Nutraceutical Potential of Five Mexican Brown Seaweeds

Abstract

In search of pharmaceutically active products to control type 2 diabetes, five brown seaweeds (Silvetia compressa, Cystoseira osmundacea, Ecklonia arborea, Pterygophora californica, and Egregia menziesii) from the Northwest Mexican Pacific coast were investigated. Proximate composition and total polyphenol content (TPC) as phloroglucinol equivalents (PGE) were determined for the five seaweed powders and their respective hydroethanolic (1 : 1) extracts. Extracts were screened for their radical scavenging activity (DPPH and ORAC) and glycosidase inhibitory activity. HPLC-DAD, HPLC-MS-TOF, and ATR-FT-IR methodologies were used to identify the most abundant phlorotannins and sulfated polysaccharides in the extracts. Hydroethanolic extracts contained minerals (17 to 59% of the dry matter), proteins (4 to 9%), ethanol-insoluble polysaccharides (5.4 to 53%), nitrogen-free extract (NFE) (24.4 to 70.1%), lipids (5 to 12%), and TPC (2.6 to 47.7 g PGE per 100 g dry extract). S. compressa and E. arborea dry extracts presented the lowest ash content (26 and 17%, respectively) and had some of the highest phenolic (47.7 and 15.2 g PGE per 100 g extract), NFE (57.3 and 70.1%), and soluble polysaccharide (19.7 and 53%) contents. S. compressa and E. arborea extracts had the highest antioxidant activity (IC50 DPPH 1.7 and 3.7 mg mL−1; ORAC 0.817 and 0.801 mmol Trolox equivalent/g extract) and the highest α-amylase and α-glucosidase inhibitory capacities (IC50 940 and 1152 μg mL−1 against α-amylase and 194 and 647 μg mL−1 against α-glucosidase). The most abundant phlorotannins identified in the extracts were phloretol, fucophloroethol, and two- and three-phloroglucinol unit (PGU) phlorotannins. Laminarin, fucoidan, and alginate were among the sulfated polysaccharides identified in the extracts. The bioactivities of S. compressa and E. arborea extracts were mainly related with their contents of three PGU phlorotannins and sulfated polysaccharides (e.g., fucoidan, laminarin, and alginate). These results suggest S. compressa and E. arborea are potential candidates for food products and nutraceutical and pharmaceutical preparations, and as additives for diabetes management.

Pressurized Hot Liquid Extraction with 15% v/v Glycerol-Water as An Effective Environment-Friendly Process to Obtain Durvillaea incurvata and Lessonia spicata Phlorotannin Extracts with Antioxidant and Antihyperglycemic Potential

“…However, their ORAC values were lower than those described for UAE extracts (50% ethanol-water), ranging from 1100 to 1600 µmol TE/g dry extract [45], and those reported for conventional methanolic extracts, which showed values between 1200 and 4200 µmol TE/g dry extract [49]. Our results were comparable to conventional 50% ethanol-water extracts obtained from brown seaweeds from the Northwest Mexican Pacific coast (190-820 µmol TE/g dry extract) [50]. All PHLE extracts characterized here presented higher ORAC values than those previously reported for D. antarctica and L. spicata 50% ethanol-water extracts [47].…”

“…Ethanolic and acetone-water A. nodosum extracts presented IC 50 values ranging between twenty and two thousand-fold lower than acarbose [54]. Although the ORAC values found in Mexican seaweed ethanolic extracts were comparable to some of the PHLE extracts, their α-glucosidase inhibition capacities were far lower (one to four-fold lower than the acarbose IC 50 ) [50]. Previous studies with D. antarctica and Lessonia extracts have presented lower α-glucosidase inhibitory activities than those found in this research.…”

Whole Alga, Algal Extracts, and Compounds as Ingredients of Functional Foods: Composition and Action Mechanism Relationships in the Prevention and Treatment of Type-2 Diabetes Mellitus

“…In addition, because of these results, the role of laminarin on T2DM complications had to be considered because it reduces the systolic blood pressure, cholesterol absorption in the gut, and the cholesterol and total serum lipid levels [ 189 ]. Continuing with brown algae polysaccharides, alginates with molecular mass over 50 kDa showed a positive prevention effect in T2DM and adiposity [ 190 , 191 ]. Thus, Kimura et al [ 190 ], after studying alginates isolated from Laminaria angustata Kjellman var.…”

Uncovering Prospective Role and Applications of Existing and New Nutraceuticals from Bacterial, Fungal, Algal and Cyanobacterial, and Plant Sources

“…Another group of brown seaweeds showed their ability to be a source of functional food and nutraceuticals products such as fucoidan, laminarin, and alginate [96]. Carrageenan production from red/brown seaweed showed promising abilities to contribute as nutraceuticals in many food industry applications [97].…”