| Summary: | 碩士 === 台北醫學院 === 藥學研究所 === 90 === In the traditional Chinese medicine, a large number of Rehmannia glutinosa is used to treat for Diabetes Mellitus (DM). The hypoglycemic activity of the dry root is most obvious of the different procession techniques of Rehmannia glutinosa (Scrophulariaceae). Several Japanese investigators reported extensive studies on the constituents of R. glutinosa. But, besides catalpol, rehmannioside D, and a part of polysaccharide, there were fewer compounds focused on the relation between the constituent and hypoglycemic activity. Therefore, a chemical investigation for hypoglycemic active components in R. glutinosa was performed. The dried roots of R. glutinosa were extracted with 60% aqueous acetone, to afford crude extract, which was partitioned between chloroform and water, than butanol and water. Preliminary screen test showed water-soluble and butanol-soluble fractions were hypoglycemic active. These active fractions were subject to various columns chromatography. Thirteen compounds were isolated and purified. The structures of these compounds were determined based on the analysis of NMR and MS spectroscropic data. They are methyl-β-D-fructofuranoside (1), raffinose [β-D-fructofuranosyl O-α-D-galactopyranosyl-(1→6)-α-D- glucopyranoside] (2), stachyose [β-D-fructofuranosyl O-α-D-galacto- pyranosyl-(1→6)-O-α-D-galactopyranosyl-(1→6)-α-D-glucopyranoside] (3), catalpol (4), dihydrocatalpol (5), uridine (6), ajugol (leonuride) (7), jioglutin B (8), adenosine (9), 1-hydroxypinoresinol (10), 6-O-E-feruloyl ajugol (11), martynoside (12), rehmarglutinoside (13). Among them, stachyose, catalpol, and ajugol showed hypoglycemic action on STZ mice. Moreover, it is noteworthy that rehmarglutinoside is a new compound, and dihydrocatalpol, 1-hydroxypinoresinol are first isolated from Rehmannia glutinosa.
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