New 12,23-Epoxydammarane Type Saponins Obtained from Panax notoginseng Leaves and Their Anti-Inflammatory Activity

Abstract

Two new 12,23-epoxydammarane-type saponins, notoginsenosides NL-I (1) and NL-J (2), were isolated and identified from Panax notoginseng leaves through the combination of various chromatographies and extensive spectroscopic methods, as well as chemical reactions. Among them, notoginsenoside NL-J (2) had a new skeleton. Furthermore, the lipopolysaccharide (LPS)-induced RAW 264.7 macrophage model was used to identify the in vitro anti-inflammatory activity and mechanisms of compounds 1 and 2. Both of them exerted strong inhibition on nitric oxide (NO) productions in a concentration-dependent manner at 1, 10, and 25 μM. Moreover, these two compounds significantly decreased the secretion of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), cyclooxygenase-2 (COX-2), nuclear factor kappa-B (NF-κB/p65), and nitric-oxide synthase (iNOS) in LPS-activated RAW 264.7 cells.