RESUMO
A new 10-membered ring meroterpene (1), named globiferin, was isolated from root extracts of Cordia globifera. Biomimetic transformations of 1 and its derivatives, either by acid cyclization or by Cope rearrangement, provided information relating to the biogenesis of cordiachromes A-C. Globiferin (1) underwent Cope rearrangement upon refluxing in xylene and DMSO-d(6) to yield cordiachrome C (3) and cordiaquinol C (4), respectively. Heating in DMSO-d(6) resulted in an unexpected reduction of a quinone moiety. Globiferin diacetate (1b) cyclized under acidic conditions to give compounds 10 and 11, respective derivatives of natural cordiachromes B (2) and A (12). The present study indicates that globiferin (1) is a genuine intermediate for the biosynthesis of cordiachromes in Cordia species. Compounds 1 and 3 exhibited significant antimycobacterial activity, with MIC values of 6.2 and 1.5 mug/mL, respectively. Antimalarial, antifungal, and cytotoxic activities of 1 and its derivatives were also evaluated.
Assuntos
Antifúngicos/isolamento & purificação , Antimaláricos/isolamento & purificação , Antituberculosos/isolamento & purificação , Benzoquinonas/isolamento & purificação , Cordia/química , Plantas Medicinais/química , Terpenos/isolamento & purificação , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Antimaláricos/química , Antimaláricos/metabolismo , Antimaláricos/farmacologia , Antituberculosos/química , Antituberculosos/metabolismo , Antituberculosos/farmacologia , Benzoquinonas/química , Benzoquinonas/metabolismo , Benzoquinonas/farmacologia , Biotransformação , Candida albicans/efeitos dos fármacos , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Raízes de Plantas/química , Plasmodium falciparum/efeitos dos fármacos , Terpenos/química , Terpenos/metabolismo , Terpenos/farmacologia , TailândiaRESUMO
Two new pimarane diterpenes, diaportheins A (1) and B (2), were isolated from a culture broth of the fungus Diaporthe sp. BCC 6140. Diaporthein B (2) strongly inhibited the growth of Mycobacterium tuberculosis with the MIC value of 3.1 microg/mL, while diaporthein A (1) showed only mild activity (MIC value of 200 microg/mL).
