Publications by authors named "Lubna Iqbal"

Extracts of nine plants were studied for DPPH radical scavenging and reducing abilities. Pentatropis spiralis, Calotropis procera, Helitropium curassavicum, Withania somnifera and Chenopodium album showed reducing power ranging from 34% to 146%. Suaeda fruticosa, Trianthema portulacastrum, Pluchea lanceolata and Rumex dentatus has excellent antioxidant potential proved by their DPPH scavenging and reducing power.

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In this study, a range of oxamide ligands were synthesized by the reaction of amines with oxalyl chloride in basic medium. Spectroscopic and analytical techniques such as IR, 1H-NMR and ESI-MS techniques were used for characterization of the synthesized oxamides. The synthesized oxamides were screened for Lipoxygenase inhibition.

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The present study explores the synthesis and inhibitory potential of vanadium(V) complexes of hydrazides (1c-12c) against oxidative enzymes including xanthine oxidase and lipoxygenase (LOX). In addition, non-enzymatic radical scavenging activities of these complexes were also determined. On the basis of spectral, elemental and physical data, synthesized vanadium(V) complexes are tentatively assigned to have an octahedral geometry with two hydrazide ligands and two oxo groups forming a negatively charged sphere complex with ammonium as counter ion.

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To treat Alzheimer's disease (AD), the available candidates are effective only against mild AD or have side effects. So, a study was planned to synthesis new candidates that may have good potential to treat AD. A series of new anthrarobin acyl derivatives (-) were synthesized by the reaction of anthrarobin () and acetic anhydride/acyl chlorides.

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Termiglaucescin (1), a new triterpene glucoside, has been isolated from the ethyl acetate extract of the root bark of Terminalia glaucescens Planch. ex Benth, together with 11 known compounds, β-D-glucopyranosyl 2α,3β,6β-trihydroxy-23-galloylolean-12-en-28-oate (2), arjunglucoside I (3), sericoside (4), arjungenin (5), sericic acid (6), arjunetin (7), chebuloside II (8), 3,3',4-tri-O-methylelagic acid (9), 3,3'-di-O-methylelagic acid (10), β-sitosterol (11) and stigmasterol (12). Compounds 2, 3, 7, 8 and 9 are reported from the plant for the first time.

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Piptadenin (1), a new triterpene along with piptadenamide (10), a new ceramide, have been isolated from the AcOEt-soluble fraction of the MeOH extract of the stem bark of Piptadeniastrum africanum along with nine known compounds, 1-O-[(3β,22β)-3,22-dihydroxy-28-oxoolean-12-en-28-yl]-β-d-glucopyranose (2), 22β-hydroxyoleanic acid (3), oleanic acid (4), lupeol (5), betulinic acid (6), 5α-stigmasta-7,22-dien-3β-ol (7), 5α-stigmasta-7,22-dien-3-one (8), (3β)-stigmast-5-en-3-yl β-d-glucopyranoside (9) and 2,3-dihydroxypropyl hexacosanoate (11). Except for compound 11, all the isolated compounds are reported for the first time from this plant. The structures of the isolated compounds were elucidated by spectroscopic data including 1D and 2D NMR.

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The antioxidant, lipoxygenase inhibitory activities and free radical scavenging capacity of the crude extract, aqueous and some organic fractions of dry and ripe fruit of Aeglemarmelos. L were studied to understand the protective and therapeutic role for the use of the fruit as a remedy in different ailments. All the tested fractions and extracts showed to possess significant antioxidant, free radical scavenging capacity and lipoxygenase inhibitory potential.

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1,4-Disubstituted-1,2,3-triazoles were synthesized by Cu(I) catalyzed click reaction, where the azides, with electron donating and electron withdrawing groups acted as 1,3-dipoles and 1-ethynyl-1-cyclohexanol served as the terminal alkyne. These synthesized triazoles were subjected to enzymatic assay which showed promising activity against α-glucosidase; 1-(2-cyano-4-nitrophenyl)-4-(1-hydroxycyclohexyl)-1H-1,2,3-triazole 3m being the most active members of the library. Molecular docking studies of these triazoles with the homology-modeled α-glucosidase protein were also performed to delineate ligand-protein interactions at molecular level which suggested that Phe157, Arg312 and His279 are the major interacting residues in the biding site of the protein and may have a significant role in the inhibition of enzyme's function.

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Phytochemical investigation of the ethyl acetate soluble fraction of the methanol soluble extract of the roots of Daphne oleoides resulted in isolation and identification of two new isomeric biisoflavonoids characterized as 8,8"-bi-6-hydroxyorobol (1) and 8,8"-bi-6, 2'-dihydroxygenistein (2). The structures of these compounds were established by analysis of their 1D and 2D NMR and HRMS data.

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The dichloromethane-methanol (1:1) soluble part of Calopogonium mucunoides (Fabaceae) resulted in the isolation of 10 isoflavones (4'-O-methylalpinumisoflavone, 4'-O-methylderrone, alpinumisoflavone, daidzeine, Calopogonium isoflavone A, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin, cabreuvin and 7-O-methylpseudobaptigenin) and a rotenoid (6a,12a-dehydroxydegueline). Among these, daidzeine, 7-O-methylcuneantin, atalantoflavone and 6a, 12a-dehydroxydegueline have been isolated for the first time from C. mucunoides while remaining are already reported from this source.

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Ophiamides A (1) and B (2), two new sphingolipids have been isolated from the n-hexane subfraction of the MeOH extract of the whole plant of Heliotropium ophioglossum along with glycerol monopalmitate (3) and β-sitosterol 3-O-β-D: -glucoside (4) reported for the first time from this species. Their structures were elucidated by spectroscopic techniques including MS and 2D-NMR spectroscopy. Both the compounds 1 and 2 showed potent inhibitory activity against the enzyme urease.

