Fatty acids, essential oil and phenolics composition of Silybum marianum seeds and their antioxidant activities.

The presentstudydescribes the biochemical evaluation of Silybum marianum seed. The analysis of essential oil composition of Silybum marianum seed by Gas Chromatography-Mass Spectrometry GC-MS showed the presence of14 volatile components with the predominance of γ-cadinene (49.8%) and α-pinene (24.5%). Whereas, the analysis of fatty acids composition, showed the predominance of linoleic (50.5%) and oleic (30.2%) acids. Silybum marainum presented also an important polyphenol contents with 29mgGAE/g DW, a good antiradical activity (CI(50)=39µg/ml) but a lower reducing power ability. Flavonoid and condensed tannin contents were about 3.39mg EC/g DW and 1.8mg EC/gDW, respectively. The main phenolic compounds identified by RP-HPLC, were silybin A (12.2%), silybin B (17.67%), isosilybin A (21.9%), isosilybin B (12.8%), silychristin (7.9%) andsilydianin (7.5%).

Ripening stage and extraction method effects on physical properties, polyphenol composition and antioxidant activities of cumin (Cuminum cyminum L.) seeds.

The effects of two extraction methods, used at three ripening stages on the total polyphenol contents and the antioxidant activities of Cumin (Cuminum cyminum L.) seed extracts were studied. The ripening stage effect on some physical properties of cumin seed was significant. The increase of dry matter (from 10.3 to 87.5%) during ripeness was correlated negatively with that of moisture content (from 89.7 to 12.5%). Besides results showed that the full ripe seeds were richer on polyphenols and condensed tannin than unripe ones, and consequently exhibited higher antioxidant activities. However, the unripe seeds had a higher total flavonoid content compared to those of half ripe and full ripe ones. The comparison of two extraction methods showed that soxhlet extracts contained the greatest amount of polyphenols and flavonoids, while maceration samples exhibited higher antiradical and bleaching power assay. Total phenolic contents and IC50 (concentration required to cause a 50% DPPH inhibition) values in cumin seed during their maturation allowed to conclude that antioxidant activity does not depend only on the high content of total phenolics but also on the phenolic composition. A total of 19 phenolic compounds were successfully identified by HPLC analysis during the ripening of cumin seeds. Rosmarinic acid was the major phenolic acid for the unripe seeds. Furthermore, half ripe and full ripe seeds were dominated by p-coumaric acid. These compounds might be considered as interesting bioactive natural substances that may be used in several fields, such as nutraceuticals, cosmetics and agro-food industry.

Salt effect on phenolics and antioxidant activities of Tunisian and Canadian sweet marjoram (Origanum majorana L.) shoots.

BACKGROUND: Two varieties of Origanum majorana (Canadian and Tunisian) were evaluated for their phenolic, flavonoid and tannin contents, individual phenolic compounds and antioxidant activities under NaCl constraint. RESULTS: The results showed a significant variability in phenolic composition and antioxidant behavior between the two varieties under salt stress. The phenolic composition of methanolic extracts was determined by reversed-phase high-performance liquid chromatography. Amentoflavone was the predominant flavonoid compound; in addition, trans-2-hydrocinnamic acid became the major phenolic acid with salt treatment of the Tunisian variety. In the control, Canadian variety extract was characterized by high levels of gallic acid and amentoflavone. However, under 75 mmol L(-1) NaCl, gallic acid content doubled, whereas amentoflavone content was maintained in the Canadian variety. Stimulation of phenolic acid biosynthesis was observed in these two varieties under salt treatment despite the fact that shoots of the Tunisian variety showed higher antioxidant activities compared to those from the Canadian variety. Tunisian O. majorana might have developed tolerance to salinity and avoided tissue damage by activating enzymes involved in the galactosylation of quercetin into quercetin-3-galactoside and quercetin-3-rhamnoside. CONCLUSION: Our results confirmed the tolerance of Tunisian O. majorana plants.

Physiological changes, phenolic content and antioxidant activity of Salvia officinalis L. grown under saline conditions.

