2-0-(beta-D-Glueopyranosyl)ascorbic acid (AA2 beta G) isolated from a popular traditional Chinese food (Lycium fruit) was synthesized using cellulase derived from Trichoderma sp. with cellobiose as a glucose donor. 6-0-(beta-D-Glucopyranosyl)ascorbic acid as well as AA2 beta G was also synthesized in this reaction. The vitamin C activity of AA2 beta G was also evaluated using inherently scorbutic (osteogenic disorder Shionogi [ODS]) rats. The rats were fed vitamin C-deficient food and water containing AA2 beta G for 21. AA2 beta G supported their growth and the level of vitamin C in tissues was moderately maintained. The vitamin C level in some tissues depended on the hydrolytic activity of AA2 beta G (beta-glucosidase activity) although the correlation was not statistically significant (P=0.08). The results indicate that AA2 beta G has pro-vitamin C activity.