Microbial transformation of laxogenin by the fungus Syncephalastrum racemosum

A new aglycone derivative from the saprophytic fungus Tubeufia rubra

A new aglycone derivative (1) and five known compounds (2-6) have been isolated from a saprophytic fungus Tubeufia rubra for the first time. Their structures and absolute configurations were determined by nuclear magnetic resonance, high resolution mass spectrometry data and electronic circular dichroism. The bioactivities of all compounds were evaluated by cell analysis. Compound 5 showed significant toxicity to human cancer A549 cells, and the IC50 value was 32. 89 μg/mL. Compound 6 could reverse the multidrug resistance of A549/DDP cells, and the reversal value was 2.92. With the extension of the action time, the IC50 value of compound 6 decreased from 424.72 μg/mL at 24 h to 9.45 μg/mL at 72 h.

New 30-norlupane derivatives through chemical-microbial semi-synthesis of betulinic acid and their neuroprotective effect

In this study, seven 30-norlupane derivatives (2-8) wasobtained from the chemical oxidation ofbetulinic acidfollowed bybiotransformationviaBacillus megateriumCGMCC 1.1741. And metabolites 2-4 and 6-8 were newly identified products. In the first step, betulinic acid was chemically oxidizedto platanic acid (1). Following the chemical oxidation, B. megaterium catalyzed the hydroxylation at C-7, C-11, C-15 and C-23 of platanic acid (1) as well as the oxidation of C-3 hydroxyl group. Compared to the labor-intensive isolation from natural plants, this chemical-microbial semi-synthesis is more capable to provide increased structural diversity of oxygenated 30-norlupane. Finally, the potential neuroprotective effect of the derivatives was assessed on neuron-like PC12 cells induced by cobalt chloride (CoCl₂). Metabolite 6 showed a potent neuroprotective activity.

Biotransformation of androst-4-ene-3,17-dione and nandrolone decanoate by genera of Aspergillus and Fusarium

The ability of five fungal species belonging to two genera of Aspergillus and Fusarium has been examined in the microbial transformation of androst-4-ene-3, 17-dione (AD). Furthermore, the biotransformation of nandrolone decanoate (2) by F. fujikuroi has been studied. AD (1) was converted by cultures of Aspergillus sp. PTCC 5266 to form 11α-hydroxy-AD (3) as the only product, with a yield of 86% in 3 days. Moreover, two hydroxylated metabolites 11α-hydroxy-AD (3, 65%) and 7β-hydroxy-AD (4; 18%) were isolated in biotransformation of AD by A. nidulans. On the other hand, it was metabolized by F. oxysporum to produce 14α-hydroxy-AD (5; 38%) and testosterone (6; 12%). Microbial transformation of AD by F. solani led to the production of 11α-hydroxy-AD (3; 54%) and testosterone (6; 14%). AD was reduced at the 17-position by F. fujikuroi to produce testosterone in the yield of 42%. Finally, nandrolone decanoate was transformed by F. fujikuroi via hydrolysis and oxidation at the 17-position to produce two metabolites namely 17β-hydroxyestr-4-en-3-one (7, 25.4%) and estr-4-en-3,17-dione (8, 33%), respectively. The all metabolites were purified and subsequently identified based on their spectra data analysis and comparing them to the literature data.