Phytochemical constituents and chemosystematic significance of Chrozophora tinctoria (L.) Raf

Twelve compounds were isolated from Chrozophora tinctoria (L.) Raf. They were identified as kaempferol, kaempferol 3-O-β-glucopyranoside, kaempferol 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside, quercetin, quercetin 3-O-β-glucopyranoside, quercetin 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside, apigenin, apigenin 7-O-β-glucopyranoside, acacetin, gallic acid, methyl gallate and β-sitosterol-3-O-β-glucopyranoside. Their structures were elucidated by chemical and spectral methods. Furthermore, chemosystematics of the isolated compounds is briefly discussed. It was indicated that C. tinctoria is the only species of Chrozophora that has the capability to synthesis kaempferol aglycone and their glycosides, and the finding is supported by its distinct morphological and anatomical aspects.     

Phenolic constituents of the aerial parts of Impatiens glandulifera Royle (Balsaminaceae) and their antioxidant activities

As a continuation of investigating Impatiens L. genus, eight flavonoids, eriodyctiol, eriodyctiol 7-O-β-?-glucoside, kaempferol 3-O-β-?-glucoside, kaempferol 3-O-β-?-galactoside, kaempferol 3-rhamnosyl-di-glucoside, kaempferol 3-O-β-?-rutinoside, quercetin 3-O-β-?-glucoside and quercetin 3-O-β-?-galactoside, two phenolic acids – p-hydroxybenzoic acid and protocatechuic acid, and 2-methoxynaphthalene-1,4-dione were isolated from the aerial parts of I. glandulifera collected in Poland. The structures of the compounds were established by analysis of their spectroscopic (¹H and ¹³C NMR) and spectrometric (MS) data, as well as by comparison of these with those reported in the literature. Quercetin 3-O-β-?-glucoside, kaempferol 3-O-β-?-galactoside and kaempferol 3-O-β-?-rutinoside were isolated for the first time from the investigated taxon. In addition, the antioxidant activities in different tests of all obtained compounds were evaluated. The results clearly showed that among analyzed constituents, quercetin 3-O-β-?-glucoside exhibited antioxidant activity comparable or better than ascorbic acid and Trolox which were used as a positive control.     

A new acylated flavonoid tetraglycoside with anti-inflammatory activity from Tipuana tipu leaves

A new acylated kaempferol glycoside, kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-O-[β-d-glucopyranosyl-(1 → 2)-4-O-acetyl-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranoside, has been isolated from the leaves of Tipuana tipu (Benth.) Lillo growing in Egypt, along with three known flavonol glycosides, kaempferol 3-O-rutinoside, quercetin 3-O-rutinoside (rutin) and kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)]-[α-l-rhamnopyranosyl-(1 → 2]-β-d-glucopyranoside. Structure elucidation was achieved through different spectroscopic methods. Structure relationship with anti-inflammatory activity using carrageenin-induced rat paw oedema model is discussed.     

Highly glycosylated flavonoids from the pods of Bobgunnia madagascariensis

Methanolic extracts of the pods of Bobgunnia madagascariensis (Leguminosae) yielded four pentaglycosylated flavonoids, including the 3-O-α-l-rhamnopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranosides of 3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-benzopyran-4-one (kaempferol) and 3,5,7-trihydroxy-2-(3,4-dihydroxyphenyl)-4H-benzopyran-4-one (quercetin), which were characterized by a novel O-linked branched tetrasaccharide. Spectroscopic and chemical methods were used to determine the structures of the latter, which co-occurred with the corresponding β-d-galactopyranosyl isomers, and two saponins. Conformational isomerism of quercetin 3-O-α-l-rhamnopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside was detected in solution by NMR, a phenomenon previously associated only with C-glycosylflavonoids.     

A novel acylated quercetin glycoside and compounds of inhibitory effects on α-glucosidase from Panax ginseng flower buds

Abstract

A novel acylated quercetin glycoside, floralpanasenoside A (1) and five known flavonoid glycosides, panasenoside (2), quercetin 3-O-(2''-β-D-glucopyranosyl)-β-D- galactopyranoside (3), trifolin (4) kaempferol 7-O-α-L-rhamnoside (5), and afzelin (6) were isolated from the flower buds of Panax ginseng. Their structures were established by spectroscopic data and comparison with the literature values. Four of the six isolated compounds including 1 (IC₅₀ = 62.4) exhibited α-glucosidase inhibitory activity with IC₅₀ values lower than acarbose (385.2?μM). The molecular docking study indicated that 1 bound to the active site of α-glucosidase with numerous hydrogen bond interactions.     

