Studies On Chemical Constituents Of Rehmannia

Objective:Rehmannia glutinosa belongs to Scrophulariaceae family, which roots are fresh or dry. It was recorded in "shen nong ben cao Jing" as well as classified as the upper grade, which is one of "four Huaiqingchinese medicines". Due to the different processing methods and medicinal effects, Rehmannia glutinosa is classified into three categories, namely, fresh roots, dried roots, and steamed roots. Previous pharmacological investigation have demonstrated its significant biological properties such as anti-diabetic, anti-aging, and hepatoprotective activities. Our previous research indicated that Rehmannia Radix has estrogenic activity firstly, and then screened the effective part. Finally, the95%aqueous EtOH extract was determined the effective part which played a role in estrogenic and immunosuppressive activities. The present study was undertaken to investigate the chemical constituents of the95%aqueous EtOH extract of the roots of R. glutinosa, which lay the foundation for its further development and utilization.Methods:The dried roots (20.0kg) of R. glutinosa were cut into small pieces and extracted with95%EtOH under heating reflux for2h twice. After concentrated under reduced pressure in a vacuum evaporator, the concentrated solution (1500mL) was centrifuged and subjected to Diaion HP-20column then eluted with H2O and MeOH successively, abtained the water extracts and the methanol extracts (101.6g). Next the methanol extracts were dissolved in10%MeOH-H20(1000mL), subjected to Diaion HP-20column once again, eluted successively with10%,30%,50%,70%,100%(v/v) MeOH-H20(10column volume each). The fractions were isolated and purified by column chromatography repeatedly by means of Toyopearl HW-40, RP-18, MCI gel CHP-20, Sephadex LH-20and recrystallization to yield compounds. And the structures were elucidated based on spectral methods (IR, ID and2D NMR, HR-ESI-MS).Results:58compounds were isolated from the dried roots of Rehmannia glutinosa and the structures were elucidated by spectroscopic and chemical methods. They were ajugol (SDH-1-1), pterolactam (SDH-1-3),1,2,4-Benzenetri (SDH-1-9), adenosine (SDH-1-10), guanosine (SDH-1-12), rehmaionoside C (SDH-1-14), rehmannioside D (SDH-1-15), catalpol (SDH-1-16),10一deoxyeucommiol(SDH-1-17),rehmapicrogenin(SDH-2),3-methoxy-2,6,6-trimethylcyclohex-1-enecarb oxylic acid(SDH-3),rehmapicrogenin A(SDH-4),leonoside F(SDH-7), frehmaglutoside G(SDH一8),rehmapicroside(SDH-9),frehmaglutoside H (SDH-10), rehmaionoside A (SDH-12), echinacoside (SDH-13), rhamnopyranosyl vanilloyl(SDH-14a),syringicacid-4-O-a-L-rhamnopyra noside(SDH-14b),8-epiloganic acid(SDH-15),4-[2’-formyl-5’-(hydroxy methyl)-1H-pyrrole-1-yl)] butanoic acid (SDH-16), guaicylglycerol (SDH-18),7-O-ethyl guai acylglycerol(SDH-19),1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid(SDH-21),sec-hydroxyaeginetic acid(SDH-25), p-hydroxylphenylethand glucoside(SDH-26),rehmalignan A(SDH-27a), rehmalignan B(SDH-27b),syringic acid(SDH-28),p-hydroxybenzoic acid (SDH-29),coniferin(SDH-30),6-O-vanillate ajugol(SDH-5-2),trans-liovil (SDH-5-3), jiofuraldehyde dimethyl acetal (SDH-5-5), E-p-hydroxy cirmamic acid methyl ester(SDH-5-6),trans-p-hydroxy cinnamic methyl ester (SDH-5-7),6-O-E-feruloyl ajugol(SDH-5-10), frehmaglutin B (SDH-5-11),martynoside(SDH-5-13),3-indolecarbxylic acid(SDH-5-14), acteoside (SDH-5-14), isoacteoside (SDH-5-18), trihydroxy-β-ionone (SDH-5-19),jionoside B1(SDH-5-20),6-O-(4"-O-a-L-rhamnopyranosyl) vanilloyl ajugol(SDH-5-21),3-methoxy-4-hydroxyl-cirmamic aldehyde (SDH-7-1),(7R,8S)-4,9,3’,-trihydroxy-3-methoxy-7,8-dihydrobenzofuran-1’-propanaln eolignan(SDH-7-2),9,12,13-trihydfoxy-10-octade-cenoic acid(SDH-7-3), dihydroxy-β-ionone (SDH-7-6),6-O-sec-hydroxyaeginetoyl ajugol (SDH-7-10), daucosterol (SDH-m-1),5α,6β-dihydroxy daucosterol (SDH-m-3), oleic acid (SDH-m-5), dibutyl phthalate (SDH-m-5a), β-sitosterol (SDH-m-7), Diincarvilone A (SDH-m-9), glutinosalactone A(SDH-m-10).Conclusion:Four new compounds,frehmaglutoside G(SDH-8)and H (SDH-10),rehmalignan A(SDH-27a)and B(SDH-27b)were isolated from this plant.The other seventeen known compounds SDH-1-3,SDH-1-12, SDH-1-17,SDH-7,SDH-16,SDH-19,SDH-21,SDH-30,SDH-5-3,SDH-5-5, SDH-5-6,SDH-5-7,SDH-5-14,SDH-7-1,SDH-7-2,SDH-m一3,SDH-m-9 were isolated from this plant for the first time.