Pharmaco-constituents of Isodon excisus var. coreanus (Labiatae) were investigated to explore a substitute for Isodon japonicus which has been used for the treatment of the anorexia, indigestion, stomachache, inflammation, microbism, esophageal carcinoma in Korean folk Medicine.
The methanolic extract of I. excisus var. coreanus was suspended in water and then extracted with diethyl ether to remove fatty substances. The aqueous fraction was further seperated by Amberlite XAD-2 column employing gradient solvent systems (H₂O, 20, 40, 60 and 100% MeOH). By successive column chromatography using Sephadex LH-20, ODS and silica gel, Compound I and Compound II were isolated from the 20% MeOH fraction. Compound III and Compound IV were obtained from the 40% and 60% MeOH fractions, respectively.
Chemical structures of these compounds were elucidated on the basis of physico-chemical and spectral data of IR, FAB-MS, ¹H-NMR, ¹³H-NMR, ¹H-¹H COSY, ¹³C-¹H COSY and HMBC (¹H-Detected Multiple-bond Heteronuclear Mutiple Quantum Coherence Spectrum). Structures of compounds I, II, III and IV were identified as α-〔 [3-(3, 4-dihydroxyphenyl)-1-oxo-2-propenyl] oxy〕 -3, 4-dihydroxy-benzenepropanoic acid, 9-methyl-dhydroferulic acid-4-O-β-D-glucopyranosyl (1→2)-α-L- rhamnopyranosyl (1→4)-β-D-glucopyranoside, ent-7 α,11 α, 15 β-trihydroxy-kaur-16-en-1-O-β-D-glucopyranoside and 2 α,3 β,7 α,23-tetrahydroxy-olean-12-en-28-oic acid 28-O-β-D-glucopyranoside, respectively.
Especially, compounds I and II were novel substances from nature and named as Isodonin A, Isodonin B in the order mentioned.