Pharmacognosy

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Browsing Pharmacognosy by Author "Asres, Kalaeb(PhD)"

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    In vitro antimicrobial and in vivo antimalarial evaluation of latex and compounds isolated from the leaves of Aloe sinana
    (Addis Ababa University, 2013-04) Minale, Genet; Bisrat, Daniel(PhD); Asres, Kalaeb(PhD)
    Aloe sinana Reynolds is endemic to Ethiopia where its leaf exudate is traditionally used in Debre Sina and in other central highlands of the country for the treatment of various illnesses, including malaria, wound and snake bite. Phytochemical investigation of the exudate led to the isolation of three anthrones identified as microdontin, aloin and aloinoside by means of spectroscopic techniques including 1H and 13C-NMR. The latex and isolated compounds were assessed for their antimicrobial activities against 20 bacterial and 4 fungal strains using disk diffusion method, and their antimalarial activities were evaluated by a 4-day suppressive test against mice infected with Plasmodium berghei. When administered up to a dose of 5,000 mg/kg, neither the latex nor the isolated compounds were found to be acutely toxic to Swiss albino mice. Both the latex and isolated compounds showed potent antibacterial activity, whilst their effect against the tested fungal strains was rather moderate. In addition the latex and all the isolated compounds showed significant chemosuppression in mice infected with P. berghei. At a dose of 400 mg/kg, the latex suppressed parasite growth by 68.2% compared to the negative control group and improved survival time considerably. Among the isolated compounds, aloinoside showed the most potent antiplasmodial activity inhibiting parasite growth by 85.2% at a dose of 100 mg/kg. From the results obtained in the present study, it can be concluded that the leaf exudate of A. sinana and its isolated compounds could serve as potential candidates for the treatment of microbial infections and malaria supporting the traditional uses of the plant. Key words: Aloe sinana; Aloaceaae; antimalarial; antibacterial; anthraquinones; microdontin; aloin; aloinoside.