Jalloul Bouajila

Eucalyptus oleosa essential oils: chemical composition and antimicrobial and antioxidant activities of the oils from different plant parts (stems, leaves, flowers and fruits).

Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature flowers and the fruit oils was 1,8-cineole, representing 31.5%, 47.0% and 29.1%, respectively. Spathulenol (16.1%) and γ-eudesmol (15.0%) were the two principal compounds of adult leaves oil. In the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, the oils of the four parts showed moderate antioxidant activity. In the ABTS (2,2’-azinobis-3-ethylbenzothiazoline-6-sulphonate) assay, the most active part was the adult leaves, with a IC50 value 13.0 ± 0.6 mg/L, followed by stems (IC50 = 43.5 ± 1.4 mg/L). The essential oils showed a better antibacterial activity against Gram-positive and Gram-negative bacteria, and a significant antifungal activity also was observed against yeast-like fungi. A strong correlations between oxygenated monoterpenes and antimicrobial activity (especially 1,8-cineole) were noted (R2 = 0.99, 0.97 and 0.79 for B. subtilis, P. aeruginosa and C. albicans, respectively).

Assessment of antioxidant, anti-inflammatory, anti-cholinesterase and cytotoxic activities of pomegranate (Punica granatum) leaves.

This study evaluated antioxidant, anti-inflammatory, anti-cholinesterase and cytotoxic activities of extracts with different polarities (hexane, dichloromethane, ethyl acetate, ethanol and methanol) obtained from Punica granatum leaves. Total phenolics (8.8-127.3mg gallic acid equivalent/g dry weight), flavonoids (1.2-76.9mg quercetin equivalent/g dry weight), tannins (63.7-260.8mg catechin equivalent/kg dry weight) and anthocyanins (0.41-3.73mg cyanidin-3-glucoside equivalent/g dry weight) of different extracts were evaluated. The methanolic extract presented a good IC50 by DPPH and ABTS assays (5.62 and 1.31mg/l respectively). The strongest 5-lipoxygenase (5-LOX), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition activities were obtained for the ethanol extract (IC50 values of 6.20, 14.83 and 2.65mg/l, respectively) and the best cytotoxic activity against MCF-7 cells was obtained for the methanol extract (IC50=31mg/l). These important biological activities showed that P. granatum leaves could be a potential source of the active molecules intended for applications in pharmaceutical industry, but only after additional in vivo experiments.

Oregano: Chemical Analysis and Evaluation of Its Antimalarial, Antioxidant, and Cytotoxic Activities

GC-FID and GC-MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p-cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50=2±0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50=4.8±0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.

Chemical Composition and Antimicrobial and Antioxidant Activities of Essential Oils and Various Extracts of Juniperus phoenicea L. (Cupressacees)

GC-FID and GC-MS analysis of essential oils of Juniperus phoenicea resulted in the identification of 30 compounds, representing more than 98% of the total composition. alpha-pinene (55.7% and 80.7%), delta-3-carene (10.7% and 4.5%), and gamma-cadinene (2.9% and 5.1%) were the main components, respectively, in leaves and berries essential oil. Extracts of J. phoenicea were obtained by different extraction solvents: methanol, ethanol, ethyl acetate, and dichloromethane and evaluated composition for polyphenols (gallic acid equivalent 52 to 217 g/kg), tannins (catechin equivalent 6.5 to 60.2 g/kg), antocyanins (cyanidin equivalent 84 to 373 mg/kg), and flavonoids (quercetin equivalent 6.4 to 29.3 g/kg). The samples (essential oils and extracts) were subjected to a screening for their antioxidant activity by using DPPH and ABTS assays; antimicrobial activity was tested with 6 bacteria (3 Gram-positive and 3 Gram-negative), 1 yeast, and 2 fungi. The strongest antioxidant activity was obtained by the methanolic extract (IC(50)= 6.5 +/- 0.3 mg/L). Flavonoids are likely to contribute to the antifungal activity against Saccharomyces cerevisiae. Correlations were studied between chemical composition and antioxidant and antimicrobial activities.

