Chemical Characterization of the Hydroethanolic Extract of the Inner Stem Bark of Dilodendron bipinnatum. Comparative Cytotoxic Evaluation and Anti-inflammatory Potential of a Simple Mixture of its Isolates 3-O-β-Glucopyranosyl-β-sitosterol and 3-O-β-Glucopyranosyl-stigmasterol

Abstract

Phytochemical investigation of the hydroethanolic extract of the inner stem bark of Dilodendron bipinnatum (HEDb) by column chromatography led to the separation of three major fractions: a) a mixture of phytosterols (ST mixture), including β-sitosterol (1), stigmasterol (2) and campesterol (3); b) a mixture of 3- O-β-glucopyranosyl-β-sitosterol (4) and 3- O-β-glucopyranosyl-stigmasterol (5) (SGP mixture); and c) epicatechin (6), as a single isolate. Their structures were determined by spectrometric analysis using 1H- and 13C-NMR spectroscopy, and GC-MS. The safety profile of the SGP mixture, when evaluated on RAW 264.7 cells, using the alamar blue® assay, exhibited no cytotoxic effects. The anti-inflammatory activity was comparatively analyzed in vivo using the lipopolysaccharide (LPS)-induced peritonitis model in mice, showing a strong reduction of leukocyte migration to the peritoneal cavity using both the SGP mixture and the HEDb. In vitro assessment of nitric oxide (NO) in the macrophagic RAW 264.7 cell line showed an inhibition of NO by the SGP mixture when cells were stimulated with LPS. Taken together, the results show an important contribution of the sterol glucoside mixture on the anti-inflammatory activity of HEDb. Also, one of the mechanisms for such inhibition seems to be a direct inhibition of NO production in stimulated macrophages.