BACKGROUND: Hydroponic culture was used to investigate the effect of NaCl concentrations on the growth, nutrient uptake, phenolic content and antioxidant activity of Salvia officinalis L. leaves. The antioxidant capacity of the methanolic extract of S. officinalis was evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and ß-carotene-linoleic acid bleaching assay. Physiological and biochemical parameters of S. officinalis were assessed after 4 weeks of salt treatment with 0, 25, 50, 75 and 100 mmol L(-1) NaCl. RESULTS: Plant growth exhibited a reduction of 61% at 100 mmol L(-1) NaCl. Assessment of Na(+), K(+) and Ca(2+) and water contents of shoots and roots showed that S. officinalis is able to regulate Na(+) concentration by active compartmentation in vacuoles. Salvia officinalis phenolics were increased in response to salinity at the threshold of 75 mmol L(-1) NaCl. This herb was also found to be able to achieve important DPPH(•) quenching activity and to inhibit the ß-carotene-linoleic acid bleaching notably enhanced by salt treatment. It is interesting to highlight the correlation between the phenolic and antioxidant activity, suggesting the involvement of these compounds in this activity. CONCLUSION: Salvia officinalis treated with 75 mmol L(-1) NaCl constitutes a potential source for production of secondary metabolites useful in several applications.

Comparison of Different Extraction Methods for the Determination of Essential oils and Related Compounds from Coriander (Coriandrum sativum L.).

The volatile oil of coriander (Coriandrum sativum L.) obtained from the fruits by soxhlet-dynamic headspace (S-DHS), solvent extraction (SE), steam distillation (SD), hydrodistillation (HYD) and supercritical CO2 extraction (SC-CO2) were analyzed by GC-FID and GC-MS. The SC-CO2 offered a higher yield (4.5%, w/w) than the other used techniques. Among the identified constituents, linalool was the main compound whatever the employed extraction procedure in contrast to the remaining components which varied according to the isolation technique showing a strong effect of the method used on the composition of these minor compounds. SC-CO2 as compared to the other extraction techniques revealed its high efficiency in addition to the integrity saving of coriander fruit volatiles. Statistical analysis showed that all the detected and identified compounds were highly (P > 0.001) affected by the extraction technique used except the a-terpineol which appear stable. On the other hand, principal component analysis (PCA) revealed on the determination of one group represented by SC-CO2, S-DHS and HYD suggesting a similar essential oil composition. Obtained results show that, in Tunisian coriander essential oil, linalool was the main compound.

Thermal stability of corn oil flavoured with Thymus capitatus under heating and deep-frying conditions.

BACKGROUND: The thermal stability of corn oil flavoured with thyme flowers was determined and compared with that of the original refined corn oil (control). The oxidative stability index (OSI) was measured and samples were exposed to heating (30 min at 150, 180 and 200 °C) and deep-frying (180 °C). Changes in peroxide value (PV), free fatty acid (FFA) content, specific absorptivity values (K(232) and K(270)), colour and chlorophyll, carotenoid and total phenol contents were monitored. RESULTS: The OSI and heating results showed that thyme incorporation was effective against thermal oxidation based on the increased induction time observed for the flavoured oil (6.48 vs 4.36 h), which was characterised by lower PV, FFA content, K(232) and K(270) than the control oil after heating from 25 to 200 °C, with higher red and yellow colour intensities and chlorophyll, carotenoid and total phenol contents. The deep-frying test showed the accelerated deterioration of both oils in the presence of French fries. CONCLUSION: Compared with the control oil, the thyme-flavoured oil showed improved thermal stability after heating. This could be attributed to the presence of thyme pigments and antioxidant compounds allowing extended oil thermal resistance.

Essential oils and fatty acids composition of Tunisian and Indian cumin (Cuminum cyminum L.) seeds: a comparative study.

