Anti-inflammatory and antihistaminic activity of triterpenoids isolated from Bursera cuneata (Schldl.) Engl

Abstract

Aim of the studyTo isolate compounds with anti-inflammatory activity from Bursera cuneata by a bioassay-guided fractionation. Materials and methodsThree extracts of different polarities were elaborated by maceration. These extracts were assayed for their inhibitory effects on phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induced edema in mice. The dichloromethane extract was subjected to activity guided fractionation using successive chromatographic procedures. Additionally, the levels of histamine were determined in the ear samples obtained from the TPA assay, which were determined by high-performance liquid chromatography (HPLC). Effect of moronic Acid on RAW 264.7 stimulated with LPS was evaluated for NO and TNF secretion. ResultsThe dichloromethane extract had the highest anti-inflammatory effect (89.1 ± 2.2% inhibition) over that of the hexane (53.3 ± 1.2%) and methanolic (77.4 ± 1.8%) extracts at a dose of 0.1 mg/ear. The FS-3 fraction, obtained from the dichloromethane extract, comprised triterpenes β-sitosterol (1), α-amyrin (2), moronic acid (3), and ursolic acid (4), and all the compounds showed significant activity in comparison with that of indomethacin (41.5 ± 0.6%) at 0.1 mg/mouse ear. However, moronic acid displayed the highest inhibitory effect (68.1 ± 1.3%). Additionally, levels of histamine were determined by HPLC in the treated tissues. moronic acid was the most active (73.3 ± 1.1%, indomethacin 33.8 ± 0.8%). The bio-guided isolation resulted in the identification of moronic acid as the principal anti-inflammatory and antihistaminic compound present in B. cuneata. To confirm a general anti-inflammatory effect, moronic acid was evaluated on the activation of RAW 264.7 cell stimulated with LPS. At 30 and 15 mg/mL a significant reduction of ON was observed (36% and 28% respectively) but had no significant effect on TNFα production. ConclusionsOur study showed that the organic extracts and isolated compounds from the aerial parts of B. cuneata had topical anti-inflammatory and antihistaminic activities in vivo, but in vitro only modified the production of ON in RAW cells. The results of this study validated the use of B. cuneata in folk medicine for the treatment of inflammatory diseases.