Iridoids from Scutellaria albida ssp. albida

Three iridoid glycosides, 6'-O-E-p-coumaroylgardoside (1), 6'-O-p-E-coumaroyl-8-epi-loganic acid (2) and scutelloside (3) were isolated from the aerial parts of Scutellaria albida subsp. albida, in addition to an anomeric mixture in equilibrium of one iridoid aglycone (4, 4a), nine iridoid glycosides (5-13), four known phenylethanoid glycosides (14-17), and six known phenolic derivatives (18-23).     

Identification of tyrosinase inhibitors from Marrubium velutinum and Marrubium cylleneum

Tyrosinase is a key enzyme in the production of melanins in plants and animals. Forty-five secondary metabolites isolated from Marrubium velutinum and Marrubium cylleneum belonging to the classes of flavonoids, phenylethanoid glycosides, phenolic acids and lignan glycosides were screened for their inhibitory activity against mushroom tyrosinase. Flavonoids and phenylethanoid glycosides showed moderate inhibitory activity, while phenolic acids were less active than phenylethanoid glycosides, suggesting that both phenolic groups are important for the activity.     

Further constituents from the bark of Tabebuia impetiginosa

Further study on the constituents from the bark of Tabebuia impetiginosa (Mart. ex DC) Standley afforded twelve compounds, consisting of four iridoid glycosides, one phenylethanoid glycoside, five phenolic glycosides, and one lignan glycoside, along with seven known compounds. The structures of these compounds were determined based on the interpretation of their NMR and MS measurements and by chemical evidence.     

Cytotoxic phenylethanol glycosides from Psidium guaijava seeds

Phytochemical investigations of the acetone extract of Psidium guaijava seeds has led to the isolation of five known flavonoid glycosides, two phenolic glycosides and two new phenylethanoid glycosides which have been identified as 1-O-3,4-dimethoxy-phenylethyl-4-O-3,4-dimethoxy cinnamoyl-6-O-cinnamoyl-beta-D-glucopyranose and 1-O-3,4-dimethoxyphenylethyl-4-O-3,4-dimethoxy cinnamoyl-beta-D-glucopyranose, on the basis of chemical, physical and spectroscopic methods of analysis.     

Phenylethanoids, iridoids and a spirostanol saponin from Veronica turrilliana

From the aerial parts of Veronica turrilliana two phenylethanoid glycosides, turrilliosides A and B and a steroidal saponin, turrillianoside were isolated and their structures elucidated as beta-(3,4-dihydroxyphenyl)ethyl-4-O-E-caffeoyl-O-[beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranosyl-(1-->6)]-beta-glucopyranoside, beta-(3,4-dihydroxyphenyl)ethyl-4-O-E-caffeoyl-[6-O-E-feruloyl-beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranosyl-(1-->6)]-beta-glucopyranoside and (23S,25S)-12beta,23-dihydroxyspirost-5-en-3beta-yl O-alpha-rhamnopyranosyl-(1-->4)-beta-glucopyranoside, respectively. Furthermore, eight known glucosides are reported namely, catalpol, catalposide, verproside, amphicoside, isovanilloylcatalpol, aucubin, arbutin, and 6-O-E-caffeoylarbutin, the latter two for the first time in the genus Veronica. The two phenylethanoid glycosides were found to be potent DPPH radical scavengers. All of the tested compounds were inactive against the representative species of fungi and bacteria.     

Phenylethanoid and lignan glycosides from Verbascum thapsus.

Verbascum thapsus afforded, in addition to three known phenylethanoid glycosides and four lignan ones, five new phenylethanoid glycosides and one new lignan glycoside. Structures of the compounds were elucidated by spectroscopic methods and chemical evidence.     

Iridoid and megastigmane glycosides from Phlomis aurea

From the leaves of Phlomis aurea, two new iridoids of unique structures named 3-epiphlomurin (1) and phlomurin (2), a new megastigmane glucoside phlomuroside (3) and a new benzyl alcohol glycoside having the structure benzyl alcohol-O-beta-xylopyranosyl-(1-->2)-beta-glucopyranoside (4) have been isolated together with four known iridoids auroside, lamiide, 8-epiloganin and ipolamiide, two known phenolic glycosides acteoside (verbascoside) and syringin, one known phenylethanoid glycoside 2-phenylethyl-O-beta-xylopyranosyl-(1-->2)-beta-glucopyranoside, one known lignan liriodendrin and three known flavonoids chrysoeriol-7-O-beta-glucopyranoside, acacetin-7-O-beta-glucopyranoside and luteolin-7-O-beta-glucopyranoside. The structures of the isolated compounds were verified by means of mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectral analyses.     

