Two new iridoids and one new flavonoid glucoside from the tender leaves of Eucommia ulmoides and their anti-inflammatory activity

Two new iridoids, (3S,4R,5R,6S,9R)-eucommiate A (1) and (1R,2R)-eucommiol-2-hydroxypropylate (2), one new flavonoid glucoside kaempferol 3-O-(6''-O- methylmalonyl)-ss-D-glucoside (7), together with six known compounds (3-6, 8-9) were isolated from the tender leaves of Eucommia ulmoides Oliv. The structures of the new compounds were elucidated by NMR and HRESIMS. The absolute configuration of 1 was determined by electronic circular dichroism (ECD). Compounds 1-9 were evaluated in RAW264.7 macrophages to determine their inhibitory effect on LPS-induced NO production. Of the nine compounds extracted, only compound 9 had inhibitory activity (IC50 = 58.4 mu M), while the IC50 values of the other eight compounds were > 100 mu M.