BACKGROUND: Cumin (Cuminum cyminum L.) seeds of two geographic origins, Tunisia (TCS) and India (ICS), were studied regarding their fatty acid and essential oil composition. RESULTS: Oil yields were 17.77 and 15.40% for TCS and ICS respectively. Petroselinic acid (C18:1n-12) was the major fatty acid in both varieties, with a higher proportion being found in TCS (55.90% of total fatty acids (TFA)) than in ICS (41.42% TFA). Moreover, the most predominant fatty acids were palmitic, petroselenic and linoleic acids, accounting for more than 91% TFA in both varieties. The unsaturated fatty acid content was high: 70.95% TFA in TCS and 62.17% TFA in ICS. Essential oil yields differed significantly (P < 0.05) between the two varieties: 1.21 and 1.62% for ICS and TCS respectively. A total of 40 compounds were identified, 34 of which were present in both essential oils. The two varieties displayed different chemotypes: γ-terpinene/1-phenyl-1,2-ethanediol for TCS and cuminaldheyde/γ-terpinene for ICS. CONCLUSION: The study revealed that the biochemical composition of cumin seeds is origin-dependent and that cumin seeds are rich in an unusual fatty acid, petroselinic acid. Besides, cumin essential oil is a rich source of many compounds, including cuminaldehyde and γ-terpinene. The overall results suggest the exploitation of cumin seeds as a low-cost renewable source for industrial processing in the fields of cosmetics, perfumes and pharmaceuticals.

Juice components and antioxidant capacity of four Tunisian Citrus varieties.

BACKGROUND: Juices from four Citrus species of Tunisia were investigated mainly for quality parameters and antioxidant capacity. RESULTS: Citrus reticulata (mandarin) juice had the highest content of total flavonoids (85.33 mg CE L(-1)). The latter also occurred in high quantity (82.01 mg CE L(-1)) in Citrus lemon (lemon) juice which was also marked by its richness in total aroma (70.16 µg mL(-1)) and in total fatty acids (48.10 µg mL(-1)). Mandarin and lemon juices had the highest antioxidant activity, as determined b the ß-carotene bleaching assay (26.67% and 22.67%, respectively). Citrus aurantium (bitter orange) juice was characterised by the highest content of total polyphenols (784.67 mg GAE L(-1)) and by the greatest inhibition of DPPH (96.10%). Citrus sinensis (blood orange) juice was only marked by the high quantity of ascorbic acid (36.90 mg mL(-1)). GC/MS analysis of juice aroma showed the predominance of limonene (48.85-69.59%) in mandarin and in bitter and blood oranges, but of camphene (89.05%) in lemon. GC analysis of juice fatty acids revealed their richness in oleic acid (23.13-39.52%). HPLC analysis of juice phenolics indicated the predominance of phenolic acids (73.13-86.40%). CONCLUSION: The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition.

Salt effects on Origanum majorana fatty acid and essential oil composition.

BACKGROUND: The effects of salt on the essential oil yield and fatty acid composition of aerial parts of two marjoram varieties were investigated. Plants with 6 leaves were treated with NaCl (75mM). RESULTS: Salt treatment led to a reduction in aerial part growth. Salinity increased the fatty acid content more significantly in Tunisian variety (TV) than in Canadian variety (CV). CV showed an increase in double-bond index (DBI) and a decrease in malondialdehyde content under salt stress, while the opposite was observed in TV. The DBI was mainly affected by a strong reduction in oleic and linoleic acids in TV, whereas a strong stimulation of linoleic acid in CV was observed. Salt decreased and increased the essential oil yield in TV and CV respectively. The main constituents of the essential oil of TV were trans-hydrate sabinene and terpinen-4-ol, which showed a significant decrease under salt stress. In contrast, the main constituents of the essential oil of CV were sabinene and trans-hydrate sabinene, which showed a significant decrease and increase respectively under salt stress. CONCLUSION: Marjoram oil is a rich source of many compounds such as essential oils and fatty acids, but the distribution of these compounds differed significantly between the two varieties studied.

Fatty acid and essential oil composition of three Tunisian caraway (Carum carvi L.) seed ecotypes.

BACKGROUND: The essential oil and fatty acid composition of Tunisian annual caraway (Carum carvi L.) seeds from three ecotypes was investigated by gas chromatography and gas chromatography-mass spectrometry analyses. RESULTS: Total fatty acid (TFA) proportion of caraway seeds varied from 2.95% to 5.68% (w/w). The fatty acid composition revealed that Tunisian caraway seed oil is rich in an unusual fatty acid-petroselinic acid-the proportion of which varied from 31.53% and 38.36% of TFA. Essential oil yields were relatively low and ranged from 0.86% to 1.20% (w/w). Forty-one volatile compounds were identified, the main ones being carvone (76.78-80.53%) and limonene (13.05-20.29%). CONCLUSION: Tunisian caraway seed oil is rich in an unusual fatty acid-petroselinic acid-which is of potential industrial significance. In addition, Tunisian caraway essential oil is carvone chemotype. This fact is of great economic interest due to the several applications of carvone in the alimentary and medicinal industries.