Three new acyltyramines from Anisodus luridus Link et Otto (Solanaceae)

Three new acyltyramines, N-[2-(4-hydroxyphenyl)ethyl]hentriacontanamide (1), N-[2-(4-hydroxyphenyl)ethyl]nonacosanamide (2) and N-[2-(4-hydroxyphenyl)ethyl]heneicosanamide (3) have been isolated from n-hexane extract of leaves of Anisodus luridus (Solanaceae). Successive extraction of defatted leaves of A. luridus with methanol afforded a residue on removal of solvent under reduced pressure. Residue was partitioned by means of chloroform and n-butanol. Chromatographic resolution of n-BuOH extract afforded six known compounds, apigenin (4), luteolin (5), quercetin (6), quercetin 3-O-α-l-rhamnoside (7), kaempferol 3-O-α-rhamnoside (8) and quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (9). The structures of the isolated compounds were assigned with the help of spectroscopic techniques. This is the first report of isolation of these compounds from this plant.     

Active Chemical Constituents from Sauropus androgynus

This paper describes the chemical investigation on BuOH-soluble EtOH extract from the aerial part of Sauropus androgynus. This study led to the characterization of six bioactive ingredients including three nucleosides—adenosine (1), 5′-deoxy-5′-methylsulphinyl-adenosine ( 2 ), and uridine ( 3 ), two flavonol dioside — 3-O-β-D-glucosyl-7-O-α-L-rhamnosyl-kaempferol ( 4 ), 3-O-β-D-glucosyl-(1→6)-β-D-glucosyl-kaempferol ( 5 ), and one rare flavonol trioside — 3-O-β-D-glucosyl-(1→6)-β-D-glucosyl-7-O-α-L-rhamno-syl-kaempferol ( 6 ). Their structures were determined on the basis of spectral analysis.     

Isolation and identification of polyphenols from Marsilea quadrifolia with antioxidant properties in vitro and in vivo

Marsilea quadrifolia is an edible aquatic medicinal plant used as a traditional health food in Asia. Four new polyphenols including kaempferol 3-O-(2″-O-E-caffeoyl)-β-d-glucopyranoside (1), kaempferol 3-O-(3″-O-E-caffeoyl)-α-l-arabinopyranoside (3), 4-methy-3′-hydroxypsilotinin (4) and (±)-(E)-4b-methoxy-3b,5b-dihydroxyscirpusin A (18) together with 14 known ones (2, 5–17) were isolated from the ethanol extract of M. quadrifolia. Structures of the new compounds were elucidated by extensive spectroscopic analyses. In DPPH and oxygen radical absorbance capacity antioxidant assays, some compounds showed stronger antioxidant activities and quercetin (9) was the most potent antioxidant in both assays. In a restraint-induced oxidative stress model in mice, quercetin significantly attenuated the increase in plasma ALT and AST levels as well as liver MDA content of restrained mice. Liver SOD activity was also significantly increased by quercetin, indicating a significant in vivo antioxidant activity. As a rich source of polyphenols with strong antioxidant activities, M. quadrifolia may be developed to a product for relieving oxidative stress.     

Dhasingreoside: new flavonoid from the stems and leaves of Gaultheria fragrantissima

A new flavonoid, dhasingreoside (1) and seven known compounds, quercetin 3-O-β-d-galacturonopyranoside (2), quercetin 3-O-β-d-galactopyranoside (3), quercetin 3-O-β-d-glucuronopyranoside (4), quercetin 3-O-α-l-rhamnopyranoside (5), (–)-epicatechin (6), salicylic acid (7) and gaultherin (8), have been isolated from the shade-dried stems and leaves of Gaultheria fragrantissima, commonly known as ‘Dhasingre’ in Nepal. The structures were elucidated on the basis of physical, chemical and spectroscopic methods. Among known compounds, five compounds (3–6 and 8) were isolated for the first time from G. fragrantissima. In vitro antioxidant activity of all the isolated compounds was evaluated by 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging assay. Dhasingreoside (1) and other compounds (2–6) showed significant free radical-scavenging activity.     

Ultra-high-performance liquid chromatography-Quadrupole-Exactive-Orbitrap-tandem mass spectrometry-based putative identification for Eucommiae Folium (Duzhongye) and its quality-marker candidate for pharmacopeia

Eucommiae Folium (Duzhongye) is a traditional Chinese medicine with a long history of use in China. However, its quality-marker in Chinese Pharmacopoeia is poorly defined nowadays. The study, therefore, conducted an ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap tandem mass spectrometry analysis to obtain accurate data. The obtained data were then compared with the authentic standards library using Xcalibur 4.1 software package and TraceFinder General Quan. Through the comparison, the study has putatively identified 26 bioactive compounds, which include 17 flavonoid derivatives (catechin, quercetin 3-gentiobioside, quercetin 3-O-β-D-glucose-7-O-β-D-gentiobioside, taxifolin, myricetin 3-O-galactoside, myricitrin, hyperoside, rutin, isoquercitrin, quercetin 3-O-β-xylopyranoside, quercitrin, isorhamnetin 3-O-β-D-glucoside, quercetin, kaempferol, S-eriodictyol, S-naringenin, and phloridzin), four caffeoylquinic acids (neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, and isochlorogenic acid C), two alkaloids (vincamine and jervine), one lignan (pinoresinol), one xanthone (cowaxanthone B), and one steroid (cholesteryl acetate). Of these, flavonoid isoquercitrin is recommended as the new and additional pharmacopeia quality-marker candidate, which can not only overcome the unreliability of old quality-marker but also recognize the possible counterfeit.     

