Laminarin from Irish Brown Seaweeds Ascophyllum nodosum and Laminaria hyperborea: Ultrasound Assisted Extraction, Characterization and Bioactivity

Abstract

Ultrasound assisted extraction (UAE), purification, characterization and antioxidant activity of laminarin from Irish brown seaweeds Ascophyllum nodosum and Laminarina hyperborea were investigated. UAE was carried out using 60% ultrasonic power amplitude and 0.1 M hydrochloric acid for 15 min. Separately, solid-liquid extraction was carried in an orbital shaker using 0.1 M hydrochloric acid at 70 °C for 2.5 h. UAE with hydrochloric acid resulted in the highest concentration of laminarin, 5.82% and 6.24% on dry weight basis from A. nodosum and L. hyperborea, respectively. Purification of all extracts was carried out using molecular weight cut off dialysis at 10 kDa. Characterization of the laminarin fraction was carried out using matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Antioxidant activity of A. nodosum and L. hyperborea extracts had 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition levels of 93.23% and 87.57%, respectively. Moreover, these extracts have shown inihibition of bacterial growth of Staphylcoccus aureus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium.

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

“…Improved yield achieved by UAE in comparison to CE is attributed to the bubble cavitation phenomenon generated by ultrasonic waves [75], that was previously observed in fucoidan extraction from Sargassum witghtii [70], Undaria pinnatifida [76] and laminarin extraction from A. nodosum and Laminaria hyperborean [75]. No statistical difference between UAE and CE was reported in fucoidan extraction from N. zanardinii [64] and Fucus evanescens [77], while Okolie et al [65] reported significantly higher yield by CE (11.9%) than by UAE (4.56%) and also no statistical differences between UAE, MAE and EAE.…”

Prospects of brown seaweed polysaccharides (BSP) as prebiotics and potential immunomodulators

“…They are located in cell vacuoles, constitute about 35% dry weight of brown seaweed, and also serve as storage polysaccharides (Kadam, Tiwari, Alvarez, & Donnell, ; O'Sullivan et al, ). Studies on laminarin have shown promising results in its antibacterial, immunomodulating, antioxidative, and anticoagulant properties (Kadam et al, ; Zhang & Row, ). Interestingly, γ‐radiated degradation of laminarin showed increased antioxidant activity and inhibition of melanin synthesis when compared to non‐irradiated laminarin (Choi, Kim, Kim, & Lee, ).…”

“…The UAE method uses sound waves migrating through a medium inducing pressure variations and creating small vacuum bubbles or voids which collapse violently (cavitation) resulting localized pressure and heat which helps to extract polysaccharides (Kadam et al, ). Comparing the efficiency of UAE with MAE and CCE, Kadam et al () discovered that extraction with ultrasound‐assisted technology (10.79%) gave better yield when compared to MAE (9.56%) and CSE (4.67%) in lesser time (Kadam et al, ; Ying, Han, & Li, ). However, high energy input and pressure required for UAE and MAE could be detrimental, as they have been associated with cleavage of sulfate esters.…”

“…However, high energy input and pressure required for UAE and MAE could be detrimental, as they have been associated with cleavage of sulfate esters. Hence moderation of extraction conditions is advised to avoid structural alteration of sulfated polysaccharides and other unintended damages (Hahn et al, ; Kadam et al, ).…”

A review of extractions of seaweed hydrocolloids: Properties and applications

“…This environmentally benign and cost effective method has successfully extracted highly purified fibrils/nanofibrils from cellulosic materials [81,110]. Although UAE method has been utilized in extraction of bioactive compounds from several marine algae or even non-hydrocolloids materials [81,94,95,111,112]. Still, these were limited studies regarding extraction of seaweed hydrocolloids with this green method.…”