Flavonoids from Camptosorus sibiricus Rupr.

Three new flavonol glycosides, kaempferol-3-O-(6-trans-caffeoyl)-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside (1), kaempferol-3-O-(6-trans-caffeoyl)-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside-7-O-β-d-glucopyranoside (2), and kaempferol-3-O-(6-trans-p-coumaroyl)-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside-7-O-β-d-glucopyranoside (3), were isolated from the aerial part of Camptosorus sibiricus. Their structures were elucidated by spectroscopic methods, including 2D NMR spectral techniques.     

Three new flavonoid glycosides from Urena lobata

Three new flavonoid glycosides, kaempferol-3-O-β-d-apiofuranosyl(1 → 2)-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside (1), kaempferol-4′-O-β-d-apiofuranosyl-3-O-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside (2), and 5,6,7,4′-tetrahydroxy-flavone-6-O-β-d-arabinopyranosyl-7-O-α-l-rhamnopyranoside (3), were isolated from the aerial parts of Urena lobata L., along with 10 known compounds (4–13). Their structures were determined based on spectroscopic methods including 1D and 2D NMR spectroscopy as well as HR-ESI-MS.     

Four new oleanane type Saponins from Morina nepalensis var. alba

Four new oleanane type saponins, monepalosides G–J (1–4), were isolated from the water-soluble part of the whole plant of Morina nepalensis var. alba Hand-Mazz. On the basis of chemical and spectroscopic evidence, their structures were determined as 3-O-α-L-arabinopyranosyl-(1→3)-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside G, 1), 3-O-α-L-arabinopyranosyl-(1→3)-β-D-xylopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside H, 2), 3-O-α-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside I, 3), 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosy-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside J, 4), respectively. Two-dimensional NMR spectra, including H–H COSY, HMQC, 2D HMQC–TOCSY, HMBC and ROESY were utilized in the structure elucidation and complete assignments of ¹H and ¹³C NMR spectra.     

Two new lignan glycosides from the seeds of Cuscuta chinensis

Two new lignan glycosides, 2′-hydroxyl asarinin 2′-O-β-D-glucopyranoside (cuscutoside C, 1) and 2′-hydroxyl asarinin 2′-O-β-D-apiofuranosyl-(1 → 2)-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranoside (cuscutoside D, 2), were isolated from the seeds of Cuscuta chinensis Lam., along with six known compounds, 2′-hydroxyl asarinin 2′-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (3), 2′-hydroxyl asarinin 2′-O-β-D-apiofuranosyl-(1 → 2)-β-D-glucopyranoside (cuscutoside A, 4), kaempferol 3,7-di-O-β-D-glucopyranoside (5), 5-caffeoyl quinic acid (6), 4-caffeoyl quinic acid (7), and cinnamic acid (8). Their structures were elucidated on the basis of spectroscopic analyses including HR-ESI-MS, ESI-MS/MS, ¹H and ¹³C NMR, HSQC, HMBC, and TOCSY.     

Pregnane glycosides from Dracaena cochinchinensis

Two new pregnane glycosides, named dracaenoside C and D, were isolated from the fresh stems of Dracaena cochinchinensis. Their structures were established as 3β,14α-dihydroxypregna-5,16(17)-diene-20-one?3-O-α-L-rhamnopyranosyl(1→2)[α-L-rhamnopyranosyl(1→4)]-β-D-glucopyranoside (1) and 3β,14α-dihydroxypregna-5,16(17)-diene-20-one?3-O-α-L-rhamnopyranosyl(1→2)[β-D-glucopyranosyl(1→3)]-β-D-glucopyranoside (2) by means of 2D NMR spectral and chemical methods.     

Flavonoids from Pyrrosia petiolosa (Christ) Ching

A new kaempferol glycoside, kaempferol-3-O-β-d-glucopyranoside-7-O-α-l-arabinofuranoside (1), was isolated from the EtOH extract of Pyrrosia petiolosa together with six known flavonoids already reported from the same plant. Structural elucidation was performed by means of physico-chemical methods including MS, and 1D and 2D NMR spectroscopy.     

