Diterpenoid glucosides with anti-inflammatory activity from Rubi Fructus

For centuries, dried unripe fruits of Rubus chingii Hu (Chinese name "Fu-pen-zi") have been widely used in traditional Chinese medicine for the treatment of various diseases, commonly associated with kidney deficiency. Rubi Fructus is an edible berry suitable for consumption either directly or in the form of juice and jam. The phytochemical investigation focused on the bioactive non-nutrient ingredient from the fruit of R. chingii, especially diterpenoid compounds. Seven diterpenoid glucosides, including three new (1-3) and four known (4-7) compounds, were obtained from the fruits of R. chingii. The structures along with the absolute configurations of the new compounds were determined by extensive NMR spectroscopic analysis. Compounds 1, 2, 4, 5, and 7 showed anti-inflammatory activity against LPS-induced NO production in RAW 264.7 macrophages. Further, the preliminary structure-activity relationships of these active compounds have been scientifically evaluated and discussed in this study.