Chemical characterization of the main bioactive constituents from fruits of Ziziphus jujuba
The fruit of Ziziphus jujuba Mill., also called hongzao in Chinese, has a long history of cultivation in China. From the fruit of Z. jujuba, twenty-seven known compounds were isolated and identified as the main constituents of these fruits. They were 3-O-(trans-p-coumaroyl)-alphitolic acid (1), 3-O-(cis-p-coumaroyl)-alphitolic acid (2), 3β-O-(trans-p-coumaroyl)-maslinic acid (3), pomonic acid (4), 2-oxo-pomolic acid (5), benthamic acid (6), terminic acid (7), oleanic acid (8), betulinic acid (9), quercetin 3-O-rutinoside (10), quercetin 3-O-robinobioside (11), apigenin (12), traumatic acid (13), (Z)-4-oxotetradec-5-enoic acid (14), 7(E)-9-keto-hexadec-7-enoic acid (15), 9(E)-11-oxo-octadecenoic acid (9CI) (16), and magnoflorine (27), etc. The HPLC fingerprint of Z. jujuba fruits was established at the same time. Compounds 4, 5, 7, 11, 14, 15 and 16 were isolated from Z. jujuba for the first time. Compound 14 was isolated from the nature for the first time. Furthermore, cytotoxicity against four human tumor cell lines (MCF-7, A549, HepG2 and HT-29) of the isolated compounds (1–17 and 27) was evaluated. Among these compounds, compounds 1, 2, 3, 6, 7, 9 and 12 had strong growth inhibitory effects on cancer cell lines. These results indicated that jujube extracts exhibited cytotoxicity on these cancer cell lines.