A new kaempferol trioside from Silphium perfoliatum

A new apiose-containing kaempferol trioside, kaempferol-3-O-α-l-rhamnosyl-(1? → 6″)-O-β-d-galactopyranosyl-7-O-β-d-apiofuranoside, along with 16 known compounds, were isolated from 50% acetone extract of Silphium perfoliatum L. Their structures were elucidated by acid hydrolysis and spectroscopic techniques including UV, IR, MS, ¹H, ¹³C, and 2D-NMR. In addition, the pharmacological activity of compound 1 was tested with HepG2 and Balb/c mice (splenic lymphocytes and thymic lymphocytes) in vitro, and it exhibited inhibitory effect on the proliferation of HepG2 cells and showed the immunosuppressive activity.     

Two new steroidal saponins from Tribulus terrestris

Two new steroidal saponins and two known flavonoid glycosides were isolated from the fruits of Tribulus terrestris. Their structures were assigned by spectroscopic analysis and chemical reaction as 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-12-one-3β,22α,26-triol-3-O-β-d-glucopyranosyl (1 → 2)-β-d-glucopyranosyl(1 → 4)-β-d-galactopyranoside (1), 26-O-β-d-glucopyranosyl-(25S)-5α-furostan-22-methoxy-2α,3β,26-triol-3-O-β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl(1 → 4)-β-d-galactopyranoside (2), kaempferol-3-gentiobioside (3), and isorhamnetin-3-gentiobioside (4).     

New furostanol glycosides from the rhizomes of Dioscorea futschauensis R. Kunth

Two new furostanol glycosides, 26-O-β-D-glucopyranosyl-3β,26-dihydroxy-23(S)-methoxyl-25(R)-furosta-5,20(22)-dien-3-O-α-L-rhamnopyranosyl(1→2)-[β-D-glucopyranosyl(1→3)]-β-D-glucopyranoside (dioscoreside E, 1) and 26-O-β-D-glucopyranosyl-3β,26-dihydroxy-25(R)-furosta-5,20(22)-dien-3-O-α-L-rhamnopyranosyl(1→2)-[β-D-glucopyranosyl (1→3)]-β-D-glucopyranoside (prtotogracillin, 2), together with 11 known furostanol glycosides were isolated from the rhizomes of Dioscorea futshauensis R. Kunth. Their structures were elucidated on the basis of spectroscopic analysis (NMR and FABMS). Their anti-fungal activity against the plant pathogenic fungus Pyricularia oryzae and cytotoxic activity on K562 cancer cell line were evaluated in vitro.     

Triterpenoid saponins from the rhizome of Polygonatum sibiricum

Three new triterpenoid saponins, polygonoides C (1), D (2), and E (3), were obtained from the ethanolic extract of the rhizome of Polygonatum sibiricum Redoute. On the basis of NMR and ESI-MS spectra, and chemical evidence, the structures of the three new compounds were elucidated as 3-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-3β,7β,22β-trihydroxy-oleanolic acid (1), 3-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-3β,7β,22β-trihydroxy-oleanolic acid methyl ester (2), and 3-O-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-(1 → 4)-[α-L-rhamno-pyranosyl-(1 → 2)]-β-D-glucopyranosyl-3β,21β-dihydroxy-oleanolic acid 28-O-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranoside (3).     

