Phytochemical composition and antioxidant activity of Lavandula dentate extracts

Le but de ce travail consiste à étudier la composition des huiles essentielles et des polyphénols des racines, des tiges et des feuilles de la Lavande dentée et d’évaluer leurs potentialités antioxydantes. L’analyse et la quantification des huiles essentielles a montré que les feuilles sont les plus riches en huiles essentielles (0.89 mg/g MS) suivies par les tiges (0.68 mg/g MS) et enfin les racines (0,23 mg/g MS). Le constituant majeur de l’HE des racines est: le β-ocimène. D’autre part, le limonène représente le composé majeur de l’HE des tiges. Quant à l’HE des feuilles, elle est dominée par le camphre. D’autre part, nos résultats ont montré que les organes de la lavande montrent des teneurs en polyphénols totaux élevées et variables selon l’organe étudié. En effet, les extraits des racines sont caractérisés par le contenu le plus élevé en polyphénols. D’autre part, l’étude de l’activité antioxydante des extraits des différents organes a indiqué que les extraits de la racine sont particulièrement les plus actifs et que leur analyse par RP-HPLC a montré que ces derniers sont riches essentiellement en acide rosmarinique. Finalement, les extraits de la Lavande dentée et particulièrement ceux de la racine peuvent être considérés comme des sources alternatives d’antioxydants naturels puissants qui peuvent être utilisés en industrie agroalimentaire et pharmaceutique.In this study, Lavandula dentata organs (roots, stems and leaves) were investigated for their essential oils, total phenolics, flavonoids contents and antioxidant activities. Essential oil yields were 0.22% in roots, 0.68 % in stems and 0.89 % in flowers. Major components of the oils were β-ocimene, limonene and 1,8 cineol in roots, stems and leaves and flowers, respectively. In all organs, total phenolics content ranged from 42.57 to 16.17 mg gallic acid equivalents per gram of dry weight (mg GAE/g DW).The antioxidant activities of Lavandula dentata extracts obtained from the three organs were assessed using two tests (DPPH and reducing power). The root extract was strongly effective as DPPH radical scavenger and reducing agent. Thus, the identification of individual target polyphenolic compounds of roots was performed by RP-HPLC. The major phenolic compound detected in roots was rosmarinic acid. This activity was high enough for the plant to be a new and natural source of strongly antioxidant substances for use as natural additives in food and pharmaceutical 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

Salinity impact on seed yield, polyphenols composition and antioxidant activity of Fennel (Foeniculum vulgarae Mill) extracts

Recently, medicinal and aromatic plants have received much attention in several fields such agroalimentary, perfumes, pharmaceutical industries and natural cosmetic products. The consumption of herbal medicines is widespread and is continuously increasing worldwide. Although, secondary metabolites in the medicinal and aromatic plants were fundamentally produced by genetic processing but, their biosynthesis is strongly influenced by environmental factors. Salinity is one of the major factors that affect essential oil biosynthesis and secretion (Heuer et al. 2002). In Tunisia, salt-affected soils cover about 10% of the total area of the country. Salinity led to biochemical disorders and can change plant behaviour regarding the biosynthesis of primary and secondary metabolites. Among all the secondary metabolites synthesized by plants, phenolic compounds are some of the most widespread. In this context, this research evaluated the effect of salinity on total and individual polyphenols contents as well as the antioxidant activities of fennel (Foeniculum vulgarae Mill.) seeds of two geographic origins, Tunisia (TFS) and Egypt (EFS). This plant is one of the most common aromatics in the Mediterranean kitchen. Plants were treated with different concentrations of NaCl treatment: 0, 50, and 75 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, 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, β-carotene/linoleic acid chelating, and reducing power assays. The highest antioxidant activities were reveled in severe stressed plants for both TFS and EFS. In this case, fennel seeds produced under saline conditions may function as a potential source of antioxidant compounds, which could support the utilization of this plant in a large field of applications such as food industry

Utilisation du chlorantraniliprole (CORAGEN 20 SC) dans le contrôle des principaux insectes ravageurs du cotonnier au Burkina Faso

Use of Chlorantraniliprole (CORAGEN 20 SC) for the Control of the Main Cotton Insects in Burkina Faso In seeking alternative molecules to pyrethroids suitable for controlling cottoninsect pests in Burkina Faso, chlorantraniliprole, a molecule of the anthranilic diamide chemical family, was tested in the research station and in the farmers’ fields. In the research station, results obtained showed a good efficacy of chlorantraniliprole at a rate of 20 g.ha-1. Helicoverpa armigera, Anomis flava and Aphis gossypii, compared to untreated plants, were controlled at 95.5 %, 93.6 % and 76 % respectively. This insect control level provided a 18% increase of healthy bolls and provided 65.4 % increase of seed cotton compared to the untreated plants. In the farmers’ fields, the yield gain was 21% by chlorantraniliprole program. This was higher compared to the plants treated with profenofos the reference control applied at the rate of 500g.ha-1. Chlorantraniliprole can therefore be recommended at the rate of 20g.ha-1 to cotton producers to optimize their incomes

Comparative assessment of phytochemical profiles and antioxidant properties of Tunisian and Egyptian anise (<i>Pimpinella anisum</i> L.) seeds

<p>Anis (<i>Pimpinella anisum</i> L.) seeds obtained from two geographic origins Tunisia (TAS) and Egypt (EAS) were studied regarding their biochemical composition and the antioxidant potential of their extracts. The results showed that the highest value of oil was detected with TAS compared to that of EAS ones. Ten (10) fatty acids were identified for the two locations and petroselinic acid was the most prevalent in oil seeds and interestingly, TAS displayed a significantly higher level of this acid than EAS. Besides, TAS exhibited slightly higher essential oil yield than the Egyptian variety and that <i>trans</i>-anethole was the dominant for the two provenances. In both accessions, the highest total phenolic, flavonoid and tannin content was obtained with ethyl acetate fraction. Therefore, TAS exhibited higher chelating and reducing powers than EAS which may be due to a slightly different phenolic composition between the two accession seed extracts. The phenolic compositions of TAS and EAS revealed that ethyl acetate extracts showed higher proportions of naringin, chlorogenic acid and rosmarinic acid. However, ethanol extracts were richer in larcitrin, rosmarinic acid and cirsimartin. The overall results revealed that aniseeds might constitute a novel source of natural antioxidants and could be used as food additive.</p