Macrocystis angustifolia is a potential source of enzyme inhibitors linked to type 2 diabetes and dementia

In continuation of the screening of South African seaweeds to identify potential candidates for the development of pharmaceutically active functional foods, we investigated the inhibitory effects of a crude 80 % methanol extract, solvent fractions and isolated compounds from the kelp Macrocystis angustifolia against enzymes involved in type 2 diabetes and dementia. Repeated column fractionation of the ethyl acetate fraction of the crude extract of M. angustifolia afforded two phenol derivatives identified by spectroscopic analyses (1D and 2D NMR): 4-(2-hydroxyethyl)phenol (tyrosol) (1) and 4-(1,2-dihydroxyethyl)phenol (2). These compounds were isolated from a marine alga for the first time. The ethyl acetate (IC₅₀?=?14.08?±?1.21 μg mL^?1) and butanol (IC₅₀?=?77.94?±?11.69 μg mL^?1) fractions exhibited potent inhibition against α-glucosidase and acetylcholinesterase (AChE) enzymes, respectively. Tyrosol (1) and its derivative, 4-(1,2-dihydroxyethyl)phenol (2), showed potent inhibition against both α-glucosidase and AChE enzymes. Based on in silico evaluation, these two compounds are anticipated to possess sufficient oral bioavailability in accordance to the Lipinski Rule of Five without any toxicity risk. Natural α-glucosidase and AChE inhibitors from M. angustifolia offer a novel approach to control type 2 diabetes and dementia.