cis-Decalinoyltetramic Acid Derivatives from the Palm Fungus Leptosporella arengae TBRC-BCC32590

Twelve hitherto undescribed cis-decalinoyltetramic acid derivatives (arengasetins A - L), a unique spiro[2.4]heptendione (spiroarengarone) and two benzoquinones (arengaquinones A and B), together with the highly oxygenated polycyclic molecule, epicolactone, were isolated from the palm fungus Leptosporella arengae TBRC-BCC 32590. Chemical structures were determined by extensive analyses of 2D NMR spectroscopic data and chemical means. The absolute configuration of arengasetin A (1) was confirmed by X-ray crystallographic information, while the absolute configurations of other related compounds were corroborated by comparison of NMR spectroscopic data and chemical reactions. The isolated compounds exhibited activity against Plasmodium falciparum (K1, multidrug-resistant strain, IC₅₀ 6.42 - > 38.76 μM), Bacillus cereus (MIC 0.78 - > 50.0 μg/mL), Staphylococcus aureus (MIC 1.56 - > 50.0 μg/mL), and Mycobacterium tuberculosis (MIC 6.25 - > 50.0 μg/mL). Cytotoxicity against both cancerous (MCF-7 and NCI-H187) and noncancerous (Vero) was also reported.