Effect of different drying methods on phenolic compounds and antioxidant capacity in different fractions of Sedum aizoon L.

This study investigated the effect of different drying treatments on phenolic composition and antioxidant activity in different fractions of Sedum aizoon L. Results showed that the highest flavonoids content was found in the flower fraction, which also possessed the strongest antioxidant capacity confirmed by DPPH, ABTS, and FRAP assays. Four phenolic compounds were detected in Sedum aizoon L. Myricetrin and quercitrin were the dominant phenolic compounds in all the fractions, whereas the stem fraction did not contain myricetin. Among the drying treatments, each freeze-dried fraction exhibited the highest antioxidant activities and total flavonoids. The oven- and sun-drying treatments resulted in a loss on the total flavonoids and antioxidant properties. A positive correlation of antioxidant activities in Sedum aizoon L. was found with myricetrin, quercitrin and total flavonoids. This study could provide useful information on the nutritional quality improvement of Sedum aizoon L. through different drying methods. Practical applications Sedum aizoon L. has been generally consumed as a folk medicine with multiple health beneficial features in China. The health beneficial properties of Sedum aizoon L. have been confirmed to be attributed primarily to phytochemicals, such as flavonoids and phenolic acids. The major consumption parts in Sedum aizoon L. in China include stems, leaves, and flowers. Normally, a drying process has been applied to Sedum aizoon L. for a longer shelf life need. The present study investigated the distribution of gallic acid, myricetrin, quercitrin, and myricetin in different parts of Sedum aizoon L., and further assessed if different drying methods could alter the level of these phenolic compounds and antioxidant properties in these parts of Sedum aizoon L. This study provides direct knowledge on the accumulation of phenolic compounds in different parts of Sedum aizoon L., and further bring a practical method on the best preserve functional compounds in Sedum aizoon L.