Yan Chen,Xue-Hui Li,Li-Yuan Zhou,Wan Li,Liu Liu,Dan-Dan Wang,Wen-Na Zhang,Sajid Hussain,Xiao-He Tian,Yong-Ming Lu
Tricholoma lobayense is a nutritious mushroom with great health benefits. Three polysaccharides with purity higher than 99% were successfully extracted from Tricholoma lobayense . The molecular weights of TLH-1, TLH-2 and TLH-3 were determined to be 8.43 × 10 5 ,5.36 × 10 5 and 4.53 × 10 3 Da, respectively. The backbones of TLH-1 and TLH-2 were mainly composed of 1,4-linked α- d -glucopyranosyl. However, polysaccharide TLH-3 was found to be a highly branched glucogalactan, which is made up of 1,3-linked α- d -glucopyranosyl branched at C-6 and 1,3-linked β - d -galactopyranosyl. In vitro antioxidant activity assays revealed that TLH-3 exhibited highest antioxidant activities among the polysaccharides from Tricholoma lobayense , which were comparable to those of ascorbic acid. The results suggested that the outstanding antioxidant activities of TLH-3 might depend on its low molecular weight, high branch degree, versatile linkage types and complex conformation. These characteristics make TLH-3 an attractive natural antioxidant for food and pharmaceutical applications.
A novel heteroglycan TLH-G was successfully isolated from Tricholoma lobayense cultivated in south China. TLH-G was composed of five monosaccharides, namely, mannose, rhamnose, glucuronic acid, glucose and galactose, and consisted of →1)-β-D-Glcp-(6→ and →1)-α-D-Galp-(3→ motifs. TLH-G had excellent scavenging activities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals. Structure-activity relationship analysis demonstrated that glycosidic bond types, monosaccharide composition, and branching degree were more important for the antioxidant activity of polysaccharides from Tricholoma lobayense than other structural factors. All the above results showed that the growth environment played a crucial role in the structure and antioxidant activity of polysaccharides from Tricholoma lobayense.
Polysaccharide TLH-3 from the fruit body of Tricholoma lobayense Heim has shown outstanding antioxidant activity. In order to further explore it, TLH-3 was successfully modified to obtain a sulfated derivative (STLH-3). The chemical characteristics of STLH-3 and TLH-3 were determined by high performance liquid chromatography and infrared spectroscopy. Antioxidant activity and cytotoxicity of the samples were investigated in vitro . The antioxidant activities of STLH-3 were significantly improved. In the four indicators of antioxidant activity, the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion scavenging activities of STLH-3 have exceeded that of Vitamin C (Vc). The cytotoxicity against tumor cells including human cervical carcinoma cell line (HeLa) and human breast cancer cell line (MCF-7) of STLH-3 was obviously stronger than that of TLH-3. STLH-3 had no toxic on human embryonic lung fibroblasts (HELF) cells. These results suggested that STLH-3 would be a promising bioactive macromolecule for potential applications in the field of health care and pharmaceutical.