| Rehmarnnia glutinosa Libosch (Scrophulariaceae) is indigenous to Mainland China, and the roots of this plant have been used in oriental medicine as an antianemic, an antipyretic, and a tonic. Due to the different processing methods, R. glutinosa is classified into three categories namely, fresh roots, dried roots, and steamed roots, which are used in different ways in traditional Chinese medicine. Previous phytochemical studies on the dried and steamed roots of R. glutinosa have led to the isolation and identification of iridoid glycosides, ionone glycosides, phenethyl alcohol glycosides, and several other components.The roots of R. glutinosa were investigated on their chemical constituents systematically by various kinds of chromatographic methods. The sructures of isolates were elucidated on the basis of spectroscopic analysis and chemical evidence. Some of them were assayed for their bioactivities.110compounds were obtained from ethanolic extract of theair-dried roots of R. glutinosa. These compounds were identified as follows:rehmaglutoside A-K (1*-11*), jioglutin F (12*), frehmaglutoside A-F (13*-18*),1,4,5,6-tetrahydro-1-methyl-6-oxo-3-pyridineacetic acid (19*), catalpol (20), ajugol (21), myoporoside (22), aucubin (23), monomelittoside (24),5-deoxyantirrhinoside (25), dihydro catalpol (26), myobontioside A (27),3’-O-β-D-glucopyranosyl-catalpol (28), melittoside (29), rehmannioside C (30), rehmannioside A (31),5-deoxylamiol (32), lamiol (33), gardoside (34),8-epiloganic acid (35), geniposidic acid (36), mussaenosidic acid (37), gardoside methyl ester (38), geniposide (39),8-epiloganin (40), jioglutoside B (41), genipin-gentiobioside (42), genipin1-O-α-L-rhamnopyran-osyl (1→6)-β-D-glucopyranoside (43), genameside C (44),6-O-E-feruloyl ajugol (45),6-O-vanillate ajugol (46),6-O-p-hydroxybenzoyl ajugol (47),6-O-(4"-O-α-L-rhamnopyranosyl) vanilloyl ajugol (48),6-oxo-4’-(3-methoxyl-4-hydroxyphenylgly-col-8")-feruloyl ajugol (49-50),6-O-E-caffeoyl ajugol (51),6-O-sec-hydroxy-aeginetoyl ajugol (52), aeginetoyl ajugol5"-O-β-D-quinovoside (53), genipin (54), jioglutins D (55),6β-hydroxy-2-oxabicyclo[4.3.0]△"9-nonen-l-one (56), jioglutins E (57), aeginetic acid (58), dihydroxy-β-ionone (59), rehmapicrogenin (60), trihydroxy-β-iononem (61), sec-hydroxyaeginetic acid (62), aeginetic acid5-O-β-D-quinovoside (63), neo-rehmannioside (64), dihydrophaseic acid4’-O-β-D-glucopyranoside (65), rehmaionoside C (66), melasmoside (67), rehmaionoside A (68), rehmaionoside B (69), oxyrehmaionoside B (70), martynoside (71), sculponiside (72),2-phenylethyl-O-β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside (73), acteoside,(74), salidroside (75), leucosceptoside A (76), jionoside D (77), deacyl-martynoside (78), jionoside A1(79), jionoside B1(80),3,4-dihydroxy-β-phenethyl-O-α-L-rhamnopyranosyl-(1→3)-O-β-D-galacopyranosyl-(1→6)-4-O-caffeoyl-β-D-glucopyra noside (81), vanillin (82),1-(4-methy-2-furanyl)-2-(5-methyl-5-ethenyl-2-tetrahydro-furanyl)-propan-l-one (83), cis-asarone (84), eugenol (85), isoeugenol methyl ether (86), ferulic acid (87), benzoic acid (88), syringic acid (89), β-sitosterol (90), adenosine (91), adenine (92), rhamnopyranosyl vanilloyl (93), syringicacid-4-O-a-L-rhamnopyranoside (94),2-methoxy-4-methylphenyl-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (95), glucose (96), galactopyranose (97), stachyose (98), sucrose (99), manninotriose (100), raffinose (101), yemuoside YM1(102-103),(7R,8S,7’R,8’S)-4,9,4’,9’-tetrahydroxy-3,3’-dimethoxy-7,7’-epoxylignan9-O-β-D-gluc-opyranoside (104),1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (105), tachioside (106), isotachioside (107), acrylic acid (108), dibutyl phthalate (109), besides, the aglycone of catalpol (110) was also obtained.Among the isolated one hundred and