[Chemical constituents from hypoglycemic active part of Plantaginis Semen]

The chemical constituents of Plantaginis Semen with hypoglycemic effect was investigated in this paper. The previous results of the in vivo hypoglycemic effect showed that 60% ethanol extract of Plantaginis Semen decreased the levels of FBG and improved the glucose tolerance in high fat diet(HFD)-induced diabetic C57BL/6 mice. Then, in the present study, the above potential bioactive extract was separated and purified by silica gel, ODS, Sephadex LH-20 column chromatography, medium pressure liquid chromatography(MPLC)and preparative HPLC. The structures of isolated compounds were identified by physicochemical properties and spectral analyses. Eight compounds were obtained and identified as 4, 4a, 5, 7a-tetrahydro-7-(hydroxymethyl)cyclopenta[c]pyran-3(1H)-one(1), iridolactone(2), pedicularislacton(3), rehmaglutin C(4), geniposidic acid(5), p-hydroxylphenylglycerol(6), 1, 2-benzenediol-4-(2-hydroxyethyl)(7), and 3-buten-2-one-4-[3-(β-D-glucopyranosyloxy)-4-hydroxyphenyl](8). Among them, compounds 1-5 were iridoids, and 6-8 were phenolic acids. Compound 1 was a new natural product, and compounds 2-4, 6 and 8 were isolated from the Plantaginaceae family for the first time.