Study on the phenolic constituents of the flowers and leaves of Trifolium repens L

The flowers and leaves of Trifolium repens L. (Fabaceae) were subjected to phytochemical investigation in order to identify their major chemical constituents and to evaluate in?vitro antioxidant activity of the isolated compounds against DPPH˙. A total of 12 flavonoids, pterocarpan and methyl caffeate were isolated, then characterised by UV, MS, NMR spectroscopy and identified as quercetin and kaempferol 3-O-(6″-α-rhamnopyranosyl-2″-β-xylopyranosyl)-β-galactopyranosides (1, 2), kaempferol 3-O-(2″,6″-α-dirhamnopyranosyl)-β-galactopyranoside, mauritianin (3), quercetin and kaempferol 3-O-(2″-β-xylopyranosyl)-β-galactopyranosides (4, 5), kaempferol and quercetin 3-O-β-(6″-O-acetyl)-galactopyranosides (6, 7), trifolin (8), hyperoside (9), myricetin 3-O-β-galactopyranoside (10), quercetin (11), ononin (12), medicarpin 3-O-β-glucopyranoside (13) and methyl caffeate (14). Mauritianin, ononin, pterocarpan and methyl caffeate have been reported in this plant for the first time. The compounds 4, 7, 9, 10, and 11 were tested for their antioxidant effect against DPPH˙. All studied compounds were found to have potent activity, but the most effective in the test were compounds 9, 10 and 11 (EC(50) values in the range 7.51-9.52?μM).     

Antioxidant, anti-glycation and anti-inflammatory activities of phenolic constituents from Cordia sinensis

Nine compounds have been isolated from the ethyl acetate soluble fraction of C. sinensis, namely protocatechuic acid (1), trans-caffeic acid (2), methyl rosmarinate (3), rosmarinic acid (4), kaempferide-3-O-β-D-glucopyranoside (5), kaempferol-3-O-β-D-glucopyranoside (6), quercetin-3-O-β-D-glucopyranoside (7), kaempferide-3-O-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside (8) and kaempferol-3-O-α-L-rhamno-pyranosyl (1→6)-β-D-glucopyranoside (9), all reported for the first time from this species. The structures of these compounds were deduced on the basis of spectroscopic studies, including 1D and 2D NMR techniques. Compounds 1-9 were investigated for biological activity and showed significant anti-inflammatory activity in the carrageen induced rat paw edema test. The antioxidant activities of isolated compounds 1-9 were evaluated by the DPPH radical scavenging test, and compounds 1, 2, 4 and 7-9 exhibited marked scavenging activity compared to the standard BHA. These compounds were further studied for their anti-glycation properties and some compounds showed significant anti-glycation inhibitory activity. The purity of compounds 2-5, 8 and 9 was confirmed by HPLC. The implications of these results for the chemotaxonomic studies of the genus Cordia have also been discussed.     

Two oleananes from Ammannia auriculata Willd

Two new compounds: 3-β,15-α,23,28-tetrahydroxyolean-12-en-3-O-arabinopyaranoside and 3-β,23,28-trihydroxy-olean-12-en-3-O-β-D-glucopyranoside were isolated from the aerial parts of Ammania auriculata along with the known compounds kaempferol, β-sitosterol-3-O-β- D-glucoside, 2-α,3-β,23-trihydroxyolean-12-en-28-oic acid-28-O-β-D-glucopyranoside, quercetin, kaempferol-3-O-α-L-arabinofuranoside, kaempferol-3-O-β-D-xylopyranoside and ellagic acid. Structures of these compounds were elucidated on the basis of their spectroscopic data (NMR, UV, MS and IR spectra). The antioxidant activities of the total extract, the fractions CH(2)Cl(2), EtOAc and the remaining aqueous together with the compounds 1, 6 and 9 were comparable with that of the standard antioxidant, ascorbic acid.     

New constituents from the rhizomes of Egyptian Iris germanica L

Chemical investigation of the methanolic extract of the rhizomes of Iris germanica L. (Iridaceae) afforded two new compounds; irigenin S (7) and iriside A (12), together with ten known compounds: stigmasterol (1), a-irone (2), γ-irone (3), 3-hydroxy-5-methoxyacetophenone (4), irilone (5), irisolidone (6), irigenin (8), stigmasterol-3-O-β-D-glucopyranoside (9), irilone 4'-O-β-D-glucopyranoside (10) and iridin (11). Their structures were established by UV, IR, 1D (1H and 13C) and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to mass spectroscopic data and comparison with literature data. The methanolic extract was evaluated for its antimicrobial activity. Both the methanolic extract and the isolated flavonoids were tested for their anti-inflammatory activity.     

