Phenolic profiles, antioxidant capacity, and acetylcholinesterase inhibitory activity of eight South African seaweeds
In the search for new, safe, and natural sources as antioxidant and acetylcholinesterase (AChE) inhibitors, eight seaweeds were collected from the intertidal region in KwaZulu-Natal, South Africa and screened. Their total phenolic, flavonoid, and condensed tannin contents were determined, and the specific phenolic acids were identified. The highest total phenolics, flavonoids, and condensed tannin were recorded in Rhodomelopsis africana (7.89 mg gallic acid equivalents g−1), Halimeda cuneata (3.64 mg catechin equivalents g−1), and Codium duthieae (0.60 mg cyanide chloride equivalents g−1), respectively. Based on UHPLC-MS/MS, different concentrations of protocatechuic acid, p-hydroxybenzoic acid, and m-hydroxybenzoic acid were quantified in the seaweeds. The highest radical scavenging ability and oxygen radical absorbance capacity (ORAC) were observed in red Gelidium foliaceum (52.2 %) and green C. duthieae (44 μmol TE g−1), respectively. In terms of AChE inhibition, the green H. cuneata exhibited greatest bioactivity (IC50 = 70 μg mL−1). Overall, the findings suggest that these seaweeds could be potential candidates as new sources of natural antioxidant and AChE inhibitors.
KeywordsAlzheimer’s disease AChE inhibitors Phenolics Macroalgae UHPLC-MS/MS
RRRK, SOA, and AOA thank the National Research Foundation, Claude Leon Foundation, and the University of KwaZulu-Natal for support in the form of postdoctoral fellowships. We also acknowledge the support of the Ministry of Education, Youth and Sports, Czech Republic (Grant L01204 from the National Program of Sustainability Land Agricultural Research), and IGA of Palacký University (Grant PrF 2013 012).
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