Sulfated Polysaccharides from Chaetoceros muelleri: Macromolecular Characteristics and Bioactive Properties

Abstract

In the present study, a culture of Chaetoceros muelleri, a cosmopolitan planktonic diatom microalga present in the Sea of Cortez, was established under controlled laboratory conditions. A sulfated polysaccharide (CMSP) extraction was carried out from the biomass obtained, resulting in a yield of 2.2% (w/w of dry biomass). The CMSP sample was analyzed by Fourier transform infrared spectroscopy, showing bands ranging from 3405 to 590 cm−1 and a sulfate substitution degree of 0.10. Scanning electron microscopy with elemental analysis revealed that the CMSP particles are irregularly shaped with non-acute angles and contain sulfur. High-performance liquid chromatography coupled to a dynamic light-scattering detector yielded molecular weight (Mw), polydispersity index (PDI), intrinsic viscosity [η], and hydrodynamic radius (Rh) values of 4.13 kDa, 2.0, 4.68 mL/g, and 1.3 nm, respectively, for the CMSP. This polysaccharide did not present cytotoxicity in CCD-841 colon cells. The antioxidant activity and the glycemic index of the CMSP were 23% and 49, respectively, which gives this molecule an added value by keeping low glycemic levels and exerting antioxidant activity simultaneously.

Physicochemical and Microstructural Characteristics of Sulfated Polysaccharide from Marine Microalga

“…Sulfated polysaccharides have been reported to regis of 45 kDa in Navicula inserta and 4810 kDa in Phaeodactylum tricornutum [14,15]. dispersity index (PI), intrinsic viscosity [η], radius of gyration (RG), hydrodynam (Rh), and α and K Mark-Houwink-Sakurada values registered for NSP are clos reported in the literature for these macromolecules in another microalga [7,16] α exponent registered was within the limits (0.5-0.8) reported in the literature fo The macromolecular characteristics of NSP are presented in Table 1. NSP's molecular weight (Mw) value was 1650 kDa, within the range reported for other sulfated polysaccharides from microalga.…”

“…The ASTRA 6.1 software was used. The specific refractive index increment (dn/dc) value of 0.146 mL/g was used [7]. The characteristic ratio (C∞) and persistence length (q) were calculated according to the following equations [10]:…”

“…NSP was analyzed by field emission scanning electron microscopy (SEM) (JEOL 5410LV, JEOL, Peabody, MA, USA) using a voltage of 10 kV and 100× or 5000× magnifications. SEM images were obtained in secondary and backscattered electron imaging modes [7].…”

“…Polysaccharides are polydisperse; they might present different conformations and molecular weights, among other molecule characteristic variations. In this regard, combining size-exclusion chromatography with multi-angle light scattering (SEC-MALS) represents an advanced technique for the absolute characterization of these macromolecules [7]. The SEC column separates the molecules by hydrodynamic volume, passing them through an MALS detector.…”

“…Sulfated polysaccharides from several microalgae have been associated with numerous bioactivities that benefit human health, making them compounds of interest and potential applications for the pharmaceutical industry and regenerative medicine. In addition, it has been reported that these polysaccharides did not present cytotoxicity, and they can keep low glycemic levels and exert antioxidant activity simultaneously [7]. Microalgae sulfated polysaccharides have also gained attention for biomedical applications, such as developing tissue engineering scaffolds [8].…”