Evaluation de la toxicité des huiles essentielles de Cymbopogon nardus (L) et Ocimum gratissimum (L) contre Sitophilus zeamais Motsch et Rhyzopertha dominica F, les principaux insectes nuisibles au maïs en stockage...

Full French Title:  Evaluation de la toxicité des huiles essentielles de Cymbopogon nardus (L) et Ocimum gratissimum (L) contre Sitophilus zeamais Motsch et Rhyzopertha dominica F, les principaux insectes nuisibles au maïs en stockage au Burkina FasoAu Burkina Faso, les pertes du maïs pendant le stockage demeurent importantes et sont provoquées par Sitophilus zeamais Motsch. et Rhyzopertha dominica F. Les méthodes de protection contre ces insectes sont l'utilisation d'insecticides chimiques. Cependant, face aux nuisances associées à ces insecticides, la recherche d’alternative s’avère indispensable. C’est dans ce cadre que s’inscrit l’utilisation des huiles essentielles dans la protection des stocks de maïs. Ainsi, les huiles essentielles de Cymbopogon nardus (L.) et de Ocimum gratissimum (L) ont été testées en vue d’évaluer leur efficacité dans la protection des stocks de maïs contre les insectes. Les expérimentations ont été conduites au laboratoire par l’utilisation de différentes doses de ces huiles pour évaluer la mortalité qu’elles provoquent sur les adultes des insectes testés. Les insectes ont été mis en présence de chaque huile essentielle dans des bocaux en verre de 1 litre pendant 24 h, 48 h et 72 h. Les doses testées ont varié de 1 à 100 μl pour les adultes de S. zeamais et de 1 à 75 μl pour R. dominica. Les résultats montrent que les taux de mortalité dus aux deux huiles atteignent 100% en fonction de l’espèce d’insecte, des doses utilisées et du temps d’exposition. Ainsi, la dose de 75 ml de l’huile de O. gratissimum provoque une mortalité de 80% des adultes de S. zeamais en 24 h contre 99,5% si on utilise 100ml d’huile essentielle de C. nardus pour une durée de 72 h. Sur les adultes de R. dominica, 48 h après application de 50 ml de l’huile de O. gratissimum, les taux de mortalité ont été de 100%. Les résultats obtenus indiquent que les huiles essentielles de C. nardus et de O. gratissimum peuvent être utilisées dans la protection des stocks de maïs contre S. zeamais et R. dominica.© 2016 International Formulae Group. All rights reserved.Mots clés: Huile essentielle, insectes, protection, maïs, stockage, Burkina FasoEnglish Title:  Evaluation of the toxicity of essential oils of Cymbopogon nardus (L) and Ocimum gratissimum (L) against maize insects Sitophilius zeamais Motsch and Rhyzopertha dominica F, the major insect pests in maize storage in Burkina FasoEnglish AbstractIn Burkina Faso, maize losses during storage are important and are due to Sitophilus zeamais Motsch and Rhyzopertha dominica F. The control methods against these insects are the use of chemical insecticides. However, because of the nuisances associated with these insecticides, the alternative research is necessary. It is in this context that the use of essential oils could be an alternative in the management of the insect pests stocks. Thus, the essential oils extracted from Cymbopogon nardus (L.) and Ocimum gratissimum were tested in order to evaluate their insecticide power on the adults of S. zeamais and R. dominica. The experiments were carried out in laboratory with different doses of these essential oils to evaluate the mortality caused on the adults of these two insects. To do this, the insects were exposed to each essential oil inside glass pots of 1 L during 24 h,48 h and 72 h. The tested doses varied between 1 μl to 100 μl for the adults of S. zeamais and between 1 μl to 75 μl for the adults of R. dominica. Results show that the rates of mortality caused by the two oils were up to 100% depending on the species of the insect, the doses used and the duration of exposure. Thus, a concentration of 75 ml of essential oil of O. gratissimum induces 80% mortality of adults of S. zeamais after 24 h. With essential oil of C. nardus, 99.5% mortality was obtained on adults of S. zeamais, after 72 h for a dose of 100 ml. On the adults of R. dominica, the rate of mortality was 100% for the concentration of 50 ml, 48 h after the application of oil of O. gratissimum. With the essential oil of C. nardus, the rates of mortality of R. dominica, were up to 100% after 48 h. The results obtained indicated that the essential oils of C. nardus and O. gratissimum can be used in the protection of maize storage against S. zeamais and R. dominica.© 2016 International Formulae Group. All rights reserved.Keywords: Essential oil, insects, protection, maize, storage, Burkina Fas

