New hydroperoxylated and 20,24-epoxylated dammarane triterpenes from the rot roots of Panax notoginseng

Abstract

Background: Root rot is a serious destructive disease of Panax notoginseng, a famous cultivated araliaceous herb called Sanqi or Tianqi in Southwest China. Methods: The chemical substances of Sanqi rot roots were explored by chromatographic techniques. MS, 1D/2D-NMR, and single crystal X-ray diffraction were applied to determine the structures. Murine macrophage RAW264.7 and five human cancer cell lines were used separately for evaluating the antiinflammatory and cytotoxic activities. Results and Conclusion: Thirty dammarane-type triterpenes and saponins were isolated from the rot roots of P. notoginseng. Among them, seven triterpenes, namely, 20(S)-dammar-25-ene-24(S)-hydroperoxyl-3β,6α,12β,20-tetrol (1), 20(S)-dammar-3-oxo-23-ene-25-hydroperoxyl-6α,12β,20-triol (2), 20(S)-dammar-12-oxo-23-ene-25-hydroperoxyl-3β,6α,20-triol (3), 20(S)-dammar-3-oxo-23-ene-25-hydroperoxyl-12β,20-diol (4), 20(S),24(R)-epoxy-3,4-seco-dammar-25-hydroxy-12-one-3-oic acid (5), 20(S),24(R)-epoxy-3,4-seco-dammar-25-hydroxy-12-one-3-oic acid methyl ester (6), and 6α-hydroxy-22,23,24,25,26,27-hexanordammar-3,12,20-trione (7), are new compounds. In addition, 12 known ones (12–16 and 19–25) were reported in Sanqi for the first time. The new Compound 1 showed comparable antiinflammatory activity on inhibition of NO production to the positive control, whereas the known compounds 9, 12, 13, and 16 displayed moderate cytotoxicities against five human cancer cell lines. The results will provide scientific basis for understanding the chemical constituents of Sanqi rot roots and new candidates for searching antiinflammatory and antitumor agents. Keywords: 20,24-epoxylated, Dammarane-type triterpenes, Hydroperoxylated, Panax notoginseng, Inhibition of NO production