Triterpenoid glycosides from the leaves of two cultivars of Medicago polymorpha L

The saponin composition of leaves from the Medicago polymorpha cultivars 'Santiago' and 'Anglona' belonging to the botanical varieties brevispina and vulgaris, respectively, was investigated by a combination of chromatographic, spectroscopic, and spectrometric techniques. Several compounds were detected and quantitated by HPLC analysis using the external standard method. Twelve triterpene saponins (1-12) were purified by reverse-phase chromatography and their structures elucidated by spectroscopic (1D and 2D NMR, ESI-MS/MS) and chemical methods. They were identified as glycosides of echinocystic acid, hederagenin, caulophyllogenin, bayogenin, and soyasapogenol B. Two of them (2, 10) were previously reported in M. polymorpha; five of them (4, 6, 7, 9, 12) were already identified in other Medicago species; and three of them (1, 8, 11) were found in other plant genera. The two saponins identified as 3-O-α-L-arabinopyranosyl-28-O-[β-D-glucopyranosyl(1→6)β-D-glucopyranoside] echinocystic acid (3) and 3-O-α-L-arabinopyranosyl-28-O-β-D-glucopyranoside echinocystic acid (5) are newly identified natural compounds. The presence of echinocystic acid is reported here for the first time in the genus Medicago. Saponins from the cultivar 'Anglona' were characterized by a higher amount of echinocystic acid glycosydes, whereas saponins from the cultivar 'Santiago' were characterized by a higher amount of hederagenin glycosydes.     

Alfalfa (Medicago sativa L.) flavonoids. 1. Apigenin and luteolin glycosides from aerial parts

Nine flavones and adenosine have been identified in aerial parts of alfalfa, and their structures were established by spectral (FABMS and NMR) techniques. Five of the identified compounds, including apigenin 7-O-[beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[2-O-feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[2-O-feruloyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], apigenin 7-O-[2-O-p-coumaroyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], and luteolin 7-O-[2-O-feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranosyl]-4'-O-beta-D-glucuronopyranoside, have not been reported before in the plant kingdom. Additionally, five known compounds, including apigenin 7-O-beta-D-glucuronopyranoside, apigenin 4'-O-beta-D-glucuronopyranoside, apigenin 7-O-[beta-D- glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside], luteolin 7-O-beta-D-glucuronopyranoside, and adenosine, were identified.     

Alfalfa (Medicago sativa L.) flavonoids. 2. Tricin and chrysoeriol glycosides from aerial parts.

Ten flavone glycosides have been isolated and identified in aerial parts of alfalfa. These included six tricin, one 3'-O-methyltricetin, and three chrysoeriol glycosides. Most of these compounds were acylated with ferulic, coumaric, or sinapic acids, and acylation occurred on the terminal glucuronic acid. Eight of these compounds, including 7-O-beta-D-glucuronopyranosyl-3'-O-methyltricetin, 7-O-beta-D-glucuronopyranosyl-4'-O-beta-D-glucuronopyranosidechrysoeriol, 7-O-[2'-O-feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]chrysoeriol, 7-O-[2'-O-feruloyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]chrysoeriol, 7-O-[2'-O-sinapoyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]tricin, 7-O-[2'-O- feruloyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]tricin, 7-O-[2'-O-p-coumaroyl-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]tricin, and 7-O-[2'-O-feruloyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]tricin, have not been reported previously in the plant kingdom. Two previously identified alfalfa flavones, 7-O-beta-D-glucuronopyranosidetricin and 7-O-[beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]tricin, were also isolated.     

Triterpene saponins from aerial parts of Medicago arabica L

Eight major triterpene saponins have been isolated from the aerial parts of Medicago arabica and their structures elucidated by FAB-MS and NMR analysis. Three of them are new compounds and are identified as 3-O-(alpha-L-arabinopyranoside) bayogenin, 3-O-(alpha-L-arabinopyranosyl), 28-O-(beta-D-glucopyranoside) bayogenin, and 3-O-[alpha-L-arabinopyranosyl(1-->2)-beta-D-glucuronopyranosyl], 28-O-beta-D-glucopyranoside 2-beta-hydroxyoleanolic acid. Two saponins, identified as 3-O-(alpha-L-arabinopyranoside) hederagenin and 3-O-(alpha-L-arabinopyranosyl), 28-O-(beta-D-glucopyranoside) hederagenin are known compounds but not previously reported as saponin constituents of Medicago species, while three other saponins, being mono- and bidesmosides of hederagenin, have been previously isolated from roots of M. sativa.     