New acylated flavonoid glycosides from flowers of Aerva javanica

Chromatographic purification of ethyl acetate soluble fraction of the methanolic extract of the flowers of Aerva javanica yielded three new acylated flavone glycosides: kaempferol-3-O-β-d-[4?-E-p-coumaroyl-α-l-rhamnosyl(1 → 6)]-galactoside (1), kaempferol-3-O-β-d-[4?-E-p-coumaroyl-α-l-rhamnosyl(1 → 6)]-(3″-E-p-coumaroyl)galactoside (2), and kaempferol-3-O-β-d-[4?-E-p-coumaroyl-α-l-rhamnosyl(1 → 6)]-(4″-E-p-coumaroyl)galactoside (3), along with p-coumaric acid (4), caffeic acid (5), gallic acid (6), eicosanyl-trans-p-coumarate (7), hexadecyl ferulate (8), and hexacosyl ferulate (9). The compounds 1–9 were characterized using 1D (¹H, ¹³C) and 2D NMR (HMQC, HMBC, and COSY) spectroscopy and mass spectrometry (EI-MS, HR-EI-MS, FAB-MS, and HR-FAB-MS) and in comparison with the reported data in the literature. Compound 1 showed weak inhibitory activity against enzymes, such as acetylcholinesterase, butyrylcholinesterase, and lipoxygenase with IC₅₀ values 205.1, 304.1, and 212.3 μM, respectively, whereas compounds 2 and 3 were only weakly active against the enzyme acetylcholinesterase.     

Two new glycosides from Carduus acanthoides

Two new glycosides, syringic acid-4-O-β-l-arabinopyranoside (1) and kaempferol-3-O-α-l-rhamnopyranosyl-7-O-β-d-glucuronopyranoside (2), were isolated from whole plants of Carduus acanthoides (Asteraceae), and their structures were elucidated on the basis of spectroscopic analysis.     

A new cerebroside from Uvaria tonkinensis var. subglabra

A new cerebroside, subglain A (1), together with five known compounds (2–6) have been isolated from the stems of Uvaria tonkinensis var. subglabra. The structure of 1 has been determined to be 1-O-β-D-glucopyranosyl-(2S,3S,4R,8Z,2′R)-2-[N-(2′-hydroxytetracosanyl)-N-(1″,2″-dihydroxyethyl)-amide]-8-tetradecene-1,3,4-triol by spectroscopic evidence. The known compounds were identified as schisandriside (2), erythritol (3), β-D-glucopyranose (4), kaempferol-3,7-O-α-L-dirhamnoside (5), and (+)-lyoniresinol (6).     

Flavonoids,cytotoxic, antioxidant and antibacterial activities of Evax pygmaea

Context: Phytochemical study and biological potential of Evax pygmaea (L.) Brot. (Asteraceae) are reported for the first time.

Objective: To identify the secondary metabolites of Evax pygmaea and to determine its antioxidant, antibacterial and cytotoxic activities.

Materials and methods: Dried aerial parts (1?kg) were macerated in 70% MeOH (5?L) during 72?h. The concentrated hydromethanolic extract was subjected to extractions with chloroform (3?×?300?mL), ethyl acetate (3?×?300?mL) and n-butanol (3?×?300?mL), successively. VLC of combined ethyl acetate (EAEP) and n-butanol (BEP) fractions was followed by column purifications. Antioxidant activity was investigated using DPPH, CUPRAC, and metal chelating, β-carotene/linoleic acid and ABTS assays. Agar method was used in the antibacterial study. Cytotoxic activity was determined by Brine shrimp lethality test in DMSO and ethanol, at varying concentrations (2, 1 and 0.2%) and (1, 0.2 and 0.1%) successively.

Results: Quercetin (1), isorhamnetin 3-O-β-d-xyloside (2), isorhamnetin 3-O-β-d-glucoside (3), quercetin 3-O-β-d-glucoside (4), quercetin 7-O-β-D-glucoside (5), patuletin 3-O-β-d-glucoside (6) were isolated from for the first time from Evax genus. The EAEP was the most active in ABTS (IC₅₀: <3.125?μg/mL) assay whereas the BEEP exhibited the highest activity in the β-carotene/linoleic acid assay (IC₅₀: <3.125?μg/mL). The EAEP and BEP exhibited good antibacterial activity (MIC: 40–80 µg/mL). The plant did not show any toxicity (LD₅₀>80 µg/mL).