Constituents of Clinopodium Umbrosum

The isolation and identification of fifteen crystalline components from the whole herb of Clinopodium umbrosum (Bieb.) C. Koch (Labiatae) are described. Their structures were determined on the basis of spectral evidence and chemical transformation. These compounds include five steroids (α-spinasterone, β-sitosterol, stigmasterol, α-spinasterol, and α-spinasteryl-3-O-β-glucopyranoside), four triterpenoids (3β-hydroxyurs-11-en-28,13-olide, betulinic acid, oleanolic acid, ursolic acid), four flavonoids (luteolin, luteolin-7-O-β-glucopyranoside, apigenin-7-O-β-glucuronide, and apigenin-7-O-β-methylglucuronate), and two lignolic acids [3-(3,4-dihydroxyphenyl)- lactic acid and rosmarinic acid].     

New lactoyl glycoside quercetin from <Emphasis Type="Italic">Melia azedarach</Emphasis> leaves

In the course of phytochemical investigations of Melia azedarach leaves, a novel cinnamoyl glycoside, cinnamoyl-1-α-L-rhamnoside (1), and a novel acylated quercetin triglycoside, quercetin-3-O-[rhamnosyl 1→6(4″-lactoyl glucoside)]-4′-O-glucoside (2), have been isolated and characterized on the basis of spectroscopic methods, together with the six known flavonoid compounds kaempferol-3-O-rutinoside, 3-O-rhamnoside, quercetin-3-O-rutinoside, 3-O-rhamnoside, and the aglycones quercetin and kaempferol. All isolated compounds have been evaluated for their structures by chromatographic methods, chemical degradation, and UV and NMR spectroscopy. The antioxidant activity of the extract was studied as well. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 12–14, January–February, 2008.     

Polyphenolic Profile of Callistemon viminalis Aerial Parts: Antioxidant,Anticancer and In Silico 5-LOX Inhibitory Evaluations

Five new compounds viz kaempferol 3-O-(4″-galloyl)-β-d-glucopyranosyl-(1‴→6″)-O-β-d-glucopyranoside (1), kaempferol 3-O-β-d-mannuronopyranoside (2), kaempferol 3-O-β-d-mannopyranoside (3), quercetin 3-O-β-d-mannuronopyranoside (4), 2, 3 (S)- hexahydroxydiphenoyl]-d-glucose (5) along with fifteen known compounds were isolated from 80% aqueous methanol extract (AME) of C. viminalis. AME and compounds exerted similar or better antioxidant activity to ascorbic acid using DPPH, O₂⁻, and NO inhibition methods. In addition, compounds 16, 4, and 7 showed cytotoxic activity against MCF-7 cell lines while 3, 7 and 16 exhibited strong activity against HepG2. An in silico analysis using molecular docking for polyphenolic compounds 2, 3, 7, 16 and 17 against human stable 5-LOX was performed and compared to that of ascorbic acid and quercetin. The binding mode as well as the enzyme-inhibitor interactions were evaluated. All compounds occupied the 5-LOX active site and showed binding affinity greater than ascorbic acid or quercetin. The data herein suggest that AME, a source of polyphenols, could be used against oxidative-stress-related disorders.     

Phenolics from Acalypha indica

Two novel hydrolysable tannins, potassium brevifolincarboxylate and acaindinin, together with eight known tannins—1-O-galloyl-β-D -glucose, 1,2,3,6-tetra-D -galloyl-β-D -glucose, corilagin, geraniin, acetonylgeraniin A, euphormisin M₂, repandusinic acid A, and chebulagic acid, as well as two flavonoid glycosides — quercetin 3-O-β-D -glucoside and rutin, were isolated from Acalypha indica. Their structures were elucidated on the basis of chemical and spectroscopic evidence.     