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Nine compounds have been isolated for the first time from Celtis africana, namely trans-N-coumaroyltyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), lauric acid (4), oleic acid (5), palmitic acid (6), lupeol (7), β-sitosterol (8) and oleanolic acid (9), respectively. Their structures have been elucidated by different spectroscopic techniques. The isolated compounds were screened for their antioxidant, anti-inflammatory and acetylcholinestrease enzyme inhibitory activities.

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New bergenin derivatives, bergecins A and B (1 and 2, resp.), have been isolated from the AcOEt-soluble fraction of Bergenia stracheyi, along with bergenin (3), and their structures were elucidated on the basis of (1) H- and (13) C-NMR spectra, and by COSY, HMQC, and HMBC experiments. Compound 2 showed potent inhibitory potential against the enzyme lipoxygenase, while 1 was moderately active.

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The object of this study is to determine the antioxidant activity of extracts from Glycyrrhiza glabra roots. The parent extract is methanolic extract while its sub fractions were prepared in ethyl acetate, chloroform, and n-butanol. The method based on scavenging activity and reduction capability of 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH).

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Two new lupene-type triterpenes, sorbicins A and B, have been isolated from the chloroform-soluble fraction of the MeOH extract from the whole plant of Sorbus cashmiriana, and their structures were elucidated by spectroscopic techniques including 2D NMR. Both compounds displayed urease and α-chymotrypsin inhibitory potential.

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Two new C-glycosylflavonoids celtisides A (1) and B (2) have been isolated from n-butanol-soluble fraction of Celtis africana, along with five known C-glycosylflavonoids vitexin (3), orientin (4), isoswertiajaponin (5), isoswertisin (6), and 2″-O-rhamnosyl vitexin (7) reported for the first time from this species. Their structures were assigned from 1D and 2D NMR spectra. These compounds were investigated for biological activities and showed significant antioxidant and urease inhibitory activities.

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Asphorodin (1), a new diglycoside, has been isolated from the ethyl acetate-soluble fraction of Asphodelus tenuifolius. It showed significant inhibitory activity against the enzyme lipoxygenase in a concentration-dependent manner. The Lineweaver-Burk and Dixon plots indicated that the nature of inhibition was non-competitive.

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Galinsosides A (1) and B (2), new flavanone glucosides together with two known flavanones, 7,3',4'-trihydroxyflavanone (3) and 3,5,7,3',4'-pentahydroxyflavanone (4) have been isolated from an ethyl acetate- soluble fraction of Galinsoga parviflora. Their structures were assigned on the basis of spectral studies. Compound 1 showed significant antioxidant and urease inhibitory activity while compound 2 was moderately active.

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Conferin (1), a new isoflavone, has been isolated from the ethyl acetate soluble fraction of Caragana conferta Benth. along with seven known compounds, namely biochanin A (2), p-hydroxybenzoic acid (3), 3,5-dimethoxybenzoic acid (4), ursolic acid (5), erythrodiol (6), pinoresinol (7), and syringresinol (8), reported for the first time from this species. The structure of the new isoflavone was deduced on the basis of spectroscopic studies.

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Mutiniside (1), new phenolic glucoside, and the flavonoidal glucoside cephacoside (2) have been isolated from the n-BuOH soluble fraction, along with lupeol (3), beta-sitosterol (4), stigmasterol (5), methyl-4-hydroxybenzoate (6), taraxacin (7), ursolic acid (8), and beta-sitosterol-3-O-beta-D-glucopyranoside (9), have been isolated from the EtOAc soluble fraction of Abutilon muticum. Compounds 2-9 are reported for the first time from this species. Compound 1 showed significant antioxidant activity while moderate inhibitory activity was observed against the enzyme lipoxygenase.

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A new lignan rhamnoside, racemiside (1), has been isolated from the ethyl acetate-soluble fraction of Cotoneaster racemiflora, along with scopoletin (2), 7,8-dimethoxy-6-hydroxycoumarin (3), 3,3',4'-tri-O-methylellagic acid (4), and cereotagloperoxide (5), reported for the first time from this species. All of them showed profound antioxidative activities in the DPPH assay.

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A new steroid leucisterol (1) and a new peroxy acid urticic acid (2) along with methoxybenzyl benzoate (3), 4-hydroxy benzoic acid (4), beta-sitosterol (5), and ursolic acid (6), have been isolated from the chloroform soluble fraction of the whole plant of Leucas urticifolia. Their structures were elucidated on the basis of nuclear magnetic resonance (1D and 2D NMR) spectral data. Leucisterol showed potent inhibitory activity against butyrylcholinesterase enzyme.

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A mild and efficient route to tetraketones (2-22) has been developed by way of tetraethyl ammonium bromide (Et(4)N(+)Br(- )) mediated condensation of dimedone (5,5-dimethylcyclohexane-1,3-dione, 1) with a variety of aldehydes. All these compounds showed significant lipoxygenase inhibitory activity and moderate to strong antioxidant potential. Compounds 19 (IC(50) = 7.

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Salsolins A (1) and B (2), the new triterpenes, have been isolated from the chloroform soluble fraction of Salsola baryosma along with 2alpha,3beta,23,24-tetrahydroxyurs-12-en-28-oic acid (3) reported for the first time from this species. Their structures have been assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC and HMBC experiments. The compounds 1-3 showed significant antioxidant activity.

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New flavonoidal glucosides leufolins A (1) and B (2), have been isolated from the ethyl acetate soluble fraction of the whole plants of Leucas urticifolia. Their structures were elucidated on the basis of extensive analysis of nuclear magnetic resonance (1D and 2D NMR) spectral data. Both of these compounds exhibited significant inhibitory potential against the enzyme butyrylcholinesterase.

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