Flavonoid glycosides from Aconitum baicalense

Two known flavonoids, the 7-O-α-L-rhamnopyranosides of kaempferol and of quercetin, and also the new acylated glycoside quercetin 3-O-[O-(6-caffeoyl-β-D-glucopyranosyl)-(1→2)-β-D-glucopyranoside 7-O-α-L-rhamnopyranoside (czekanoside A) have been isolated from the epigeal part ofAconitum baicalense Turcz, ex Rapaics (A. Czekanovskyi Steinb.). Their structures have been demonstrated by the methods of IR, UV,¹H, and¹³C NMR spectroscopies and FAB mass spectrometry and also with the aid of acid hydrolysis.     

Antioxidant secondary metabolites from Geranium lasiopus Boiss. & Heldr

Chromatographic studies on the EtOAc soluble portion of the MeOH extract of Geranium lasiopus led to the isolation of eight flavonoids (kaempferol (1), quercetin (2), quercetin 3-O-β-glucopyranoside (3), quercetin 3-O-β-galactopyranoside (4), kaempferol 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (5), quercetin 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (6), kaempferol 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (7) and quercetin 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (8)), two simple phenolic compounds (gallic acid (9) and its methyl ester (10)) and a hydrolysable tannin (pusilagin (11)). The structures of the compounds were elucidated by 1- and 2-dimensional NMR techniques ((1)H, (13)C, COSY, HMBC, HMQC) and ESI-TOF-MS spectrometry. Inhibitory effects on H(2)O(2)-induced lipid peroxidation in human red blood cells of the different extracts of G. lasiopus, as well as isolated compounds, were investigated. All tested compounds showed comparable or higher activity than that of ascorbic acid and trolox.     

Terpene glycosides from the roots of Sanguisorba officinalis L. and their hemostatic activities

Guided by a hemostasis bioassay, seven terpene glycosides were isolated from the roots of Sanguisorba officinalis L. by silica gel column chromatography and preparative HPLC. On the grounds of chemical and spectroscopic methods, their structures were identified as citronellol-1-O-α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside (1), geraniol-1-O-α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside (2), geraniol-1-O-α-Larabinopyranosyl-(1→6)-β-D-glucopyranoside (3), 3β-[(α-L-arabinopyranosyl)oxy]-19α-hydroxyolean-12-en-28-oic acid 28-β-D-glucopyranoside (4), 3β-[(α-L-arabinopyranosyl)-oxy]-19α-hydroxyurs-12-en-28-oic acid 28-β-D-glucopyranoside (ziyu-glycoside I, 5), 3β,19α-hydroxyolean-12-en-28-oic acid 28-β-D-glucopyranoside (6) and 3β,19α-dihydroxyurs-12-en-28-oic acid 28-β-D-glucopyranoside (7). Compound 1 is a new mono-terpene glycoside and compounds 2, 3 and 5 were isolated from the Sanguisorba genus for the first time. Compounds 1–7 were assayed for their hemostatic activities with a Goat Anti-Human α2-plasmin inhibitor ELISA kit, and ziyu-glycoside I (5) showed the strongest hemostatic activity among the seven terpene glycosides. This is the first report that ziyu-glycoside Ι has strong hemostatic activity.     

Chemical constituents and antibacterial activity of Melastoma malabathricum L

The aqueous methanolic extracts of Melastoma malabathricum L. exhibited antibacterial activity when assayed against seven microorganisms by the agar diffusion method. Solvent fractionation afforded active chloroform and ethyl acetate fractions from the leaves and the flowers, respectively. A phytochemical study resulted in the identification of ursolic acid (1), 2α-hydroxyursolic acid (2), asiatic acid (3), β-sitosterol 3-O-β-D-glucopyranoside (4) and the glycolipid glycerol 1,2-dilinolenyl-3-O-β-D-galactopyanoside (5) from the chloroform fraction. Kaempferol (6), kaempferol 3-O-α-L-rhamnopyranoside (7), kaempferol 3-O-β-D-glucopyranoside (8), kaempferol 3-O-β-D-galactopyranoside (9), kaempferol 3-O-(2″,6″-di-O-E-p-coumaryl)-β-D-galactopyranoside (10), quercetin (11) and ellagic acid (12) were found in the ethyl acetate fraction. The structures of these compounds were determined by chemical and spectral analyses. Compounds 1-4, the flavonols (6 and 11) and ellagic acid (12) were found to be active against some of the tested microorganisms, while the kaempferol 3-O-glycosides (7-9) did not show any activity, indicating the role of the free 3-OH for antibacterial activity. Addition of p-coumaryl groups results in mild activity for 10 against Staphylococcus aureus and Bacillus cereus. Compounds 2-5, 7 and 9-12 are reported for the first time from M. malabathricum. Compound 10 is rare, being reported only once before from a plant, without assignment of the double bond geometry in the p-coumaryl moiety.     