Steroidal saponins from the aerial parts of Tribulus alatus Del

Six steroidal glycosides (1-6) were isolated from the aerial parts of Tribulus alatus Del. (Zygophyllaceae), together with one known cholestane, one spirostane, and six flavonol glycosides. Among them, 1 and 2 possess a furostane-type aglycone, 3 and 6 a cholestane structure, and 4 and 5 a spirostane skeleton. Their structural elucidation was accomplished by extensive spectroscopic methods including 1D ((1)H, (13)C, (13)C DEPT, TOCSY, ROESY) and 2D NMR experiments (DQF-COSY, HSQC, HMBC) as well as ESI-MS analysis.     

Four new immunomodulating steroidal glycosides from the stems of Stephanotis mucronata

Four new C-21 steroidal glycosides, mucronatosides E (1), F (2), G (3), and H (4), were isolated from the stems of Stephanotis mucronata. Two of them had the rare aglycone with a double bond between C-6 and C-7. Their structures were elucidated on the basis of spectroscopic data and chemical evidence. These isolated compounds were assayed for their immunological activities in vitro against concanavalin A (Con A)- and lipopolysaccharide (LPS)-induced proliferation of mice splenocytes. Compounds 2 and 4 showed immunosuppressive activities in a dose-dependent manner, while compounds 1 and 3 possessed immunoenhancing activities.     

Newbouldiosides A-C, phenylethanoid glycosides from the stem bark of Newbouldia laevis

From the stem bark of Newbouldia laevis three phenylethanoid glycosides, designated as newbouldioside A-C, were isolated together with a sodium salt of analogue B and the known compounds, verbascoside, 5-hydroxydehydro-iso-alpha-lapachone, 3,8-dihydroxydehydro-iso-alpha-lapachone, apigenin and luteolin. The structures of the phenylethanoid glycosides were elucidated by spectroscopic methods as beta-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-beta-D-glucopyranoside, ss-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-6-O-E-feruloyl-beta-D-glucopyranoside, and beta-(3,4-dihydroxyphenyl)ethyl 3-O-E-feruloyl-beta-D-apiofuranosyloxy-(1-->2)-O-alpha-L-rhamnopyranosyl-(1-->2)-6-O-E-sinapoyl-beta-D-glucopyranoside, respectively.     

Phenolic glycosides from Kaempferia parviflora

Three phenolic glycosides were isolated together with two known flavonol glycosides from the H2O-soluble fraction of rhizomes of Kaempferia parviflora. Their structures were determined to be rel-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranoside] (1), its rel-5aS,10bR isomer (2), and (2R,3S,4S)-3-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranosyl]-3'-O-methyl-ent-epicatechin-(2alpha-->O-->3,4alpha-->4)-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside] (3). The structures were elucidated on the basis of analyses of chemical and spectroscopic evidence.     

Acylated flavonoid and phenylethanoid glycosides from Marrubium velutinum

From the aerial parts of Marrubium velutinum, one acylated flavonoid glycoside, chrysoeriol 7-O-(3",6"-di-O-E-p-coumaroyl)-beta-D-glucopyranoside, and two tetrasaccharidic phenylethanoid glycosides, velutinosides I-II, have been isolated together with ten known flavonoids and seven known phenylethanoid glycosides. The structures of the isolated compounds were established by means of NMR, MS, and UV spectral analyses.     

通光藤甙F,G,H和I结构

从通光藤(Marsdeniatenacissima)的茎中分离得到4个新的C21甾体甙———通光藤甙F(3),G(4),H(5)和I(6),以及2个已知化合物通光藤甙A(1)和B(2)。根据光谱数据和化学方法推定了其结构。同时,通过COLOC谱和二维核磁共振谱指定了这些化合物中甙元上11和12位的酯基确切连接位置。     

Chemotaxonomic markers in Digitalideae (Plantaginaceae)

In a chemosystematic investigation of Digitalideae (Plantaginaceae), the water-soluble part of extracts of two species of Digitalis, two species of Isoplexis, as well as Erinus alpinus and Lafuentea rotundifolia were studied with regard to their content of main carbohydrates, iridoids and caffeoyl phenylethanoid glycosides (CPGs). Digitalis and Isoplexis contained sorbitol, cornoside and a number of other phenylethanoid glycosides including the new tyrosol beta-D-mannopyranoside, sceptroside but were found to lack iridoid glucosides. Erinus contained mainly glucose, the new 8,9-double bond iridoid, erinoside, and a number of known iridoid glucosides including two esters of 6-rhamnopyranosylcatalpol, as well as the CPG poliumoside. Finally, Lafuentea was characterized by the presence of glucose, aucubin and cryptamygin B but apparently lacked CPGs. The chemosystematic significance of the isolated compounds is discussed.     

