Trachyloban-19-oic acid (1) is a diterpene very abundant in nature and its structural modification can furnish new bioactive compounds. Biotransformation of 1 by fungus Syncephalastrum racemosum provided three derivatives, two hydroxylated products (2-3) and one product of rearrangement (4). Products 3 and 4 have never been reported so far, to the best of our knowledge. Structure of 3 was formed after oxidation and rearrangement of compound 2. Compounds 1-4 were evaluated for inhibition of acetylcholinesterase, enzyme linked to the symptomatic control of Alzheimer's disease. All the compounds presented inhibitory activity higher than starting material 1, and product 3 presented IC50 = 0.06 μM, which is about six times higher than activity found for galanthamine (IC50 = 0.38 μM), the positive control used in this assay.
Keywords: Acetylcholinesterase; Alzheimer’s disease; Biotransformation; Syncephalastrum racemosum; Trachyloban-19-oic acid.
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