Variation of lignan content and alpha-glucosidase inhibitory activity of Schisandra chinensis fruit at different maturation stages: Comparison with stem, leaf and seed

Abstract

The fruit of Schisandra chinensis has been used for the treatment of various metabolic diseases for a long time. The bioactive constituents of the fruit are known as lignans with dibenzocyclooctadienes skeletons. In this study, changes in the content of four main lignans of S. chinensis, schizandrin (S1), schizandrin A (S2), gomisin N (S3) and wuweizisu C (S4), and anti-diabetic activities at the different maturation stages of fruits were investigated. In addition, comparison of stem, leaf and seed with fruit was conducted in order to determine the optimum harvest time of fruit with high functionality and seek an alternative to use the other parts of plant except the fruit. In the results, the total content of four lignans were kept relatively constant and the amount of S1 and S3 were more than that of S2 and S4. According to fruit maturity, the content of S1 and S2 increased, on the contrary, S3 and S4 decreased. alpha-Glucosidase inhibitory effect was higher in early matured fruits and decreased in medium and late matured fruits. Considering the correlation between lignan content and alpha-glucosidase inhibitory effect, the content of S4 appeared to be highly related to the inhibitory effect. All of examined lignans were also detected in other parts of the plant, especially showed higher level in stem and seed than in leaf. However, the content of each lignan was different in each part, that is, high content of S4 was detected in stem whereas the content of S3 was higher in seed. For the breeding of new cultivars of S. chinensis, it is necessary to cultivate early-maturing varieties with a high content of active ingredients as well as to find an alternative approach to use the various plant parts including stem, leaf and seed.