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EVALUATION ET ESSAIS D’OPTIMISATION DE L’ACTIVITE ANTIFONGIQUE DES EXTRAITS DE TERMINALIA MANTALY H.PERRIER, SUR LA CROISSANCE IN VITRO DE ASPERGILLUS FUMIGATUS, CANDIDA ALBICANS, CRYPTOCOCCUS NEOFORMANS ET TRICHOPHYTON MENTAGROPHYTES

Abstract : Despite the progress being made in medicine, which aims at ensuring best control over the evolution of many previously deadly diseases, the development of medicinal techniques, the proliferation of immunosuppressive treatments and the emergence of new diseases such as HIV / AIDS (responsible for an ever-increasing number of opportunistic fungal infections), the frequency of these fungal infections has unfortunately increased considerably, especially in recent years, due mainly to the increased number of immunocompromised patients. In addition, the mortality rate associated with these fungal infections has become very high. However antifungal drugs especially the most used ones have limitations in their efficacy. So, it is necessary to find new antifungals with improved biological activity. To achieve this, researchers have agreed to come up with new, more effective and less toxic antifungals. So to achieve this goal various approaches have been adopted. Among these, the investigation of the natural environment is very important, necessary and indispensable for the identification and the isolation of new series of molecules or substance with well pronounced biological activity. For this purpose, among the plants selected by our research team is Terminalia mantaly H. Perrier, a combretaceae. This species is well known in the traditional environment especially in southern Africa and Malagasy for its anti-infectious properties. So we decided to investigate these anti-infectious properties and optimize this activity. Thus, we tested different extracts (aqueous, hydro-ethanolic, hexane, acetal and dichloromethanol) obtained either by maceration or by degreasing with Soxhlet from the vegetable powder of Terminalia mantaly. These extracts were tested on the in vitro growth of Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and Trichophyton mentagrophytes. These fungal isolates are all sensitive to these different extracts in a dose-response relationship. Among these extracts, the T4-2 extract from the degreasing of hexane to Soxhlet is the most active. Of the 18 fractions obtained from Sephadex G25 filtration gel chromatography of the T4-2 extract, only the fractions F8, F9 and F10 grouped in the P fraction have the best antifungal activity: - Aspergillus fumigatus: MFC = 24.37 μg/mL, IC50 = 23 μg/mL -Candida albicans: MFC = 12.1875 μg/mL, IC50 = 1l.23 μg/mL -Cryptococcus neoformans: MFC = 12.1875 μg/mL, IC50 = 5.87 μg/mL -Trichophyton mentagrophytes: MFC = 6.09375 μg/mL, IC50 = 4.75 μg/mL Furthermore, a phytochemical screening coupled with thin layer chromatography and HPLC chromatography revealed that the antifungal activity of the most active fraction P would be due to polyphenols including phenols and Quinones. Therefore, the method used for preparing the T4-2 extract, hexane degreasing of the hydroethanolic extract using soxhlet followed by chromatography on Sephadex G25 filtration gel is a method that not only allows for better concentration but also purify and isolate the active ingredient. We have being able to achieve our goal through this method.
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Submitted on : Tuesday, November 12, 2019 - 1:07:51 AM
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Guillaume Yapi Yayé. EVALUATION ET ESSAIS D’OPTIMISATION DE L’ACTIVITE ANTIFONGIQUE DES EXTRAITS DE TERMINALIA MANTALY H.PERRIER, SUR LA CROISSANCE IN VITRO DE ASPERGILLUS FUMIGATUS, CANDIDA ALBICANS, CRYPTOCOCCUS NEOFORMANS ET TRICHOPHYTON MENTAGROPHYTES. Chimie thérapeutique. Université Félix Houphouët Boigny, Abidjan (Côte d'Ivoire), 2013. Français. ⟨tel-02358473⟩

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