Flavonol glycosides and novel iridoid glycoside from the leaves of Morinda citrifolia

One new iridoid glycoside and five known flavonol glycosides have been isolated from the leaves of Morinda citrifolia. The new iridoid exists as an epimeric mixture in solution. Complete assignments of the proton and carbon chemical shifts for the individual epimers were accomplished on the basis of high-resolution 1D and 2D NMR data. Their antioxidative activities were measured. All of these compounds showed DPPH free radical scavenging activity at the concentration of 30 microM.     

Use of a shrub (Medicago arborea) to control water erosion on steep slopes

Abstract. The effect of Medicago arborea on erosion on a burnt area was studied in experimental plots near Valencia, Spain, between 1989 and 1992. Its growth and development was studied, and its effect was compared with the natural vegetation (matorral) and bare soil. Medicago decreased soil loss by 41.7% and runoff by 25.7% compared with bare soil. However, under natural vegetation soil loss was 27.5% less than under Medicago.     

Acetophenone glycosides from thyme (Thymus vulgaris L.).

Four acetophenone glycosides were isolated from the butanol-soluble fraction of thyme extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR). Among them, two new compounds, 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D -gl ucopyranoside (1) and 4-hydroxyacetophenone 4-O-[5-O-(4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D-+ ++gluc opyranoside (2), were determined. Compound 1 showed weak cytotoxicity, inhibiting DNA synthesis of human leukemia cells.     

Phenolic antioxidants from the leaves of Corchorus olitorius L.

Six phenolic antioxidative compounds [5-caffeoylquinic acid (chlorogenic acid), 3,5-dicaffeoylquinic acid, quercetin 3-galactoside, quercetin 3-glucoside, quercetin 3-(6-malonylglucoside), and quercetin 3-(6-malonylgalactoside) (tentative)] were identified from the leaves of Corchorus olitorius L. (moroheiya) by NMR and FAB-MS. The contents of these phenolic compounds, ascorbic acid, and alpha-tocopherol in C. olitorius leaves were determined, and their antioxidative activities were measured using the radical generator-initiated peroxidation of linoleic acid. The results obtained showed that 5-caffeoylquinic acid was a predominant phenolic antioxidant in C. olitorius leaves.     

Isolation and structural elucidation of two new glycosides from sage (Salvia officinalis L.)

Six compounds, 1-O-(2,3, 4-trihydroxy-3-methyl)butyl-6-O-feruloyl-beta-D-glucopyranoside, ethyl beta-D-glucopyranosyl tuberonate, p-hydroxybenzoic acid, (-)-hydroxyjasmonic acid, caffeic acid, and 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofrunosyl]-(1-->2)-beta-D- glu copyranoside, were isolated from the n-butanol-soluble fraction of sage leaf extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR), and their antioxidant activities were measured. Among them, two new glycosides were elucidated. All of these compounds showed DPPH free radical scavenging activity at the concentration of 30 mM, and caffeic acid was the most active compound.     

Triterpenoid saponins from the shells of Argania spinosa seeds

Two new oleanene saponins were isolated from the MeOH extract of the shell of Argania spinosa.They possess protobassic acid and 16alpha-protobassic acid as aglycons. The disaccharide moiety linked to C-3 of the aglycon is made up of two glucose units; the pentasaccharide moiety linked to C-28 is made up of arabinose, xylose, and three rhamnose units. Their structures were elucidated by 1D and 2D NMR experiments including (1)H-(1)H (DQF-COSY, 1D TOCSY, and 2D HOHAHA) and (1)H-(13)C (HSQC and HMBC) spectroscopy along with mass spectrometry.     

Flavonoid glycosides of Barbarea vulgaris L. (Brassicaceae)

Seven flavonoid derivatives were for the first time isolated from aerial parts of an alimentary and medicinal plant of the Brassicaceae family, Barbarea vulgaris L. The products were characterized on the basis of spectroscopic NMR ((1)H, (13)C, COSY, HMQC, HMBC) and FAB-MS data. The occurrence of flavonoids in this plant is interesting for their important nutritional properties and for chemotaxonomical pourposes.     

