Extraction, Structural Characterization, and Potential Antioxidant Activity of the Polysaccharides from Four Seaweeds

Abstract

Four seaweed polysaccharides were extracted from Sarcodia ceylonensis, Ulva lactuca L., Gracilaria lemaneiformis, and Durvillaea antarctica, respectively, by microwave-assisted extraction. The effect of three significant variables (extraction time, extraction temperature, and the ratio of water to raw material) on the process for extracting polysaccharides was investigated, along with the optimization of the extraction using the response surface method (RSM) with a Box–Behnken design. The polysaccharide structure, monosaccharide composition, degree of sulfation, and molecular weight (MW) distribution were analyzed by infrared (IR) spectrometry, gas chromatography (GC), and high-performance gel permeation chromatography (HPGPC). IR spectrometry showed that Sarcodia ceylonensis polysaccharide (SCP), Ulva lactuca L. polysaccharide (ULLP), and Durvillaea antarctica polysaccharide (DAP) were all sulfated polysaccharides and, except Gracilaria lemaneiformis polysaccharide (GLP), all belong to β-pyranosidic polysaccharides. The average molecular weight (MW) of SCP, ULLP, GLP, and DAP was 466, 404, 591, and 482 kDa, respectively. The quantitative and comparative results with external standards indicated that the main monosaccharide in SCP and ULLP was mannose; and GLP and DAP were mainly composed of galactose and glucose, respectively. Then the in vitro antioxidant activity of all of the polysaccharides was evaluated using different assays—2,2–azino –bis (3-ethylbenzthiazoline-6- sulfonate) (ABTS), hydroxyl radical, nitrite scavenging capacity, and reducing power—and the relationship between their antioxidant activity and chemical characteristics were also examined. ULLP presented the highest ABTS radical scavenging activity; ULLP, SCP and DAP also showed a strong effect on the ABTS radical scavenging activity. SCP and ULLP exhibited excellent hydroxyl radical scavenging activities, about 83.33% ± 2.31% and 80.07% ± 2.17%, respectively, at 4 mg/mL. The reducing power of DAP was relatively more pronounced than that of the three other polysaccharides. However, the nitrite scavenging activities of the four seaweed polysaccharides were weaker than other antioxidant activity (ABTS), hydroxyl radical scavenging capacity, and reducing power. In addition, GLP exhibited lower activities than the other three samples in all of the tests for the antioxidant activity.

Potential Using of Ulvan Polysaccharide from Ulva lactuca as a Prebiotic in Synbiotic Yogurt Production

“…The total carbohydrates content was 26.41% in the obtained ulvan. This result is higher than that obtained by He et al [24], and lower than Siddhanta et al [22], which was 23.71% and 47.4%, respectively. The obtained results for sulfate and carbohydrates are in the same trend of Jaulneau et al [25] who found that the ethanol-soluble ulvan had low quantities of sulfate and neutral sugars.…”

Natural Products of Marine Macroalgae from South Eastern Australia, with Emphasis on the Port Phillip Bay and Heads Regions of Victoria

“…Interestingly, compounds 37-39 and 48 were all isolated and characterized from the alga C. fragile and following this study, it was suggested that sterol compounds may prove to be useful biomarkers for this genus allowing for easier taxonomic distinction between other members of the Codiaceae family [44,45]. Much of the literature available for the genus Ulva involves biological activity studies on polysaccharides [46][47][48][49], many of the sterols found within this genus have shown promising in vitro bioactivity. In particular, the glycosidic sterol (47) from U. lactuca has been shown to be an effective anti-bacterial, anti-fungal and anti-inflammatory agent in vitro [41].…”

“…Firstly, green algae produce a greater variety of sterolic compounds, and secondly, some structural differences are apparent. Green algal derived sterols appear to have a higher inclination towards glycosidic moieties along with long lipid esters that branch from the hydroxyl group on ring A of the steroid skeleton (38,47,48). Steroids derived from the brown algae appear to have no glycosidic attachments but display more diversity in the lipidic chains sprouting from the D ring (200-202).…”

Study on physicochemical properties and antioxidant activity of polysaccharides from Desmodesmus armatus

“…The IR spectra of DAP1, DAP2, DAP3, and DAP4 are shown in Figure 6. The absorption peak at 3,419-3,447 cm -1 is the stretch vibration of O-H (He, Xu, Chen, & Sun, 2016), but there is interference of the hydration peak. The weak peaks at 2,931-2,936 and 1,227-1,239 cm -1 are caused by the stretch vibration of C-H (Fan, Lin, Luo, Chun, & Luo, 2014).…”