Anti-inflammatory Constituents and New Pterocarpanoid of Crotalaria pallida

Abstract
One new pterocarpanoid, crotafuran E (1), and three known compounds were isolated from the bark of Crotalaria pallida. The structure of 1 was determined by spectral methods. Two pterocarpanoids, crotafurans A (2) and B (3), previously isolated from this plant, showed significant concentration-dependent inhibitory effects on the NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage-like cells, with IC50 values of 23.0 ± 1.0 and 19.0 ± 0.2 μM, respectively. Compound 3 also inhibited the LPS/interferon-γ (IFN-γ)-stimulated NO production in N9 microglial cells with an IC50 value of 9.4 ± 0.9 μM. Moreover, compound 2 produced a concentration-dependent inhibition of the release of β-glucuronidase and lysozyme from rat neutrophils in response to formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB) with IC50 values of 7.8 ± 1.4 and 9.5 ± 2.1 μM, respectively.