Microbial transformation of neoandrographolide by Aspergillus niger (AS 3.739)

Abstract

The biotransformation of neoandrographolide (1) was investigated by using Aspergillus niger (AS 3.739). Five products were obtained and identified as 8(17),13-ent-labdadien-16,15-olid-19-oic acid (2), 19-hydroxy-8(17),13-ent-labdadien-16,15-olide (3), 18-hydroxy-8(17),13-ent-labdadien-16,15-olid-19-oic acid (4), 3α-hydroxy-8(17),13-ent-labdadien-16,15-olid-19-oic acid (5) and 8β,19-dihydroxy-ent-labd-13-en-16,15-olide (6) by spectroscopic and chemical means. Products 4, 5 and 6 are new compounds.

Keywords:

• Neoandrographolide
• Microbial transformation
• Aspergillus niger
• ent-Labdane diterpenoid