Discussion and conclusions: Six flavonoids were isolated for the first time from Evax pygmaea which exhibited good antioxidant and antibacterial activities.     

Compounds from the pods of Astragalus armatus with antioxidant,anticholinesterase, antibacterial and phagocytic activities

Context: The phytochemical study and biological activities of Astragalus armatus Willd. subsp. numidicus (Fabaceae) pods, an endemic shrub of Maghreb, are reported.

Objective: This study isolates the secondary metabolites and determines the bioactivities of Astragalus armatus pods.

Materials and methods: The chloroform, ethyl acetate and n-butanol extracts of hydro-ethanolic extracts were studied. Antioxidant activity was investigated using DPPH and ABTS radical scavenging, CUPRAC and ferrous chelating assays at concentrations ranging from 3 to 200?μg/mL. Anticholinesterase activity was determined against acetylcholinesterase and butyrylcholinesterase enzymes at 50, 100 and 200?μg/mL. Antibacterial activity was performed according to minimum inhibitory concentration (MIC) method. Carbon clearance method in albino mice was used for the phagocytic activity at concentrations 50, 70 and 100?mg/kg body weight. Spectroscopic techniques were used to elucidate the compounds.

Results: Ethyl acetate extract afforded a flavonoid (1) while the n-butanol extract gave four flavonoids (2–5), a cyclitol (6) and a cycloartane-type saponin (7). The ethyl acetate extract exhibited highest antioxidant activity in DPPH (IC₅₀: 67.90?±?0.57?μg/mL), ABTS (IC₅₀: 11.30?±?0.09?μg/mL) and CUPRAC (A_0.50: 50.60?±?0.9?μg/mL) assays. The chloroform extract exhibited the best antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, each with 80?μg/mL MIC values. The n-butanol extract enhanced phagocytic activity.

Discussion and conclusion: Isorhamnetin (1), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside (2), isorhamnetin-3-O-β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-galactopyranoside (3), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-β-d-galactopyranoside (4), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside (5), pinitol (6) and cyclomacroside D (7) were isolated whereas 1, 2, 6 and 7 are reported for the first time from A. armatus.     

Isolation,structural elucidation of flavonoid constituents from Leptadenia pyrotechnica and evaluation of their toxicity and antitumor activity

An investigation of Leptadenia pyrotechnica (Forsk.) Decne (Asclepiadaceace) chemical constituents led to the isolation of six flavonoids, kaempferol-3-O-α-l-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.1), kaempferol-3-O-β-d-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.2), texasin-7-O-β-d-glucopyranoside E-II.2, kaempferol-3-O-β-d-glucopyranoside (E-III.1), kaempferol (E-IV.1) and kaempferide-3-O-α-l-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.1a). The isolation of these compounds was carried out using Sephadex LH-20 low pressure liquid chromatography (LPLC), preparative paper chromatography (PC), and high performance liquid chromatography (HPLC). The chemical structures of the isolated compounds were established by mass spectrometry (FAB- and EI- techniques), nuclear magnetic resonance NMR (¹H-, ¹³C- and COSY) spectral data and ultraviolet (UV) spectroscopic techniques. The acute toxicity of total alcoholic and total flavonoid extracts were examined by brine shrimp. The LC₅₀ values were 11.89 and 84.14 ppm for the total alcoholic and total flavonoid extracts, respectively. The mortality rates of the isolated flavonoid fractions of E-I, E-I.1, E-I.2 represent the higher percentages of mortality compared with the rest of the flavonoid fractions. The plant exhibited activity as an antitumor agent in the initial potato disc screen.     