Identification and screening of active components from Ziziphora clinopodioides Lam. in regulating autophagy

This study investigated the flavonoid constituents of a traditional Chinese medical plant Ziziphora clinopodioides Lam. by using ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry and screened the active components in regulating autophagy.Normal rat kidney (NRK) cells transfected with green fluorescent protein- microtubule-associated protein 1 light Chain 3(GFP-LC3) were treated with Z. clinopodioides flavonoids and its chemical compositions. After 4 h of treatment, the auto-phagy spot aggregation in NRK cells was photographed and observed by laser scanning confocal microscopy. The following 10 flavonoid components of Z. clinopodioides were identified: baicalein(1), quercetin(2), hyperoside(3), quercetin3-O-β-d-glucopyranoside(4), apigenin(5), kaempferol(6), chrysin(7), diosimin(8), linarin(9) and rutin(10). Among these flavonoids, chrysin, apigenin and quercetin were identified as the active principles in activating autophagy. This research may provide a reference for further developing and utilizing Z. clinopodioides.     

狗枣猕猴桃叶化学成分研究(Ⅱ)

从狗枣猕猴桃叶中分离出4个新的黄酮类化合物, 经1D NMR, 2D NMR及ESI-MS等波谱分析鉴定了其结构, 分别是4'-甲氧基-槲皮素-7-O-(4"-O-乙酰基-鼠李糖基)-3-O-β-D-吡喃葡萄糖苷(1), 山柰甲黄素-7-O-(3"-O-乙酰基-鼠李糖基)-3-O-芸香糖苷(2), 山柰酚-7-O-(4"-O-乙酰基-鼠李糖基)-3-O-芸香糖苷(3)和4'-甲氧基-槲皮素-7-O-(4"-O-乙酰基-鼠李糖基)-3-O-芸香糖苷(4).     

Three new flavonoid glycosides, byzantionoside B 6'-O-sulfate and xyloglucoside of (Z)-hex-3-en-1-ol from Ruellia patula

Three new flavonoid glycosides, demethoxycentaureidin 7-O-β-D-galacturonopyranoside, pectolinarigenin 7-O-α-L-rhamnopyranosyl-(1?→4″)-β-D-glucopyranoside and 7-O-α-L-rhamnopyranosyl-(1?→4″)-β-D-glucuronopyranoside, a new megastigmane glucoside, byzantionoside B 6'-O-sulfate, and a new (Z)-hex-3-en-1-ol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, were isolated from leaves of Ruellia patula JACQ., together with 12 known compounds, β-sitosterol glucoside, vanilloside, bioside (decaffeoyl verbascoside), acteoside (verbascoside), syringin, benzyl alcohol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, cistanoside E, roseoside, phenethyl alcohol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, (+)-lyoniresinol 3α-O-β-D-glucopyranoside, isoacteoside and 3,4,5-trimethoxyphenol O-α-L-rhamnopyranosyl-(1″→6')-β-D-glucopyranoside. Their structures were elucidated by means of spectroscopic analyses.     

Cytotoxic and antimicrobial aporphine alkaloids from Fissistigma poilanei (Annonaceae) collected in Vietnam

Two new aporphine alkaloids: 8-hydroxy-9-methoxy-1,2-methylenedioxyaporphine (1) and 8-hydroxy-3,9-dimethoxy-1,2-methylenedioxyaporphine (2) were isolated from the ethyl acetate extract of Fissistigma poilanei along with five known compounds: oxocrebanine (3), kuafumine (4), (2R,3R)-3',4',5,7-tetrahydroxydihydroflavonol-3-O-α-L-rhamnopyranoside (5), (+)-catechin 3-O-α-L-rhamnopyranoside (6) and quercetine 3,7-dimethoxy-3'-O-α-L-rhamnopyranosyl-(1?→?2)-β-D-glucopyranoside (7). These two new aporphine alkaloids exhibited a moderate cytotoxic activity against four human cancer cell lines (KB, Hep-G2, MCF-7, LU) as well as antimicrobial activity against Lactobacillus fermentum, Enterococcus faecium, Staphylococcus aureus and Bacillus subtillis.     

