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4 results on '"Koffi Koba"'

1. Euclasta condylotricha flowers essential oils: A new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae).

Author

Roméo Barnabé Bohounton, Oswald Yédjinnavênan Djihinto, Oronce Sedjro-Ludolphe Dedome, Réné Mahudro Yovo, Laurette Djossou, Koffi Koba, Aristide Adomou, Pierre Villeneuve, Luc Salako Djogbénou, and Fidèle Paul Tchobo

Subjects
Medicine, Science
Abstract

The essential oil (EO) of plants of the Poaceae family has diverse chemical constituents with several biological properties. But, data on the chemical constituents and toxicity are still unavailable for some species belonging to this family, such as Euclasta condylotricha Steud (Eu. condylotricha). In this study, the chemical composition of the EOs of Eu. condylotricha flowers was evaluated by gas chromatography coupled with mass spectrometry (GC-MS). The EOs larvicidal property was assessed against third instar larvae of three Anopheles gambiae laboratory strains (Kisumu, Acerkis and Kiskdr) according to the WHO standard protocol. The percentage yields of the EOs obtained from hydro distillation of Eu. condylotricha flowers varied 0.070 to 0.097%. Gas Chromatography-Mass Spectrometry (GC-MS) applied to the EOs revealed fifty-five (55) chemical constituents, representing 94.95% to 97.78% of the total essential oils. Although different chemical profiles of the dominant terpenes were observed for each sample, EOs were generally dominated by sesquiterpenoids with juvenile hormones as the major compounds. The primary compounds were juvenile hormone C16 (JH III) (35.97-48.72%), Methyl farnesoate 10,11-diol (18.56-28.73%), tau-Cadinol (18.54%), and β-Eudesmene (12.75-13.46%). Eu. condylotricha EOs showed a strong larvicidal activity with LC50 values ranging from 35.21 to 52.34 ppm after 24 hours of exposition. This study showed that Eu. Condylotricha flowers essential oils are potent sources of juvenile hormones that could be a promising tool for developing an eco-friendly malaria vector control strategy.

Published
2023
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2. Characterization of Grazed Vegetation within Mountainous Areas in the Plateau Region of Togo (West Africa)

Author

Koffi Koba, Kodjovi Mawuégnigan Léonard Agbodan, Kossi Béssan Amegnaglo, Kodjo Akonta Dewa Kassa, and Amen Yawo Nenonene

Subjects
Psychiatry and Mental health
Abstract

Objectives: Livestock production systems in Togo are still dependent on availability of natural vegetation for livestock feed. The present study aims at characterizing grazed vegetation of the Plateau Region. More specifically, the aim is to inventory forage species and analyze their diversity. Methodology: In order to characterize the grazed plant communities of the zone, phytosociological surveys were carried out at six sites, namely: Nyidové and Djamakondji (Agou), Dalia (Haho), Tchella (Ogou), Onè (Amou) and Mempeassem (Danyi). A total of 140 plots (10mx10m), twenty per site, were installed and investigated using the Braun-Blanquet method. Ecological parameters (bush fires, grazing, biomass removal, etc.) are the main factors responsible for the loss of forage diversity and degradation of plant cover on the sites. Abstract: A total of 87 species were inventoried, mainly in the families Asteraceae, Poaceae, Fabaceae, Euphorbiaceae and Rubiaceae. Among the species identified, the most palatable are Panicum maximum (Poaceae), Centrosema pubescens (Fabaceae) and Sporobolus pyramidalis (Poaceae).The palatability index of available vegetation varies from site to site. It is low (IS

Published
2023
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4. Activité antifongique des extraits aqueux des graines d’Azadirachta indica A. Juss. sur le développement de Sclerotium rolfsii, agent pathogène des rhizomes de Zingiber officinale

Author

Nafadjara Abouwaliou Nadio, Essolakina Magnim Bokobana, Komlan Pikassalé Akantetou, Panawé Tozoou, Wiyao Poutouli, Koffi Koba, and Komla Sanda

Subjects
Materials Science (miscellaneous), Extraits aqueux, Azadirachta indica, Sclerotium rolfsii, antifongique, sclérote, croissance mycélienne, food and beverages, Business and International Management, General Agricultural and Biological Sciences, General Business, Management and Accounting, Industrial and Manufacturing Engineering
Abstract

With the aim of contributing to the fight against phytopathogens, an evaluation of the antifungal activity of the aqueous extracts of the seeds of Azadirachta indica on the development of Sclerotium rolfsii, a pathogenic fungus of the rhizomes of Zingiber officinale , was carried out through bioassays on mycelial growth and sclerotia formation. The biological tests were carried out in vitro by systemic application on S. rolfsii . The results obtained revealed a sensitivity of the fungus S. rolfsiidifferent concentrations of seed extracts and the commercial fungicide product Mancozeb. The concentration of 50 gl-1 of the extracts and of Mancozeb induced high inhibition rates which are respectively 76.37±7.35% and 80.14±3.4% on the mycelial growth of S. rolfsii . The numbers of sclerotia formed were reduced in the dishes at concentrations of 50 gl-1 (4.1±1.1 of sclerotia) and 20 gl-1 (7±1.8 of sclerotia) of the extracts. The 50 gl-1 concentration of the plant extract was more effective in inhibiting mycelial growth and sclerotia formation of S. rolfsii . The results of this study suggest that the aqueous extract from the seeds of A. indica can be used preventively in S. rolfsii control strategies .

Published
2022

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