Microbial transformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus.
The biotransformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus MT 5.3 yielded a rare derivative that was elucidated by spectrometric methods. The fungus led to the formation of a different product through an unusual epoxidation reaction between C4 and C5, formation of a C3,C10 ether bridge, and a methoxylation of the C1 of tagitinin C. The chemical structure of the product, namely 1β-methoxy-3α-hydroxy-3,10β-4,5α-diepoxy-8β-isobutyroyloxygermacr-11(13)-en-6α,12-olide, is the same as that of a derivative that was recently isolated from the flowers of a Brazilian population of Mexican sunflower (Tithonia diversifolia), which is the source of the substrate tagitinin C. The in vitro cytotoxic activity of the substrate and the biotransformed product were evaluated in HL-60 cells using an MTT assay, and both compounds were found to be cytotoxic. We show that soil fungi may be useful in the biotransformation of sesquiterpene lactones, thereby leading to unusual changes in their chemical structures that may preserve or alter their biological activities, and may also mimic plant biosynthetic pathways for production of secondary metabolites.
Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Av. do Café s/no., Ribeirão Preto, SP 14040-903, Brazil.
Bruno Alves
BA
Rocha
Mônica Tallarico
MT
Pupo
Gilmara Ausech
GA
Antonucci
Suely Vilela
SV
Sampaio
Raquel
R
de Melo Alves Paiva
Suraia
S
Said
Leonardo
L
Gobbo-Neto
Fernando Batista
FB
Da Costa
D001230:Aspergillus / Q000378:metabolism*; D019659:Asteraceae / Q000737:chemistry / Q000378:metabolism; D053898:Biosynthetic Pathways; D001711:Biotransformation; D001938:Brazil; D018922:HL-60 Cells; D006801:Humans; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity; D012988:Soil Microbiology
D007783:Lactones; D012717:Sesquiterpenes; C012565:tagitinin