Cyanidin-3-O-galactoside and Blueberry Extracts Supplementation Improves Spatial Memory and Regulates Hippocampal ERK Expression in Senescence-accelerated Mice

Objective To investigate whether the antioxidation and the regulation on the Extracellular Regulated Protein Kinases （ERK） signaling pathway are involved in the protective effects of blueberry on central nervous system. Methods 30 Senescence-accelerated mice prone 8 （SAMP8） mice were divided into three groups and treated with normal diet, blueberry extracts （200 mg/kg.bw/day） and cyaniding-3-O-galactoside （Cy-3-GAL） （50 mg/kg.bw/day） from blueberry for 8 weeks. 10 SAMR1 mice were set as control group. The capacity of spatial memory was assessed by Passive avoidance task and Morris water maze. Histological analyses on hippocampus were completed. Malondialdehyde （MDA） levels, Superoxide Dismutase （SOD） activity and the expression of ERK were detected. Results Both Cy-3-GAL and blueberry extracts were shown effective functions to relieve cellular injury, improve hippocampal neurons survival and inhibit the pyramidal cell layer damage. Cy-3-GAL and blueberry extracts also increased SOD activity and reduced MDA content in brain tissues and plasma, and increased hippocampal phosphorylated ERK （p-ERK） expression in SAMP8 mice. Further more, the passive avoidance task test showed that both the latency time and the number of errors were improved by Cy-3-GAL treatment, and the Morris Water Maze test showed significant decreases of latency were detected by Cy-3-GAL and blueberry extracts treatment on day 4. Conclusion Blueberry extracts may reverse the declines of cognitive and behavioral function in the ageing process through several pathways, including enhancing the capacity of antioxidation, altering stress signaling. Cy-3-GAL may be an important active ingredient for these biological effects.

Enzymatic synthesis of myricetin 3-O-galactoside through a whole-cell biocatalyst

Objective:Myricetin 3-O-galactoside is an active compound with pharmaceutical potential.The insufficient supply of this compound becomes a bottleneck in the druggability study of myricetin 3-Ogalactoside.Thus,it is necessary to develop a biosynthetic process for myricetin 3-O-galactoside through metabolic engineering.Methods:Two genes OcSUS1 and OcUGE1 encoding sucrose synthase and UDP-glucose 4-epimerase were introduced into BL21(DE3)to reconstruct a UDP-D-galactose(UDP-Gal)biosynthetic pathway in Escherichia coli.The resultant chassis strain was able to produce UDP-Gal.Subsequently,a flavonol 3-O-galactosyltransferase DkFGT gene was transformed into the chassis strain producing UDP-Gal.An artificial pathway for myricetin 3-O-galactoside biosynthesis was thus constructed in E.coli.Results:The obtained engineered strain was demonstrated to be capable of producing myricetin 3-Ogalactoside,reaching 29.7 mg/L.Conclusion:Biosynthesis of myricetin 3-O-galactoside through engineered E.coli could be achieved.This result lays the foundation for the large-scale preparation of myricetin 3-O-galactoside.

A novel antimicrobial flavonoidic glycoside from the leaves of Alstonia macrophylla Wall ex A.DC(Apocynaceae)

A new flavonoidic glycoside,tricin-4’-O-β-L-arabinoside(1) was isolated from the leaves of Alstonia macrophylla along with two known flavonoids,vitexin and myricetin-3′-rhamnoside-3-O-galactoside.Their structures were established by chemical and spectral evidences.The known compounds were reported for the first time from this plant.Moreover compound 1 was tested for antifungal and antibacterial activities.