34 research outputs found
Does Public Debt Matter For Economic Growth? Evidence from southern Mediterranean countries.
This paper aims to examine the impact of public debt on economic growth using the dynamic panel data for a 9 southern Mediterranean countries over the period 1990-2015. Our empirical results showed that public debt is negatively and significantly related to economic growth. They also indicate that inflation, investment and total reserves are the main factors of economic growth in the southern Mediterranean countries
Does Public Debt Matter For Economic Growth? Evidence from southern Mediterranean countries.
This paper aims to examine the impact of public debt on economic growth using the dynamic panel data for a 9 southern Mediterranean countries over the period 1990-2015. Our empirical results showed that public debt is negatively and significantly related to economic growth. They also indicate that inflation, investment and total reserves are the main factors of economic growth in the southern Mediterranean countries
Natural Products among Brown Algae: The Case of Cystoseira schiffneri HAMEL (Sargassaceae, Phaeophyceae)
A chemotaxonomic study on the marine brown alga Cystoseira schiffneri collected from the Tunisian marine coast
allowed us to identify kjellmanianone (1) and a new isololiolide derivative named schiffnerilolide (2). The structu re
elucidati on and the assignment of relative con figurations of the isolated natur al products were based on advanced
mass spectrometric and nuclear magnetic resonance techniques. This outcome suggested a close phylogenetic
relationship of C. schiffneri with brown algae bel onging to genus Sargassum C. A
GARDH. Molecular characterization
using the nuclear small subunit rRNA (SSU rRNA) gene (18S) sequence as genetic marker was made. Pigme nt analysis
showed a significant seasonal change of carotenoids, in particular of fucoxanthin and fucoxanthinol. Also
galactolipids, the main constituents of the thylakoid membranes, showed remarkable seasonal changes
Chemical composition and biological activities of Salvia officinalis essential oil from Tunisia
The aim of this study is to evaluate the chemical composition, antioxidant, antimicrobial,
insecticidal and allelopa- thic activities of Tunisia Salvia officinalis essential oil (SoEO). The
SoEO was characterized by the presence of 49 components with camphor (25.14 %), α-thujone (18.83
%), 1,8-cineole (14.14 %), viridiflorol (7.98 %), β-thu- jone (4.46 %) and β-caryophyllene (3.30 %)
as the major components, determined by gas chromatography-mass spectrometry. The level of
antioxidant activity, determined by complementary tests, namely 2,2-diphenyl-1-pic- rylhydrazyl
radical-scavenging (IC50= 6.7 mg/mL), linoleic acid peroxidation (IC50= 9.6 mg/mL) and ferric
reduc- ing assays (IC50= 28.4 mg/mL), was relatively moderate. The SoEO was also screened for its
antimicrobial activity. Good to moderate inhibitions were recorded for most of tested
microorganisms. It also exhibited important insec- ticidal activity against Spodoptera littoralis
larvae and Tribolium castaneum adults with LC50 values of 55.99 and
97.43 µl/L air, respectively. The effect of the SoEO on seeds germination and growth showed
different activities against radical and hypocotyl elongation of the tested species. These results
suggest the potential use of the SoEO
as natural antimicrobial preservative in cosmetic, pharmaceutical industry and in pest management
Essential Oil Constituents and Antioxidant Activity of Asplenium Ferns
Two fern species Asplenium adiantum-nigrum L. and Asplenium trichomanes L. collected from the Kroumiria region (Northwest of Tunisia) were individually submitted to hydrodistillation in a Clevenger type apparatus. Volatile organic compounds were identified by GC-MS and GC-FID. Thus, 35 compounds were identified in A. adiantum-nigrum essential oil accounting for 77.5% of the whole constituents dominated by palmitic acid (34.5%); however, only 29 volatiles were identified in A. trichomanes showing a high amount of phytol, an odorous diterpene alcohol, representing 14.4% of the total oil contents. The total phenolic content and the antioxidant effects of crude extracts from both pteridophytes were determined using Folin-Ciocalteu and 2,2′-diphenyl-1-picrylhydrazyl free radical-scavenging assays, respectively. A. adiantum-nigrum ethyl acetate extract is shown to be lower in total phenolic contents (49.3 mg gallic acid equivalent/g) than similar extract from A. trichomanes (55.4 mg GAE/g)
Antifungal effects of secondary metabolites isolated from marine organisms collected from the Tunisian coast
Rhaponticum acaule (L) DC essential oil: chemical composition, in vitro antioxidant and enzyme inhibition properties
Background: α-glucosidase is a therapeutic target for diabetes mellitus (DM) and α-glucosidase inhibitors play a
vital role in the treatments for the disease. Furthermore, xanthine oxidase (XO) is a key enzyme that catalyzes
hypoxanthine and xanthine to uric acid which at high levels can lead to hyperuricemia which is an important cause
of gout. Pancreatic lipase (PL) secreted into the duodenum plays a key role in the digestion and absorption of fats.
