Search

Four bacterial isolates were obtained from marine sediments collected from Sahl Hashish, Hurghada Red Sea, Egypt. This study was designed to search for promising anti-Alzheimer natural polysaccharide; therefore, four isolates were screened for exopolysaccharides (EPSs) production and acetylcholinesterase inhibition. The isolate S16 provided the highest EPS yield (7.51 g/L) and acetylcholinesterase inhibition. It was identified morphologically and genetically using 16S rRNA gene sequence analysis as Bacillus maritimus. A Physicochemical analysis of S16 exopolysaccharide (BMEPS) was estimated, which pointed to the presence of uronic acid and sulfate (24.7% and 18.3%, respectively). HPLC analysis indicated that mannuronic acid, glucuronic acid, glucose, and mannose are presented in a molar ratio of 0.8:1.0:2.8:2.3, respectively. Furthermore, FT-IR revealed an abundance of β-configurations. The GPC estimated the average molecular weight (Mw) as 4.31 × 104 g/mol. BMEPS inhibited AChE (IC50; 691.77 ± 8.65 μg/ ml), BChE (IC50; 288.27 ± 10.50 μg/ ml), and tyrosinase (IC50; 3.34 ± 0.09, 14.00 ± 0.14, and 22.96 ± 1.23 μg/ ml during incubation durations of 10, 20, and 40 min). It also demonstrated a selective anti-inflammatory action against COX-2 rather than COX-1. Moreover, BMEPS exhibited antioxidant capabilities as free radical and oxygen reactive species (ROS) scavenger, metal chelator, reductant agent, and lipid peroxidation suppressor. These activities are due to the distinct chemical composition. The findings of this study indicate that BMEPS could be considered as promising anti-disease Alzheimer's (AD) material in an in-vitro model, which qualifies it for advanced in-vivo studies in the discovery of alternative Alzheimer's treatment. [ABSTRACT FROM AUTHOR]

Background: Exopolysaccharides are extremely powerful molecules with a wide range of uses in pharmaceuticals due to their structural and compositional complexity. Marine microorganisms often produce bioactive substances with novel functions and structures because of their special living conditions. Polysaccharides from marine microorganisms are of interest to new drug discovery. Results: The current research focused on the isolation of bacteria from Red Sea, Egypt, that have the ability to produce a new natural exopolysaccharide in order to be examined in treating Alzheimer's illness to obviate side effects of synthetic drugs. Properties of exopolysaccharide (EPS) produced by an isolated Streptomyces strain were investigated for its capability to play as anti-Alzheimer. This strain was identified morphologically, physiologically, and biochemically and actually was confirmed by molecularly 16S rRNA analysis as Streptomyces sp. NRCG4 with accession number MK850242. The produced EPS was fractionated by precipitation 1:4 volumes of chilled ethanol and the third major fraction (1:3) listed as NRCG4, and then the functional groups, MW, and chemical evaluation have been detected via Fourier-transform infrared (FTIR), high-performance gel permeation chromatography (HPGPC), and high-performance liquid chromatography (HPLC). The findings showed that NRCG4 was an acidic EPS composed of mannuronic acid, glucose, mannose, and rhamnose in a molar ratio of 1.2:1.5:2.8:1.0, respectively. NRCG4 Mw was determined to be 4.25 × 105 gmol−1 and the Mn to be 1.97 × 105 gmol−1. Also, the NRCG4 included uronic acid (16.0%) and sulfate (0.0%), but no protein was found. In addition, antioxidant and anti-inflammation activity was measured through various methods. This study confirmed that NRCG4 exopolysaccharide exerted anti-Alzheimer's characters via inhibition of cholinesterase and tyrosinase as well as anti-inflammatory and antioxidant abilities. Additionally, it occurred a potential role in the suppression of Alzheimer's disease risk factors through its antioxidant (metal chelation, radical scavenging capability), anti-tyrosinase and anti-inflammatory characteristics. The anti-Alzheimer's disease efficacy of NRCG4 exopolysaccharide may be assigned to its unique determined chemical composition. Conclusions: The present study highlighted those exopolysaccharides could be harnessed to improve pharmaceutical industry (anti-Alzheimer, anti-tyrosinase, anti-inflammatory, and antioxidant agents). [ABSTRACT FROM AUTHOR]