Browsing by Author "Sitotaw, Rediet"

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    Lovastatin: an Inhibitor of Cholesterol Biosynthsis from Pleurotus Mushroom
    (Addis Ababa University, 2008-01) Sitotaw, Rediet; Abate Dawit (PhD)
    Lovastatin is a secondary metabolite of certain filamentous fungi. It is one of the members of the drug family, statins. Lovastatin, inhibitor of cholesterol biosynthesis, is widely prescribed for the treatment of hypercholesterolemia. Statins have also recently been shown to inhibit HIV-1 infection by targeting cholesterol in the HIV and host membrane. This research was performed to determine the production of lovastatin from fruit body cultivated on sugarcane bagasse and solidstate fermentation on different substrate (Sorghum, Rice and Wheat bran) of two Pleurotus mushrooms species that are edible and commercially cultivated in Ethiopia. The two mushrooms investigated, P. ostreatus and P. sajor-caj, grown in mushroom growing house on sugarcane bagasse (60% moisture content), and yielded an average bioconversion efficiency of 22.58% and 17.67 % respectively. Ethyl acetate was selected as better solvent for extraction of lovastatin in lactone form from acidified samples that were detected on Thin Layer Chromatography (TLC). The crude extracts from fruit bodies of both species show positive result on TLC with same Retention factor (Rf= 0.57and 0.3 for lactone and acid form respectively) which was identical to the standard lovastatin. The TLC result of Solid-State Fermentation (SSF) on rice and wheat bran showed the presence of lovastatin whereas sorghum gives a negative result. For quantification, extraction of lovastatin (β-hydroxyl acid) from fruit body as well as SSF was performed with mixture of methanol: water (1:1 V/V) that was chosen as the most effective solvent for High-performance liquid chromatography (HPLC) analysis at pH 7.7. Highest amount of lovastatin was found from methanol: water (1:1 V/V) extracts of P. ostreatus fruiting body (132μg/g) of dry weight followed by P. sajor-caju (129μg/g). Among SSF, methanol: water extracts of fermented wheat bran and rice gave (11.7μg/g) and (3.69μg/g) of dry weight respectively. The HPLC result of samples prepared with ethyl acetate show low amount of lovastatin. The health benefits of consuming the Pleurotus mushroom particularly for individuals with high plasma cholesterol as well as HIV infection is promising and it grows on a variety of agricultural residues with high bioconversion efficiency.