Specific 12α-hydroxylation of grandiflorenic acid by permeabilised fungus Fusarium graminearum

An Overview of Biotransformation and Toxicity of Diterpenes

Diterpenes have been identified as active compounds in several medicinal plants showing remarkable biological activities, and some isolated diterpenes are produced at commercial scale to be used as medicines, food additives, in the synthesis of fragrances, or in agriculture. There is great interest in developing methods to obtain derivatives of these compounds, and biotransformation processes are interesting tools for the structural modification of natural products with complex chemical structures. Biotransformation processes also have a crucial role in drug development and/or optimization. The understanding of the metabolic pathways for both phase I and II biotransformation of new drug candidates is mandatory for toxicity and efficacy evaluation and part of preclinical studies. This review presents an overview of biotransformation processes of diterpenes carried out by microorganisms, plant cell cultures, animal and human liver microsomes, and rats, chickens, and swine in vivo and highlights the main enzymatic reactions involved in these processes and the role of diterpenes that may be effectively exploited by other fields.

Synthesis of a new allelopathic agent from the biotransformation of ent-15α-hydroxy-16-kauren-19-oic acid with Fusarium proliferatum

The use of kaurane diterpenes as substrates in fungal biotransformation to achieve bioactive compounds has been widely reported. In this work, the natural product kaurenoic acid, a diterpene widely distributed in the plant Kingdom, was chemically converted into ent-15α-hydroxy-kaur-16-en-19-oic acid (1). Substrate 1 was subjected to biotransformation by the fungus Fusarium proliferatum, furnishing a new derivative, ent-2α,15α-dihydroxy-kaur-16-en-19-oic acid (2). The structure of metabolite 2 was deduced on the basis of spectroscopy and MS data. Derivative 2 showed allelopathic activity on germination and growth of root and stem of lettuce (Lactuca sativa), inhibiting 100% of germination and growth of roots and stem, at higher concentration assayed (10-4 mol/L).

A new helvolic acid derivative from an endophytic Fusarium sp. of Ficus carica

A new helvolic acid derivative named helvolic acid methyl ester (1), together with two known helvolic acid compounds, helvolic acid (2) and hydrohelvolic acid (3), were isolated from the fermentation of endophytic fungus Fusarium sp. in Ficus carica leaves. Their structures were elucidated and identified by spectroscopic methods. Compounds 1-3 showed potent antifungal and antibacterial activities.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes, labdanes, clerodanes, pimaranes, abietanes, kauranes, gibberellins, cembranes and their cyclization products. The literature from January to December, 2014 is reviewed.