Chemical composition and anticancer, antiinflammatory, antioxidant and antimalarial activities of leaves essential oil of Cedrelopsis grevei

The essential oil from Cedrelopsis grevei leaves, an aromatic and medicinal plant from Madagascar, is widely used in folk medicine. Essential oil was characterized by GC-MS and quantified by GC-FID. Sixty-four components were identified. The major constituents were: (E)-β-farnesene (27.61%), δ-cadinene (14.48%), α-copaene (7.65%) and β-elemene (6.96%). The essential oil contained a complex mixture consisting mainly sesquiterpene hydrocarbons (83.42%) and generally sesquiterpenes (98.91%). The essential oil was tested cytotoxic (on human breast cancer cells MCF-7), antimalarial (Plasmodium falciparum), antiinflammatory and antioxidant (ABTS and DPPH assays) activities. C. grevei essential oil was active against MCF-7 cell lines (IC50=21.5 mg/L), against P. falciparum, (IC50=17.5mg/L) and antiinflammatory (IC50=21.33 mg/L). The essential oil exhibited poor antioxidant activity against DPPH (IC50>1000 mg/L) and ABTS (IC50=110 mg/L) assays. A bibliographical review was carried out of all essential oils identified and tested with respect to antiplasmodial, anticancer and antiinflammatory activities. The aim was to establish correlations between the identified compounds and their biological activities (antiplasmodial, anticancer and antiinflammatory). According to the obtained correlations, 1,4-cadinadiene (R(2)=0.61) presented a higher relationship with antimalarial activity. However, only (Z)-β-farnesene (R(2)=0.73) showed a significant correlation for anticancer activity.

The influence of organ, season and drying method on chemical composition and antioxidant and antimicrobial activities of Juniperus phoenicea L. essential oils

BACKGROUND Juniperus phoenicea is an important medicinal plant. In the present study, essential oils (18 samples) from leaves and berries of Juniperus phoenicea L. (Cupressaceae), obtained by various drying methods and in different collection months, were analysed by gas chromatography-mass spectrometry and also evaluated for in vitro antimicrobial and antioxidant activities. Correlations were studied between antimicrobial activity and the chemical composition of essential oils. RESULTS Sixty-seven compounds were identified in essential oils, representing 97.7-100%. Essential oils were dominated by monoterpenes and sesquiterpenes, which presented 35.0-93.3% and 6.7-62.0%, respectively, depending of organ, season and drying method. Antimicrobial tests showed that essential oils strongly inhibited the growth of Gram-positive microorganisms and Mucor ramamnianus, but was inactive against Gram-negative strains. Antioxidant activity was tested using the ABTS radical-scavenging assay. Most samples showed good activity (the best IC(50) = 41.7 + or - 1.5 mg L(-1)). CONCLUSIONS It could be concluded that drying of leaves of J. phoenicea in the sun and berries in oven-drying was more suitable and was recommended for obtaining higher essential oil yield, but for a higher percentage of some special components such as alpha-pinene and delta-3-carene shade-drying was more suitable.

Synthesis and antiplasmodial activity of new indolone N-oxide derivatives.

A series of 66 new indolone-N-oxide derivatives was synthesized with three different methods. Compounds were evaluated for in vitro activity against CQ-sensitive (3D7), CQ-resistant (FcB1), and CQ and pyrimethamine cross-resistant (K1) strains of Plasmodium falciparum (P.f.), as well as for cytotoxic concentration (CC(50)) on MCF7 and KB human tumor cell lines. Compound 26 (5-methoxy-indolone-N-oxide analogue) had the most potent antiplasmodial activity in vitro (<3 nM on FcB1 and = 1.7 nM on 3D7) with a very satisfactory selectivity index (CC(50) MCF7/IC(50) FcB1: 14623; CC(50) KB/IC(50) 3D7: 198823). In in vivo experiments, compound 1 (dioxymethylene derivatives of the indolone-N-oxide) showed the best antiplasmodial activity against Plasmodium berghei, 62% inhibition of the parasitaemia at 30 mg/kg/day.