Ornithosaponins A-D, four new polyoxygenated steroidal glycosides from the bulbs of Ornithogalumthyrsoides

By analyzing the steroidal glycoside content of fresh bulbs of Ornithogalum thyrsoides (Liliaceae), we were able to isolate four new polyoxygenated steroidal glycosides, which we named ornithosaponins A-D (1-4). The structures of 1-4 were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic or alkaline hydrolysis. The aglycone structure of 1-4 has not been previously reported. It is also notable that ornithosaponins B-D (2-4) have been found to contain 6-deoxy-beta-D-gulopyranose as a sugar component, which is rarely encountered in plant glycosides.     

Anticancer diarylheptanoid glycosides from the inner bark of Betula papyrifera

Phytochemical investigations of the MeOH extract of Betula papyrifera inner bark led to the isolation of ten phenolic compounds of the following types: diarylheptanoid glycosides (1-4), a diarylheptanoid (5), a lignan (6), flavonoids (7-8) and chavicol glycosides (9-10). Among them, the diarylheptanoid glycoside, (S)-1,7-bis-(4-hydroxyphenyl)-heptan-3-one-5-O-alpha-L-arabinofuranosyl-(1-->6)-beta-D-glucopyranoside, papyriferoside A (1), was isolated and its structure was determined on the basis of 1D and 2D NMR, HPLC-MS, as well as high resolution mass spectroscopic data. Platyphylloside (4) exerted the strongest cytotoxic activity of all isolated compounds with IC(50) values ranging from 10.3 to 13.8 microM.     

In vivo anti-inflammatory and antinociceptive activity evaluation of phenolic compounds from Sideritis stricta

An acetone extract obtained from aerial parts of S. stricta Boiss. & Heldr. apud Bentham, its fractions and phenolic compounds were investigated for their in vivo anti-inflammatory and antinociceptive activities. For the anti-inflammatory activity and for the antinociceptive activity assessment, carrageenan-induced hind paw edema and p-benzoquinone-induced abdominal constriction tests were used, respectively. The acetone extract of the plant and its phenolic fraction exhibited potent inhibitory activity against both bioassay models in mice. From the active phenolic fraction a well-known phenylethanoid glycoside, verbascoside (acteoside) (1), and two flavonoid glycosides, isoscutellarein 7-O-[6"'-O-acetyl-beta-D-allopyranosyl-(1-->2)]-beta-D-glucopyranoside (2) and isoscutellarein 7-O-[6"'-O-acetyl-beta-D-allopyranosyl-(1-->2)]-6"-O-acetyl-beta-D-glucopyranoside (3), were isolated. During phytochemical studies we also isolated a methoxyflavone, xanthomicrol (4), from the non-polar fraction. The structures of the isolated compounds were established by spectroscopic evidence (UV, IR, 1D- and 2D-NMR, MS). Although antinociceptive and anti-inflammatory activities of the phenolic components were found not significant in the statistical analysis, compounds 1 to 3 showed a notable activity without inducing any apparent acute toxicity as well as gastric damage. Furthermore, a mixture of flavonoid glycosides (2 + 3) exhibited a significant inhibitory effect in both models at a higher dose.     

Neo-clerodane diterpenoids and phenylethanoid glycosides from Teucrium chamaedrys L

A neo-clerodane type diterpenoid, 12(S)-15,16-epoxy-19-hydroxy-neo-cleroda-13(16),14-dien-18,6alpha:20,12-diolide, and two phenylethanoid glycosides, teucrioside-3(IIII)-O-methylether and teucrioside-3(IIII),4(IIII)-O-dimethylether were isolated from the aerial parts of Teucrium chamaedrys. Their structures were identified on the basis of extensive NMR spectra, LC-ESIMS analysis, and molecular modeling studies.     

Comparative phytochemical characterization of three Rhodiola species

In comparison to the well-recognized adaptogenic herb Rhodiola rosea, phytochemical constituents of two other Rhodiola species (R. heterodonta and R. semenovii) were elucidated and characterized. Two major phytochemical groups; phenolic and/or cyanogenic glycosides and proanthocyanidins, were isolated and identified in the three species. Chemical similarities among the three species were observed; however, each species displayed differences in phytochemical constituents. R. heterodonta contained a newly detected phenylethanoid glycoside, heterodontoside, in addition to the known compounds tyrosol, viridoside, salidroside, and rhodiocyanoside A. Both R. heterodonta and R. rosea contained phenylethanoid/propanoid compounds that were not detected in R. semenovii. For R. semenovii, the cyanogenic glucosides rhodiocyanoside A and lotaustralin were detected. Although the three species have proanthocyanidins composed of (-)-epigallocatechin and its 3-O-gallate esters in common, the degree of polymerization greatly differed between them. In contrast to R. heterodonta and R. semenovii, R. rosea has higher molecular weight polymeric proanthocyanidins. This study resulted in the identification and isolation of phytochemical constituents for direct cross-comparison between three Rhodiola species of medicinal and pharmacological value.