On-line screening and identification of polyphenolic antioxidant compounds of <i>Convolvulus trabutianus</i>

Convolvulus trabutianus Schweinf. & Muschl. is an endemic plant from northern Sahara used in folk medicine. Herein we report, the isolation, characterization and evaluation of the radical scavenging properties of twenty three compounds from different extracts of this species by on-line HPLC-ABTS•+ screening. These compounds include nine phenolic acids: 2, 6, 10–16, two phytosterols: 3–4, four coumarins: 5, 7–9, two quinic acids: 21 and 22 and six flavonoids: 1, 17–20 and 23 among which the most active were: 10, 16, 21 and 22. All the extracts showed a significant antioxidant activity on-line. These results were validated off-line by ORAC and TEAC assays. Four compounds: 1, 5, 18 and 19 were described for the first time from the Convolvulaceae family, whereas compounds 2, 6, 8, 10, 13 and 21 were new for the genus Convolvulus.</p

A new isoflavonoid derivative, evaluation of the antioxidant capacity and phenolic content of <i>Genista lobelii</i> DC

The phytochemical investigation of both chloroform and ethyl acetate extracts of Genista lobelii DC from an Algerian endemic plant led to the isolation of a new isoflavonoid Aspalathoidin compound (1) and nine known compounds (laburnetin, isokaempferide, retamasin B, ephedrodin, sakuretin, isoprunetin, genistein −7-O-β-glucoside, derrone-4′-O-methyl ether and eriodictyol-7,3′-dimethylether). Twelve phenolic compounds were identified in ethyl acetate and n-butanol extracts through a qualitative investigation of phenolic compounds using HPLC. Finally, both extracts were estimated for their phenolic and flavonoid contents as well as the evaluation of their antioxidant activity using five different assays DPPH, CUPRAC, ABTS, GOR and the sun protection factor SPF was determined as an index of the photoprotective capacity of the G.lobelii DC extracts. The extract of chloroform and ethyl acetate has good antioxidant and includes significant levels of phenolic and flavonoid components.</p

Chemical composition, <i>in vitro</i> antiparasitic, antimicrobial and antioxidant activities of <i>Frankenia thymifolia</i> Desf.

This study was performed on the derived fractions [chloroform (FT-C), ethyl acetate (FT-E) and n-butanol (FT-B)] of the 70% ethanol extract prepared from Frankenia thymifolia, endemic to North Africa. The fractions showed high total phenolic and flavonoid contents particularly FT-E. These results agreed with their antioxidant effects. Indeed, all the fractions were able to scavenge 1,1-diphenyl-2-picrylhydrazyl radical, with a better power of FT-E. These results were supported by the inhibition of β-carotene oxidation assay. The fractions showed moderate activity against Acanthamoeba castellanii and Leishmania amazonensis with a better activity of FT-E against A. castellanii. Moreover, FT-B exhibited an interesting antimicrobial activity against all tested bacteria. The phytochemical investigation of the most active fractions (FT-E and FT-B) led to the isolation and structural determination of six compounds. The observed biological activities may be associated with the presence of quercetin and its derivatives found in the chemical composition of these fractions.</p

Essential oil constituents of <i>Juniperus oxycedrus</i> L. and <i>Cupressus sempervirens</i> L. (Cupressaceae) growing in Aures region of Algeria

The purpose of this study was to determine the chemical composition of essential oils from the aerial parts of two species belonging to the Cupressaceae family growing in the Aures region of Algeria Juniperus oxycedrus and Cupressus Sempervirens. The analysis by GC-MS and GC-FID techniques showed the presence of 38 compounds in J. oxycedrus oil where the major constituents were manoyl oxide (23.5%), pentadecan-2-enone 6Z (12.6%), abietatriene (8.0%), abieta-8,11,13-triene-7-one (6.5%), cubebol (4.6%), epi-torilenol (3.8%) and α-cadinol (2.6%), while, a total of 65 compounds were showed in C. sempervirens oil where the major constituents were α-pinene (68.0%), epi-cedrol (6.1%), α-terpenyl acetate (3.5%) and germacrene D (2.5%). It is the first time that the compounds pentadecan-2-enone 6Z, abieta-8,11,13-trien-7-one, cubebol and epi-torilenol have been identified in our J. oxycedrus and epi-cedrol in C. sempervirens essential oils with high contents, as we noticed the absence of α-pinene in our J. oxycedrus essential oil.</p

Iridoids and anti-inflammatory properties of <i>n</i>-butanol extract of <i>Linaria tingitana</i> Boiss. & Reut.