Phenolic composition and biological activities of Tunisian Nigella sativa L. shoots and roots.

In the present investigation, methanolic extracts from shoots and roots of Tunisian Nigella sativa were assayed for their antioxidant and antimutagenic activities. The phenolic composition of the methanolic extracts was determined by RP-HPLC. The predominant phenolic compound was vanillic acid with a mean concentration of 143.21 and 89.94 mg per 100 g dry weight of shoots and roots, respectively. Shoots and roots showed comparable and strong superoxide scavenger activity; however, shoots exhibited higher DPPH radical scavenging, reducing and chelating activities than roots. Mutagenic and antimutagenic activities were determined by using the Ames test. Shoots and roots demonstrated important antimutagenic effects. Roots exhibited stronger activity than shoots with an inhibition percentage of 71.32%.

Biochemical evaluation of borage (Borago officinalis) rosette leaves through their essential oil and fatty acid composition.

Borago officinalis rosette leaves were sampled in the region of Amdoun (Tunisia) during different stages of their development. Essential oil contents varied from 0.01% to 0.13% respectively in young and adult leaves. Twenty three volatile compounds were identified. Hydrocarbons, mainly represented by nonadecane (29.8%), tetracosane (11.3%) and heptacosane (4.7%), constituted the major class in the young leaves (45.8%), followed by aldehydes (22.4%). The percentages of these two classes decreased to reach respectively 15% and 8.1% in adult leaves in favour of alcohols (57.9%) where cis-3-hexenol (29.6%) and hexanol (14.5%) were the main compounds. Total fatty acids amounts increased from 5.03 mg/g DW in young leaves to 32.23 mg/g DW in adult ones. The predominant fatty acids were alpha-linolenic (C18:3 n-3), stearidonic (C18:4 n-3), gamma-linolenic (C18:3 n-6), palmitic (C16: 0) and linoleic (C18:2 n-6) acids.

Essential oil composition of two myrtus communis L. varieties grown in North Tunisia.

Two Myrtus communis varieties (var. italica and baetica) were studied in order to investigate their essential oil yield and composition. Essential oil yield varied in leaves, fruits and stems. So, in leaves, it was 0.5% for italica and 0.3% for baetica and was higher than in fruits and stems with respectively 0.1% and 0.04% for italica and 0.07% and 0.03% for baetica. The essential oil analysis performed by GC and GC/MS showed a composition characterized by a high percentage of monoterpene hydrocarbons in leaves, largely due to alpha-pinene with 51.3% for italica and 27.7% for baetica; 1,8-cineole, the alone compound of ether class, was predominant in fruits and stems with respectively 31.6% and 34.7% for italica and 19.8% and 25.8% for baetica.

Nitrogen effects on proteins, chlorophylls and fatty acids during the growth of Arthrospira platensis.

Spirulina platensis (=Arthrospira platensis) is a tunisian strain which has been isolated for the first time in Oued Essed (Sousse, Sidi Bou Ali). Biomass evolution, proteins, chlorophylls and fatty acids composition of this alga were monitored by varying nitrogen concentrations in the culture medium. Nitrogen stress was provoked by adding sodium nitrate (NaNO3) in the culture medium with concentrations varying from 0 to 5 g/l. Results obtained showed that nitrogen depletion increased total proteins and total chlorophylls. The addition of NaNO3 (5g/l) led to an increase of total fatty acids amounts and modify fatty acids composition. Optimal quantities of palmitic, gamma -linolenic and oleic acids were obtained with NaNO3 free-cultures. Thus, the tunisian strain has valuable biological substances, worthy to determine the optimal conditions for its propagation.

Variations in the essential oil composition from different parts of Coriandrum sativum L. cultivated in Tunisia.

