Journal Article
%T Phenolic composition, antioxidant activity, anticholinesterase potential and modulatory effects of aqueous extracts of some seaweeds on ¦Â-amyloid aggregation and disaggregation
%A Ademola O. Olaniran
%A Anthony I. Okoh
%A Tosin A. Olasehinde
%J Pharmaceutical Biology
%D 2019
%R https://doi.org/10.1080/13880209.2019.1634741
%X Abstract Context: Seaweeds contain bioactive compounds with different biological activities. They are used as functional ingredients for the development of therapeutic agents to combat degenerative diseases. Objective: This study investigated the phenolic composition, antioxidant activity, cholinesterase inhibitory and anti-amyloidogenic activities of aqueous extracts of Gracilaria beckeri (J.Agardh) Papenfuss (Gracilariaceae) (RED-AQ), Ecklonia maxima (Osbeck) Papenfuss (Lessoniaceae) (ECK-AQ), Ulva rigida (C.Agardh) Linnaeus (Ulvaceae) (URL-AQ) and Gelidium pristoides (Turner) K¨¹tzing (Gelidiaceae) (GEL-AQ). Materials and methods: Phenolic composition of the seaweed extracts was determined using liquid chromatography mass spectrometry. Radical scavenging and metal chelating activities were assessed in vitro. The effect of the extracts (21¨C84£¿¦Ìg/mL) on acetylcholinesterase and butyrylcholinesterase activities were also investigated using an in vitro colorimetric assay. Transmission electron microscope and thioflavin-T fluorescence assay were used to examine the anti-amyloidogenic activities of the extracts. Results: Phloroglucinol, catechin, epicatechin 3-glucoside were identified in the extracts. ECK-AQ (IC50=30.42 and 280.47£¿¦Ìg/mL) exhibited the highest OH£¿ scavenging and metal chelating activities, while RED-AQ (41.23 and 334.45£¿¦Ìg/mL) exhibited the lowest. Similarly, ECK-AQ (IC50£¿=£¿49.41 and 52.11£¿¦Ìg/mL) exhibited higher inhibitory effects on acetylcholinesterase and butyrylcholinesterase activities, while RED-AQ (64.56 and 63.03£¿¦Ìg/mL) showed the least activities. Rapid formation of ¦Â-amyloid (A¦Â1-42) fibrils and aggregates was observed in electron micrographs of the control after 72 and 96£¿h. The reduction of A¦Â1-42 aggregates occurred after co-treatment with the seaweed extracts. Discussion and conclusion: ECK-AQ, GEL-AQ, URL-AQ and RED-AQ may possess neuroprotective potential and could be explored for the management of Alzheimer¡¯s disease
%U https://www.tandfonline.com/doi/full/10.1080/13880209.2019.1634741