Biotransformation of arenobufagin and cinobufotalin byAlternaria alternata

Biotransformation of selected secondary metabolites by Alternaria species and the pharmaceutical, food and agricultural application of biotransformation products

Biotransformation is a process in which molecules are modified in the presence of a biocatalyst or enzymes, as well as the metabolic alterations that occur in organisms from exposure to the molecules. Microbial biotransformation is an important process in natural product drug discovery as novel compounds are biosynthesised. Additionally, biotransformation products offer compounds with improved efficacy, solubility, reduced cytotoxic and allows for the understanding of structure activity relationships. One of the driving forces for these impeccable findings are associated with the presence of cytochrome P450 monooxygenases that is present in all organisms such as mammals, bacteria, and fungi. Numerous fungal strains have been used and reported for their ability to biotransform different compounds. This review focused on studies using Alternaria species as biocatalysts in the biotransformation of natural product compounds. Alternaria species facilitates reactions that favour stereoselectivity, regioselectivity under mild conditions. Additionally, microbial biotransformation products, their application in food, pharmaceutical and agricultural sector is discussed in this review.

Biotransformation of Gambogenic Acid by Chaetomium Globosum CICC 2445

Microbial transformation of gambogenic acid (1), a caged polyprenylated xanthone isolated from the resin of Garcinia hanburyi, was carried out with Chaetomium globosum CICC 2445, after screening forty-six strains of filamentous fungi. A new caged polyprenylated xanthone, 16,17-dihydroxygambogenic acid (2), was specifically obtained, as a result of hydroxylation at C-16, and C-17. Its structure was elucidated on the basis of spectroscopic methods. The cytotoxicity of compounds 1 and 2 against HeLa tumor cell line was evaluated, with both of them being modestly active.