Inhibitory effects of constituents from Euphorbia lunulata on differentiation of 3T3-L1 cells and nitric oxide production in RAW264.7 cells

A new flavonol galactopyranoside, myricetin 3-O-(2',3'-digalloyl)-β-D-galactopyranoide (1), and 23 known constituents, including myricetin 3-O-(2'-galloyl)-β-D-galactopyranoide (2), myricitrin (3), myricetin (4), quercetin 3-O-(2', 3'-digalloyl)-β-D-galactopyranoide (5), quercetin 3-O-(2'-galloyl)-β-D-galactopyranoide (6), hyperin (7), isoquercetrin (8), quercetin (9), kaempferol (10), apigenin (11), luteolin (12), 3-O-methylquercetin (13), 5,7,2',5'-tetrahydroxyflavone (14), 1,3,4,6-tetra-O-galloyl-β-D-glucose (15), 1,2,6-tri-O-galloyl-β-D-glucose (16), 1,3,6-tri-O-galloyl-β-D-glucose (17), gallic acid (18), protocatechuic acid (19), 3,4,5-trimethoxybenzoic acid (20), 2,6-dihydroxyacetophenone (21), 3,3'-di-O-methylellagic acid (22), ellagic acid (23) and esculetin (24) were isolated from Euphorbia lunulata Bge. Their structures were determined by spectroscopic analysis. Isolated hydrolysable tannins, flavonoids, and flavonol galactopyranoside gallates showed significant inhibition of the differentiation of 3T3-L1 preadipocytes and triglyceride accumulation in maturing adipocytes, and nitric oxide production in RAW 264.7 cells.     

Antioxidant flavonol glycosides from Elaeocarpus serratus and Filicium decipiens

Chemical investigation of the leaves of Elaeocarpus serratus yielded myricitrin (1), mearnsetin 3-O-β-D-glucopyranoside (2), mearnsitrin (3), tamarixetin 3-O-α-L-rhamnopyranoside (4) and the fruits of Filicium decipiens yielded three flavonol glycosides, kaempferol 3-O-rutinoside (5), kaempferol 3-O-robinobioside (6) and trifolin (7). Compound 1 showed strong antioxidant activity against DPPH.     

Chemical composition and antioxidant activities of extracts from Apocyni Veneti Folium

An expeditious and effective HPLC-UV method has been developed for the simultaneous determination of seven major flavonoids in Apocyni Veneti Folium (AVF) extract. The chemical profile of seven flavonoids, including quercetin-3-O-β-D-glc(2?→?1)-β-D-glucoside, rutin, isoquercetin, kaempferol-3-O-β-D-glucoside, quercetin-3-O-(6″-O-malonyl)-β-D-glucoside, quercetin and kaempferol was acquired by HPLC-UV. The analysis was performed on a Diamosil C18 analytical column with a gradient solvent system of acetonitrile-0.1% aqueous acetic acid. Full validation of the method was carried out (linearity, reproducibility, repeatability, accuracy and limit of detection). The results indicated that the contents of investigated flavonoids in Apocyni Veneti Folium varied significantly from habitat to habitat, with contents ranging from 0.01 to 5.57 mg g?1. The antioxidant activity results demonstrate that the seven flavonoids showed great efficiency in scavenging DPPH radicals. The high content of flavonoid components of AVF could be responsible for its high antioxidant activity. This study provides powerful evidence for the relationship between the chemical ingredients of and bioactivity in AVF.     

A novel lignan glycoside with antioxidant activity from Tinospora sagittata var. yunnanensis

A novel lignan glysocide, namely sagitiside A (1), together with two known ones, (+)-lyoniresinol-2α-O-β-D-glucopyranoside (2) and (+)-5'-methoxyisolariciresinol 3α-O-β-D-glucopyranoside (3), was isolated from the 95% ethanol extract of dry roots of Tinospora sagittata var. yunnanensis. The structure of the new compound (1) was determined based on MS, 1D and 2D NMR spectral data. Compounds 1-3 showed antioxidant activity with EC(50) values 55, 75 and 80?μM by 1,1-diphenyl-2-picryhydrazyl (DPPH) radical-scavenging assay.     

