Labdane and norlabdane diterpenoids from the aerial parts of Leonurus japonicus

Publication date: December 2017 Source:Phytochemistry Letters, Volume 22 Author(s): Ly T.T. Nguyen, Huong K.T. Vo, Son V. Dang, Tho H. Le, Ly D. Ha, Le-Thu T. Nguyen, Lien-Hoa D. Nguyen A new labdane diterpenoid, leojaponicin (1), a novel norlabdane, methyl 15,16-dinor-7-oxolabda-8-ene-14-oate (2), along with four known labdanes, hispanone (3), leoheteronins A (4) and B (5), 15-methoxyleoheteronin B (6), and three norlabdanes, 14,15,16-trinor-7-oxolabda-8-ene-13-oic acid (7), methyl 14,15,16-trinor-7-oxolabda-8-ene-13-oate (8), 14,15-dinor-8-labdene-7,13-dione (9), and a steroid, stigmast-4-ene-3-one (10), were isolated from a hexane extract of Leonurus japonicus. Their structures were determined using spectroscopic methods, mainly 1-D and 2-D NMR. Compounds 7 and 8 were previously semisynthesized but are reported here for the first time as naturally occurring compounds. In addition, α-glucosidase inhibitory activity of the isolated compounds was evaluated and compound 6 exhibited the strongest effect with IC50 value of 26.7μM (compared with the positive control acarbose, IC50 =214.5μM). Graphical abstract

Source: Phytochemistry Letters - October 10, 2017 Category: Chemistry Source Type: research