Three triterpenoid saponins acylated with monoterpenic acid from Gymnocladus chinensis

A new triterpenoid saponin acylated with monoterpenic acid, together with two known triterpenoid saponins, has been isolated from the fruit of Gymnocladus chinensis Baill. Their structures were elucidated as 2β,23-dihydroxy-3-O-α-L-rhamnopyranosyl-21-O-{(6S)-2-trans-2,6-dimethyl-6-O-[3-O-(β-D-glucopyranosyl)-4-O-((6S)-2-trans-2,6-dimethyl-6-hydroxy-2,7-octadienoyl)-β-L-arabinopyranosyl]-2,7-octadienoyl}-acacic acid 28-O-β-D-xylopyranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-[α-L-rhamnopyranosyl-(1 → 6)]-β-D-glucopyranosyl ester (1), gymnocladus saponin E (2), and gymnocladus saponin F₂ (3).     

New sesquiterpenoid glycoside and phenylpropanoid glycosides from the tuber of Ophiopogon japonicus

A new sesquiterpenoid glycoside, cryptomeridiol 11-O-β-d-xylopyranosyl-(1→6)-β-d- glucopyranoside (1), two new phenylpropanoid glycosides, 3,4-dihydroxy-allylbenzene 3-O-β-d-glucopyranosyl-4-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (2), and 3,4,5-trihydroxy-allylbenzene 3-O-β-d-glucopyranosyl-4-O-β-d-glucopyranoside (3), along with four known phenylpropanoid glycosides (4–7), were isolated from the tuber of Ophiopogon japonicus. Compounds 4–7 were obtained from the genus Ophiopogon for the first time. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR and HR-ESI-MS.     

Flavonoids of Calligonum polygonoides and their cytotoxicity

Context Calligonum polygonoides L. subsp. comosum L’ Hér. (Polygonaceae), locally known as “arta”, is a slow-growing small leafless desert shrub.

Objective Isolation, structure elucidation and evaluation of cytotoxic activity of flavonoids from C. polygonoides aerial parts.

Materials and methods Flavonoids in the hydroalcoholic extract of the of C. polygonoides were isolated and purified using column chromatography and preparative HPLC. The structures of the isolated flavonoids were elucidated on the basis of spectroscopic data including 2D NMR techniques. The cytotoxic activity of the isolated flavonoids (6.25, 25, 50 and 100?μg/mL) was evaluated against liver HepG2 and breast MCF-7 cancer cell lines using sulphorhodamine-B assay.

Results A new flavonoid, kaempferol-3-O-β-D-(6″-n-butyl glucuronide) (1), and 13 known flavonoids, quercetin 3-O-β-D-(6″-n-butyl glucuronide) (2), kaempferol-3-O-β-D-(6″-methyl glucuronide) (3), quercetin-3-O-β-D-(6″-methyl glucuronide) (4), quercetin-3-O-glucuronide (5), kaempferol-3-O-glucuronide (6), quercetin-3-O-α-rhamnopyranoside (7), astragalin (8), quercetin-3-O-glucopyranoside (9), taxifolin (10), (+)-catechin (11), dehydrodicatechin A (12), quercetin (13), and kaempferol (14), were isolated from the aerial parts of C. polygonoides. Quercetin showed significant cytotoxic activity against HepG2 and MCF-7 cell lines with IC₅₀ values of 4.88 and 0.87?μg/mL, respectively. Structure–activity relationships were analyzed by comparing IC₅₀ values of several pairs of flavonoids differing in one structural element.

Discussion and conclusion The activity against breast cancer cell lines decreased by glycosylation at C-3. The presence of 2,3-double bond in ring C, carbonyl group at C-4 and 3’,4’-dihydroxy substituents in ring B are essential structural requirements for the cytotoxic activity against breast cancer cells.     

Steroidal saponins from the rhizomes of Polygonatum prattii

Seven steroidal saponins including two new furostanol glycosides were isolated from the rhizomes of Polygonatum prattii collected from Panzhihua, Sichuan province of China. The new compounds were determined as 26-O-β-d-glucopyranosyl-(25R)-3β,22ξ-dihydroxy-furost-5-en-7-one (pratioside G) and 26-O-β-D-glucopyranosyl-(25R)-22ξ-hydroxy-furost-5-en-3β-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (pratioside H), on the basis of detailed spectroscopic and chemical analysis.