Extraction optimisation and lipid-lowering activity of Auricularia heimuer polysaccharides

Abstract

Assessments of molecular weight distribution and activity/efficacy of Auricularia heimuer polysaccharides (AAP) are of substantial significance for its extraction process optimisation. In the present study, single-factor orthogonal test and response surface methodology were employed to optimise extraction conditions of AAP. Furthermore, a rat hyperlipidaemia model was established to compare the lipid-lowering activity of polysaccharides obtained by three extraction methods. Conditions for enzymatic hydrolysis were optimised as pH 5.0, 1% cellulase, 2.5% substrate concentration and enzymolysis time of 1.5 h, leading to an up to 31.8% polysaccharide yield and 89.13% of polysaccharides within the molecular weight range of 5 000 Da to 10 000 Da. The results of animal experiments showed that the lipid-lowering activity of enzymolysis-extracted polysaccharides was significantly higher than that of water- and ultrasonic-extracted ones (P < 0.01). So the present study revealed that enzymatic hydrolysis-extracted polysaccharides showed the strongest hypolipidaemia activity, providing a basis for the development of A. heimuer-based functional foods and drugs.

Extraction, physicochemical properties, and antioxidant activity of natural melanin from Auricularia heimuer fermentation

“…Auricularia heimuer, the third most important cultivated mushroom in China (10), has high economic and medicinal value (11). It is known for its bioactive compounds, mostly polysaccharides (12,13), which have numerous beneficial biological properties, including antioxidant, antitumor, anti-radiation, immunomodulatory, and hyperlipidemic (14)(15)(16). Melanin, as one of the main active ingredients of A. heimuer, has been reported to have strong antioxidant, radical scavenging, quorum sensing inhibition, and antibiofilm activities (17).…”