Dammarane-type glycosides from steamed notoginseng

Notoginseng, the root of Panax notoginseng (Burk.) F. H. Chen (Araliaceae), is a Chinese traditional medicine, which is used in both raw and processed forms due to their different pharmacological activities. Detailed chemical investigation on steamed notoginseng led to the isolation of 27 dammarane-type triterpenoids (1-27), including 4 new glycosides, namely, notoginsenosides ST-1-ST-3 and ST-5 (1-4), in addition to 3 other known compounds. Of the new compounds, 1-3 possess new aglycones. Their structures were elucidated on the basis of detailed analyses of their 1D and 2D NMR spectra and chemical reactions. The known compounds, koryoginsenoside-R1 (19), yesanchinoside D (20), 6'-O-acetylginsenoside Rg3 (24), and 3beta,6alpha,12beta-trihydroxydammar-20(21),24-diene ( 25), were isolated from notoginseng for the first time.     

超声波辅助提取紫丁香叶叶绿素的工艺

以深秋的紫丁香树叶为原料,利用超声波辅助提取其中的叶绿素。首先研究了4种不同溶剂对提取的影响,然后在单因子试验基础上,探讨了料液比、超声波功率、超声波处理时间和超声提取次数4个因素对叶绿素提取的影响,用正交试验法优化了超声波辅助提取叶绿素的条件。最后将超声波法与传统提取法进行了对比。结果表明,紫丁香树叶中叶绿素a和叶绿素b的含量分别为0.37%和0.15%,叶绿素的总含量为0.52%;以乙醇∶丙酮为1∶2之混合溶剂的提取效果最好;优化的叶绿素超声波辅助提取条件为:料液比1∶7.5,超声波功率400W,提取3次,每次处理时间20min,提取率能达到(91.85±0.8)%。室温条件下,超声波辅助提取的提取率高于传统提取法17.13个百分点。     

Natural fungicides from Ruta graveolens L. leaves,including a new quinolone alkaloid

Bioassay-directed isolation of antifungal compounds from an ethyl acetate extract of Ruta graveolens leaves yielded two furanocoumarins, one quinoline alkaloid, and four quinolone alkaloids, including a novel compound, 1-methyl-2-[6'-(3' ',4' '-methylenedioxyphenyl)hexyl]-4-quinolone. The (1)H and (13)C NMR assignments of the new compound are reported. Antifungal activities of the isolated compounds, together with 7-hydroxycoumarin, 4-hydroxycoumarin, and 7-methoxycoumarin, which are known to occur in Rutaceae species, were evaluated by bioautography and microbioassay. Four of the alkaloids had moderate activity against Colletotrichum species, including a benomyl-resistant C. acutatum. These compounds and the furanocoumarins 5- and 8-methoxypsoralen had moderate activity against Fusarium oxysporum. The novel quinolone alkaloid was highly active against Botrytis cinerea. Phomopsis species were much more sensitive to most of the compounds, with P. viticola being highly sensitive to all of the compounds.     

C(13)-Norisoprenoid glucoconjugates from lulo (Solanum quitoense L.) leaves

With the aid of multilayer coil countercurrent chromatography, subsequent acetylation, and liquid chromatographic purification of a glycosidic mixture obtained from lulo (Solanum quitoense L.) leaves, three C(13)-norisoprenoid glucoconjugates were isolated in pure form. Their structures were elucidated by NMR, MS, and CD analyses to be the novel (6R,9R)-13-hydroxy-3-oxo-alpha-ionol 9-O-beta-D-glucopyranoside (4a), the uncommon (3S,5R,8R)-3, 5-dihydroxy-6,7-megastigmadien-9-one 5-O-beta-D-glucopyranoside (citroside A) (5a), and the known (6S,9R)-vomifoliol 9-O-beta-D-glucopyranoside (6a). Enzymatic treatment of compound 5a showed the formation of 3-hydroxy-7,8-didehydro-beta-ionone (7), an important lulo peeling volatile, which in its turn after chemical reduction and heated acid catalyzed rearrangement generates beta-damascenone (9) and 3-hydroxy-beta-damascone (10).     

