Purification, structural characterization, and bioactivities of a polysaccharide from Coreopsis tinctoria

Coreopsis tinctoria Nutt. has been widely cultivated in Xinjiang, Yunnan as well as other western regions of China. In folk medicine, the flower tea C. tinctoria is often used as an adjunctive therapy for diabetes and Alzheimer's disease. To explore the chemicals responsible for the health benefits of C. tinctoria, a water-soluble polysaccharide (CT70-1) was isolated from C. tinctoria. The structure feature analyses revealed that CT70-1 was a heteropolysaccharide with a relative molecular weight of 2.1x10(3) Da. It consisted of alpha-D-Glcp-(1 ->, -> 4)-alpha-D-Glcp-(1 ->, -> 5)-alpha-L-Araf-(1 ->, -> 6)-2-OAc-/3-D-Galp-(1 ->, -> 3)-alpha-L-Rhap-(1 ->, -> 3,6)-/3-D-Manp-(1 ->, -> 6)/3-D-Manp-(1 ->, -> 1,6)-/3-D-Fruf-(2 ->, alpha-L-Araf-(1 ->, and -> 3)-/3-D-Manp-(1 ->. Further, CT70-1 exhibited alpha-amylase and alpha-glucosidase inhibitory activity with IC50 values of 2.79 +/- 0.17 mM and 3.00 +/- 0.02 mM, respectively. Moreover, CT70-1 significantly inhibited lipopolysaccharide-stimulated nitric oxide production of RAW264.7 and BV2 cells with IC50 values of 0.07 mM and 0.12, respectively. In conclusion, the above findings provide a foundation for promising natural ingredient CT70-1 in the food and pharmaceutical industries.