No abstract

To test the metabolic mechanism, the ␤-glucosidase activity of the fungus P. crustosum 2T01Y01 was assayed with -nitrophenyl-␤-D-glucopyranoside as a probe substrate, and the pathway of GPS biotransformation by strain 2T01Y01 is proposed. In addition, the hepatoprotective activities of GPS and metabolite compounds 2, 5, and 6 against human hepatocyte line HL-7702 injury induced by hydrogen peroxide were evaluated.

Neoandrographolide is one of the principal constituents of ent-labdane diterpenoid lactones and has antiinflammatory 1,2 , antiviral 3 , anti-radical 4 , hepatoprotective 5 , and antihuman immunodeficiency virus properties 6 . Studies on the structural modifications of neoandrographolide have been increasingly conducted to improve its activities and solubility. Microbial transformation is an important approach for modifying bioactive substrates by microorganism enzymes. Microbial transformation presents advantages such as high stereoselectivity or high regio-selectivity and mild reaction conditions over chemical synthesis. Microbial transformation is considered a useful in vitro model for identifying metabolites in vivo 7 . The microbial biotransformation of neoandrographolide by Aspergillus niger (AS 3.739) 8 and Mucor spinosus (AS 3.2450) 9 have recently been reported. To obtain more types of diterpenoid derivatives and acquire compounds with better activities than the substrate, we used endophytic fungi to transform neoandrographolide for the first time.Endophytes are bacterial or fungal microorganisms that colonize healthy plant tissues intercellularly and/or intra-

No abstract