Anti-inflammatory oleanolic triterpenes from Chinese acorns

Abstract

Acorns play an important role in human history and are a source of food and recipes for many cultures around the world. In this study, eleven oleanolic triterpenes, one of which was novel, were isolated from Chinese acorns (Quercus serrata var. brevipetiolata). The chemical structure of the novel triterpene, which was identified as 2α,3β,19α-trihydroxy-24-oxo-olean-12-en-28-oic acid (1), was established based on the interpretation of chemical and spectroscopic analyses, including IR, HR-ESI-MS, and NMR experiments (1H, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC, and NOESY). All isolated compounds were tested for their inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages. Compared with the positive control drug indomethacin (IC50 = 47.4 μM), compounds 1, 3, 6 and 8 exhibited remarkable anti-inflammatory activities with IC50 values of 5.4, 7.8, 4.0 and 8.9 μM, respectively. Besides, compounds 2, 4, 7 and 9 also showed moderate anti-inflammatory activities with IC50 values of 10.1, 13.0, 20.1 and 17.2 μM, respectively. Furthermore, Compound 1 could inhibit TNF-α-induced IL-6 and IL-8 production in MH7A cells.