<p>The analysis of the <i>n</i>-butanol extract of <i>Linaria tingitana</i> (BELT) by HPLC-DAD–ESI/MS allowed the identification of four iridoids structurally confirmed by NMR and ESI–MS/MS extensive experiments data. The subjection of BELT to the anti-inflammatory activity showed that it exhibited a concentration dependent stabilisation of HRBC membrane, inhibition of protein denaturation and nitric oxide scavenging effect in the <i>in vitro</i> process. These results were confirmed in the <i>in vivo</i> experiments which showed that BELT was found to be most pronounced at 200 mg/kg after carrageenan injection which significantly reduced the swelling in both early and late phases of carrageenan-evoked oedema, as well as a significant reduce at the accumulation of infiltrating cells, inhibition of the myeloperoxidase activity and suppressed the lipid peroxidation. These results were supported by the histological analysis which revealed the reduction of oedema and cells infiltration, this might be influenced by the synergistic action of the above isolated compounds.</p

Phytochemical investigation of <i>Volutaria lippii</i> and evaluation of the antioxidant activity

Volutaria lippii (L.) Cass. ex Maire, syn. Centaurea lippii (L.), (Asteraceae) is a plant from the central region of Algeria, considerably distributed in all Mediterranean areas. Herein, the antioxidant activity of the three derived fractions [chloroform (CHCl3), ethyl acetate (EtOAc) and n-butanol (n-BuOH)] of the 70% methanol extract of the aerial parts (leaves and flowers), was assessed by using CUPRAC, ABTS, DPPH free radical scavenging, and β-carotene bleaching methods. The results obtained allowed to guide the fractionation of EtOAc and n-BuOH fractions by CC followed by purification by TLC and reverse phase HPLC. A guaianolide glucoside, 3β-hydroxy-11β,13-dihydrodehydrocostuslactone 8α-O-(6'-acetyl-β-glucopyranoside) (1), never reported in the literature, was isolated together with other known compounds (2–14). Their structures were elucidated by the extensive use of 1 D- and 2 D-NMR experiments along with ESI-MS analyses and with comparison with literature data.</p

Isolation from <i>Eucalyptus </i><i>o</i><i>ccidentalis</i> and Identification of a New Kaempferol Derivative that Induces Apoptosis in Human Myeloid Leukemia Cells

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2α,3β-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release

Chemical constituents, in vitro antioxidant and antimicrobial properties of ethyl acetate extract obtained from <i>Cytisus triflorus</i> l’Her

The present study investigates the phenolic composition, antioxidant and antimicrobial activities of an ethyl acetate extract from C. triflorus L’Her. The phytochemical study on the aerial parts of C. triflorus belonging to the Fabaceae family led to the isolation and structural elucidation of 5-Hydroxy-7-O-glucosylflavone (P1), 5-Hydroxy-7-O-galactosylflavone (P2), 5,7-Dihydroxy-flavone (P3), 5,7,3’-Trihydroxy,4’-methoxy-flavone (P4). These compounds were identified by 1D and 2D NMR combined analysis as well as by UV. Ethyl acetate extract of C. triflorus showed a significant and dose-dependent antioxidant activity in vitro, related to the presence of phenolics (180.33 ± 12.22 µg GAE/mg) and flavonoids (16.78 ± 1.54 µg QE/mg). The antimicrobial activity was evaluated in vitro against Staphylococcus aureus CECT 240 and Escherichia coli CECT 4099, by agar-diffusion method. The most active antibacterial activity was expressed by ethyl acetate extract of C. triflorus against Gram-positive bacteria S. aureus. The gathered results suggest that C. triflorus polyphenols and flavonoids are closely associated to its antioxidant and antimicrobial properties. </p

Polyphenolic content and bioactivities of <i>Crataegus oxyacantha</i> L. (Rosaceae)

Solid-Liquid Extraction (SLE) using solvent of different polarities (CHCl3, EtOAc, and n-BuOH) has been applied to leaves and fruits from (Crataegus oxyacantha L.), a deciduous shrub with an expected rich phytochemical profile. The total polyphenols content and the radical scavenging activity of each extract were evaluated. These extracts were analyzed by HPLC-DAD and rutin, quercetin-3-glucoside, caftaric and caffeic acid had been positively identified. The phytochemical study of the ethyl acetate extract of C. oxyacantha, led to the isolation and structural elucidation of quercetin (1); quercetin-3-O-β-glucoside (2); epicatechin (3); naringenin (4), reported for the first time from this species except caffeic acid and epicatechin. These compounds were identified by 1D and 2D NMR combined analysis as well as by MS and UV. The antimicrobial activity of these extracts has also been tested, showing strong antibacterial activity-solvent dependent-against Gram positive bacteria. Additionally, bactericidal power was demonstrated in fruit extracts.</p

Isolation from <i>Eucalyptus </i><i>o</i><i>ccidentalis</i> and Identification of a New Kaempferol Derivative that Induces Apoptosis in Human Myeloid Leukemia Cells

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2α,3β-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release