ten compounds, there were fifty-one iridoid and iridoid glycosides (1*-12*,20-57,110), nineteen monoterpene and sesquiterpenes and nor sesquiterpenes (13*-18*,58-70), ten phen ethyl alcohol glycosides (71-72,74-81) and thirty other components (19*,73,82-109). Nineteen compounds (1*-19*) were new compounds.The crude extracts and ninety-seven compounds obtained from the roots of R. glutinosa were tested for their cytotoxicity against five human tumor cell lines by MTT method. However, all were inactive for all cell lines used (IC50>10μM is defined as "inactive").By the model of inhibiting the production of lipid peroxide induced by Fe2+-Cys system in the liver microsomal, ninety-seven compounds were evaluated for their antioxidant activities and compounds5,51,76-77exhibited weak activities. Compounds71-72,74-75,79-80and100exhibited moderate hepatoprotecti-ve activities against APAP-induced HepG2cell damage. They were also bioassayed for their hepatoprotective activities against D-galactosamine induced toxicity in HL-7702cells, using the hepatoprotective activity drug bicyclol as the positive control, fractions1,3,5,10-14exhibited moderated hepatoprotective activities, and compounds11,23,30,34,58,62,68,73,75,90,93and95exhibited pronounced hepatoprotective activities.Fractions5,10,13and14exhibited anti-inflammatory activities in vivo. Th e inhibitory effects of the isolates against nitric oxide (NO) production in mou seperitoneal macrophages were examined. Some compounds inhibited NO elevat ion at a concentration of10μM.All ninety-seven compounds were inactive for anti influenza virus NA (neuramidinase) tested model.All crude extracts exhibited weak sedative-hypnotic activites and were inactive in inhibiting H+-K+-ATPase activity.All crude extracts were inactive in decreasing triglyceride level.The protective activities of the crude extracts and compounds against neuroto xicity induced by serum deprivation in PC12cells were investigated by the M TT method. The results showed that serum deprivation induced significant inhi-bition of MTT reduction. Fraction7increased cell viability at a concentration of1μg/ml and10μg/ml, respectively. Furthermore, compounds74,77,81and98exhibited protective activity on cell damage induced by nicouline at a conc-entration of10μM, indicating that they may be effective in neurodegenerative disorders.It has been found22possible potassium channel inhibitors by detecting fluorescent membrane potential in PC12cells.For antidiabetic bioactivities, all crude extracts exhibited weak activities in inhibiting PTP1B (protein-tyrosine phosphatase-1B) and FBPasel. Fraction1and compound74possesed obvious inhibition agaist aldose reductase, with IC50values of3.5μg/ml and2.68×10-7μM, respectively, and other compounds showed inhibitory rates less than69.4%at a concentration of10μM. All crude extracts exhibited weak activities in inhibiting a-glucosidase at a concentration of40μg/ml and all compounds tested showed inhibitory rates less than32.4%at a concentration of40μM. Compounds51,74,77and81exhibited pronounced activities in inhibiting lipidase on a concentration of10μM. All crude extracts exhibited weak activities in inhibiting DPP-IV and PPARγ transcription. Fractions3and12exhibited significant GK (glucokinase) enzymatic activity, which was comparative to the positive control. Further more, in vivo, compound20exhibited weak antihyperglycemic activity at a concentration of200mg/kg on hyperglycemic mice induced by alloxan by intragastric administration, but no significant activity at a concentration of300mg/kg by intraperitoneal injection. In T2DM Kkay mice model, compound20exhibited no significant activity at a concentration of200mg/kg by intragastric administration. |
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