Essential oils obtained by hydrodistillation from different organs (flowers, leaves, stems and roots) of Tunisian coriander (Coriandrum sativum L.) was analyzed. GC and GC-MS analysis enabled us to identify 64 compounds and revealed great qualitative and quantitative differences between the analyzed parts. In all organs, the main compound was (E)-2-dodecenal, followed by (E)-2-tridecenal, gamma-cadinene, (Z)-myroxide, neryl acetate and eugenol. Multivariate analysis (PCA) revealed a high similarity in the essential oils composition between upper leaves and flowers in one hand and basal leaves, roots and stems on the other hand. Further, it has been reported an organ-dependant distribution of essential oil compounds.

Comparison of pistachio hull essential oils from different Tunisian localities.

Pistachio (Pistacia vera L.) fruit is well known for its oleaginous and edible seed. Less information is available about the hull constituted by the epicarp and the mesocarp. This part of the fruit contains an essential oil that can be valorized. Tunisia is one of the countries cultivating pistachio trees. This work presents essential oil composition of pistachio hulls (Mateur variety) from different geographical localities: Grombalia (North-East), Kairouan (Middle) and Sfax (Middle-East). Yields were more important in Sfax samples (0.53% on a dry weight basis). Alpha-terpinolene was the major compound for Grombalia fruits (35.7%), whereas Kairouan and Sfax samples where characterized by alpha-pinene (42.5 and 43.8% respectively). For all samples, monoterpene hydrocarbons predominated (more than 79.8% of the essential oil).

A review of Tunisian medicinal plants with anticancer activity.

Cancer is a major public health problem in the world. The use of the medicinal plants in cancer prevention and management is frequent in Africa, especially in Tunisia, and it is transmitted from generation to generation within cultures. Many previous studies showed that a wide range of Tunisian medicinal plants exerted cytotoxic and anticancer activity. A comprehensive review was conducted to collect information from scientific journal articles, including indigenous knowledge researches, about Tunisian medicinal plants used for the prevention and management of cancer. The aim of this review article is to provide the reader with information concerning the importance of Tunisian medicinal plants in the prevention and management of cancer and to open the door for the health professionals and scientists working in the field of pharmacology and therapeutics to produce new drug formulations to treat different types of cancer.

Relation between salt tolerance and biochemical changes in cumin (Cuminum cyminum L.) seeds.

In this study, the effects of salinity on growth, fatty acid, essential oil, and phenolic composition of cumin (Cuminum cyminum L.) seeds as well as the antioxidant activities of their extracts were investigated. Plants were treated with different concentrations of NaCl treatment: 0, 50, 75, and 125 mmoL. Plant growth was significantly reduced with the severity of saline treatment. This also caused important reductions in the seed yield and yield components. Besides, NaCl treatments affected fatty acid composition. Petroselinic and linoleic acids proportions diminished consistently with the increase in NaCl concentration, whereas palmitic acid proportion increased. Furthermore, NaCl enhanced essential oil production in C. cyminum seeds and induced marked changes on the essential oil quality. Essential oil chemotype was modified from γ-terpinene/1-phenyl-1,2 ethanediol in control to γ-terpinene/ß-pinene in salt stressed plants. Total polyphenol content was higher in treated seeds, and salinity improved the amount of individual phenolic compounds. Moreover, antioxidant activities of the extracts were determined by four different test systems, namely 2,2-diphenyl-1-picrylhydrazyl, ß-carotene/linoleic acid chelating, and reducing power assays. The highest antioxidant activities were reveled in severe stressed plants. In this case, cumin seeds produced under saline conditions may function as a potential source of essential oil and antioxidant compounds, which could support the utilization of this plant in a large field of applications such as food industry.

Antioxidant and antimicrobial phenolic compounds from extracts of cultivated and wild-grown Tunisian Ruta chalepensis.

The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa. From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry.

Phospholipid changes in seqA and dam mutants of Escherichia coli.

SeqA and Dam proteins were known to be responsible for regulating the initiation of replication and to affect the expression of many genes and metabolisms. We have examined here the fatty acids composition and phospholipids membrane in dam and/or seqA mutants. The dam mutant showed an accumulation of the acidic phospholipids cardiolipin, whereas, the seqA mutant showed a higher proportion of phosphatidylglycerol compared with the wild-type strain. The seqA dam double mutant showed an intermediate proportion of acidic phospholipids compared with the wild-type strain. Based on these observations, we discuss the role of Dam and SeqA proteins in the regulation of phospholipids synthesis.