For its importance in lipid digestion, PL represents an attractive target for obesity prevention.
Methods: The flowers essential oil of Rhaponticum acaule (L) DC (R. acaule) was characterized using gas
chromatography-mass spectrometry (GC-MS). The antioxidant activities of R. acaule essential oil (RaEO) were also
determined using 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power,
phosphomolybdenum, and DNA nicking assays. The inhibitory power of RaEO against α-glucosidase, xanthine
oxidase and pancreatic lipase was evaluated. Enzyme kinetic studies using Michaelis-Menten and the derived
Lineweaver-Burk (LB) plots were performed to understand the possible mechanism of inhibition exercised by the
components of this essential oil.
Results: The result revealed the presence of 26 compounds (97.4%). The main constituents include germacrene D
(49.2%), methyl eugenol (8.3%), (E)-β-ionone (6.2%), β-caryophyllene (5.7%), (E,E)-α-farnesene (4.2%),
bicyclogermacrene (4.1%) and (Z)-α-bisabolene (3.7%). The kinetic inhibition study showed that the essential oil
demonstrated a strong α-glucosidase inhibiton and it was a mixed inhibitor. On the other hand, our results
evidenced that this oil exhibited important xanthine oxidase inhibitory effect, behaving as a non-competitive
inhibitor. The essential oil inhibited the turkey pancreatic lipase, with maximum inhibition of 80% achieved at
2 mg/mL. Furthermore, the inhibition of turkey pancreatic lipase by RaEO was an irreversible one.
Conclusion: The results revealed that the RaEO is a new promising potential source of antioxidant compounds,
endowed with good practical applications for human health.
Keywords: α-glucosidase, Antioxidant activity, Chemical composition, Pancreatic lipase inhibition, Rhaponticum
acaule essential oil, Xanthine oxidase
Essential Oil Composition, Antioxidant, Cytotoxic and Antiviral Activities of Teucrium pseudochamaepitys Growing Spontaneously in Tunisia
The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Thirty-one compounds were identified representing 88.6% of the total essential oil. Hexadecanoic acid was found to be the most abundant component (26.1%) followed by caryophyllene oxide (6.3%), myristicin (4.9%) and α-cubebene (3.9%). The antioxidant capacity of the oil was measured on the basis of the scavenging activity to the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH). The IC50 value of the oil was evaluated as 0.77 mg·mL−1. In addition, the essential oil was found to possess moderate cytotoxic effects on the HEp-2 cell line (50% cytotoxic concentration (CC50) = 653.6 µg·mL−1). The potential antiviral effect was tested against Coxsackievirus B (CV-B), a significant human and mouse pathogen that causes pediatric central nervous system disease, commonly with acute syndromes. The reduction of viral infectivity by the essential oil was measured using a cytopathic (CPE) reduction assay
Structural Study of Europium Doped Gadolinium Polyphosphates LiGd(PO 3 ) 4 and Its Effect on Their Spectroscopic, Thermal, Magnetic, and Optical Properties
International audienc