A single-step isolation by centrifugal partition chromatography of the potential anti-inflammatory glaucolide B from Lepidaploa chamissonis

Abstract

Sesquiterpene lactones (SL) are commonly found in Asteraceae and present a promising anti-inflammatory activity. Previously described in Lepidaploa genus, glaucolide B has never been investigated for its anti-inflammatory potential. This study aimed to establish an efficient process for the extraction of glaucolide B (1) from Lepidaploa chamissonis leaves and to develop a simple and fast method for its purification by using centrifugal partition chromatography (CPC), as well as to investigate in vitro the anti-inflammatory effects of glaucolide B. Thus, an optimized washing extractive process performed on L. chamissonis leaves allowed to obtain a SL enriched extract (4.11 g). After a successful defatting pretreatment of the crude extract, the glaucolide B enriched ethyl acetate portion (2.00 g) was fractionated by CPC affording, in a single-step isolation, compound 1 (1.04 g) in great yield (25%) and purity (97%). Cytotoxicity effect of 1 on RAW 264.7 macrophages was determined by using MTT assay, revealing a CC10 of 14.11 μM. Compound 1 at 1, 3 and 10 μM inhibited the nitrite/nitrate (NOx) metabolites production and the pro-inflammatory interleukin 6 (IL-6) secretion on lipopolysaccharide-stimulated RAW 264.7 cells. The extractive process used turned to be selective for SL and CPC technique proved a simple and effective tool for the isolation of 1 within few hours. Isolated for the first time from L. chamissonis leaves, glaucolide B presented a significant inhibitory effect on both NO and IL-6 secretion under non-toxic concentrations.