Flavonoid constituents from the roots of Acanthopanax brachypus

Two new natural products, (3R)-5,7-dihydroxy-8-(2″-O-veratroyl-β-D-glucopyranosyl)-3-(4'-hydroxyphenyl)-6-methylchroman-4-one (1) and 4'-hydroxyisoflavone-7-O-[α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside] (2), along with eleven other known flavonoids, were isolated from the roots of Acanthopanax brachypus. Their structures were elucidated on the basis of spectroscopic and chemical evidence.     

Inhibitory effects of constituents from Morus alba var. multicaulis on differentiation of 3T3-L1 cells and nitric oxide production in RAW264.7 cells

A new arylbenzofuran, 3',5'-dihydroxy-6-methoxy-7-prenyl-2-arylbenzofuran (1), and 25 known compounds, including moracin R (2), moracin C (3), moracin O (4), moracin P (5), artoindonesianin O (6), moracin D (7), alabafuran A (8), mulberrofuran L (9), mulberrofuran Y (10), kuwanon A (11), kuwanon C (12), kuwanon T (13), morusin (14), kuwanon E (15), sanggenon F (16), betulinic acid (17), uvaol (18), ursolic acid (19), β-sitosterol (20), oxyresveratrol 2-O-β-D-glucopyranoside (21), mulberroside A (22), mulberroside B (23), 5,7-dihydroxycoumarin 7-O-β-D-glucopyranoside (24), 5,7-dihydroxycoumarin 7-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranoside (25) and adenosine (26), were isolated from Morus alba var. multicaulis Perro. (Moraceae). Their structures were determined by spectroscopic methods. The prenyl-flavonoids 11-14, 16, triterpenoids 17,18 and 20 showed significant inhibitory activity towards the differentiation of 3T3-L1 adipocytes. The arylbenzofurans 1-10 and prenyl-flavonoids 11-16 also showed significant nitric oxide (NO) production inhibitory effects in RAW264.7 cells.     

A new eudesmane sesquiterpene glucoside from Liriope muscari fibrous roots

The screening of several Chinese medicinal herbs for nematocidal properties showed that the ethanol extract of Liriope muscari fibrous roots possessed significant nematocidal activity against the pine wood nematode (Bursaphelenchus xylophilus). From the ethanol extract, a new constituent (1,4-epoxy-cis-eudesm-6-O-β-D-glucopyranoside) and three known glycosides [1β,6α-dihydroxy-cis-eudesm-3-ene-6-O-β-D-glucopyranoside (liriopeoside A), 1β,6β-dihydroxy-cis-eudesm-3-ene-6-O-β-D-glucopyranoside, and 1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β D-glucopyranoside] were isolated by bioassay-guided fractionation. The structures were elucidated by 1D and 2D NMR and MS techniques. 1,4-Epoxy-cis-eudesm-6-O-β-D-glucopyranoside possessed moderate nemato-cidal activity against B. xylophilus with a LC(50 )value of 339.76 μg/mL, while liriopeoside A (LC(50) = 82.84 μg/mL) and 1β,6β-dihydroxy-cis-eudesm-3-ene-6-O-β-D-glucopyranoside (LC(50) = 153.39 μg/mL) also exhibited nematocidal activity against B. xylophilus. The crude extract of L. muscari fibrous roots exhibited nematocidal activity against the pine wood nematode with a LC(50) value of 182.56 μg/mL.     

Identification of the antioxidant principles of Polyalthia longifolia var. pendula using TEAC assay

Activity-guided fractionation of the ethanolic extract of the leaves of the Polyalthia longifolia var. pendula led to the identification of quercetin (1), quercetin-3-O-β-glucopyranoside (2), kaempferol-3-O-α-rhamnopyranosyl-(1 → 6)-β-galactopyranoside (3), kaempferol-3-O-α-rhamnopyranosyl-(1 → 6)-β-glucopyranoside (4), rutin (5) and allantoin (6) as the active constituents from the butanol fraction. Compounds 2-4 are reported for the first time from this natural source. Structures of the compounds were confirmed on the basis of their 1D and 2D NMR coupled with other spectroscopic methods. All the isolated compounds and the fractions were evaluated for their antioxidant potential using the TEAC assays and it was found that the activity of the active fraction was due to quercetin (1) and its glycosides (2 and 5), with TEAC values of 4.10, 1.91 and 2.38 mM, respectively, while the kaempferol glycosides were found to be inactive. This is the first study on the antioxidant activity of this plant species.