Chemical synthesis and mechanism of a natural product from endolichenic fungus with a broad-spectrum anti microorganism activity.

Background: The antibiotic resistance in various bacteria is consistently increasing and is posing a serious threat to human health, prompting the need for the discovery of novel structurally featured natural products with promising biological activities in drug research and development. Endolichenic microbes have been proven to be a fertile source to produce various chemical components, and therefore these microbes have been on a prime focus for exploring natural products. In this study, to explore potential biological resources and antibacterial natural products, the secondary metabolites of an endolichenic fungus have been investigated.

Mahimbrine A, a Novel Isoquinoline Alkaloid Bearing a Benzotropolone Moiety from .

A novel isoquinoline alkaloid, mahimbrine A, possessing a rare benzotropolone framing scaffold, was isolated from the endemic plant of . Its structure was established on the basis of extensive spectroscopic analysis. A plausible biosynthetic route of mahimbrine A was proposed.

Two new echinocystic acid derivatives catalyzed by filamentous fungus CGMCC 3.3657.

Biotransformation of Echinocystic acid (EA,) using CGMCC 3.3657 has been investigated, which leads to the isolation and identification of two novel Echinocystic acid derivatives, 4, 16α-dihydroxy-3,4-seco-olean-12-en-3,28-dioic acid () and 16α-hydroxy, A-homo-3α-oxa-olean-12-en-3-one-28-oic acid (). Their structures have been elucidated by analysis of spectroscopic data.

Biotransformation of ursolic acid by Syncephalastrum racemosum CGMCC 3.2500 and anti-HCV activity.

Microbial transformation of ursolic acid (UA, 3β-hydroxy-urs-12-en-28-oic acid, 1) by filamentous fungus Syncephalastrum racemosum CGMCC 3.2500 was conducted. Five metabolites 3β, 7β, 21β-trihydroxy-urs-12-en-28-oic acid (2); 3β, 21β-dihydroxy-urs-11-en-28-oic acid-13-lactone (3); 1β, 3β, 21β-trihydroxy-urs-12-en-28-oic acid (4); 3β, 7β, 21β-trihydroxy-urs-1-en-28-oic acid-13-lactone (5); and 21-oxo-1β, 3β-dihydroxy-urs-12-en-28-oic acid (6) were afforded.

Biotransformation of ursolic acid by an endophytic fungus from medicinal plant Huperzia serrata.

Endophytic fungi were used not only for their producing bioactive products but also for their ability to transform natural compounds. An endophytic fungus, isolated from medicinal plant Huperzia serrata, was identified as Umbelopsis isabellina based on the internal transcribed spacer of ribosomal DNA (rDNA-ITS) region. It was used to transform ursolic acid (1), a pentacyclic triterpene.

Multihydroxylation of ursolic acid by Pestalotiopsis microspora isolated from the medicinal plant Huperzia serrata.

The structural modification of ursolic acid by an endophytic fungus Pestalotiopsis microspora, isolated from medicinal plant Huperzia serrata was reported for the first time. The structure diversity was very important for the SAR study of ursolic acid and its derivatives. Incubation of ursolic acid 1 with P.

Microbial transformation of diosgenin by filamentous fungus Cunninghamella echinulata.

Microbial transformation of diosgenin (1) by suspended-cell cultures of the filamentous fungus Cunninghamella echinulata CGMCC 3.2000 was investigated. Incubation of the substrate diosgenin (1) with this fungus led to the isolation of three products: two known compounds, (25R)-spirost-5-en-3β,7β,12β-triol and (25R)-spirost-5-en-3β,7β,11α-triol, and a new compound (25R)-spirost-5-en-3β,7α,11α-triol.