Native wild plants in Karachi, Pakistan: Rich source of antioxidant raw material.

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. 1000µg/10µl chloroform extract of S. fruticosa gave 92% scavenging with IC50 value less than 0.7µg/10µl while its hexane extract possessed 80% reducing activity at 100µg/10µl concentration. DPPH free radical scavenging by methanolic extract of Trianthema portulacastrum was 60% and 76% at 1000 and 100µg/10µl respectively with IC50 value of 0.03µg/10µl while the reducing activity of 124% at 100µg/10µl. Methanolic extract of P. lanceolata showed 91% and 70% scavenging activity at 1000 and 100µg/10µl with IC50 value of 0.7µg/ 10µl. Reducing power is comparable with the reference BHA standard that is 98% at 100µg/10µl concentration. Rumex dentatus' extracts are excellent DPPH scavengers and hydrogen donators produced 156% reduction. Chloroform extract was inefficient antioxidant. These results make these plants a candidate for future research for treating ailments due to imbalance in free radicals.

Synthesis, lipoxygenase inhibition activity and molecular docking of oxamide derivative.

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. Biological screening revealed that the oxamides possessed good lipoxygenase inhibition activities, whereas, the unsubstituted oxamide did not show any distinct lipoxygenase inhibition activity. Molecular docking studies of the oxamides were also carried out for lipoxygenase inhibition. The results obtained from molecular docking were well correlated with the empirical data.

Vanadium(V) complexes with hydrazides and their spectroscopic and biological properties.

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. This is further verified by the conductivity studies of the complexes. Results show that hydrazide ligands (1-12) and their respective vanadium(V) complexes (1c-12c) posses scavenging and inhibition potential against DPPH and LOX, respectively. However, contrary to that uncoordinated ligands showed no activity against nitric oxide, superoxide and xanthine oxidase whereas their complexes showed varying degree of activity. These studies indicate that geometry of complex, nature and position of substituent groups play a vital role in scavenging and inhibition potential of these compounds.

New anthrarobin acyl derivatives as butyrylcholinesterase inhibitors: synthesis, in vitro and in silico studies.

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 (2-8) were synthesized by the reaction of anthrarobin (1) and acetic anhydride/acyl chlorides. The product were characterized by 1H NMR and EI-MS, and evaluated for butyrylcholinesterase (BuChE) inhibition activity. Compounds 5 and 4 showed notable BuChE inhibitory potential with IC50 5.3 ± 1.23 and 17.2 ± 0.47 µM, respectively when compared with the standard eserine (IC50 7.8 ± 0.27 µM), compound 5 showed potent BuChE inhibition potential than the standard eserine. The active compounds 5 and 4 have acyl groups at 2-OH and 10-OH positions which may be responsible for inhibitory potential as this orientation is absent in other products. In silico studies of 5 and 4 products revealed the high inhibitory potential due to stable binding of ligand with the BuChE active sites with docking energy score -18.8779 kcal/mol and -23.1159 kcal/mol, respectively. Subsequently, compound 5 that have potent BuChE inhibitory activity could be the potential candidate for drug development for Alzheimer's disease.

Dry and ripe fruit of Aegle marmelos. L: A potent source of antioxidant, lipoxygenase inhibitors and free radical scavenger.

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. However, chloroform and aqueous fractions showed significant ability to quench radicals, to reduce ferric chloride and to inhibit soyabean lipoxygenase. Their antioxidant and lipoxygenase inhibition was estimated by IC50 values, for antioxidant ranging from 88-65% activity at concentration of 5-0.15µ/mL and similarly for lipoxygenase inhibition ranging from 89-69% at various concentrations of 5-0.15µ/mL, in chloroform and aqueous fractions respectively. The scavenger molecules in the dry and ripe fruit of A. marmelos may attribute to therapeutic and protective effect during different progressive stages of ailments.

Synthesis, in vitro and computational studies of 1,4-disubstituted 1,2,3-triazoles as potential α-glucosidase inhibitors.

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.

Urease inhibitory isoflavonoids from different parts of Calopogonium mucunoides (Fabaceae).

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. Structures of all the isolated constituents were elucidated with the aid of NMR spectroscopic and mass spectrometric techniques. Among all the isolated constituents, nine were evaluated for their urease inhibitory potential. However, six were found potent. These include 4'-O-methylderrone, daidzeine, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin and 6a, 12a-dehydroxydegueline.

Ophiamides A-B, new potent urease inhibitory sphingolipids from Heliotropium ophioglossum.

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 ß-sitosterol 3-O-ß-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.

Bioactive phenolic amides from Celtis africana.

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), ß-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. Compounds 1-3 showed significant antioxidant and anti-inflammatory activities and weak to moderate acetylcholinestrease enzyme inhibition activity.

Biologically active bergenin derivatives from Bergenia stracheyi.

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. On the other hand, both compounds exhibited significant antioxidant activities in 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay.

Evaluation of antioxidant and urease inhibition activities of roots of Glycyrrhiza glabra.

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). Urease inhibition activities of these extracts were also evaluated. Chloroform fraction was the most effective antioxidant with 87.7% activity but the activity is less than the crude methanolic extract i.e. 90%. Chloroform fraction showed the same trend in reducing power as that in radical scavenging activity. However n- butanol extract was devoid of any activity when compared to standard BHA. Crude methanolic fraction and its sub-fractions were also screened for enzyme inhibition activities using jackbean urease as substrate. Significant anti urease activity i.e. 72 % was observed in the ethyl acetate fraction with respect to standard inhibitor thiourea.

Two new biisoflavonoids from the roots of Daphne oleoides.

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.

Sorbicins A and B, new urease and serine protease inhibitory triterpenes from Sorbus cashmiriana.

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.

Antioxidant and urease inhibitory C-glycosylflavonoids from Celtis africana.

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.

Conferin, potent antioxidant and anti-inflammatory isoflavone from Caragana conferta Benth.

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. Compounds 1 and 2 were investigated for biological activities and showed significant anti-inflammatory activity in carrageenan induced paw edema of rats. Evaluation of antioxidant activity by the radical scavenging method indicated that compound 1 is a potent antioxidant while 2 is moderately active. It was also shown that the reducing capability of compound 2 was remarkably increased in a concentration dependent manner as compared to 1. Compound 1 showed moderate inhibitory activity against the enzyme lipoxygenase, while 2 showed weak activity.

Galinsosides A and B, bioactive flavanone glucosides from Galinsoga parviflora.

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. On the other hand, 2 showed inhibitory potential against alpha-glucosidase.

Mutiniside, new antioxidant phenolic glucoside from Abutilon muticum.

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.

Antioxidant constituents from Cotoneaster racemiflora.

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.

Asphorodin, a potent lipoxygenase inhibitory triterpene diglycoside from Asphodelus tenuifolius.

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.

New butyrylcholinesterase inhibitory steroid and peroxy acid from Leucas urticifolia.

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.