Comparative Study of Two Monoterpenes Effect on Rhipicephalus microplus Tick

The cattle tick Rhipicephalus microplus is one of the most important ectoparasites for livestock in tropical and subtropical areas worldwide. This tick hurts the economy of the milk and meat production chain. In addition, it constitutes a vector for the transmission of Anaplasmosis and Babesiosis pathogens. The control of R. microplus populations is mainly based on the use of synthetic acaricides. However, using this control method presents a danger to humans and the environment and leads to the emergence of resistant tick populations. In this situation, searching for ecological and effective control alternatives is essential. Thus, plant extracts constitute a promising solution, particularly essential oils and their active compounds. Thus, the present study aims to assess the acaricidal activity of two monoterpenes (Thymol and 1.8 cineole) abundantly found in essential oils to find an alternative to synthetic acaricides. The acaricidal activity was determined according to the method of larval immersion test (LIT). Eight concentrations were tested and R software version 4.0.3 was used for data analysis. Results showed 100 % larval mortality rates for the two monoterpenes with LC50 and LC90 values of (0.28 and 0.64) and (0.64 and 2.66) respectively, for thymol and 1.8 cineole for the immersion time of 5 min. For 10 min of immersion, all LC values decreased for the two monoterpenes. These findings highlight the potential of the thymol and 1.8 cineole as an alternative for managing R. microplus tick

Comparative Study of Two Monoterpenes Effect on Rhipicephalus microplus Tick

The cattle tick Rhipicephalus microplus is one of the most important ectoparasites for livestock in tropical and subtropical areas worldwide. This tick hurts the economy of the milk and meat production chain. In addition, it constitutes a vector for the transmission of Anaplasmosis and Babesiosis pathogens. The control of R. microplus populations is mainly based on the use of synthetic acaricides. However, using this control method presents a danger to humans and the environment and leads to the emergence of resistant tick populations. In this situation, searching for ecological and effective control alternatives is essential. Thus, plant extracts constitute a promising solution, particularly essential oils and their active compounds. Thus, the present study aims to assess the acaricidal activity of two monoterpenes (Thymol and 1.8 cineole) abundantly found in essential oils to find an alternative to synthetic acaricides. The acaricidal activity was determined according to the method of larval immersion test (LIT). Eight concentrations were tested and R software version 4.0.3 was used for data analysis. Results showed 100 % larval mortality rates for the two monoterpenes with LC50 and LC90 values of (0.28 and 0.64) and (0.64 and 2.66) respectively, for thymol and 1.8 cineole for the immersion time of 5 min. For 10 min of immersion, all LC values decreased for the two monoterpenes. These findings highlight the potential of the thymol and 1.8 cineole as an alternative for managing R. microplus tick

