New triterpenoids and anti-inflammatory constituents from Eriobotrya japonica

Eriobotrya japonica (Thunb.) Lindl. (Rosaceae) is a small tree native to Japan and China that is widely cultivated for its succulent fruit. Previous studies of this plant have reported the isolation of triterpenes, sesquiterpenes, flavonoids, megastigmane glycosides, and tannins. Some of these compounds have been reported to be biologically active, exhibiting anti-inflammatory, anti-tumor, antioxidant, antifungal, anti-HIV, or hypoglycemic properties. Investigation on EtOAc-soluble fraction of the methanol extract of the leaves E. japonica has led to the isolation of two new triterpenoids, methyl 2α-O-(E)-p-methoxycinnamoyl-3β-hydroxy-urs-12-en-28-oate (1) and methyl 2α-O-(E)-p-methoxycinnamoyl-3β-hydroxy-olean-12-en-28-oate (2), together with 6 known compounds. The structures of two new compounds 1 and 2 were determined through spectroscopic and MS analyses. Among the isolated compounds, ursolic acid and oleanolic acid were the most effective among the isolated compounds, with IC₅₀ values of 1.86 ± 0.16 and 1.48 ± 0.83 µg/ml, respectively, against fMLP-induced elastase release and superoxide generation. Our study suggests E. japonica and its triterpenoid derivatives (especially ursolic acid and oleanolic acid) as potential candidates for the treatment of various inflammatory diseases.

Acknowledgement: This research was supported by grants from the National Science Council (NSC, Taiwan) (No. NSC 98 – 2320-B-127 – 001-MY3 and NSC 101 – 2320-B-127 – 001-MY3), awarded to Prof. J.-J. Chen.