Helichrysum gymnocephalum Essential Oil: Chemical Composition and Cytotoxic, Antimalarial and Antioxidant Activities, Attribution of the Activity Origin by Correlations

Helichrysum gymnocephalum essential oil (EO) was prepared by hydrodistillation of its leaves and characterized by GC-MS and quantified by GC-FID. Twenty three compounds were identified. 1,8-Cineole (47.4%), bicyclosesquiphellandrene (5.6%), γ-curcumene (5.6%), α-amorphene (5.1%) and bicyclogermacrene (5%) were the main components. Our results confirmed the important chemical variability of H. gymnocephalum. The essential oil was tested in vitro for cytotoxic (on human breast cancer cells MCF-7), antimalarial (Plasmodium falciparum: FcB1-Columbia strain, chloroquine-resistant) and antioxidant (ABTS and DPPH assays) activities. H. gymnocephalum EO was found to be active against MCF-7 cells, with an IC50 of 16 ± 2 mg/L. The essential oil was active against P. falciparum (IC50 = 25 ± 1 mg/L). However, the essential oil exhibited a poor antioxidant activity in the DPPH (IC50 value > 1,000 mg/L) and ABTS (IC50 value = 1,487.67 ± 47.70 mg/L) assays. We have reviewed the existing results on the anticancer activity of essential oils on MCF-7 cell line and on their antiplasmodial activity against the P. falciparum. The aim was to establish correlations between the identified compounds and their biological activities (antiplasmodial and anticancer). β-Selinene (R² = 0.76), α-terpinolene (R² = 0.88) and aromadendrene (R² = 0.90) presented a higher relationship with the anti-cancer activity. However, only calamenene (R² = 0.70) showed a significant correlation for the antiplasmodial activity.

Insights into the redox cycle of human quinone reductase 2

Abstract NRH:quinone oxidoreductase 2 (QR2) is a cytosolic enzyme that catalyzes the reduction of quinones, such as menadione and co-enzymes Q. With the aim of understanding better the mechanisms of action of QR2, we approached this enzyme catalysis via electron paramagnetic resonance (EPR) measurements of the by-products of the QR2 redox cycle. The variation in the production of oxidative species such as H2O2, and subsequent hydroxyl radical generation, was measured during the course of QR2 activity under aerobic conditions and using pure human enzyme. The effects on the activity of the following were compared: (i) synthetic (N-benzyldihydronicotinamide, BNAH) or natural (nicotinamide riboside, NRH) co-substrates; (ii) synthetic (menadione) or natural (co-enzyme Q0, Q2) substrates; (iii) QR2 modulators and inhibitors (melatonin, resveratrol and S29434); (iv) a pro-drug activated via a redox cycle [CB1954, 5-(aziridin-1-yl)-2,4-dinitrobenzamide]. The results were also compared with those obtained with human QR1. The production of hydroxyl radicals is: (i) observed whatever the substrate/co-substrate used; ii) quenched by adding catalase; (iii) not observed with the specific QR2 inhibitor S29434; (iv) observed with the pro-drug CB1954. While QR2 produced free radicals with this pro-drug, QR1 gave no EPR signal showing the strong reducing capacity of QR2. In conclusion, EPR analysis of QR2 enzyme activity through free radical production enables modulators and effective inhibitors to be distinguished.

Chemical Composition and Antioxidant, Anti-Inflammatory, and Antiproliferation Activities of Pomegranate (Punica granatum) Flowers

The chemical composition, antioxidant (DPPH and ABTS assays), anti-inflammatory (5-LOX), and cytotoxic (MCF-7) activities from flowers of seven pomegranate varieties (Punica granatum) were investigated. The highest phenolics (330.9±11.3 mg gallic acid equivalent/g dry weight (dw)), flavonoids (29.5±0.8 mg quercetin equivalent/g dw), tannins (30.6±0.6 mg catechin equivalent/g dw), and anthocyanins (0.70±0.03 mg cyanidin-3-glucoside equivalent/g dw) content were determined in the Chetoui (CH) variety. It was found that Garsi (GR) (IC₅₀=4.9±0.2 mg/L by ABTS assay) and Zaghwani (ZG) (IC₅₀=3.9±0.2 mg/L by ABTS assay) varieties exhibited the highest antioxidant activity. For the anti-inflammatory activity, all varieties were active; the ZH variety was the strongest (2.5±0.1 mg/L). The CH, ES, and RA pomegranate varieties were not active against human breast cancer cells MCF-7, whereas inhibition was more evident with extracts from ZH and GR varieties (IC₅₀=33.00±2.64 and 35.00±4.58 mg/L, respectively). Statistical analysis showed that the variety factor influenced significantly (P<.01) the chemical composition and biological activities of pomegranate flowers.