Comparative Study of Two Monoterpenes Effect on Rhipicephalus microplus Tick

The cattle tick Rhipicephalus microplus is one of the most important ectoparasites for livestock in tropical and subtropical areas worldwide. This tick hurts the economy of the milk and meat production chain. In addition, it constitutes a vector for the transmission of Anaplasmosis and Babesiosis pathogens. The control of R. microplus populations is mainly based on the use of synthetic acaricides. However, using this control method presents a danger to humans and the environment and leads to the emergence of resistant tick populations. In this situation, searching for ecological and effective control alternatives is essential. Thus, plant extracts constitute a promising solution, particularly essential oils and their active compounds. Thus, the present study aims to assess the acaricidal activity of two monoterpenes (Thymol and 1.8 cineole) abundantly found in essential oils to find an alternative to synthetic acaricides. The acaricidal activity was determined according to the method of larval immersion test (LIT). Eight concentrations were tested and R software version 4.0.3 was used for data analysis. Results showed 100 % larval mortality rates for the two monoterpenes with LC50 and LC90 values of (0.28 and 0.64) and (0.64 and 2.66) respectively, for thymol and 1.8 cineole for the immersion time of 5 min. For 10 min of immersion, all LC values decreased for the two monoterpenes. These findings highlight the potential of the thymol and 1.8 cineole as an alternative for managing R. microplus tick

Effet des extraits du thé de Gambie (Lippia multiflora Moldenk) et du neem (Azadirachta indica A. Juss.) sur Helicoverpa armigera et les Thrips de la tomate (Lycopersicon esculentum Mill.)

Objectif : l’objectif de l’étude est d’accroitre la production de la tomate par la proposition d’une alternative respectueuse de l’environnement. Il a s’agit de tester l'efficacité des extraits acqueux des graines de Azadirachta indica et des feuilles du Lippia multiflora sur Helicoverpa armigera et les Thrips inféodés à la tomate en présence d’un témoin non traité et du Décis (témoin positif) au champ.Méthodologie et Résultats : le dispositif expérimental utilisé est un Bloc Fischer randomisé en 3 répétitions et 4 traitements. Les extraits d’amande de neem et de feuilles du Lippia sont obtenus après macération pendant 12 heures dans l’alcool 75°. La fréquence des traitements était de 10 jours et les observations sur les larves de Helicoverpa et les Thrips, de 7 jours après le premier traitement. La parcelle à pulvériser est isolée des voisines avec une bâche noire. Les doses de 1L/ha pour le Décis et de 5L/ha pour les extraits végétaux ont été appliquées. L’étude a révélé 5,33 Thrips et 1,33 larve de Helicoverpa armigera avec le traitement au Décis ; 11,67 Thrips et 3 larves de Helicoverpa armigera avec l’extrait des graines de neem. Par contre, l’extrait des feuilles de Lippia multiflora ne présente pas de différences significatives avec le témoin. À ce niveau l’étude a révélé respectivement 24 et 32 Thrips.d’une part et 9,66 et 12,30 larves de Helicoverpa armigera d’autre part pour l’extrait de Lippia et le témoin.Conclusion et Application : il ressort de cette étude que l’extrait de neem a donné des résultats satisfaisants proches de ceux obtenus avec le Décis contrairement au Lippia qui a donné des résultats mitigés. En effet, l’extrait de neem peut être recommandé comme une alternative contre les Thrips et Helicoverpa armigera inféodés à la tomate au Burkina FasoMots clés : tomate ; ravageurs, extraits végétaux, activité insecticideObjective: the objective of the study is to increase tomato production by the proposal of an environmental friendly alternative. It is to test the efficacy of aqueous extracts of Azadirachta indica seeds and leaves of Lippia multiflora on Helicoverpa armigera and Thrips subservient to the tomato in the presence of an untreated control and decis (positive control) in the wild.Methodology and Results: the experimental was a randomized complete block Design of 3 repetitions and 4 treatements. Neem seed and Lippia leaf extracts were obtained after maceration for 12 hours in alcohol 75 °. The frequency of treatment was 10 days and observations on the larvae of Helicoverpa and Thrips done 7 days after the first treatment. The plot spray is isolated from the neighboring with a black tarp. Doses of 1L / ha for Decis and 5L / ha for the plant extracts were applied. The study found 5.33 and 1.33 thrips larva Helicoverpa armigera with the decis treatment; 11.67 Thrips and 3 larvae of Helicoverpa armigera with the extract of neem seeds. By against the extract from the leaves of Lippia multiflora presents no significant differences with the control. At this level the study revealed 24 and 32 respectively Thrips.d'une both 9.66 and 12.30 larvae of Helicoverpa armigera secondly to extract Lippia and the witness.Conclusion and Application: it appears from this study that neem extract gave satisfactory results close to those obtained with the decis unlike Lippia that has been mitigated. Indeed, neem extract can be recommended as an alternative against Thrips and Helicoverpa armigera subservient tomato in Burkina Faso.Keywords: tomato; pests; plant extracts; insecticidal activity

Chemical composition, antioxidant, anti-inflammatory and anti-proliferative activities of essential oils of plants from Burkina Faso.