An expeditious synthesis of quercetin 3-O-β-d-glucuronide from rutin

We report the synthesis of the major human metabolite of quercetin, quercetin 3-O-β-d-glucuronide, from rutin (quercetin-3-rutinoside), which is commercially available at low cost. This straightforward synthesis is based on the key intermediate 3′,4′,5,7-tetra-O-benzyl-quercetin which is obtained in only two steps by the total benzylation of rutin followed by acid hydrolysis of the rutinoside residue. Glycosylation of the free 3 hydroxyl group by 1-bromo-3,4,6-tetra-O-acetyl-α-d-glucopyranoside yields the protected glucoside. TEMPO-mediated oxidation of primary alcohol on the deprotected glucoside gives access to the benzylated glucuronide. Removal of the benzyl groups which protect the quercetin hydroxyl groups by H₂ (10% Pd/C) yields quercetin 3-O-β-d-glucuronide.     

Two new quercetin glycoside derivatives from the fruits of Gardenia jasminoides var. radicans

Two new quercetin glycoside derivatives named quercetin-3-O-[2-O-trans-caffeoyl-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (1) and quercetin-3-O-[2-O-trans-caffeoyl-β-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (2) along with three known flavonoids, 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavone (3), 5,7-dihydroxy-8-methoxyflavone (4) and kaempferol 3-O-β-d-glucopyranoside (5), were isolated from the fruits of Gardenia jasminoides var. radicans. The structures of the new compounds were determined by means of extensive spectroscopic analysis (1D, 2D NMR and HR-ESI-MS), glycoside hydrolysis and sugar HPLC analysis after derivatisation. This is the first report on the isolation of a pair of compounds with α or β-l-rhamnopyranosyl configuration from plant and the first detail assignment of their NMR data.     

NMR spectral analysis of flavonoids from <Emphasis Type="Italic">Chrysanthemum coronarium</Emphasis>

Naringenin 5-O-glucoside, apigenin 7-O-glucoside, luteolin 7-O-glucoside, kaempferol 3-O-glucoside, quercetin 3-O-glucoside, apigenin, luteolin, kaempferol, and quercetin, nine flavonoid derivatives, were isolated for the first time from the aqueous methanolic extract of the aerial parts of Chrysanthemum coronarium. Their structures were elucidated on the basis of chemical and spectroscopic (UV, ¹H, ¹³C NMR) analyses. 1-and 2-dimensional NMR spectroscopy of the rare naringenin 5-O-glucoside have been recorded and assigned for the first time. The flavonoid glucosides from Chrysanthemum coronarium showed week activity against Poliovirus I and Adenovirus type 7. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 546–548, November–December, 2007.     

A Convenient Synthesis of 2, 3 - DI- O - Acetyl-1, 6 - Anhydro- β - D – Glucopyranose

Abstract

1, 2, 3-Tri-O-acetyl-6-O-benzyl-4-O-chloroacetyl-α- and -β-D-glucopyranose (4α β)were derived from 1, 2, 3-tri-O-acetyl-4, 6- O -benzyl-idehe-β-D-giucopyranose (1) in two steps. Compound 1, 1, 2, 3-tri-O -acetyl-β-D-glucopyranose (2), and 4α,β were subjected to the cyclization reaction using Lewis acids ( SnCl₄ and BF₃-etherate), to give corresponding 1, 6-anhydro derivatives.     

New flavonoid and pentacyclic triterpene from Sesamum indicum leaves

Two new and one known compounds were isolated from the methanol extract of Sesamum indicum leaves. By means of spectroscopic methods, their structures were elucidated and identified to be 3-epibartogenic acid (1), kaempferol 3-O-[2-O-(trans-p-coumaroyl)-3-O-α-L-rhamnopyranosyl]-β-d-glucopyranoside (2) and epigallocatechin (3). Compound 1 and 3 strongly inhibited α-amylase with the IC₅₀ values of 146.7 and 303.9 μM, respectively, in comparison with acarbose (IC₅₀ 124.0 μM).     

New Flavonoids from Lysimachia christinae Hance

A chemical investigation of Lysimachia christinae, a traditional Chinese medicine used as an effective conservative treatment for gall stones, hepatolithiasis, and urinary calculi, resulted in the isolation of two new flavonoids, myricetin 3,3′‐di‐α‐L ‐rhamnopyranoside ( 1 ) and quercetin 3,3′‐di‐α‐L ‐rhamnopyranoside ( 2 ), along with the five known flavonoids quercetin 3‐[O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐galactopyranoside], amentoflavone, hyperin, quercetin 3‐β‐D ‐glucopyranoside, and kaempferol 3‐α‐L ‐rhamnopyranoside. Amentoflavone was reported for the first time from the genus Lysimachia, and quercetin 3‐[O‐α‐L ‐rhamopyranosyl‐(1→2)‐β‐D ‐galactopyranoside] was isolated from this plant for the first time. The structures of the new compounds were elucidated on the basis of their chemical reactions and extensive spectroscopic analyses, including UV, mass, and NMR spectra.