Biotransformation of common bean (Phaseolus vulgaris L.) flavonoid glycosides by bifidobacterium species from human intestinal origin

Bifidobacteria strains from human origin were screened for the specific activity (beta-glucosidase activity) involved in the metabolism of dietary flavonoids. Five strains with high beta-glucosidase activity were selected for further metabolism analyses (high-performance liquid chromatography separations) of flavonoid glycosides occurring in Phaseolus vulgaris L. (common bean) seeds and seedlings. All selected strains were found to be active in the conversion of kaempferol 3-O-glucoside, daidzin, genistin, and glycitin into their aglyconic forms. No metabolites were detected after the fermentation tests with the diglucosidic compound kaempferol 3-O-xylosylglucoside. In addition, to verify the effective bioavailability of flavonoid aglycones, the degradation rates of daidzein, genistein, glycitein, and kaempferol, following incubation with selected strains, were monitored. The results showed that the five selected strains of bifidobacteria, being active in the biotranformation of flavonoid glycosides occurring in common bean seeds and seedlings, could be considered as probiotic dietary adjuncts to improve the nutritional and health properties of flavonoid-based products, comprising hypothetical common bean food derivatives.     

Protective activities of stilbene glycosides from Acer mono leaves against H2O2-induced oxidative damage in primary cultured rat hepatocytes

In our previous study, we isolated two new hepatoprotective stilbene glycosides, 5-O-methyl-(E)-resveratrol 3-O-beta-D-glucopyranoside (MRA) and 5-O-methyl-(E)-resveratrol 3-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (MRAG), from the methanolic extract of Acer mono leaves. Thereby, we have attempted to elucidate the hepatoprotective mechanism of these compounds, focusing on antioxidative effects, using hydrogen peroxide (H2O2)-injured primary cultures of rat hepatocytes. Both MRA and MRAG showed potent hepatoprotective activities in pretreatment but showed little effects in posttreatment. In addition, they increased the glutathione (GSH) level in the normal control cultures and significantly prevented the depletion of GSH in H2O2-injured primary cultured rat hepatocytes. Moreover, these compounds significantly restored the level of GSH depleted by buthionine sulfoximine or diethylmaleate in the presence or absence of H2O2. Furthermore, these compounds preserved the activities of antioxidant enzymes such as superoxide dismutase, glutathione reductase, and glutathione peroxidase reduced by H2O2 insults. Meanwhile, MRA and MRAG showed moderate scavenging effects with IC50 values of 103.6 and 80.5 microM, respectively, as determined by 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging activity. Taken together, these results suggest that MRG and MRAG exert significant hepatoprotective activities against H2O2-induced hepatotoxicity by maintaining the antioxidative defense system rather than scavenging free radicals.     

Growth,Survival, Protein Content,and Phytoremediation Potency of Various Rangeland Plant Species (Medicago polymorpha L., Medicago rigidula L., and Onobrychis sativa L.) Grown in Vermicompost-Containing Potting Media

A pot experiment based on completely randomized factorial arrangement design with four replications was conducted under greenhouse condition at Malayer University, Malayer, Iran. Pots contained a mixture of soil and different concentrations (0% and 60% w/w) of vermicompost. Plants were exposed to three lead nitrate concentrations: 0, 4, and 8 mM. Based on the results of this research, shoot height and root length of the studied plants significantly decreased with increased lead concentrations in all vermicompost application levels. Generally, plants exposed to lower levels of lead and vermicompost application had higher root:shoot ratio. The survival capacity of all the studied plants was significantly reduced with increased lead concentrations, but increased with increased vermicompost application level. The total protein content increased with decrease in lead nitrate concentration, but decreased with decrease in vermicompost application. Generally, translocation factor increased significantly as vermicompost application rate increased. The highest root concentration factor of lead was found in V1×Pb2 as compared to the other treatment levels. Generally, tolerance index values of all the studied plants were significantly higher in the lower lead concentration treatments.     

Triterpene saponins from the roots of Medicago hybrida

Fourteen triterpene saponins (1-14) have been isolated from the roots of Medicago hybrida and their structures elucidated by FAB-MS and NMR analysis. Two of them are new compounds and were identified as hederagenin 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-28-O-beta-D-glucopyranoside (7) and oleanolic acid 3-O-[beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl]-28-O-[alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranoside] (14). Seven saponins being mono- and bidesmosides of hederagenin (1, 5, 6, 9), one bidesmoside of bayogenin (2), and two bidesmosides of 2beta,3beta-dihydroxyolean-12-en-23-al-28-oic acid (11) and oleanolic acid (13) are known compounds but not previously reported as saponin constituents of Medicago, whereas five other saponins, being mono- and bidesmosides of medicagenic acid (3, 4, 8, 10, 12), and one monodesmoside of hederagenin (8) have been previously isolated from other Medicago species. The presence of 2beta,3beta-dihydroxyolean-12-en-23-al-28-oic acid might represent an interesting intermediate in the biosynthesis of these substances.