This research highlights the chemical composition, antioxidant, anti-inflammatory and anti-proliferative activities of essential oils from leaves of Ocimum basilicum, Ocimum americanum, Hyptis spicigera, Lippia multiflora, Ageratum conyzoides, Eucalyptus camaldulensis and Zingiber officinale. Essential oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. Major constituents were α-terpineol (59.78%) and β-caryophyllene (10.54%) for Ocimum basilicum; 1, 8-cineol (31.22%), camphor (12.730%), α-pinene (6.87%) and trans α-bergamotene (5.32%) for Ocimum americanum; β-caryophyllene (21%), α-pinene (20.11%), sabinene (10.26%), β-pinene (9.22%) and α-phellandrene (7.03%) for Hyptis spicigera; p-cymene (25.27%), β-caryophyllene (12.70%), thymol (11.88), γ-terpinene (9.17%) and thymyle acetate (7.64%) for Lippia multiflora; precocene (82.10%)for Ageratum conyzoides; eucalyptol (59.55%), α-pinene (9.17%) and limonene (8.76%) for Eucalyptus camaldulensis; arcurcumene (16.67%), camphene (12.70%), zingiberene (8.40%), β-bisabolene (7.83%) and β-sesquiphellandrène (5.34%) for Zingiber officinale. Antioxidant activities were examined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. O. basilicum and L. multiflora exhibited the highest antioxidant activity in DPPH and ABTS tests, respectively. Anti-inflammatory properties were evaluated by measuring the inhibition of lipoxygenase activity and essential oil of Z. officinale was the most active. Anti-proliferative effect was assayed by the measurement of MTT on LNCaP and PC-3 prostate cancer cell lines, and SF-763 and SF-767 glioblastoma cell lines. Essential oils from A. conyzoides and L. multiflora were the most active on LNCaP and PC-3 cell lines, respectively. The SF-767 glioblastoma cell line was the most sensitive to O. basilicum and L. multiflora EOs while essential oil of A. conyzoides showed the highest activity on SF-763 cells. Altogether these results justify the use of these plants in traditional medicine in Burkina Faso and open a new field of investigation in the characterization of the molecules involved in anti-proliferative processes

Time-dependent anti-proliferative activity of EOs after 24, 48 and 72 hours of exposure.

<p>Cells were incubated at IC₅₀ of each EO. a, LNCaP cells; b, PC-3 cells; c, SF-767 cells; d, SF-763 cells. *, p<0.05 compared to 24 hrs of treatment; §, p<0.05 compared to 48 hrs of treatment. Experiments were performed 3 times in octuplets.</p

Dose-dependent anti-proliferative activity of purified compounds and their combination with essential oils after 72 hours of exposure on LNCaP and PC-3 cell lines of prostate cancer, and on SF-767 and SF-763 cell lines of glioblastoma.

<p>Experiments were performed 3 times in octuplets.</p

Anti-radical activity of essential oils by DPPH and ABTS methods.

<p>DPPH, (2,2-diphenyl-1-picrylhydrazyl); ABTS (2,2′-azinobis-[3-ethylbenzothiazoline-6-sulfonic acid]); Values are expressed as mean values ± standard deviation (n = 3 experiments in quadruplicate); DPPH activities is expressed as inhibitory percentage at and ABTS activities are given in mmol TE/g (10⁻³ mol Throlox equivalent/g of extract); Concentrations of the extracts Throlox of 100 µg/mL for DPPH and 1 mg/mL for ABTS used as standard; A, B, C, D: means followed by the same letter are not significantly different (p>0.05).</p