New Insight into Marine Biotechnology: Carrageenans Chemical Features and Acetylcholinesterase (AChE) Inhibition Activity of Two Edible Seaweeds of the Genus Kappaphycus

The red seaweed, Kappaphycus sp. is cultivated extensively as a source of carrageenans which have been used for decades in food applications and are generally regarded as safe. A deep chemical investigation has been performed on carrageenans from two species of Kappaphycus, K. alvarezii and K. striatum, by means of NMR spectroscopy technique. The NMR spectra study suggested the presence for both samples of a mixture of prevailing κ- and τ-carrageenans. Results confirmed that NMR spectroscopy represents actually the preferred technique to determine and quantify the composition of carrageenan from different algae sources. Moreover, the acetylcholinesterase (AChE) inhibition activity of different extracts of K. alvarezii and K. striatus  has have been evaluated by using two different assays, thin layer chromatography (TLC) assay with Fast Blue B salt as a reagent and a multiwell plate assay based on Ellman’s method. Chloroform/methanol extracts of both samples showed the best AChE inhibition activity starting from 0.01 mg ml⁻¹.